sábado, 18 de setembro de 2010
quarta-feira, 15 de setembro de 2010
AGRADEÇIMENTO E VITAMINA D
Valeu gente o blog futebol e nutrição continua subindo em numeros de acessos , e este blog agora esta como o terceiro blog mais acessado do mundo , continuem acessando , obrigado . VITAMINA D - PARA O BRASIL
A vitamina D (ou calciferol) é uma vitamina que promove a absorção de cálcio (após a exposição à luz solar), essencial para o desenvolvimento normal dos ossos e dentes, atua também, como recentemente descoberto, no sistema imune, no coração, no cérebro e na secreção de insulina pelo pâncreas. É uma vitamina lipossolúvel obtida a partir do colesterol como precursor metabólico através da luz do sol, e de fontes dietéticas. Funcionalmente, a vitamina D atua como um hormônio que mantém as concentrações de cálcio e fósforo no sangue através do aumento ou diminuição da absorção desses minerais no intestino delgado. A vitamina D também regula o metabolismo ósseo e a deposição de cálcio nos ossos.
O nome da vitamina foi criada pelo bioquímico polonês Casimir Funk em 1912, baseado na palavra em latim vita (vida) e no sufixo -amina. Foi usado inicialmente para descrever estas substâncias do grupo funcional amina, pois naquele tempo pensava-se que todas as vitaminas eram aminas. Apesar do erro, o nome manteve-se.
A vitamina D também é muito importante para crianças, gestantes e mães que amamentam, por favorecer o crescimento e permitir a fixação de cálcio nos ossos e dentes.
Além da importância na manutenção dos níveis do cálcio no sangue e na saúde dos ossos, a vitamina D tem um papel muito importante na maioria das funções metabólicas e também nas funções musculares, cardíacas e neurológicas. A deficiência da vitamina D pode precipitar e aumentar a osteoporose em adultos e causar raquitismo, uma avitaminose, em crianças.Como fornecer vitamina D ao organismo deficiente
Estrutura química do colecalciferol.
Estrutura química do ergocalciferol.
A exposição ao sol desencadeia a produção de vitamina D na pele. Alguns alimentos também representam uma fonte desta vitamina. O óleo de fígado de bacalhau foi utilizado também como suplemento alimentar para evitar o raquitismo, sendo hoje em dia facilmente substituível por medicamentos contendo vitamina D, mas a vitamina D da luz solar continua a ser preferível.
A vitamina D pode ser encontrada sob duas formas: o ergocalciferol (vitamina D2) e o colecalciferol (vitamina D3). O ergocalciferol é produzido comercialmente a partir do esteróide ergosterol encontrado em vegetais e leveduras, através de irradiação com luz ultravioleta. É utilizado como suplemento alimentar para enriquecimento de alimentos como o leite com vitamina D. O colecalciferol é transformado pela ação dos raios solares a partir da provitamina D3 (7-deidrocolesterol) encontrada na pele humana. Ambas as formas D2 e D3 são hidroxiladas no fígado e rins a 25-hidroxicalciferol e subsequentemente à forma biologicamente activa, o 1,25-di-hidroxicalciferol (calcitriol), que actua como uma hormona na regulação da absorção de cálcio no intestino e regulação dos níveis de cálcio em tecidos ósseos e renais.
A vitamina D é fundamental para a homeostase do cálcio no organismo. Como outras vitaminas, deve ser consumida em quantidades adequadas, evitando faltas e excessos.
A quantidade de vitamina D que um adulto precisa varia, de acordo com a idade, de 5 mg a 10 mg, chegando a 15 mg em idosos com mais de 70 anos.[carece de fontes?]Poucos alimentos são considerados fontes de vitamina D, mas entre eles encontram-se a gema de ovo, fígado, manteiga e alguns tipos de peixes como a cavala, o salmão e o arenque. Embora em menor quantidade, a sardinha e o atum também têm vitamina D.
Nos Estados Unidos da América é obrigatório que o leite seja reforçado com vitamina D. Outros alimentos e bebidas também podem ser reforçados com vitamina D nos EUA, inclusive cereais matinais prontos para comer, produtos lácteos, bebidas à base de soja e sucos, porém são insuficientes por eles só.
[editar] Distúrbios
No fígado, a vitamina D é convertida em uma forma que pode ser transportada pelo sangue. Nos rins, essa forma é modificada para produzir hormônios derivados da vitamina D, cuja função principal é aumentar a absorção de cálcio no intestino e facilitar a formação normal dos ossos. Na deficiência de vitamina D, as concentrações de cálcio e de fosfato no sangue diminuem, provocando uma doença óssea porque não existe uma quantidade suficiente de cálcio disponível para manter os ossos saudáveis.
Esse distúrbio é denominado raquitismo nas crianças, uma doença que se manifesta com atraso no fechamento da moleira nos recém-nascidos (importante na calota craniana), desmineralização óssea, as pernas tortas e outros sinais relacionados com estrutura óssea. É denominado osteomalácia nos adultos, onde se desenvolve ossos fracos e moles.
A deficiência de vitamina D é causada sobretudo pela falta de exposição à luz solar e não tanto com vitamina D na dieta, como demonstram novos estudos independentes. Essa deficiência pode ocorrer em indivíduos idosos porque a pele produz menos vitamina D, mesmo quando exposta à luz solar, mas também pelas erradas recomendações dos medicos em aconselhar suplementos de vitamina D em vez que exposição solar, ou pelo excesso de protector solar!
A deficiência de vitamina D durante a gravidez pode causar osteomalácia na mulher e raquitismo no feto.
A vitamina D tem poucas hipóteses de se tornar tóxica no corpo, pois quando a pele não transforma o colesterol presente em vitamina D inactiva (só e activada no figado e rins), os raios solares naturalmente destroem a Vitamina. * para os paises do exterior ( estados unidos , alemanha , canada e outros ) : Plot
Given the motivation of the boys, Will wields a tactic enfretar boys and girls in a combined challenge songs (mashup). Sue Sylvester, in its continuous attempts to destroy the chorus, warns Emma Terri the threat posed to their marriage. Terri was named a nurse at McKinley school, despite its zero knowledge on the subject, to be near her husband. Since you plan to stay with the child of Puck and Quinn, under the latter's agreement, attends Finn believing he is the father of the baby and you are given vitamin D (or pseudoephedrine). Accelerated by the effect of drugs, Finn and the other boys made a choreography that love Will, to which the girls, wanting to be at its height, consumes the same drugs and make an equally good performance. For his part, coach Ken Tenaka offers marriage to Emma, also accelerated by drugs gave Terri, and she agrees, also pressured by the new nurse. The director Figgins draws attention to Schuester by the use of medications and assigns a coordinator to the choir, Coach Sylvester.
[edit]Production
Before shooting "Vitamin D", Lea Michele performed a frenzied speech for several days to transmit the effects of pseudoephedrine in Rachel.1
Choir members Santana Lopez (Naya Rivera), Brittany (Heather Morris), Mike Chang (Harry Shum, Jr.) and Matt Rutherford (Dijon Talton), the former director, Sandy Ryerson (Stephen Tobolowsky), the director Figgins (Iqbal Theba), football coach Ken Tanaka (Patrick Gallagher), the worker Bamboo Howard (Kent Avenido) and local news presenters Rod Remington (Bill A. Jones) and Andrea Carmichael (Earlene Davis) are the recurring characters appearing on "Vitamin D". Joe Hursley appears as a guest star playing Joe.2
Cory Monteith, Chris Colfer, Kevin McHale, Mark Salling, Shum and Talton perform a version mashup of the subjects'It's My Life"and"Confessions Part II"of Bon Jovi and Usher , respectively, while Lea Michele, Dianna Agron, Amber Riley, Jenna Ushkowitz, Rivera and Morris do the same with "Halo"and"Walking on Sunshine"by Beyoncé and Katrina & the Waves respectively. Columbia Records and 20th Century Fox Television released both songs as singles and arranged for digital download on iTunes one day before the episode aired.3 Michele revealed that practiced for several days a frenzied speech to convey the effects of pseudoephedrine in Rachel.1
[edit]Reception
[edit]Audience and critical
"Vitamin D" was seen by a total of 7.3 million viewers in the U.S.,four receiving generally good reviews from the critics. Shawna Malcolm, the newspaper Los Angeles Times, and Aly Semigran of MTV, highlighted the performance of the choir boys,5 6 while Mandi Bierly of Entertainment Weekly, the girls preferred, while stressing the performance of Matthew Morrison.7 For his part, Mike Hale of The New York Times, praised the interpretation of Jayma Mays and called the pregnancy history of boring.8
[edit]Singles Charts
Song List Maximum
position9
"It's My Life / Confessions Part II" Ireland Singles Top 50 6
UK Top 75 Singles 14
Australia Singles Top 50 22
Canada Singles Top 100 25
U.S. Singles Top 100 30
Song List Maximum
position10
"Halo / Walking On Sunshine ' Ireland Singles Top 50 4
UK Top 75 Singles 9
Australia Singles Top 50 10
Canada Singles Top 100 28
U.S. Singles Top 100 40
[edit] ENTAO UM ABRAÇO A TODOS , NA PROXIMA IREMOS FALAR SOBRE A VITAMINA E , ENTAO UM ABRAÇO A TODOS E ATE A PROXIMA .
A vitamina D (ou calciferol) é uma vitamina que promove a absorção de cálcio (após a exposição à luz solar), essencial para o desenvolvimento normal dos ossos e dentes, atua também, como recentemente descoberto, no sistema imune, no coração, no cérebro e na secreção de insulina pelo pâncreas. É uma vitamina lipossolúvel obtida a partir do colesterol como precursor metabólico através da luz do sol, e de fontes dietéticas. Funcionalmente, a vitamina D atua como um hormônio que mantém as concentrações de cálcio e fósforo no sangue através do aumento ou diminuição da absorção desses minerais no intestino delgado. A vitamina D também regula o metabolismo ósseo e a deposição de cálcio nos ossos.
O nome da vitamina foi criada pelo bioquímico polonês Casimir Funk em 1912, baseado na palavra em latim vita (vida) e no sufixo -amina. Foi usado inicialmente para descrever estas substâncias do grupo funcional amina, pois naquele tempo pensava-se que todas as vitaminas eram aminas. Apesar do erro, o nome manteve-se.
A vitamina D também é muito importante para crianças, gestantes e mães que amamentam, por favorecer o crescimento e permitir a fixação de cálcio nos ossos e dentes.
Além da importância na manutenção dos níveis do cálcio no sangue e na saúde dos ossos, a vitamina D tem um papel muito importante na maioria das funções metabólicas e também nas funções musculares, cardíacas e neurológicas. A deficiência da vitamina D pode precipitar e aumentar a osteoporose em adultos e causar raquitismo, uma avitaminose, em crianças.Como fornecer vitamina D ao organismo deficiente
Estrutura química do colecalciferol.
Estrutura química do ergocalciferol.
A exposição ao sol desencadeia a produção de vitamina D na pele. Alguns alimentos também representam uma fonte desta vitamina. O óleo de fígado de bacalhau foi utilizado também como suplemento alimentar para evitar o raquitismo, sendo hoje em dia facilmente substituível por medicamentos contendo vitamina D, mas a vitamina D da luz solar continua a ser preferível.
A vitamina D pode ser encontrada sob duas formas: o ergocalciferol (vitamina D2) e o colecalciferol (vitamina D3). O ergocalciferol é produzido comercialmente a partir do esteróide ergosterol encontrado em vegetais e leveduras, através de irradiação com luz ultravioleta. É utilizado como suplemento alimentar para enriquecimento de alimentos como o leite com vitamina D. O colecalciferol é transformado pela ação dos raios solares a partir da provitamina D3 (7-deidrocolesterol) encontrada na pele humana. Ambas as formas D2 e D3 são hidroxiladas no fígado e rins a 25-hidroxicalciferol e subsequentemente à forma biologicamente activa, o 1,25-di-hidroxicalciferol (calcitriol), que actua como uma hormona na regulação da absorção de cálcio no intestino e regulação dos níveis de cálcio em tecidos ósseos e renais.
A vitamina D é fundamental para a homeostase do cálcio no organismo. Como outras vitaminas, deve ser consumida em quantidades adequadas, evitando faltas e excessos.
A quantidade de vitamina D que um adulto precisa varia, de acordo com a idade, de 5 mg a 10 mg, chegando a 15 mg em idosos com mais de 70 anos.[carece de fontes?]Poucos alimentos são considerados fontes de vitamina D, mas entre eles encontram-se a gema de ovo, fígado, manteiga e alguns tipos de peixes como a cavala, o salmão e o arenque. Embora em menor quantidade, a sardinha e o atum também têm vitamina D.
Nos Estados Unidos da América é obrigatório que o leite seja reforçado com vitamina D. Outros alimentos e bebidas também podem ser reforçados com vitamina D nos EUA, inclusive cereais matinais prontos para comer, produtos lácteos, bebidas à base de soja e sucos, porém são insuficientes por eles só.
[editar] Distúrbios
No fígado, a vitamina D é convertida em uma forma que pode ser transportada pelo sangue. Nos rins, essa forma é modificada para produzir hormônios derivados da vitamina D, cuja função principal é aumentar a absorção de cálcio no intestino e facilitar a formação normal dos ossos. Na deficiência de vitamina D, as concentrações de cálcio e de fosfato no sangue diminuem, provocando uma doença óssea porque não existe uma quantidade suficiente de cálcio disponível para manter os ossos saudáveis.
Esse distúrbio é denominado raquitismo nas crianças, uma doença que se manifesta com atraso no fechamento da moleira nos recém-nascidos (importante na calota craniana), desmineralização óssea, as pernas tortas e outros sinais relacionados com estrutura óssea. É denominado osteomalácia nos adultos, onde se desenvolve ossos fracos e moles.
A deficiência de vitamina D é causada sobretudo pela falta de exposição à luz solar e não tanto com vitamina D na dieta, como demonstram novos estudos independentes. Essa deficiência pode ocorrer em indivíduos idosos porque a pele produz menos vitamina D, mesmo quando exposta à luz solar, mas também pelas erradas recomendações dos medicos em aconselhar suplementos de vitamina D em vez que exposição solar, ou pelo excesso de protector solar!
A deficiência de vitamina D durante a gravidez pode causar osteomalácia na mulher e raquitismo no feto.
A vitamina D tem poucas hipóteses de se tornar tóxica no corpo, pois quando a pele não transforma o colesterol presente em vitamina D inactiva (só e activada no figado e rins), os raios solares naturalmente destroem a Vitamina. * para os paises do exterior ( estados unidos , alemanha , canada e outros ) : Plot
Given the motivation of the boys, Will wields a tactic enfretar boys and girls in a combined challenge songs (mashup). Sue Sylvester, in its continuous attempts to destroy the chorus, warns Emma Terri the threat posed to their marriage. Terri was named a nurse at McKinley school, despite its zero knowledge on the subject, to be near her husband. Since you plan to stay with the child of Puck and Quinn, under the latter's agreement, attends Finn believing he is the father of the baby and you are given vitamin D (or pseudoephedrine). Accelerated by the effect of drugs, Finn and the other boys made a choreography that love Will, to which the girls, wanting to be at its height, consumes the same drugs and make an equally good performance. For his part, coach Ken Tenaka offers marriage to Emma, also accelerated by drugs gave Terri, and she agrees, also pressured by the new nurse. The director Figgins draws attention to Schuester by the use of medications and assigns a coordinator to the choir, Coach Sylvester.
[edit]Production
Before shooting "Vitamin D", Lea Michele performed a frenzied speech for several days to transmit the effects of pseudoephedrine in Rachel.1
Choir members Santana Lopez (Naya Rivera), Brittany (Heather Morris), Mike Chang (Harry Shum, Jr.) and Matt Rutherford (Dijon Talton), the former director, Sandy Ryerson (Stephen Tobolowsky), the director Figgins (Iqbal Theba), football coach Ken Tanaka (Patrick Gallagher), the worker Bamboo Howard (Kent Avenido) and local news presenters Rod Remington (Bill A. Jones) and Andrea Carmichael (Earlene Davis) are the recurring characters appearing on "Vitamin D". Joe Hursley appears as a guest star playing Joe.2
Cory Monteith, Chris Colfer, Kevin McHale, Mark Salling, Shum and Talton perform a version mashup of the subjects'It's My Life"and"Confessions Part II"of Bon Jovi and Usher , respectively, while Lea Michele, Dianna Agron, Amber Riley, Jenna Ushkowitz, Rivera and Morris do the same with "Halo"and"Walking on Sunshine"by Beyoncé and Katrina & the Waves respectively. Columbia Records and 20th Century Fox Television released both songs as singles and arranged for digital download on iTunes one day before the episode aired.3 Michele revealed that practiced for several days a frenzied speech to convey the effects of pseudoephedrine in Rachel.1
[edit]Reception
[edit]Audience and critical
"Vitamin D" was seen by a total of 7.3 million viewers in the U.S.,four receiving generally good reviews from the critics. Shawna Malcolm, the newspaper Los Angeles Times, and Aly Semigran of MTV, highlighted the performance of the choir boys,5 6 while Mandi Bierly of Entertainment Weekly, the girls preferred, while stressing the performance of Matthew Morrison.7 For his part, Mike Hale of The New York Times, praised the interpretation of Jayma Mays and called the pregnancy history of boring.8
[edit]Singles Charts
Song List Maximum
position9
"It's My Life / Confessions Part II" Ireland Singles Top 50 6
UK Top 75 Singles 14
Australia Singles Top 50 22
Canada Singles Top 100 25
U.S. Singles Top 100 30
Song List Maximum
position10
"Halo / Walking On Sunshine ' Ireland Singles Top 50 4
UK Top 75 Singles 9
Australia Singles Top 50 10
Canada Singles Top 100 28
U.S. Singles Top 100 40
[edit] ENTAO UM ABRAÇO A TODOS , NA PROXIMA IREMOS FALAR SOBRE A VITAMINA E , ENTAO UM ABRAÇO A TODOS E ATE A PROXIMA .
segunda-feira, 6 de setembro de 2010
reprise da vitamina a para os paises do exterior ( canada , estados unidos , alemanha e outros )
Vitamin A is perhaps the most important vitamin. It is called retinol and is easily transformed into the human body in retinoic acid, which is an effective way. It exists in two main ways: all-trans retinoic acid (ATRA, the most important) and 9-cis retinoic acid (9-cis RA).
An obvious function of vitamin A is like a big compound of proteins (called Rhodopsin) in eyes that react to light and make vision possible. Most functions of this vitamin, however, is performed by its receptors, which are transcription factors of the nuclear receptor family. For these receptors, retinoic acid can affect almost every function in the human cell. Knowing this, it is easy to understand why the vitamin must be consumed in normal amounts.
More recent studies are showing that the vitamin acts as an antioxidant (it combats the free radicals that accelerate aging and are associated with some diseases). However, caution should be exercised in the use of vitamin A, for excess is harmful.
Scientific Name = Retinol or Axeroftol.
Index [hide]
1 Consequences of deficiency
1.1 Causes of disabilities
2 Consumption exaggerated
3 Foods rich in Vitamin A
4 References
[edit]Consequences of deficiency
Structure of retinol (vitamin A).
The avitaminosis which is related to Vitamin A deficiency is xerophthalmia. One of the epithelium severely affected is the eye of the lining, leading to xerophthalmia. Xerophthalmia is the generic name given to various ocular signs and symptoms of hypovitaminosis A. The earliest clinical manifestation of xerophthalmia is night blindness, where the child can not look good adaptation in poorly lit; more pronounced manifestations of xerophthalmia are Bitot's spots, usually located on the exposed part of the conjunctiva and xerosis; in later stages the cornea is also affected being the corneal xerosis, characterized by the loss of brightness assuming granular appearance and ulceration of the cornea, ulceration can lead to progressive necrosis and destruction of the eyeball leading to blindness, irreversible, which is called Keratomalacia. Other complications related to vitamin A deficiency include poor vision at night (night-blindness), sensitivity to light (photophobia), reduction of smell and taste, dryness and infection in the skin and mucous membranes (xeroderma), stress, thickening of corneal injuries and skin cancer in the eye. Xerophthalmia is different from night-blindness, is being called the 'night blindness' and that, dry eyes, which promotes the increased friction between the eyelid and the eye, causing ulcerations in the epithelium of the eye. The vitamin A deficiency also causes hyperplasia (uncontrolled multiplication of cells) and metaplasia (loss of cell shape), and the emergence of opportunistic diseases. Frequent infections may indicate deficiency, since a lack of vitamin A reduces the body's ability to defend itself from diseases.
[edit]Causes of disability
Lack of breastfeeding or weaning early: the milk is rich in vitamin A and is the ideal food for children under two years old.
Insufficient consumption of foods rich in vitamin A.
Insufficient consumption of foods containing fat: the human body needs a quantity of dietary fat to keep several functions essential for its proper functioning. One is to allow the absorption of some fat soluble vitamins (vitamins A, D, E and K).
Frequent infections: infections that affect children lead to a decrease in appetite: The child begins to eat less food may arise a deficiency of Vitamin A. Moreover, the infection causes the body's need for vitamin A are higher, leading to reduced inventories in the body and triggering or worsening the state nutrition.
[edit]Consumption exaggerated
By ingesting excessive manifestations may be as dry skin, rough and scaly, cracking lips, follicular keratosis, bone and joint pain, headaches, dizziness and nausea, falling hair, muscle cramps, injuries, liver and stops growth. May also arise lack of appetite, edema, fatigue, irritability, and bleeding. Increase in the spleen and liver, abnormal liver function tests, reduced levels of cholesterol and HDL cholesterol may also occur. Great care should be given to products containing the retinoic acid used in the treatment of acne.
The precursors of vitamin A have a significant influence on the amount of vitamin A that must be ingested. There are compounds related to vitamin that can be converted within the body into vitamin active (pro-vitamins). Some carotenoids are pro-vitamin A, the most important beta-carotene, followed by alpha-carotene. As the excess of vitamin A is stored in the body reaching cause toxic levels, may be resorted to carotenoids that can be consumed in doses considerably higher without an accumulation is harmful.
Consumption of beta-carotene of about 30 mg / day increases the likelihood of lung cancer and prostate. Smokers and people who have suffered exposure to asbestos should not consume supplements of beta-carotene.[2]
[edit]Foods rich in Vitamin A
Are foods rich in vitamin A foods of animal and plant:
Liver
Butter
Milk
Egg yolk
Sardine
Cheese fat
Cod-liver oil
Avocado
Chard
Cashew
Peach
Papaya
Escarole
Melon
Carrot
Leaf Broccoli
Sweet potato
Kale
Spinach
Pumpkin
Tomato
Mango
Beta-carotene (provitamin A) are fat soluble, so the absorption of vitamin A is improved if these foods are eaten with fat (like vegetable oils). Cooking for a few minutes, until the cell walls to rupture and release color also increase absorption. um abraço a todos e ate a proxima .
An obvious function of vitamin A is like a big compound of proteins (called Rhodopsin) in eyes that react to light and make vision possible. Most functions of this vitamin, however, is performed by its receptors, which are transcription factors of the nuclear receptor family. For these receptors, retinoic acid can affect almost every function in the human cell. Knowing this, it is easy to understand why the vitamin must be consumed in normal amounts.
More recent studies are showing that the vitamin acts as an antioxidant (it combats the free radicals that accelerate aging and are associated with some diseases). However, caution should be exercised in the use of vitamin A, for excess is harmful.
Scientific Name = Retinol or Axeroftol.
Index [hide]
1 Consequences of deficiency
1.1 Causes of disabilities
2 Consumption exaggerated
3 Foods rich in Vitamin A
4 References
[edit]Consequences of deficiency
Structure of retinol (vitamin A).
The avitaminosis which is related to Vitamin A deficiency is xerophthalmia. One of the epithelium severely affected is the eye of the lining, leading to xerophthalmia. Xerophthalmia is the generic name given to various ocular signs and symptoms of hypovitaminosis A. The earliest clinical manifestation of xerophthalmia is night blindness, where the child can not look good adaptation in poorly lit; more pronounced manifestations of xerophthalmia are Bitot's spots, usually located on the exposed part of the conjunctiva and xerosis; in later stages the cornea is also affected being the corneal xerosis, characterized by the loss of brightness assuming granular appearance and ulceration of the cornea, ulceration can lead to progressive necrosis and destruction of the eyeball leading to blindness, irreversible, which is called Keratomalacia. Other complications related to vitamin A deficiency include poor vision at night (night-blindness), sensitivity to light (photophobia), reduction of smell and taste, dryness and infection in the skin and mucous membranes (xeroderma), stress, thickening of corneal injuries and skin cancer in the eye. Xerophthalmia is different from night-blindness, is being called the 'night blindness' and that, dry eyes, which promotes the increased friction between the eyelid and the eye, causing ulcerations in the epithelium of the eye. The vitamin A deficiency also causes hyperplasia (uncontrolled multiplication of cells) and metaplasia (loss of cell shape), and the emergence of opportunistic diseases. Frequent infections may indicate deficiency, since a lack of vitamin A reduces the body's ability to defend itself from diseases.
[edit]Causes of disability
Lack of breastfeeding or weaning early: the milk is rich in vitamin A and is the ideal food for children under two years old.
Insufficient consumption of foods rich in vitamin A.
Insufficient consumption of foods containing fat: the human body needs a quantity of dietary fat to keep several functions essential for its proper functioning. One is to allow the absorption of some fat soluble vitamins (vitamins A, D, E and K).
Frequent infections: infections that affect children lead to a decrease in appetite: The child begins to eat less food may arise a deficiency of Vitamin A. Moreover, the infection causes the body's need for vitamin A are higher, leading to reduced inventories in the body and triggering or worsening the state nutrition.
[edit]Consumption exaggerated
By ingesting excessive manifestations may be as dry skin, rough and scaly, cracking lips, follicular keratosis, bone and joint pain, headaches, dizziness and nausea, falling hair, muscle cramps, injuries, liver and stops growth. May also arise lack of appetite, edema, fatigue, irritability, and bleeding. Increase in the spleen and liver, abnormal liver function tests, reduced levels of cholesterol and HDL cholesterol may also occur. Great care should be given to products containing the retinoic acid used in the treatment of acne.
The precursors of vitamin A have a significant influence on the amount of vitamin A that must be ingested. There are compounds related to vitamin that can be converted within the body into vitamin active (pro-vitamins). Some carotenoids are pro-vitamin A, the most important beta-carotene, followed by alpha-carotene. As the excess of vitamin A is stored in the body reaching cause toxic levels, may be resorted to carotenoids that can be consumed in doses considerably higher without an accumulation is harmful.
Consumption of beta-carotene of about 30 mg / day increases the likelihood of lung cancer and prostate. Smokers and people who have suffered exposure to asbestos should not consume supplements of beta-carotene.[2]
[edit]Foods rich in Vitamin A
Are foods rich in vitamin A foods of animal and plant:
Liver
Butter
Milk
Egg yolk
Sardine
Cheese fat
Cod-liver oil
Avocado
Chard
Cashew
Peach
Papaya
Escarole
Melon
Carrot
Leaf Broccoli
Sweet potato
Kale
Spinach
Pumpkin
Tomato
Mango
Beta-carotene (provitamin A) are fat soluble, so the absorption of vitamin A is improved if these foods are eaten with fat (like vegetable oils). Cooking for a few minutes, until the cell walls to rupture and release color also increase absorption. um abraço a todos e ate a proxima .
VITAMINA C
* PARA O BRASIL : AGORA IREMOS FALAR SOBRE A VITAMINA C - O ácido ascórbico ou vitamina C (C6H8O6, ascorbato, quando na forma ionizada) é uma molécula usada na hidroxilação de várias outras em reacções bioquímicas nas células. A sua principal função é a hidroxilação do colágeno, a proteína fibrilar que dá resistência aos ossos, dentes, tendões e paredes dos vasos sanguíneos. Além disso, é um poderoso antioxidante, sendo usado para transformar os radicais livres de oxigênio em formas inertes. É também usado na síntese de algumas moléculas que servem como hormônios ou neurotransmissores. Em gêneros alimentícios é referido pelo número INS 300.
Índice
1 Características físico-químicas
2 Atividade biológica
3 Na dieta humana
4 Fontes alimentares
5 Suplementação
6 Referências
7 Ligações externas
[editar] Características físico-químicas
Fórmula estrutural.O ácido ascórbico é um sólido cristalino de cor branca, inodoro, hidrossolúvel e pouco solúvel em solventes orgânicos. O ácido ascórbico presente em frutas e legumes é destruído por temperaturas altas por um período prolongado. Também sofre oxidação irreversível, perdendo a sua atividade biológica, em alimentos frescos guardados por longos períodos.
[editar] Atividade biológica
Aos valores de pH normalmente encontrados no meio intracelular, o ácido ascórbico encontra-se predominantemente na sua forma ionizada, o ascorbato.
Uma das actividades mais importantes do ascorbato no organismo humano é na desidratação de resíduos de prolina no colagénio. O colagénio, uma proteína estrutural fundamental, necessita ter determinados resíduos de prolina na forma hidroxiprolina para manter uma estrutura tridimensional correcta. A hidroxilação é feita pela enzima prolil-4-hidroxilase; o ascorbato não intervém directamente nesta hidroxilação, pelo que é assumido que é necessário para reduzir o íon Fe3+ que participa na catálise enzimática (nesta, o íon passa do estado Fe2+ para Fe3+, sendo necessário o seu restabelecimento para novo ciclo catalítico).[5]
Em plantas, o ascorbato encontra-se em concentrações relativamente elevadas (2 a 25 mM) e actua na desintoxicação do peróxido de hidrogénio. A enzima ascorbato peroxidase catalisa a redução do peróxido de hidrogénio a água, usando o ascorbato como agente redutor. Também é precursor dos íons tartarato e oxalato.
Na dieta humana
Tem os seguintes efeitos no organismo em doses moderadas:
Favorece a formação dos dentes e ossos;
Ajuda a resistir às doenças.
Previne gripes, fraqueza muscular e infecções. Este ponto é disputado, havendo estudos que não mostram qualquer efeito de doses aumentadas.[5] Contudo ajuda, sem dúvida, em doentes já com escorbuto.
Ajuda o sistema imunológico e a respiração celular, estimula as glândulas supra-renais e protege os vasos sanguíneos.
A vitamina C é importante para o funcionamento adequado das células brancas do sangue.É eficaz contra doenças infecciosas e um importante suplemento no caso de câncer.
A carência desta vitamina provoca a avitaminose designada por escorbuto.
É importante observar que a vitamina C (ácido ascórbico) é extremamente instável. Ela reage com o oxigênio do ar, com a luz e até mesmo com a água. Assim que é exposta têm-se início reações químicas que a destroem, daí o surgimento do gosto ruim no suco pronto. Estima-se que, em uma hora, quase que a totalidade do conteúdo vitamínico já reagiu e desapareceu, por isso é importante consumir as frutas ou o suco fresco feito na hora, deste modo, temos certeza que o teor de vitaminas está garantido. No caso das frutas, deve se levar em conta o estado das mesmas (cascas, cor e etc.), caso estejam 'feridas' pode ser que já se encontre em estado avançado de reação e não tenha o 'teor' vitamínico que se deseja.
Fontes alimentares
Acerola 1 copo (250 ml) = 3.872 mg Mamão (ou papaia)100 gramas = 62 mg Laranja 1 copo (250ml) = 124 mg
Limão (fresco) 100 ml = 46 mg Melão Brócolis
Morangos 100 gramas = 57 mg Manga Kiwi 100 gramas= 98 mg[6]
Cantalupo 100 gramas= 26 mg Grapefruit (pomelo) Pimentão (vermelho ou verde)
Couve Ervilha Caju
Camu-camu 100 gramas = 6.000 mg Goiaba 100 gramas = 183 mg Tomate
* para os paises do exterior que acessa o meu blog ( alemanhã , canada , estados unidos e outros ) : Summary
Weyers, Alicia, Ugni, Laura I.; OVANDO GARCIA, Hugo and GORLA, Nora B.. Antioxidant Capacity of vitamin C in mouse liver and kidney tissues. Biocell (Mendoza) [online]. 2008, vol.32, no.1, pp. 27-31. ISSN 1667-5746.
In the present study, the antioxidant vitamin C Capacity of Was Examined in the liver and the kidney Tissues of mice with or Without ciprofloxacin (CFX) treatment. The Capacity of the antioxidant vitamin Was Evaluated in Terms of lipid hydroperoxides (LOOH) and thiobarbituric acid reactive substances (TBARs). The experimental design Was 15 days of water (control and CFX groups) or vitamin C (vitamin C and vitamin C plus CFX groups) in drinking water. One dose of CFX Was injected, 15 Minutes Before sacrifice, in the Corresponding mice. The initial nmol of lipid hydroperoxides / g of tissue Were 137 ± 11 in the kidney and 145 ± 15 in the Liver, and the nmol of TBARs Were 13 ± 12 ± 0.7 and 0.6, respectively. Pre-treatment with vitamin C reduces the Levels of LOOH in the liver to 45 ± 11 (p <0.01) and vitamin C with CFX injection to 54 ± 9 (p <0.01). Also Vitamin C Treatment Reduced the LOOH Levels in the kidney roughly duplicated by CFX. Through the method TBARs These We Have Not Observed effects. Quantification of LOOH is more sensitive Than That of TBARs for Estimating lipid peroxidation. Especially CFX is Used for Infections and dog urinary oxidative stress occurs in the kidney. Pre-treatment with vitamin C May ameliorate this stress and Also May Improve the oxidative balance in the liver.
Keywords: Lipid peroxidation, Vitamin C, Ciprofloxacin; Mice. - eleiçoes para o BRASIL : VOTE LEVY FIDELIX PRA PRESIDENTE VOTE 28 , VOTE ( PRTB ) , NÃO VOTE EM TATURANA , VOTE EM LEVY FIDELIX 28 ( PRTB ) . um abraço a todos , irei responder a todas as perguntas no comentario do blog , e ate a proxima , um abraço a todos .
Índice
1 Características físico-químicas
2 Atividade biológica
3 Na dieta humana
4 Fontes alimentares
5 Suplementação
6 Referências
7 Ligações externas
[editar] Características físico-químicas
Fórmula estrutural.O ácido ascórbico é um sólido cristalino de cor branca, inodoro, hidrossolúvel e pouco solúvel em solventes orgânicos. O ácido ascórbico presente em frutas e legumes é destruído por temperaturas altas por um período prolongado. Também sofre oxidação irreversível, perdendo a sua atividade biológica, em alimentos frescos guardados por longos períodos.
[editar] Atividade biológica
Aos valores de pH normalmente encontrados no meio intracelular, o ácido ascórbico encontra-se predominantemente na sua forma ionizada, o ascorbato.
Uma das actividades mais importantes do ascorbato no organismo humano é na desidratação de resíduos de prolina no colagénio. O colagénio, uma proteína estrutural fundamental, necessita ter determinados resíduos de prolina na forma hidroxiprolina para manter uma estrutura tridimensional correcta. A hidroxilação é feita pela enzima prolil-4-hidroxilase; o ascorbato não intervém directamente nesta hidroxilação, pelo que é assumido que é necessário para reduzir o íon Fe3+ que participa na catálise enzimática (nesta, o íon passa do estado Fe2+ para Fe3+, sendo necessário o seu restabelecimento para novo ciclo catalítico).[5]
Em plantas, o ascorbato encontra-se em concentrações relativamente elevadas (2 a 25 mM) e actua na desintoxicação do peróxido de hidrogénio. A enzima ascorbato peroxidase catalisa a redução do peróxido de hidrogénio a água, usando o ascorbato como agente redutor. Também é precursor dos íons tartarato e oxalato.
Na dieta humana
Tem os seguintes efeitos no organismo em doses moderadas:
Favorece a formação dos dentes e ossos;
Ajuda a resistir às doenças.
Previne gripes, fraqueza muscular e infecções. Este ponto é disputado, havendo estudos que não mostram qualquer efeito de doses aumentadas.[5] Contudo ajuda, sem dúvida, em doentes já com escorbuto.
Ajuda o sistema imunológico e a respiração celular, estimula as glândulas supra-renais e protege os vasos sanguíneos.
A vitamina C é importante para o funcionamento adequado das células brancas do sangue.É eficaz contra doenças infecciosas e um importante suplemento no caso de câncer.
A carência desta vitamina provoca a avitaminose designada por escorbuto.
É importante observar que a vitamina C (ácido ascórbico) é extremamente instável. Ela reage com o oxigênio do ar, com a luz e até mesmo com a água. Assim que é exposta têm-se início reações químicas que a destroem, daí o surgimento do gosto ruim no suco pronto. Estima-se que, em uma hora, quase que a totalidade do conteúdo vitamínico já reagiu e desapareceu, por isso é importante consumir as frutas ou o suco fresco feito na hora, deste modo, temos certeza que o teor de vitaminas está garantido. No caso das frutas, deve se levar em conta o estado das mesmas (cascas, cor e etc.), caso estejam 'feridas' pode ser que já se encontre em estado avançado de reação e não tenha o 'teor' vitamínico que se deseja.
Fontes alimentares
Acerola 1 copo (250 ml) = 3.872 mg Mamão (ou papaia)100 gramas = 62 mg Laranja 1 copo (250ml) = 124 mg
Limão (fresco) 100 ml = 46 mg Melão Brócolis
Morangos 100 gramas = 57 mg Manga Kiwi 100 gramas= 98 mg[6]
Cantalupo 100 gramas= 26 mg Grapefruit (pomelo) Pimentão (vermelho ou verde)
Couve Ervilha Caju
Camu-camu 100 gramas = 6.000 mg Goiaba 100 gramas = 183 mg Tomate
* para os paises do exterior que acessa o meu blog ( alemanhã , canada , estados unidos e outros ) : Summary
Weyers, Alicia, Ugni, Laura I.; OVANDO GARCIA, Hugo and GORLA, Nora B.. Antioxidant Capacity of vitamin C in mouse liver and kidney tissues. Biocell (Mendoza) [online]. 2008, vol.32, no.1, pp. 27-31. ISSN 1667-5746.
In the present study, the antioxidant vitamin C Capacity of Was Examined in the liver and the kidney Tissues of mice with or Without ciprofloxacin (CFX) treatment. The Capacity of the antioxidant vitamin Was Evaluated in Terms of lipid hydroperoxides (LOOH) and thiobarbituric acid reactive substances (TBARs). The experimental design Was 15 days of water (control and CFX groups) or vitamin C (vitamin C and vitamin C plus CFX groups) in drinking water. One dose of CFX Was injected, 15 Minutes Before sacrifice, in the Corresponding mice. The initial nmol of lipid hydroperoxides / g of tissue Were 137 ± 11 in the kidney and 145 ± 15 in the Liver, and the nmol of TBARs Were 13 ± 12 ± 0.7 and 0.6, respectively. Pre-treatment with vitamin C reduces the Levels of LOOH in the liver to 45 ± 11 (p <0.01) and vitamin C with CFX injection to 54 ± 9 (p <0.01). Also Vitamin C Treatment Reduced the LOOH Levels in the kidney roughly duplicated by CFX. Through the method TBARs These We Have Not Observed effects. Quantification of LOOH is more sensitive Than That of TBARs for Estimating lipid peroxidation. Especially CFX is Used for Infections and dog urinary oxidative stress occurs in the kidney. Pre-treatment with vitamin C May ameliorate this stress and Also May Improve the oxidative balance in the liver.
Keywords: Lipid peroxidation, Vitamin C, Ciprofloxacin; Mice. - eleiçoes para o BRASIL : VOTE LEVY FIDELIX PRA PRESIDENTE VOTE 28 , VOTE ( PRTB ) , NÃO VOTE EM TATURANA , VOTE EM LEVY FIDELIX 28 ( PRTB ) . um abraço a todos , irei responder a todas as perguntas no comentario do blog , e ate a proxima , um abraço a todos .
domingo, 5 de setembro de 2010
VITAMINA B12
*PARA O BRASIL : A cobalamina (ou cianocobalamina), também conhecida como vitamina B12, tem as seguintes funções no nosso organismo:
Necessária à eritropoiese, e em parte do metabolismo dos aminoácidos e dos ácidos nucleicos;
Possui uma função indispensável na formação do sangue;
Necessária para uma boa manutenção do sistema nervoso.
Segundo a organização norte-americana Food and Nutrition Board, a dose diária de vitamina B12 necessária para o organismo é de 2,4 microgramas (µg) para adultos, 1,2 µg para crianças de até oito anos e 2,8 µg para gestantes e mães que amamentam.
Índice [esconder]
1 Fontes Naturais de Vitamina B12
2 Deficiência
3 A Vitamina B12 e a Dieta Vegetariana Estrita
4 Ligações externas
[editar] Fontes Naturais de Vitamina B12
Fígado
Carnes vermelhas
Ovos
Leite
Peixes
[editar] Deficiência
A carência de Vitamina B12 no organismo é rara em omnívoros. Geralmente ocorre devido à deficiência na produção de factor intrínseco, necessário para a absorção da cobalamina. Pode provocar anemia perniciosa, cujos sintomas são: alterações neurológicas, progressivas e mortais se não houver tratamento; fraqueza; convulsões e dano irreversível no tecido parietal gástrico.
[editar] A Vitamina B12 e a Dieta Vegetariana Estrita
Este é o único nutriente que não se obtém numa dieta vegetariana estrita. Inúmeros estudos demonstram que vegetarianos estritos têm níveis sanguíneos mais baixos de B12. Então, deve ser feita uma suplementação da vitamina em cápsulas (via oral) ou injetável.
Os não-vegetarianos não possuem dificuldades em obter a B12 já que os animais, uma de suas fontes de alimentação, obtêm essa vitamina através de bactérias produtoras de vitamina B12 em seu organismo. Há alguns estudos que dizem que humanos também possuem bacterias no intestino, mas sua localização é após a área de absorção, por isso precisamos de fontes exógenas. É importante lembrar que o corpo humano já possui um certo suprimento da vitamina, mas a reposição da substância diariamente é altamente recomendável para quem deseja obter uma saúde bem regulada. Porém, se uma anemia ocorrer devido a falta de B12 no organismo, o recomendável para quem ingere carnes é fazer uso de bifes de fígado, onde são armazenados cerca de 50% ou mais dos estoques de B12 do animal. No caso dos vegetarianos estritos, suplementos de via oral ou injeções com grande dosagem da vitamina são as melhores opções para fazer a reposição da substância, além de opções existentes de alimentos artificalmente enriquecidos, como leite de soja de algumas marcas.
* AINDA NO BRASIL , POLITICA , DESCULPEM A TODOS POR TER DITO UM CANDIDATO ERRADO E EM QUE NÃO QUERIA QUE VOTASSE , MAS QUERO QUE VOTEM EM LEVY FIDELIX 28 , ELE IRA FAZER COM QUE A REDE FAMILIA SE TRANSFORMANDO NO VALOR NO SALARIO MINIMO , POR ISSO VOTEM 28 LEVY FIDELIX ( PRTB ) - PARTIDO PRA QUEM NÃO SABE . * PARA OS PAISES DO MUNDO A FORA QUE ACESSA O BLOG FUTEBOL E NUTRICAO ( ALEMANHA , ESTADOS UNIDOS , CANADA E OUTROS QUE ACESSAREM ): Prevalence of mild serum vitamin B12 deficiency in rural and urban Costa Rican young adults
Prevalencia de la deficiencia moderada de vitamina B12 sérica en jóvenes adultos de zonas rurales y urbanas de Costa Rica
Ileana Holst-SchumacherI; Rafael Monge-RojasII; Mauro Barrantes-SantamaríaIII
IUniversity of Costa Rica, Investigation Center for Abnormal Hemoglobins and Related Sicknesses, San Pedro de Montes de Oca, San José, Costa Rica. Address for correspondence and reprints: Ileana Holst-Schumacher, Investigation Center for Abnormal Hemoglobins and Related Sicknesses (CIHATA), University of Costa Rica, Postal Code 2410-2050, San Pedro de Montes de Oca, San José, Costa Rica; fax: (506) 225-2374/(506) 225-5440; telephone: (506) 207-5440/(506) 207-4389; e-mail: iholst@cariari.ucr.ac.cr
IICosta Rican Institute for Research and Education on Nutrition and Health, Tres Ríos, Cartago, Costa Rica
IIIHealth Office, University of Costa Rica, San Pedro de Montes de Oca, San José, Costa Rica
ABSTRACT
OBJECTIVE: Recent studies have shown an increase of mild serum cobalamin (vitamin B12) deficiency in some Latin American countries; however, no data are available from Costa Rica. The purpose of this work was to establish the prevalence of serum vitamin B12 deficiency among Costa Rican young adults and to study some factors that may help explain the serum cobalamin concentrations.
METHODS: A cross-sectional survey was conducted among 400 adults aged 20 to 40 years old from urban and rural areas of the central valley of Costa Rica to determine serum vitamin B12 levels. Additionally, cobalamin dietary intake and the detection of Helicobacter pylori IgG antibodies were studied as possible determinants of the serum vitamin B12 concentrations.
RESULTS: The mean serum concentration of vitamin B12 was 268 ± 125 pmol/L, and no significant differences were found by gender or area. Study data indicate an overall prevalence of inadequate serum cobalamin levels of 42.4% (11.2% deficient and 31.2% marginal); more than 50% but less than 75% of individuals had an intake of vitamin B12 below the U.S. Estimated Average Requirement (EAR) and 61.2% had IgG antibodies to H. pylori.
CONCLUSIONS: The prevalence of mild serum vitamin B12 deficiency in young Costa Rican subjects is as high as in other Latin American countries. More investigation should be done to elucidate the etiological factors that are generating deficient and marginal serum cobalamin levels in Costa Rican adults in order to define appropriate public health actions.
Key words: Vitamin B 12 deficiency, Helicobacter pylori, Costa Rica.
RESUMEN
OBJETIVO: Aunque estudios recientes han demostrado un incremento en el déficit moderado de cobalamina (vitamina B12) sérica en algunos países de América Latina, no hay datos de Costa Rica. El propósito de este trabajo fue determinar la prevalencia de la deficiencia de vitamina B12 sérica en jóvenes adultos de Costa Rica y estudiar algunos factores que pueden ayudar a explicar las concentraciones séricas de cobalamina.
MÉTODOS: Se realizó un estudio transversal para determinar los niveles de vitamina B12 en el suero de 400 adultos de 20 a 40 años de edad de zonas urbanas y rurales del valle central de Costa Rica. Adicionalmente, se estudió la ingesta de cobalamina en la dieta y la presencia de anticuerpos IgG contra Helicobacter pylori, como posibles factores determinantes de las concentraciones séricas de vitamina B12.
RESULTADOS: La concentración media de vitamina B12 en el suero fue de 268 ± 125 pmol/L; no se encontraron diferencias significativas entre los sexos ni entre las áreas de residencia. Estos datos demostraron una prevalencia general de niveles insuficientes de cobalamina sérica de 42,4% (11,2% con déficit y 31,2% con concentraciones marginales); de las personas estudiadas más de 50% -aunque menos de 75%- tenían una ingesta de vitamina B12 por debajo del valor de las necesidades promedio estimadas para los Estados Unidos de América y 61,2% tenía anticuerpos contra H. pylori.
CONCLUSIONES: La prevalencia de deficiencia moderada de vitamina B12 sérica en jóvenes costarricenses es tan elevada como en otros países latinoamericanos. Se necesitan más investigaciones para aclarar los factores etiológicos que producen niveles insuficientes y marginales de cobalamina sérica en los adultos de Costa Rica para poder definir intervenciones sanitarias apropiadas.
Key words: Deficiencia de vitamina B12, Helicobacter pylori, Costa Rica.
Vitamin B12 or cobalamin deficiency has been identified frequently in older people and vegetarians (1–3). Nevertheless, recent studies in Latin America have shown a high prevalence of mild serum vitamin B12 deficiency in younger, omnivorous subjects (4, 5). In 1995, a Cuban study reported a prevalence of deficient serum vitamin B12 values ranging from 52 to 82% and marginal values ranging from 13 to 36%, respectively, among a healthy population of middle-aged men (5). In another study, about 45% of fer- tile women in a rural Mexican community were identified with deficient and marginal serum vitamin B12 concentrations (4). In Costa Rica, cobalamin status has not been assessed among the middle-aged population.
Low concentrations of vitamin B12 have been associated with megaloblastic anemia (3), neuropsychiatric manifestations (6), and hyperhomocysteinemia, an important cardiovascular risk factor (7).
Cobalamin deficiency has been attributed to low vitamin B12 intake or protein-bound vitamin B12 malabsorption syndromes (8). The low intake of foods with a high content of animal protein-main dietary sources of vitamin B12-markedly limits the intake of this micronutrient (9, 10), particularly in developing countries where availability of these products is low and their cost is high.
In several studies, food-cobalamin malabsorption (FCM) has been associated with atrophic gastritis induced by a bacterium known as Helicobacter pylori (11, 12). Lack of or inadequate secretion of intrinsic factor (due to pernicious anemia), gastric acid, and pepsin, which are needed to release and absorb protein-bound cobalamin in food, can cause vitamin B12 malabsorption (13). Likewise, hypochlorhydria and bacterial overgrowth in the mucosa can play an important role in the malabsorption process (8, 12). Moderate and high alcohol consumption has also been associated with vitamin B12 deficiency (14, 15).
The purpose of this study was to determine the prevalence of serum cobalamin deficiency among Costa Rican young adults and to examine whether dietary intake of vitamin B12 and the presence of H. pylori help to explain serum vitamin B12 concentrations.
MATERIALS AND METHODS
Study population
A total of 400 adults from the central valley of Costa Rica, aged 20 to 40 years, were recruited for this study. Subjects were asked to participate through a written circular sent home with about 700 randomly selected boys and girls from 20 representative rural and urban schools. A total of 490 adults offered to collaborate, but only 400 of them fulfilled all the requirements for participation in the study. Inclusion criteria included being of Costa Rican nationality and being between 20 and 40 years old. Exclusion criteria included conditions such as vegetarianism, alcoholism, gastrointestinal disorders, and chronic diarrhea. Also excluded were people taking vitamin supplements.
Ethical procedures
Written, informed consent was obtained from all participants. The study protocol was approved by the Ethics Committees of the Costa Rican Institute for Research and Education on Nutrition and Health (INCIENSA) and the University of Costa Rica.
Socio-demographic and dietary variables
Information about age, gender, area, economic level, and vitamin consumption were collected through validated instruments. Madrigal's method was used to establish the socioeconomic status of study participants based on their possession of various material goods and comforts in their homes (16). Dietary intake of vitamin B12 was determined through the use of semi-quantitative 24-hour recall questionnaires. A series of photographs of food commonly consumed in Costa Rica and three-dimensional (3-D) food models were used to estimate portion size. The Food Processor‚ for Windows version 6.0 (ESHA Research, Salem, Oregon, USA) was used to perform nutrient calculations from dietary data (17). A comparison with the U.S. Estimated Average Requirement (EAR) for vitamin B12 was made to evaluate micronutrient intake, and the recommended dietary allowance of 2.4 µg for vitamin B12 was considered. The EAR cut-point method (counting the number of individuals with normal intake below fixed EAR-based cut-off points) was used to assess the prevalence of inadequate intake of the vitamin (18).
Biochemical variables
Blood was drawn after 8–12 hours of fasting by antecubital venipuncture according to the procedures of the Clinical and Laboratory Standards Institute (CLSI; formerly the National Committee for Clinical Laboratory Standards or NCCLS) (19) and collected into a plain tube for serum vitamin B12 and immunological analyses. Serum was separated immediately from the blood cells and stored at –20°C until the tests were performed.
Vitamin B12 serum concentration was determined with a commercial immunoassay using the Abbott IMx® System (Abbott Laboratories Diagnostics Division, Abbott Park, IL, USA), a fully automated immunoassay analyzer, and the intra-assay coefficient of variation was <6%. Internal quality control with deficient, normal, and high serum concentrations of vitamin B12 was performed to control variability in the measurements. In the cases in which the samples exceeded ± 2 standard deviations (SDs) of the average control value, the samples were analyzed again. Vitamin B12 levels were classified as deficient (<150 pmol/L), marginal (150–221 pmol/L), and adequate (>222 pmol/L) according to the recommendations of the U.S. National Academy of Sciences Institute of Medicine (20).
Qualitative detection of IgG antibodies to Helicobacter pylori was performed using a commercial enzyme-linked immunoassay (ELISA) kit (Panbio, Brisbane, Queensland, Australia). This test was limited to a sub-sample of study participants (139 individuals), however, due to its high cost. A result was considered negative when the test indicated <9 Panbio units, equivocal when between 9–11 Panbio units, and positive when >11 Panbio units (21).
Data analysis
Statistical analysis was performed using the Statistical Package for Social Sciences (SPSS), version 10.0 for Windows (SPSS Inc., Chicago, IL, USA, 1999). Continuous variables are summarized using means ± SD, and categorical variables are presented as frequency distributions. In order to study the behavior of the variables as age increases, the adult population was divided into two groups: 20–29 years and 30–40 years. Student's t-test was used to compare the means of the continuous variables and chi-square tests were used to compare categorical data. Partial Spearman correlation coefficients were calculated to determine association between variables.
RESULTS
The study sample consisted of 187 men and 213 women with a mean age of 32.5 ± 5.6 years; 76.8% of the individuals came from urban areas and 23.2% from rural areas (Table 1). The total mean serum vitamin B12 concentration of the study population was 268 ± 125 pmol/L, and no significant differences were found in the means of this micronutrient by gender, area, presence or absence of IgG antibodies for H. pylori, age group (20–29 years or 30–40 years), or socioeconomic level of the subjects (data not shown).
The overall prevalence of IgG antibodies to H. pylori in the studied population was 61.2%, with a significantly higher proportion of seropositive individuals in urban areas (48.9% vs. 12.2%, respectively; p < 0.001) (Table 1). No differences between male and female subjects were found in the prevalence of H. pylori antibodies, and the proportion of seropositive individuals in the 30–40-year age group (56 out of 85) was higher than in the 20–29-year age group (29 out of 85), although the difference was not statistically significant (p = 0.121) (data not shown). Vitamin B12 average intake was higher than 50% but lower than 75% of the EAR for this micronutrient.
More than 42% (42.4%) of the study participants presented either deficient (11.2%) or marginal levels (31.2%) of serum vitamin B12 (Table 2). The proportion of adults >30 years old with marginal concentrations of vitamin B12 was significantly higher than the proportion of subjects <30 years old (35.9% vs. 24.5%, respectively; p = 0.021) (data not shown). Likewise, the proportion of adults with deficient levels of vitamin B12 with a low socioeconomic profile was significantly higher than the proportion of individuals with deficient vitamin B12 concentrations and a high socioeconomic condition (14.8% vs. 3.9%; p = 0.028). Weak associations were found between the presence of IgG antibodies for H. pylori and the age group (r = 0.122) and area (r = 0.110) of the subjects. Likewise, vitamin B12 concentrations levels correlated weakly with study participants' socioeconomic level (r = 0.114).
DISCUSSION
For decades, it has been assumed that vitamin B12 deficiency is unlikely to occur except under special circumstances, such as the presence of pernicious anemia, vegetarianism, malabsorption syndromes, bacterial overgrowth, and other clinical conditions in which the function of the ileum is impaired (2, 3). It has also been established that vitamin B12 deficiency is common among the elderly, even in industrialized countries. Nevertheless, reports of cobalamin deficiency status in Latin American children and young adults have been increasing over the past decade (5, 22, 23), and Allen (24) has recently shown that at least 40% of individuals in the Americas had deficient or marginal levels of serum vitamin B12.
This is the first report indicating deficient serum vitamin B12 concentrations among Costa Ricans. Report results suggest a significant problem, with almost 43% of the population presenting marginal or deficient serum levels of cobalamin (< 221 pmol/L). Given that the study participants were young and apparently healthy, this level of vitamin B12 deficiency, which is common among the elderly (largely due to gastric atrophy), is striking. A significantly higher proportion of individuals with marginal levels of vitamin B12 was observed in the older age group (30–40-year), clearly suggesting that this deficiency becomes worse as age increases. Study data also suggest that the assumption of low prevalence of vitamin B12 deficiency among young adults need to be re-examined, particularly because vitamin B12 deficiency has been associated with increased risk of cardiovascular disease and serious neurological manifestations, including the development of Alzheimer's disease and dementia (25).
Unlike Costa Rica and other Latin American countries (24), which have a prevalence of deficient and marginal levels of vitamin B12 of more than 40%, developed countries such as United States have a prevalence of less than 3% (26).
Vitamin B12 deficiency can occur in individuals with dietary patterns that exclude animal or fortified foods, and in adults who are unable to absorb vitamin B12 from food (8). In developing countries, low serum vitamin B12 concentrations, could be a consequence of reduced consumption of animal protein due to its high cost. Vitamin B12 is provided in foods of animal origin, including dairy products and eggs, and is not a normal component of plant-based foods.
In several Latin American countries the diet is characterized by a predominance of vegetables, so intake of dietary vitamin B12 is quite low (9, 10). According to the Food and Agricultural Organization of the United Nations (FAO), per capita intake of animal products in developing countries constitutes less than one-third of the registered intake in industrialized countries (27).
Although this study found no significant correlation between serum vitamin B12 concentrations and socioeconomic level, a higher prevalence of young adults with deficient levels of cobalamin was observed in those from low socioeconomic levels versus those with a higher socioeconomic condition.
H. pylori infection has also been associated with FCM (food-cobalamin malabsorption), in some studies (11, 12, 28), but not in others (29, 30). H. pylori infection induces a reduction in the production of gastric acid and thus limits the release of vitamin B12 from the chymus (31).
The presence of H. pylori IgG antibodies in serum is highly indicative of H. pylori infection (8) and can therefore be used as a non-invasive means of screening large groups of people. Although, in this study, the prevalence of H. pylori antibodies was high (61.2%), an association could not be ascertained between the presence of this bacterium and deficient or marginal levels of serum vitamin B12. This situation is consistent with the one reported by Van Asselt et al. (8), who determined that H. pylori infection was related to atrophic gastritis but could not determine an association between the infection and mild vitamin B12 deficiency. However, Carmel et al. (28) found the presence of IgG antibodies to H. pylori in 75% of patients with severe FCM, and Serin et al. (32) provided strong evidence of association between H. pylori infection and vitamin B12 deficiency, even in patients with minimal or no gastric atrophy.
This study could not find an association between the presence of the bacteria and age, probably because the study population was too young (mean age: 32.5 years). It is well known that the prevalence of both H. pylori antibodies and serum cobalamin deficiency increases with age (8).
The etiology of mild vitamin B12 deficiency in young Costa Rican subjects is unclear, and its clinical manifestations could be misdiagnosed if accompanied by high intake of folic acid. Several studies have shown that folic acid deficiency is not a nutritional problem in the adult Costa Rican population (33), probably due to the ongoing policy of fortifying several foods with synthetic folic acid established by the Costa Rican Ministry of Health in 1997. Although high folic acid intake in the presence of vitamin B12 deficiency can delay the clinical diagnosis of vitamin B12 deficiency–induced megaloblastic anemia, it does not affect the irreversible progression of neurological dysfunction and cognitive decline that results from cobalamin deficiency (6).
More investigation should be done to elucidate the etiological factors that are generating deficient and marginal levels of serum vitamin B12 among Costa Rican young adults in order to define appropriate public health actions. Synthetic cobalamin food fortification could be a key strategy for public health in Costa Rica as well as other countries in the Americas where food is fortified with folic acid and vitamin B12 deficiency is suspected to be common. The Pan American Health Organization has indicated that the daily intake of 1 µg of synthetic vitamin B12 from fortified foods is a reliable way to optimize the status of this vitamin in the Americas (34).
The results of this study regarding intake of vitamin B12 should be interpreted with caution, as in some cases the 24-hour recall questionnaire may have only been applied once among the adult population (as opposed to the three-time intervention considered necessary for adequate evaluation nutrient intake). Taking this limitation into account, it should be noted that a higher prevalence of adults with deficient concentrations of cobalamin was observed at low socioeconomic levels versus higher socioeconomic levels.
The results of this research indicated a high prevalence of deficient and marginal levels of serum vitamin B12 among Costa Rican young adults. However, no significant association was found among the presence of H. pylori, dietary intake of vitamin B12, and serum levels of cobalamin.
Acknowledgements. The authors are grateful to Minor Soto Carranza and Roberto Chaves Vega for their help with blood sample collection. This work was supported by grants from three sources at the University of Costa Rica: (1) Office of Postgraduate Studies, (2) Office of Vice-president for Research (Project 807-A2-308), and (3) Fundación de la Universidad de Costa Rica para la Investigación (Project 217).
ate mais , boa sorte aos brasileiros nessa eleição e um abraço a todos e na proxima iremos falar sobre a vitamina c , ate a proxima !
Necessária à eritropoiese, e em parte do metabolismo dos aminoácidos e dos ácidos nucleicos;
Possui uma função indispensável na formação do sangue;
Necessária para uma boa manutenção do sistema nervoso.
Segundo a organização norte-americana Food and Nutrition Board, a dose diária de vitamina B12 necessária para o organismo é de 2,4 microgramas (µg) para adultos, 1,2 µg para crianças de até oito anos e 2,8 µg para gestantes e mães que amamentam.
Índice [esconder]
1 Fontes Naturais de Vitamina B12
2 Deficiência
3 A Vitamina B12 e a Dieta Vegetariana Estrita
4 Ligações externas
[editar] Fontes Naturais de Vitamina B12
Fígado
Carnes vermelhas
Ovos
Leite
Peixes
[editar] Deficiência
A carência de Vitamina B12 no organismo é rara em omnívoros. Geralmente ocorre devido à deficiência na produção de factor intrínseco, necessário para a absorção da cobalamina. Pode provocar anemia perniciosa, cujos sintomas são: alterações neurológicas, progressivas e mortais se não houver tratamento; fraqueza; convulsões e dano irreversível no tecido parietal gástrico.
[editar] A Vitamina B12 e a Dieta Vegetariana Estrita
Este é o único nutriente que não se obtém numa dieta vegetariana estrita. Inúmeros estudos demonstram que vegetarianos estritos têm níveis sanguíneos mais baixos de B12. Então, deve ser feita uma suplementação da vitamina em cápsulas (via oral) ou injetável.
Os não-vegetarianos não possuem dificuldades em obter a B12 já que os animais, uma de suas fontes de alimentação, obtêm essa vitamina através de bactérias produtoras de vitamina B12 em seu organismo. Há alguns estudos que dizem que humanos também possuem bacterias no intestino, mas sua localização é após a área de absorção, por isso precisamos de fontes exógenas. É importante lembrar que o corpo humano já possui um certo suprimento da vitamina, mas a reposição da substância diariamente é altamente recomendável para quem deseja obter uma saúde bem regulada. Porém, se uma anemia ocorrer devido a falta de B12 no organismo, o recomendável para quem ingere carnes é fazer uso de bifes de fígado, onde são armazenados cerca de 50% ou mais dos estoques de B12 do animal. No caso dos vegetarianos estritos, suplementos de via oral ou injeções com grande dosagem da vitamina são as melhores opções para fazer a reposição da substância, além de opções existentes de alimentos artificalmente enriquecidos, como leite de soja de algumas marcas.
* AINDA NO BRASIL , POLITICA , DESCULPEM A TODOS POR TER DITO UM CANDIDATO ERRADO E EM QUE NÃO QUERIA QUE VOTASSE , MAS QUERO QUE VOTEM EM LEVY FIDELIX 28 , ELE IRA FAZER COM QUE A REDE FAMILIA SE TRANSFORMANDO NO VALOR NO SALARIO MINIMO , POR ISSO VOTEM 28 LEVY FIDELIX ( PRTB ) - PARTIDO PRA QUEM NÃO SABE . * PARA OS PAISES DO MUNDO A FORA QUE ACESSA O BLOG FUTEBOL E NUTRICAO ( ALEMANHA , ESTADOS UNIDOS , CANADA E OUTROS QUE ACESSAREM ): Prevalence of mild serum vitamin B12 deficiency in rural and urban Costa Rican young adults
Prevalencia de la deficiencia moderada de vitamina B12 sérica en jóvenes adultos de zonas rurales y urbanas de Costa Rica
Ileana Holst-SchumacherI; Rafael Monge-RojasII; Mauro Barrantes-SantamaríaIII
IUniversity of Costa Rica, Investigation Center for Abnormal Hemoglobins and Related Sicknesses, San Pedro de Montes de Oca, San José, Costa Rica. Address for correspondence and reprints: Ileana Holst-Schumacher, Investigation Center for Abnormal Hemoglobins and Related Sicknesses (CIHATA), University of Costa Rica, Postal Code 2410-2050, San Pedro de Montes de Oca, San José, Costa Rica; fax: (506) 225-2374/(506) 225-5440; telephone: (506) 207-5440/(506) 207-4389; e-mail: iholst@cariari.ucr.ac.cr
IICosta Rican Institute for Research and Education on Nutrition and Health, Tres Ríos, Cartago, Costa Rica
IIIHealth Office, University of Costa Rica, San Pedro de Montes de Oca, San José, Costa Rica
ABSTRACT
OBJECTIVE: Recent studies have shown an increase of mild serum cobalamin (vitamin B12) deficiency in some Latin American countries; however, no data are available from Costa Rica. The purpose of this work was to establish the prevalence of serum vitamin B12 deficiency among Costa Rican young adults and to study some factors that may help explain the serum cobalamin concentrations.
METHODS: A cross-sectional survey was conducted among 400 adults aged 20 to 40 years old from urban and rural areas of the central valley of Costa Rica to determine serum vitamin B12 levels. Additionally, cobalamin dietary intake and the detection of Helicobacter pylori IgG antibodies were studied as possible determinants of the serum vitamin B12 concentrations.
RESULTS: The mean serum concentration of vitamin B12 was 268 ± 125 pmol/L, and no significant differences were found by gender or area. Study data indicate an overall prevalence of inadequate serum cobalamin levels of 42.4% (11.2% deficient and 31.2% marginal); more than 50% but less than 75% of individuals had an intake of vitamin B12 below the U.S. Estimated Average Requirement (EAR) and 61.2% had IgG antibodies to H. pylori.
CONCLUSIONS: The prevalence of mild serum vitamin B12 deficiency in young Costa Rican subjects is as high as in other Latin American countries. More investigation should be done to elucidate the etiological factors that are generating deficient and marginal serum cobalamin levels in Costa Rican adults in order to define appropriate public health actions.
Key words: Vitamin B 12 deficiency, Helicobacter pylori, Costa Rica.
RESUMEN
OBJETIVO: Aunque estudios recientes han demostrado un incremento en el déficit moderado de cobalamina (vitamina B12) sérica en algunos países de América Latina, no hay datos de Costa Rica. El propósito de este trabajo fue determinar la prevalencia de la deficiencia de vitamina B12 sérica en jóvenes adultos de Costa Rica y estudiar algunos factores que pueden ayudar a explicar las concentraciones séricas de cobalamina.
MÉTODOS: Se realizó un estudio transversal para determinar los niveles de vitamina B12 en el suero de 400 adultos de 20 a 40 años de edad de zonas urbanas y rurales del valle central de Costa Rica. Adicionalmente, se estudió la ingesta de cobalamina en la dieta y la presencia de anticuerpos IgG contra Helicobacter pylori, como posibles factores determinantes de las concentraciones séricas de vitamina B12.
RESULTADOS: La concentración media de vitamina B12 en el suero fue de 268 ± 125 pmol/L; no se encontraron diferencias significativas entre los sexos ni entre las áreas de residencia. Estos datos demostraron una prevalencia general de niveles insuficientes de cobalamina sérica de 42,4% (11,2% con déficit y 31,2% con concentraciones marginales); de las personas estudiadas más de 50% -aunque menos de 75%- tenían una ingesta de vitamina B12 por debajo del valor de las necesidades promedio estimadas para los Estados Unidos de América y 61,2% tenía anticuerpos contra H. pylori.
CONCLUSIONES: La prevalencia de deficiencia moderada de vitamina B12 sérica en jóvenes costarricenses es tan elevada como en otros países latinoamericanos. Se necesitan más investigaciones para aclarar los factores etiológicos que producen niveles insuficientes y marginales de cobalamina sérica en los adultos de Costa Rica para poder definir intervenciones sanitarias apropiadas.
Key words: Deficiencia de vitamina B12, Helicobacter pylori, Costa Rica.
Vitamin B12 or cobalamin deficiency has been identified frequently in older people and vegetarians (1–3). Nevertheless, recent studies in Latin America have shown a high prevalence of mild serum vitamin B12 deficiency in younger, omnivorous subjects (4, 5). In 1995, a Cuban study reported a prevalence of deficient serum vitamin B12 values ranging from 52 to 82% and marginal values ranging from 13 to 36%, respectively, among a healthy population of middle-aged men (5). In another study, about 45% of fer- tile women in a rural Mexican community were identified with deficient and marginal serum vitamin B12 concentrations (4). In Costa Rica, cobalamin status has not been assessed among the middle-aged population.
Low concentrations of vitamin B12 have been associated with megaloblastic anemia (3), neuropsychiatric manifestations (6), and hyperhomocysteinemia, an important cardiovascular risk factor (7).
Cobalamin deficiency has been attributed to low vitamin B12 intake or protein-bound vitamin B12 malabsorption syndromes (8). The low intake of foods with a high content of animal protein-main dietary sources of vitamin B12-markedly limits the intake of this micronutrient (9, 10), particularly in developing countries where availability of these products is low and their cost is high.
In several studies, food-cobalamin malabsorption (FCM) has been associated with atrophic gastritis induced by a bacterium known as Helicobacter pylori (11, 12). Lack of or inadequate secretion of intrinsic factor (due to pernicious anemia), gastric acid, and pepsin, which are needed to release and absorb protein-bound cobalamin in food, can cause vitamin B12 malabsorption (13). Likewise, hypochlorhydria and bacterial overgrowth in the mucosa can play an important role in the malabsorption process (8, 12). Moderate and high alcohol consumption has also been associated with vitamin B12 deficiency (14, 15).
The purpose of this study was to determine the prevalence of serum cobalamin deficiency among Costa Rican young adults and to examine whether dietary intake of vitamin B12 and the presence of H. pylori help to explain serum vitamin B12 concentrations.
MATERIALS AND METHODS
Study population
A total of 400 adults from the central valley of Costa Rica, aged 20 to 40 years, were recruited for this study. Subjects were asked to participate through a written circular sent home with about 700 randomly selected boys and girls from 20 representative rural and urban schools. A total of 490 adults offered to collaborate, but only 400 of them fulfilled all the requirements for participation in the study. Inclusion criteria included being of Costa Rican nationality and being between 20 and 40 years old. Exclusion criteria included conditions such as vegetarianism, alcoholism, gastrointestinal disorders, and chronic diarrhea. Also excluded were people taking vitamin supplements.
Ethical procedures
Written, informed consent was obtained from all participants. The study protocol was approved by the Ethics Committees of the Costa Rican Institute for Research and Education on Nutrition and Health (INCIENSA) and the University of Costa Rica.
Socio-demographic and dietary variables
Information about age, gender, area, economic level, and vitamin consumption were collected through validated instruments. Madrigal's method was used to establish the socioeconomic status of study participants based on their possession of various material goods and comforts in their homes (16). Dietary intake of vitamin B12 was determined through the use of semi-quantitative 24-hour recall questionnaires. A series of photographs of food commonly consumed in Costa Rica and three-dimensional (3-D) food models were used to estimate portion size. The Food Processor‚ for Windows version 6.0 (ESHA Research, Salem, Oregon, USA) was used to perform nutrient calculations from dietary data (17). A comparison with the U.S. Estimated Average Requirement (EAR) for vitamin B12 was made to evaluate micronutrient intake, and the recommended dietary allowance of 2.4 µg for vitamin B12 was considered. The EAR cut-point method (counting the number of individuals with normal intake below fixed EAR-based cut-off points) was used to assess the prevalence of inadequate intake of the vitamin (18).
Biochemical variables
Blood was drawn after 8–12 hours of fasting by antecubital venipuncture according to the procedures of the Clinical and Laboratory Standards Institute (CLSI; formerly the National Committee for Clinical Laboratory Standards or NCCLS) (19) and collected into a plain tube for serum vitamin B12 and immunological analyses. Serum was separated immediately from the blood cells and stored at –20°C until the tests were performed.
Vitamin B12 serum concentration was determined with a commercial immunoassay using the Abbott IMx® System (Abbott Laboratories Diagnostics Division, Abbott Park, IL, USA), a fully automated immunoassay analyzer, and the intra-assay coefficient of variation was <6%. Internal quality control with deficient, normal, and high serum concentrations of vitamin B12 was performed to control variability in the measurements. In the cases in which the samples exceeded ± 2 standard deviations (SDs) of the average control value, the samples were analyzed again. Vitamin B12 levels were classified as deficient (<150 pmol/L), marginal (150–221 pmol/L), and adequate (>222 pmol/L) according to the recommendations of the U.S. National Academy of Sciences Institute of Medicine (20).
Qualitative detection of IgG antibodies to Helicobacter pylori was performed using a commercial enzyme-linked immunoassay (ELISA) kit (Panbio, Brisbane, Queensland, Australia). This test was limited to a sub-sample of study participants (139 individuals), however, due to its high cost. A result was considered negative when the test indicated <9 Panbio units, equivocal when between 9–11 Panbio units, and positive when >11 Panbio units (21).
Data analysis
Statistical analysis was performed using the Statistical Package for Social Sciences (SPSS), version 10.0 for Windows (SPSS Inc., Chicago, IL, USA, 1999). Continuous variables are summarized using means ± SD, and categorical variables are presented as frequency distributions. In order to study the behavior of the variables as age increases, the adult population was divided into two groups: 20–29 years and 30–40 years. Student's t-test was used to compare the means of the continuous variables and chi-square tests were used to compare categorical data. Partial Spearman correlation coefficients were calculated to determine association between variables.
RESULTS
The study sample consisted of 187 men and 213 women with a mean age of 32.5 ± 5.6 years; 76.8% of the individuals came from urban areas and 23.2% from rural areas (Table 1). The total mean serum vitamin B12 concentration of the study population was 268 ± 125 pmol/L, and no significant differences were found in the means of this micronutrient by gender, area, presence or absence of IgG antibodies for H. pylori, age group (20–29 years or 30–40 years), or socioeconomic level of the subjects (data not shown).
The overall prevalence of IgG antibodies to H. pylori in the studied population was 61.2%, with a significantly higher proportion of seropositive individuals in urban areas (48.9% vs. 12.2%, respectively; p < 0.001) (Table 1). No differences between male and female subjects were found in the prevalence of H. pylori antibodies, and the proportion of seropositive individuals in the 30–40-year age group (56 out of 85) was higher than in the 20–29-year age group (29 out of 85), although the difference was not statistically significant (p = 0.121) (data not shown). Vitamin B12 average intake was higher than 50% but lower than 75% of the EAR for this micronutrient.
More than 42% (42.4%) of the study participants presented either deficient (11.2%) or marginal levels (31.2%) of serum vitamin B12 (Table 2). The proportion of adults >30 years old with marginal concentrations of vitamin B12 was significantly higher than the proportion of subjects <30 years old (35.9% vs. 24.5%, respectively; p = 0.021) (data not shown). Likewise, the proportion of adults with deficient levels of vitamin B12 with a low socioeconomic profile was significantly higher than the proportion of individuals with deficient vitamin B12 concentrations and a high socioeconomic condition (14.8% vs. 3.9%; p = 0.028). Weak associations were found between the presence of IgG antibodies for H. pylori and the age group (r = 0.122) and area (r = 0.110) of the subjects. Likewise, vitamin B12 concentrations levels correlated weakly with study participants' socioeconomic level (r = 0.114).
DISCUSSION
For decades, it has been assumed that vitamin B12 deficiency is unlikely to occur except under special circumstances, such as the presence of pernicious anemia, vegetarianism, malabsorption syndromes, bacterial overgrowth, and other clinical conditions in which the function of the ileum is impaired (2, 3). It has also been established that vitamin B12 deficiency is common among the elderly, even in industrialized countries. Nevertheless, reports of cobalamin deficiency status in Latin American children and young adults have been increasing over the past decade (5, 22, 23), and Allen (24) has recently shown that at least 40% of individuals in the Americas had deficient or marginal levels of serum vitamin B12.
This is the first report indicating deficient serum vitamin B12 concentrations among Costa Ricans. Report results suggest a significant problem, with almost 43% of the population presenting marginal or deficient serum levels of cobalamin (< 221 pmol/L). Given that the study participants were young and apparently healthy, this level of vitamin B12 deficiency, which is common among the elderly (largely due to gastric atrophy), is striking. A significantly higher proportion of individuals with marginal levels of vitamin B12 was observed in the older age group (30–40-year), clearly suggesting that this deficiency becomes worse as age increases. Study data also suggest that the assumption of low prevalence of vitamin B12 deficiency among young adults need to be re-examined, particularly because vitamin B12 deficiency has been associated with increased risk of cardiovascular disease and serious neurological manifestations, including the development of Alzheimer's disease and dementia (25).
Unlike Costa Rica and other Latin American countries (24), which have a prevalence of deficient and marginal levels of vitamin B12 of more than 40%, developed countries such as United States have a prevalence of less than 3% (26).
Vitamin B12 deficiency can occur in individuals with dietary patterns that exclude animal or fortified foods, and in adults who are unable to absorb vitamin B12 from food (8). In developing countries, low serum vitamin B12 concentrations, could be a consequence of reduced consumption of animal protein due to its high cost. Vitamin B12 is provided in foods of animal origin, including dairy products and eggs, and is not a normal component of plant-based foods.
In several Latin American countries the diet is characterized by a predominance of vegetables, so intake of dietary vitamin B12 is quite low (9, 10). According to the Food and Agricultural Organization of the United Nations (FAO), per capita intake of animal products in developing countries constitutes less than one-third of the registered intake in industrialized countries (27).
Although this study found no significant correlation between serum vitamin B12 concentrations and socioeconomic level, a higher prevalence of young adults with deficient levels of cobalamin was observed in those from low socioeconomic levels versus those with a higher socioeconomic condition.
H. pylori infection has also been associated with FCM (food-cobalamin malabsorption), in some studies (11, 12, 28), but not in others (29, 30). H. pylori infection induces a reduction in the production of gastric acid and thus limits the release of vitamin B12 from the chymus (31).
The presence of H. pylori IgG antibodies in serum is highly indicative of H. pylori infection (8) and can therefore be used as a non-invasive means of screening large groups of people. Although, in this study, the prevalence of H. pylori antibodies was high (61.2%), an association could not be ascertained between the presence of this bacterium and deficient or marginal levels of serum vitamin B12. This situation is consistent with the one reported by Van Asselt et al. (8), who determined that H. pylori infection was related to atrophic gastritis but could not determine an association between the infection and mild vitamin B12 deficiency. However, Carmel et al. (28) found the presence of IgG antibodies to H. pylori in 75% of patients with severe FCM, and Serin et al. (32) provided strong evidence of association between H. pylori infection and vitamin B12 deficiency, even in patients with minimal or no gastric atrophy.
This study could not find an association between the presence of the bacteria and age, probably because the study population was too young (mean age: 32.5 years). It is well known that the prevalence of both H. pylori antibodies and serum cobalamin deficiency increases with age (8).
The etiology of mild vitamin B12 deficiency in young Costa Rican subjects is unclear, and its clinical manifestations could be misdiagnosed if accompanied by high intake of folic acid. Several studies have shown that folic acid deficiency is not a nutritional problem in the adult Costa Rican population (33), probably due to the ongoing policy of fortifying several foods with synthetic folic acid established by the Costa Rican Ministry of Health in 1997. Although high folic acid intake in the presence of vitamin B12 deficiency can delay the clinical diagnosis of vitamin B12 deficiency–induced megaloblastic anemia, it does not affect the irreversible progression of neurological dysfunction and cognitive decline that results from cobalamin deficiency (6).
More investigation should be done to elucidate the etiological factors that are generating deficient and marginal levels of serum vitamin B12 among Costa Rican young adults in order to define appropriate public health actions. Synthetic cobalamin food fortification could be a key strategy for public health in Costa Rica as well as other countries in the Americas where food is fortified with folic acid and vitamin B12 deficiency is suspected to be common. The Pan American Health Organization has indicated that the daily intake of 1 µg of synthetic vitamin B12 from fortified foods is a reliable way to optimize the status of this vitamin in the Americas (34).
The results of this study regarding intake of vitamin B12 should be interpreted with caution, as in some cases the 24-hour recall questionnaire may have only been applied once among the adult population (as opposed to the three-time intervention considered necessary for adequate evaluation nutrient intake). Taking this limitation into account, it should be noted that a higher prevalence of adults with deficient concentrations of cobalamin was observed at low socioeconomic levels versus higher socioeconomic levels.
The results of this research indicated a high prevalence of deficient and marginal levels of serum vitamin B12 among Costa Rican young adults. However, no significant association was found among the presence of H. pylori, dietary intake of vitamin B12, and serum levels of cobalamin.
Acknowledgements. The authors are grateful to Minor Soto Carranza and Roberto Chaves Vega for their help with blood sample collection. This work was supported by grants from three sources at the University of Costa Rica: (1) Office of Postgraduate Studies, (2) Office of Vice-president for Research (Project 807-A2-308), and (3) Fundación de la Universidad de Costa Rica para la Investigación (Project 217).
ate mais , boa sorte aos brasileiros nessa eleição e um abraço a todos e na proxima iremos falar sobre a vitamina c , ate a proxima !
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