A Conspectus of Research on Vitamin A Requirements of Man

Rodríguez, M.; Irwin, M. Isabel

doi:10.1093/jn/102.7.909

Cited by 67 publications

(24 citation statements)

References 333 publications

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“…British diets, on average, provide 1,300 pg retinol equivalents/day of which approximately two-thirds is in the form of carotene [19]. The mean intake in our group of patients was very similar.…”

Section: Discussionsupporting

confidence: 50%

Relationship between Vitamin A and Bone Disease in Chronic Renal Failure

Rylance

Brown

Howells

et al. 1984

Nephron

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A study has been made of possible interrelationships between circulating vitamin A concentration and indicators of altered calcium homeostasis in 31 patients with stable chronic renal failure. Plasma retinol concentrations were high, possibly as a result of increased retinol-binding-protein concentrations secondary to renal failure. There was no correlation between retinol concentration and any other measurement, including vitamin A intake. However, there were significant correlations between plasma parathyroid hormone and calcium, phosphate, alkaline phosphatase, urea, and creatinine concentrations; and those patients with radiological sub-periosteal erosions tended to have the highest concentrations of circulating parathyroid hormone. Our data give no support to the contention that vitamin A status has any bearing on the progression and severity of the hyperparathyroid bone disease of renal failure.

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Section: Discussionsupporting

confidence: 50%

Relationship between Vitamin A and Bone Disease in Chronic Renal Failure

Rylance

Brown

Howells

et al. 1984

Nephron

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“…The absorption of ß-carotene supplements that are solubilized with emulsifiers and protected by antioxidants can be 70 percent or more. In contrast, less than 5 percent bioavailability of carotenes has been reported from raw foods such as carrots (Rodriguez and Irwin, 1972). Recently, van het Hof et al (1999) reported substantial differences between the relative bioavailabilities of ß-carotene (14 percent) compared to lutein (67 percent) when feeding a highvegetable diet (490 g of vegetables without supplements) and comparing it to a low-vegetable diet (130 g of vegetables) supplemented with ß-carotene (6 mg/day) or lutein (9 mg/day), both of which were assumed to be 100 percent bioavailable.…”

Section: Food Matrixmentioning

confidence: 98%

“…The extent of conversion of a highly bioavailable source of dietary ß-carotene to vitamin A in humans has been shown to be between 60 and 75 percent, with an additional 15 percent of the ß-carotene absorbed intact (Goodman et al, 1966). However, absorption of most carotenoids from foods is considerably lower and can be as low as 2 percent (Rodriguez and Irwin, 1972). The effects of dietary and nondietary factors on the efficiency of carotenoid absorption are reviewed later.…”

Section: Metabolism Transport and Excretionmentioning

confidence: 99%

Establishment of Dietary Reference Intakes for Dietary Antioxidants

Meyers¹

2000

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“…Outros fatores que afetam a biodisponibilidade dos compostos provitamínicos A são a forma química dos carotenóides ingeridos numa refeição, o tamanho da partícula do alimento e a presença de gordura e quantidade e tipo de fibras 4,14 .…”

Section: B I O D I S P O N I B I L I D a D E D A V I T A M I N A Aunclassified

Biodisponibilidade de vitaminas lipossolúveis

et al. 2005

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O termo biodisponibilidade representa a parte do nutriente ingerido que tem o potencial de suprir as demandas fisiológicas em tecidos alvos; por definição, não corresponde, na maioria das vezes, à quantidade ingerida. Apesar da concordância entre alguns pesquisadores no que se refere ao conceito de biodisponibilidade, vários termos são comumente utilizados em trabalhos científicos como sinônimos desse, em função das peculiaridades dos métodos empregados na sua determinação. Estudos de balanço, relação dose-efeito e uso de isótopos são alguns dos métodos mais comumente utilizados para determinar a biodisponibilidade de vitaminas. Tais metodologias, além de avaliar a biodisponibilidade do nutriente, devem tanto quanto possível procurar elucidar ou levar em consideração os fatores que interferem na sua absorção e utilização. Dentre esses fatores, estão a interação com outros nutrientes ou componentes da dieta e as condições fisiológicas dos organismos submetidos ao estudo. As vitaminas lipossolúveis, devido ao seu metabolismo complexo, diversidade funcional e mecanismo de absorção relacionado a lipoproteínas, apresentam alguns problemas específicos no que se refere à avaliação de sua biodisponibilidade em alimentos ou dietas, necessitando, por ocasião dos ensaios, de um criterioso planejamento e análise de resultados. Dessa forma, ressaltaram-se, nesta revisão, alguns aspectos importantes com relação à biodisponibilidade das vitaminas lipossolúveis, como: diversidade de termos usados, metodologia para avaliação, fatores que interferem na absorção e utilização, entre outros, visto que a avaliação da biodisponibilidade de algumas vitaminas lipossolúveis ainda não possui métodos validados, gerando uma grande variação nos resultados obtidos nas pesquisas realizadas nesta área. Termos de indexação: absorção, biodisponibilidade, vitaminas lipossolúveis. A B S T R A C TThe term bioavailability represents the part of the nutrient ingested that has the potential to supply the physiological demands of target tissues and, by definition, does not correspond to the amount ingested in the

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A Conspectus of Research on Vitamin A Requirements of Man

Cited by 67 publications

References 333 publications

Relationship between Vitamin A and Bone Disease in Chronic Renal Failure

Relationship between Vitamin A and Bone Disease in Chronic Renal Failure

Establishment of Dietary Reference Intakes for Dietary Antioxidants

Biodisponibilidade de vitaminas lipossolúveis

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