Effect of orange juice, folic acid, and oral contraceptives on serum folate in women taking a folate-restricted diet.

Rhode, Barbara; Cooper, Bernard A.; Farmer, Florence A.

doi:10.1080/07315724.1983.10719926

Cited by 22 publications

(8 citation statements)

References 23 publications

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“…Orange juice was chosen since it contains mainly reduced methyl derivatives of folic acid with both free (derivatives with up to three glutamic acid residues) and conjugated (four or more glutamic acid residues) forms present. It is one of the few foods in which the folate content is sufficiently high to provide almost 200 μg in one test dose, and it has been shown to be as effective as folic acid tablets in increasing serum folate levels in OC users (Rhode et al 1983).…”

Section: Discussionmentioning

confidence: 99%

Investigation of folate intake and metabolism in women who have had two pregnancies complicated by neural tube defects

Wild

Seller

Schorah

et al. 1994

BJOG

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Object To investigate folate intake and blood levels of folic acid and vitamin C in women with and without a history of two NTD‐affected pregnancies and to measure the increase in serum folate following ingestion of orange juice. Subject Sixteen women with a history of two NTD‐affected infants and 16 controls with no such history, none of whom were either pregnant or taking vitamin supplements. The orange juice loading test was carried out on eight matched pairs. Main outcome measures Dietary intake of folate was assessed by questionnaire and blood levels of folate and vitamin C were measured. Results There was no evidence of decreased intake of folate in subjects who had had two NTD‐affected pregnancies. In controls, both serum and red cell folate showed significant correlation with dietary folate, while in subjects there was no such correlation. Subjects also had smaller increases in serum folate following an oral load than controls, although the differences were not significant. Conclusion Women who have had two NTD‐affected pregnancies may have defective folate metabolism. Further investigations on short term utilisation of ingested food folates in these women are required.

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Section: Discussionmentioning

confidence: 99%

Investigation of folate intake and metabolism in women who have had two pregnancies complicated by neural tube defects

Wild

Seller

Schorah

et al. 1994

BJOG

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“…Area under the curve has also been used to compare the relative absorption of food folates with folic acid. Thus Rhode et al 175 considered that orange juice folate had over 50% bioavailability compared to folic acid when given in small daily oral doses. This contrasted with its poor bioavailability as determined by urinary excretion when given in large test doses 176…”

Section: Bioavailabilitymentioning

confidence: 99%

Folic acid and folates: the feasibility for nutritional enhancement in plant foods

Scott¹,

Rébeillé²,

Fletcher³

2000

J. Sci. Food Agric.

289

237

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In mammalian and plant cells the folates play a key role in the methylation cycle and in the DNA biosynthesis cycle (in the de novo biosynthesis of purines and pyrimidines). Deficiency of folate in the diet is likely to result in a reduction in the capacity to synthesise DNA and maintain the usual rate of cell division. This most evidently results in the production of anaemia from folate deficiency due to a reduction in the biosynthesis of cells in the bone marrow. In addition it has been shown that high levels of plasma homocysteine occur which is an important risk factor in cardiovascular disease. Furthermore it has been shown that reduced maternal folate status is associated with the progressive increase in neural tube defects in infants. There is good evidence for folate deficiency in a considerable number of the population in developed countries, even where folate supplementation of foods is practised, and for a level of intake in excess of the recommended dietary allowance. This paper reviews the principal routes of folate biosynthesis in plants and the potential for increasing the levels of natural folates through conventional plant breeding and biotechnological means. The effect of the major food preservation processes on the levels of folates in plants is also reviewed. The current information about the bioavailability of folates from plant food sources, and how this might be improved, is also summarised. The important health benefits that would arise from increasing folate intake in the diet provide a strong incentive for considering how this might be achieved. © 2000 Society of Chemical Industry

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“…These results were confirmed in later stud ies that suggested that the low pH of the intestinal contents induced by the administration of large doses of orange juice reduced folate absorption (9). Rhode et al (32) reported that the bioavailability of folate in or ange juice was equivalent to that of oral folie acid sup plements for human subjects.…”

Section: Determination By Point Interpolation Oã-the Apparent Bioavaimentioning

confidence: 99%

Determination of Folate Bioavailability with a Rat Bioassay

Abad

Gregory

1987

The Journal of Nutrition

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Variations of a recently proposed rat bioassay were examined and applied to the measurement of biologically available folate. The concentration of hepatic folate was found to be inconsistent as a response indicator, although fasting levels of plasma folate accurately reflected available dietary folate. Studies involving the control of coprophagy suggested that fecal folate significantly contributes to the folate status of the rat. Bioassays employing multiple dietary levels of dried orange juice solids or blanched cabbage without control of coprophagy were conducted to determined available folate by slope-ratio methods. The apparent bioavailability of endogenous folate in the dried orange juice and cabbage was 146 and 68%, respectively, relative to folic acid. The presence of dried orange juice solids or cabbage did not inhibit the utilization of folate pentaglutamate added to the diets. These results illustrate the usefulness and several limitations of the rat bioassay for evaluating the bioavailability of folate. However, the appropriateness of the rat as a model of human folate digestion and absorption requires further investigation.

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Effect of orange juice, folic acid, and oral contraceptives on serum folate in women taking a folate-restricted diet.

Cited by 22 publications

References 23 publications

Investigation of folate intake and metabolism in women who have had two pregnancies complicated by neural tube defects

Investigation of folate intake and metabolism in women who have had two pregnancies complicated by neural tube defects

Folic acid and folates: the feasibility for nutritional enhancement in plant foods

Determination of Folate Bioavailability with a Rat Bioassay

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