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Influence of folic acid-fortified foods on folate status in a folate depletion–repletion rat model

Published online by Cambridge University Press:  09 March 2007

K. O'Leary*
Affiliation:
Nutritional Sciences, Department of Food Science and Technology, University College, Cork, Republic of Ireland
P. J. A. Sheehy
Affiliation:
Nutritional Sciences, Department of Food Science and Technology, University College, Cork, Republic of Ireland
*
*Corresponding author: Ms K. O'Leary, fax +353 21 4270244, email [email protected]
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Abstract

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An increasing number of foods fortified with varying levels of folic acid are appearing in the market place, targeted either at the general population or at specific consumer groups. Although it is assumed that the folate in these products should be highly bioavailable, there is a need to carry out studies to ascertain that this is, in fact, the case. The present study investigated the ability of selected folic acid-fortified foods (targeted at different types of consumer) to increase the folate status of folate-deficient rats. Forty-two weanling male rats (Wistar strain) were fed a folate-deficient diet containing 1 % succinyl sulfathiazole (w/w) for 28 d. Following depletion, seven rats were randomly assigned to each of five repletion diets containing folic acid, Complan®, Slim Fast®, Opti-Fuel2® or Cola Coa® calculated to provide 200 μg folate/kg of each diet. Calculations were based on folate information from the product labels. After a further 28 d, plasma, liver and kidney folate concentrations were determined by microbiological assay. Plasma homocysteine was measured by HPLC as a functional indicator of folate status. The folate content of the foods was measured by tri-enzyme extraction followed by microbiological assay. Our analyses suggest that there may be considerable inaccuracies on the part of the manufacturers in relation to the folate declarations on the product labels. Despite this, the four foods evaluated were highly effective in elevating plasma, liver and kidney folate and lowering plasma homocysteine concentrations in rats. These results lend support to the policy of food fortification with folic acid as a means of raising the folate status of the population, and in particular to the fortification of specific foods which may target areas of the population where increased folate status is most needed.

Type
Research Article
Copyright
Copyright © The Nutrition Society 2001

References

Araki, A & Sako, Y (1987) Determination of free and total homocysteine in human plasma by high-performance liquid chromatography with fluorescence detection. Journal of Chromatography 422, 4352.CrossRefGoogle ScholarPubMed
Babu, S & Lakshmaiah, N (1987) Availability of food folate by liver folate repletion in rats. Nutrition Reports International 35, 831836.Google Scholar
Boushey, CJ, Beresford, SAA, Omenn, GS & Motulsky, AG (1995) A quantitative assessment of plasma homocysteine as a risk factor for vascular disease. Journal of the American Medical Association 274, 10491057.CrossRefGoogle ScholarPubMed
Cerna, J & Kas, J (1983) New conception of folacin assay in starch or glycogen containing food samples. Nährung 27, 957964.CrossRefGoogle Scholar
Clifford, AJ, Heid, MK, Muller, HG & Bills, ND (1990) Tissue distribution and prediction of total body folate of rats. Journal of Nutrition 120, 16331639.CrossRefGoogle ScholarPubMed
Clifford, AJ, Jones, AD & Bills, ND (1990) Bioavailability of folates in selected foods incorporated into amino acid-based diets fed to rats. Journal of Nutrition 120, 16401647.CrossRefGoogle ScholarPubMed
De #Souza, S & Eitenmiller, R (1990) Effects of different enzyme treatments on extraction of total folate from various foods prior to microbiological assay and radioassay. Journal of Micronutrient Analysis 7, 3757.Google Scholar
Gregory, JF (1997) Bioavailability of folate European Journal of Clinical Nutrition 51S, 5459.Google Scholar
Keagy, PM & Oace, SM (1982) Development of a folacin bioassay in rats. Journal of Nutrition 112, 8791.CrossRefGoogle ScholarPubMed
Kloeblen, AS (1999) Folate knowledge, intake from fortified grain products and periconceptional supplementation patterns of a sample of low-income pregnant women according to the health belief model. Journal of the American Dietetic Association 99, 3338.CrossRefGoogle ScholarPubMed
Martin, CA (1999) The quantitation and bioavailability of food folate. PhD Thesis, National University of Ireland.Google Scholar
Martin, JI, Landen, WO & Soliman, AM (1990) Application of a Tri-Enzyme extraction for total folate determination in foods. Journal of the Association of Analytical Chemists 73, 805808.Google ScholarPubMed
Martinez, OB & Roe, DA (1977) Lack of effect of Norethindrone and Mestranol on folacin depletion and repletion in rats. Journal of Nutrition 120, 172177.Google Scholar
Miller, WM, Nadeau, MR, Smith, D & Selhub, J (1994) Vitamin B6 deficiency vs folate deficiency: Comparison of responses to methionine loading in rats. American Journal of Clinical Nutrition 59, 10331039.CrossRefGoogle ScholarPubMed
Miller, WM, Nadeau, MR, Smith, J, Smith, D & Selhub, J (1994) Folate-deficiency-induced-homocysteinemia in rats: Disruption of S-adenosyl methionine's co-ordinate regulation of homocysteine metabolism. Biochemical Journal 298, 415419.CrossRefGoogle Scholar
Pedersen, JC (1988) Comparison of γ-glutamyl hydrolase (conjugase; EC 3.4.22.12) and amylase treatment procedures in the microbiological assay for food folates. British Journal of Nutrition 59, 261271.CrossRefGoogle ScholarPubMed
Pfeiffer, CM, Rogers, LM & Gregory, JF (1997) Determination of folate in cereal-grain food products using Tri-enzyme Extraction and Combined Affinity and Reversed-Phase Liquid Chromatography. Journal of Agricultural and Food Chemistry 45, 407413.CrossRefGoogle Scholar
Scott, JM, Ghanta, V & Herbert, V (1974) Trouble-free microbiological serum and red cell folate assays. American Journal of Medical Technology 40, 125134.Google ScholarPubMed
Swiatlo, N, O'Connor, DL, Andrews, J & Picciano, MF (1990) Relative folate bioavailability from diets containing human, bovine and goat milk. Journal of Nutrition 120, 172177.CrossRefGoogle ScholarPubMed
Tamura, T, Mizuno, Y, Johnston, KE & Jacob, RA (1997) Food folate assay with protease, α-amylase, folate conjugase treatments. Journal of Agricultural and Food Chemistry 45, 135139.CrossRefGoogle Scholar
Walzem, RL & Clifford, AJ (1988) Folate deficiency in rats fed diets containing free amino acids or intact proteins. Journal of Nutrition 118, 10891096.CrossRefGoogle ScholarPubMed
Willett, WC (1992) Folic acid and neural tube defects: Can't we come to closure?. American Journal of Public Health 82, 666668.CrossRefGoogle ScholarPubMed
Wilson, SD & Horne, DW (1982) Use of glycerol-cryoprotected Lactobacillus casei for microbiological assay. Clinical Chemistry 28, 19982000.CrossRefGoogle ScholarPubMed
Yamada, M (1979) Folate contents in milk. Vitamins (Japan) 53, 221227.Google Scholar
Yetley, EA & Rader, JI (1996) The challenge of regulating health claims and food fortification. Journal of Nutrition 118, 1089-1096.Google Scholar