VITAMIN B12 AND FOLATE BIOAVAILABILITY FROM TWO PRENATAL MULTIVITAMIN/MULTIMINERAL SUPPLEMENTS

Earl B. Dawson; Douglas R. Evans; Maureen E. Conway; William J. McGanity

doi:10.1055/s-2000-9420

American Journal of Perinatology, Table of Contents

Am J Perinatol 2000; Volume 17(Number 04): 193-200
DOI: 10.1055/s-2000-9420

VITAMIN B12 AND FOLATE BIOAVAILABILITY FROM TWO PRENATAL MULTIVITAMIN/MULTIMINERAL SUPPLEMENTS

Earl B. Dawson¹ , Douglas R. Evans¹ , Maureen E. Conway² , William J. McGanity¹

¹Department of Obstetrics & Gynecology, The University of Texas Medical Branch at Galveston, Texas
²Wyeth-Ayerst Pharmaceuticals, Philadelphia, Pennsylvania

Abstract

ABSTRACT

In this crossover, single-blind study, the bioavailability of B₁₂ and folate, fasting and postprandially, was measured in 30 pregnant women for two prenatal multivitamin/multimineral supplements (Stuartnatal Plus^℗ and Materna^℗, Wyeth-Ayerst Pharmaceuticals, Philadelphia, PA) and a placebo. Blood samples were obtained before supplementation and at 1, 3, 6, and 8 hr after supplementation serum levels of the two vitamins were measured by radioimmunoassay. The maximum postabsorption serum level was multiplied by the total body plasma levels to obtain the total rate of body absorption. The absorption peak of both vitamins occurred at 3 hours after ingestion of a supplement. The total body absorption of the two vitamins was greater during fasting than it was postprandially. There was 30% greater B₁₂ absorption for Stuartnatal Plus (371 ± 56 vs. 285 ± 34 pmol) and 33% for Materna (315 ± 34 vs. 236 ± 4 pmol, p ≤ 0.05). Similarly, there was 117% greater folate absorption fasting for Stuartnatal Plus (163 ± 15 vs. 75 ± 15 nmol, p ≤ 0.001) and 57% greater absorption for Materna (207 ± 21 vs. 132 ± 13 nmol, p ≤ 0.01). Both vitamins were readily absorbed (within 3 hours) into the maternal hepatic portal circulation. The absorption of both vitamins was significantly less when ingested after the test meal than when fasting.

KEYWORD

Vitamin B₁₂ - folate - bioavailability

Full Text

References

REFERENCES

1 MRC Vitamin Study Research Group. Prevention of neural tube defects: results of the Medical Research Council vitamin study. Lancet . 1991; 338 131-137
2 Smithells R W, Nevin N C, Seller M J. Further experience of vitamin supplementation for prevention of neural tube defect recurrences. Lancet . 1983; 1 1027-1031
3 Czeil A E, Dudas I. Prevention of the first occurrence of neural tube defects by periconceptual vitamin supplementation. N Engl J Med . 1992; 327 1832-1835
4 Mills J L, McParttin J M, Kirke P N. Homocysteine metabolism in pregnancies complicated by neural-tube defects. Lancet . 1995; 345 149-151
5 Kirke P M, Molloy A, Daly L E. Maternal plasma folate and vitamin B₁₂ are independent risk factors for neural tube defects. Q J Med . 1983; 86 703-708
6 Scott J, Kirke P M, Molloy A, Daly L E. The role of folate in the prevention of neural tube defects. Proc Nutr Soc . 1994; 53 631-636
7 Sciver C R, Rosenderg L E. Amino Acid Metabolism and Its Disorders. Philadelphia: Saunders 1973: 53
8 Brönstrup A, Hages M, Prinz-Langenohl, Pietrzik K. Effects of folic acid and combinations of folic acid and vitamin B12 on plasma homocysteine concentrations in healthy, young women. Am J Clin Nutr . 1998; 68 1104-1110
9 Herbert V. Folate and neural tube defects. Nutr Today . 1992; 27 30-33
10 Herbert V. Folate supplements should be appropriately labeled to protect consumers. Pediatrics . 1994; 93 694-695
11 Herbert V. Vitamin B₁₂ . In: Ziegler EE, Filer LJ, eds. Present Knowledge in Nutrition 7th ed. Washington, DC: International Life Sciences Institute (ILSI) Press 1996: 191-205
12 Pfeiffer C M, Rogers L M, Bailey L B, Gregory III J F. Absorption of folate from fortified cereal-grain products and of supplemented folate consumed with or without food determined by using a dual-labeled stable-isotope protocol. Am J Clin Nutr . 1997; 66 1388-1397
13 Bhandari S D, Gregory J F. Folic acid, 5-methyl-tetrahydrofolate and 5-formyl-tetrahydrofolate exhibit equivalent intestinal absorption, metabolism and in vivo kinetics in rats. J Nutr . 1992; 122 1847-1854
14 Schuster D, Weimann H J, Muller J, Menke A, Menke G. Pharmacokinetics and relative bioavailability of iron and folic acid in healthy volunteers. Arzneimittelforschung . 1993; 43 761-766
15 Dawson E B, McGanity W J. Iron bioavailability studies in teenage pregnancy. Clin Ther . 1988; 10 429-435
16 Dawson E B, McGanity W J. Serum ferritin levels after multivitamin iron ingestion during teenage pregnancy. Clin Ther . 1989; 11 151-160
17 Dawson E B, Dawson R, Behrens J, DeVora M A, McGanity W J. The bioavailability of iron in four prenatal multivitamin/multimineral supplements. J Reprod Med . 1998; 43 133-140
18 Committee on Dietary Allowances, Food and Nutrition Board. Recommended Dietary Allowances 10th ed. Washington, DC: National Research Council, National Academy of Sciences; 1989
19 Anatomical Values for Reference Man. Elmsford, NY: Peramon Press Ltd; 1975: 229
20 Hytten F E, Leitch I. The Physiology of Human Pregnancy. Philadelphia: FA Davis; 1964
21 Metz J, Festenstein H, Welch P. Effect of folic acid and vitamin B₁₂ supplementation on tests of folate and vitamin B₁₂ nutrition in pregnancy. Am J Clin Nutr . 1965; 16 472-479
22 Hamfelt A, Tuvemo T. Pyridoxal phosphate and folic acid concentration in blood and erythrocyte aspartate amintransferase activity during pregnancy. Clin Chim Acta . 1972; 41 287-298
23 Dawson E B, McGanity W J. Protection of maternal iron stores in pregnancy. J Reprod Med . 1987; 32 478-487
24 Chanarin I, Rothman D, Ward A, Perry J. Folate status and requirement in pregnancy. Br Med J . 1985; 390-394
25 Bailey L B. Folate requirements and dietary recommendations. In: Bailey LB ed. Folate in Health and Disease. New York: Marcel Dekker, Inc 1995: 123-151
26 Coleman N. Addition of folic acid to staple foods as a selective nutrition intervention strategy. Nutr Rev . 1982; 40 225-233