Vitamin E from supplements has good bioavailability

VERIS
5325 South Ninth Avenue
La Grange, IL 60525
E-mail: slandvik{at}aol.com

Dear Sir:

The results of a study published in the January 2004 issue of the Journal suggest that synthetic vitamin E in capsules is less bioavailable than is synthetic vitamin E in fortified cereal (1). As the manager of VERIS, a nonprofit information service on vitamin E and other antioxidants, I had the opportunity to review the results of numerous studies on vitamin E for >15 y. Several of these studies have shown benefits of supplemental vitamin E in amounts higher than are regularly consumed in the diet. The results have been somewhat variable, however, most likely due to differences in the dosages and forms of the vitamin E supplements evaluated. For example, research suggests that the bioavailability of natural-source vitamin E is approximately twice that of synthetic vitamin E (2–4).

Although it is recommended that vitamin E supplements be taken with a meal containing fat (because dietary fat generally promotes vitamin E absorption), no fat was provided with the vitamin E supplements in the study by Leonard et al. In addition, the physical form of the vitamin E added to the cereal differed from the vitamin E capsules used in the study. In contrast with the results of this study, the results of other published studies have shown a high bioavailability of vitamin E from capsules when consumed with a meal providing adequate fat (2, 5)

Fortification of foods with vitamin E is of course a means of significantly increasing vitamin E intake, and the results of the study by Leonard et al suggest that formulation characteristics can affect the absorption of fat-soluble nutrients. Unfortunately, the study does not provide a meaningful comparison of the bioavailability of vitamin E from fortified cereal and that from capsules, because no fat was consumed with the vitamin E supplements. Further research is needed to provide a valid comparison of the bioavailability of vitamin E from fortified cereal and that from supplements consumed with fat.

REFERENCES

1. Leonard SW, Good CK, Gugger ET, Traber MG. Vitamin E bioavailability from fortified breakfast cereal is greater than that from encapsulated supplements. Am J Clin Nutr 2004;79:86–92.
2. Acuff RV, Thedford SS, Hidiroglou NN, et al. Relative bioavailability of RRR- and all-rac-alpha-tocopherol acetate in humans: studies using deuterated compounds. Am J Clin Nutr 1994;60:397–402.
3. Kiyose C, Muramatsu R, Kameyama Y, et al. Biodiscrimination of alpha-tocopherol stereoisomers in humans after oral administration. Am J Clin Nutr 1997;65:785–9.
4. Acuff RV, Dunworth RG, Webb LW, Lane JR. Transport of deuterium-labeled tocopherols during pregnancy. Am J Clin Nutr 1998;67:459–64.
5. Cheeseman KH, Holley AE, Kelly FJ, et al. Biokinetics in humans of RRR-alpha-tocopherol: the free phenol, acetate ester and succinate ester forms of vitamin E. Free Radic Biol Med 1995;19:591–8.