By Jack Challem
Copyright © 1998 by Jack Challem, The Nutrition Reporter
All rights reserved.
Researchers have long known that natural vitamin E, milligram for milligram, is about 36 percent more potent than the synthetic form of the vitamin. In fact, the "international unit," or IU, standard was developed to compensate for these differences.
But two new studies using different groups of people - not laboratory animals - have found that natural vitamin E is utilized twice as efficiently as the synthetic form.
"Natural vitamin E may cost twice as much , but you get twice as much bang for your buck," Graham W. Burton, PhD, told The Nutrition Reporter. Burton, a researcher at the National Research Council of Canada, Ottawa, directed one of the studies.
In the study, Burton and his American colleagues gave five healthy men and women a single 30 mg dose of vitamin E, which was half natural and half synthetic. A month later, the same people took an identical vitamin E supplement for eight days.
Another five subjects took a single 300 mg dose of vitamin E, which was also half natural and half synthetic. A month later, they took an identical vitamin E supplement for eight days.
By biochemically labeling the natural and synthetic vitamin E supplements, Burton and his colleagues were able to tell them apart and to also distinguish dietary vitamin E.
While natural and synthetic vitamin E were absorbed equally well through the digestive tract, the liver selected for the natural form over the synthetic: blood levels of natural vitamin E were consistently twice those of the synthetic form.
"What we found was that blood and organ levels of natural vitamin E were almost double those of synthetic vitamin E, and they were consistently so," Burton explained. "The beauty of this study design is that each participant served as both a control and experimental subject."
A similar trend was found in the blood of 22 surgical patients given the half-natural, half-synthetic vitamin E supplements for up to six weeks and in two terminally ill patients given the supplements for one to two years.
Tissue levels of natural vitamin E - based of organs removed during surgery - also increased compared with the synthetic. However, it appeared to take at least a year or two for the 2:1 natural-to-synthetic ratio to develop in tissues.
In the other study, Robert V. Acuff, MD, of East Tennessee State University, Johnson City, gave vitamin E supplements - again, half natural and half synthetic - to 15 pregnant women five days before giving birth. At delivery, natural vitamin E levels in the mothers' blood were consistently double those of the synthetic vitamin. Furthermore, natural vitamin E levels in the placental cords was almost 3.5 times higher than the synthetic form.
References: Burton GW, Traber MG, Acuff RV, et al., "Human plasma and tissue a-tocopherol concentrations in response to supplementation with deuterated natural and synthetic vitamin E," American Journal of Clinical Nutrition, 1998;67:669-684. Acuff RV, Dunsworth RG, Webb LW, et al., "Transport of dueterium-labeled tocopherols during pregnancy," American Journal of Clinical Nutrition, 1998;67:459-464.
This article originally appeared in The Nutrition Reporter newsletter. The information provided by Jack Challem and The Nutrition Reporter