|Source: American Journal of Clinical Nutrition, April 1998.|
Source: American Journal of Clinical Nutrition, March 1998.
New research is confirming what some experts have argued for years: Natural vitamin E wins hands down over synthetic. Scientists have long known that natural E is more biologically active than the manufactured kind. The International Unit (IU) system of measurement supposedly takes this into account, by making 1 milligram of synthetic vitamin E equal to 1 IU, while it takes only 0.67 milligrams or 0.74 milligrams of natural E to equal 1 IU, depending on the form it’s in.
But these conversion factors were based on animal, not human, studies. For years, scientists have suspected that the currently used factors don’t accurately account for how much more potent natural E is over synthetic.
Now, two studies confirm their suspicions. In one, researchers gave 10 healthy adults and 22 elective surgery patients varying doses of a combo vitamin E supplement?half natural, half synthetic. When the researchers tested the participants? blood, they found natural E was retained twice as well as synthetic at all dosages. Another study, of 15 pregnant women, also found natural E outshone synthetic two to one.
Why the difference? Natural and synthetic vitamin E do have the same molecular formula, but they differ in their three-dimensional structure. It’s believed the body prefers natural E precisely because of its configuration. Bottom line? If you buy synthetic vitamin E, you may be getting short-changed.
What to do? Vitamin E occurs naturally as compounds called tocopherols, mostly as alpha-tocopherol. To get the most from your supplement, look for one that contains natural vitamin E (also called d-alpha tocopherol or the new designation RRR-alpha) rather than synthetic (dl-alpha tocopherol or all-rac-alpha). If you can’t find natural E, consider taking higher amounts of synthetic to make up for its poorer retention. Aim for about one-third to one-half more than what you?d take of the natural.
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