Jewish World Review March 19, 2002 / 6 Nisan, 5762
Dr. Ed Blonz
Dear J.M.: There are definite differences between synthetic and natural vitamin E, and two important factors to consider are potency and ease of absorption. First, here are some facts about vitamin E. The main vitamin E compound is tocopherol (toe-KAH-pher-awl), which comes from the Greek words tokos (offspring) and pherein (to bear). It was so named because it was first thought to be an essential factor in reproduction. There are a number of different tocopherols in nature, the four most important ones being alpha-, beta-, gamma- and delta-tocopherol. Alpha-tocopherol is the one we hear about most, because it is the form with the greatest vitamin activity in the human body. There are natural and synthetic forms of all the tocopherols. The natural versions start with a "d," as in d-alpha-tocopherol, and synthetics start with "dl," as in dl-alpha-tocopherol.
Natural vitamin E is the most potent of the vitamin E compounds on a weight basis. Vitamin E supplements, however, are not sold by weight. They are typically sold by IU, or international units, which are a measure of biological activity. This means that 200 IU of synthetic vitamin E has the same potency as 200 IU of the natural vitamin. To complicate matters, scientists have stopped using the IU and now talk about vitamin E in terms of a more precise unit of measure, the alpha-tocopherol equivalent (alpha-TE). One alpha-TE equals 1 milligram of natural d-alpha-tocopherol, which equals 1.67 IU.
Absorption is another factor to consider, and some studies have shown that natural vitamin E is more easily absorbed. The differences, however, are not significant.
A final point is that natural vitamin E supplements often contain the beta-, gamma- and delta-tocopherols along with the alpha. A study in the December 2001 American Journal of Clinical Nutrition suggests that gamma-tocopherol, the most prominent form of vitamin E in many plant seeds, has some unique beneficial qualities. And one year earlier, in the December 2000 Journal of the National Cancer Institute, a population study found that those with the highest concentrations of gamma-tocopherol had the lowest risk of developing prostate cancer.
My advice, then, is that if price and convenience are important issues, by all means buy the synthetic. If you feel that natural is the way to go, try to find a supplement that contains mixed tocopherols.
DEAR DR. BLONZ: I believe I heard at some point in my schooling that rinsing and draining canned vegetables reduces their sodium content by as much as 25 percent to 30 percent. I have searched through everything I have (old textbooks, lecture notes, etc.) and cannot find a single reference. Do you know how much the sodium content is reduced when canned vegetables are rinsed? Are you aware of any research articles on the subject? -- K.L., Jordan, Minn.
Dear J.L.: Salt, or sodium chloride, dissolves easily in water, so rinsing canned vegetables and beans will certainly reduce salt (sodium) content. As for the exact formula or percent reduction for a particular food, it depends on total sodium in the food, the amount of added salt and the volume of water exchanged. There is no specific data that I am aware of that works for all foods. A reasonable way of expressing it is to say that rinsing canned vegetables can cut sodium content by up to 40 percent. I hope this
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