Antioxidants and Diabetes: The Latest News on Vitamins and Minerals
We live in a toxic environment. Much of what we consume is simply not good for our bodies-it builds up and eventually damages our health. Antioxidant vitamins-vitamins C and E, and beta carotene-may be what we need to "clean up" our systems.
Excess sugar in the bloodstream can have very serious side effects. The extra sugar impedes blood flow, causing wounds to heal more slowly and infections to become more virulent. Just how this excess sugar causes damage remains a topic of debate. One plausible mechanism was suggested in Time magazine by Dr. Michael Brownlee of Albert Einstein College of Medicine in New York City (November 26, 1990, p. 52-59).
Glucose is known to be chemically active and can form a temporary bond with many proteins, including hemoglobin. Over time, some of these proteins become permanently attached to the glucose and these sticky fragments aggregate to form what Brownlee calls "biological superglue". Brownlee suggests that this superglue is a "source of constant irritation" that acts like a splinter. The body reacts by thickening the walls of capillaries and arteries which constricts blood flow even more.
People with diabetes also have more oxygen free radicals in their bodies. Free radicals are harmful molecules that are believed to contribute to cataracts, microvascular problems, and neuropathy, and to advance the aging process. In the presence of free radicals, protein molecules can cross-link, or become glycosylated, which is the same action that cures meat. Beef jerky is tough, not easily penetrated by bacteria and does not decay. Obviously, these are good qualities for a food product, but not for the human body.
Antioxidants prevent rancidity and deterioration and are thought to inhibit the effects of free radicals. Vitamin E has been of particular interest to researchers.
Scientists in Italy and Belgium have shown that vitamin E will keep the "biological superglue" from forming. Extensive studies reported by Dr. A. Ceriello and other diabetes researchers (Diabetes Care, 14:1, January 1991) demonstrated "for the first time vitamin E administration in diabetic patients reduces the protein glycosylation."
Thirty insulin-requiring diabetic patients were divided into three well-matched groups. One group served as a control and took no vitamin E, one group took 600 mg of vitamin E each day and one group took 1200 mg vitamin E each day. Serum vitamin E concentrations increased in proportion to the amount taken, while blood sugar remained about the same for all three groups. After the first month, there was a significant decrease in protein glycosylation. This was shown to be dose related. There was even less biological superglue after two months, as old sticky blood cells were replaced by newly formed ones.
The mechanism of this inhibition remains uncertain. But the researchers postulate that since vitamin E is a "potent antioxidant, it may interfere with glucose oxidation."
Vitamin E has been proven effective in other studies as well. Last year Brownlee reported at the 55th Annual Meeting and Scientific Session that, "After two weeks of diabetes, aortic intracellular Advanced Glycation Endproducts (AGEs) were already increased 4.4 fold compared to non-diabetics. Treatment of diabetics with vitamin E reduced this increase by 76%, an affect that was equivalent to aminoguanadine treatment."
Aminoguanadine (also called pimagedine) is thought to be useful in preventing neuropathy and diabetes-related heart disease because it blocks the process by which AGEs become self-perpetuating. (see DIABETES HEALTH, September 1995). Clinical trials of pimagedine are currently under way and are expected to last several years. Some professionals feel that pimagedine may have unknown long term side effects.
Vitamin E, however, is easily accessible and inexpensive, and it is safe in amounts less than 800 mg per day. Vitamin E in large amounts of 1000 mg or more per day, may cause hemorrhaging, and may actually act as a pro-oxidant. Daniel J. Claes, MD, of Pacific Palisades, Calif., says, "I prescribe synthetic vitamin E because some natural sources of vitamin E contain large amounts of phytoestrogens [or plant estrogens]."
A study conducted by Hoffmann-LaRoche in Switzerland reported, "Doses as low as 200 IU of vitamin E significantly reduced platelet adhesion... In diabetic patients a decrease in the non-enzymatic glycation of proteins by vitamin E supplementation has been observed."
Thanks to chemist Marjory Beers-King, MA, for her contribution to this article.Click Here To View Or Post Comments