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You rely on your physicians to recommend the best therapy, but how much do they know about vitamins and nutrition?
About two hours worth is what they probably learned during medical school.
"Next to nothing," is how much Elson Haas, MD, learned about nutrition in his formal training. Haas is a physician in San Rafael, California, and the author of Staying Healthy with Nutrition, but he had to discover this field on his own.
Chances are that, like Haas, most doctors keep up on the latest studies regarding vitamin and mineral supplementation, but the background in preventive medicine through proper nutrition might not be there.
Jeffrey Blumberg, PhD, a professor of nutrition at Tufts University, is an antioxidant expert. "Physicians still are largely untrained in nutrition. It's often considered alternative medicine today, but if you go back to the 1920s, all physicians were trained in nutritional medicine, especially diabetologists. There wasn't a clinician around who didn't know how to work with their diabetic patients in dealing with diets. But, as oral hypoglycemics and insulin came around, they abandoned the dietary approaches. Now, I think we're coming around full circle to realize that the drugs are good, but we need to also look at diet in its many factors, everything from calories and obesity to the power of these vitamins and minerals in dealing with the condition."
Keith Campbell, RPh, CDE, professor of pharmacy at Washington State University, says, "We had about one or two hours of nutrition lectures during our training." A type 1 for 49 years, Campbell is considered a vitamin expert in the diabetes community, having studied them extensively for years.
Antioxidants, chromium, vanadium, beta carotene and many others are popping up in the news as good things that people with diabetes should be loading up on. But, how much is too much? Will they really help? Those who have studied vitamin supplementation say yes.
Vitamin supplementation can help you fight free radicals that cause complications, help your insulin function and help lower your blood sugar levels, but supplementation must be done safely.
Diabetes: A "Free Radical Disease"
Antioxidant is now a household word. Every person needs them to fight the free radicals that cause destruction throughout the body, including clogging the blood vessels and leading to complications. The major antioxidant vitamins are A (also known as beta carotene), C and E.
Many studies in recent years have proven that antioxidants help prevent diabetic complications, especially neuropathy and retinopathy. Most people know what they do and why we need them, but questions remain, like how much and which ones.
Blumberg is an antioxidant expert who has been studying nutrition for 20 years. He calls diabetes a "free radical disease." People with diabetes use up their antioxidant stores more quickly, so their requirements are actually higher.
"It's not so much that your levels are depleted and you're going to get scurvy; it's that your requirements are higher than other people in order to maintain usual health. Because your disease is creating more free radicals, and free radicals use up the vitamins, therefore you need more."
How does diabetes create more free radicals? Says Blumberg, "We don't know entirely. The process of glycating, or adding glucose molecules onto proteins and lipids, makes them more susceptible to oxidation. The oxidation process itself generates free radicals. It sets off a chain reaction of oxidation. But then we have what we call chain-breaking antioxidants, like vitamin E, which gets into this chain and stops it."
For people with diabetes, Blumberg suggests 250 to 1000 milligrams of C and 100 to 400 IU of E daily. Campbell is a "big believer" in vitamin E supplementation, and takes 800 IU per day.
Niacin has many health benefits in the general population, but people with diabetes need to be more careful.
"Some of the free radical damage to DNA and mitochondria also deprives cells of niacin, so increasing niacin intakes might be worthwhile," says Blumberg.
Campbell says niacin in high doses has been proven to reduce cholesterol levels, but it can also increase glucose levels. To avoid elevated BGs, Campbell recommends sticking pretty close to the RDA of 20 milligrams.
Haas recommends selenium supplements for diabetes. A study performed in France, published in the April 1998 Lipids, gave selenium and vitamin E supplements to diabetic rats. The study concludes that both substances "could play a role in controlling oxidative status and altered lipid metabolism in the liver."
The recommended daily Selenium dose for people with diabetes given by K. P. Khalsa, a natural healing specialist from Seattle, is 400 micrograms.
What about other antioxidants, like grapeseed extract, milk thistle or Pycnogenol? Is it better to take another antioxidant than vitamins A, C and E?
"If you said, 'I'm a diabetic and I'm taking Pycnogenol,' I wouldn't say, 'That's the stupidest thing I've ever heard,'" answers Blumberg. "There's a plausible reason for doing that. I just don't know of any evidence. I am not aware of any studies that have been done with those compounds in people with diabetes. I don't think it would hurt; there's just not the clinical data."
Pycnogenol may not have been tested in people with diabetes, but studies have proven its success as an antioxidant. One study, from a 1996 Ophthalmic Research, proves that it fights lipid peroxidation in cow and pig retinas. The study states, "Lipid peroxidation is considered a prominent feature of diabetic retinopathy."
The ability of the element chromium, usually taken as chromium picolinate to improve blood sugars, is a hotly debated diabetes topic. Experts disagree on whether or not chromium decreases HbA1c levels, and both have studies to back them up.
A review of the evidence for chromium supplementation for diabetes in the January 1998 Journal of Family Practice says, "There is some evidence, including results from human studies, that it has a role in glucose homeostasis [equilibrium]." The authors then call for more studies, because of chromium's "unproven benefits and unknown risks."
Nutrition experts say the typical supplement's levels of chromium can't hurt. Campbell takes chromium picolinate supplements at a dose of 400 micrograms per day. "I have mixed feelings about chromium but I take it every day, because it's not going to do any harm."
• Alpha-lipoic acid
Recent studies give convincing evidence of alpha-lipoic acid's aid in glucose control. Haas sees alpha-lipoic acid as a very strong antioxidant in the fight against diabetes.
In a recent test on humans, alpha-lipoic acid alone "significantly" reduced fasting glucose levels in type 2s. In a study published in the February Diabetes Care, German doctors gave lean and obese type 2s 600 milligrams of alpha-lipoic acid twice per day. Although more drastic changes were noted in lean people, both groups had lower fasting glucose concentrations. The researchers believe that alpha-lipoic acid works through lowering the levels of lactate and pyruvate that are increased after people ingest carbohydrates. Lactate and pyruvate are products of the digestive process that can lead to damage like lactic acidosis.
Many other studies have led to similar conclusions of alpha-lipoic acid's beneficial effects on BGs. ABC news did a television story on its power as an antioxidant, and an entire book has been written about it.
"Lipoic Acid in Health and Disease" is edited by Jurgen Fuchs, MD, PhD, and Guido Zimmer, MD, PhD, of Johann Wolfgang Goethe University in Frankfurt, Germany, and Lester Packer, PhD, of the University of California, Berkeley. The book contains numerous studies with evidence that alpha-lipoic acid fights insulin resistance and neuropathy.
Natural Health magazine, in its "Consumer Guide to Vitamins & Minerals," in the July-August 1998 issue, sees 100 to 600 milligrams as a helpful amount of alpha-lipoic acid for people with diabetes.
• Gamma-linolenic acid (Evening Primrose Oil)
Gamma-linolenic acid has been shown to improve nerves that have been damaged from diabetes. Its natural sources are evening primrose oil and borage oil. Recent years have seen the testing of both alpha-lipoic acid and gamma-linolenic acid in combination for diabetes treatment.
Researchers from the University of Aberdeen found promise for future studies of gamma-linolenic acid and alpha-lipoic acid in humans. In the April 1998 Diabetologia, researchers tested the effects of alpha-lipoic acid, gamma-linolenic acid and other essential fatty acid ingestion on the nerve function of diabetic rats. The conclusion was that the combination improved the rats' nerve function and is "worthy of consideration for clinical trials."
A few months later, another study confirmed this evidence. The July Diabetologia told of a British study, also of alpha-lipoic acid and gamma-linolenic acid on diabetic rats. The final word was the combination "is effective in improving both electrophysiological and neurochemical" aspects of experimental neuropathy.
Natural Health recommends 200 to 500 milligrams per day of gamma-linolenic acid for people with diabetes.
Insulin Action Supplements
Vanadium, usually taken in the form vanadyl sulfate, is another contested substance. Some lofty claims have been made about its effects of lowering insulin requirements and even preserving beta cell function, but others say side effects are harmful.
Vanadium has been studied throughout the 1990s. In 1996 the Albert Einstein College of Medicine in the Bronx, published in the May 1996 Diabetes, reported that vanadyl sulfate improved type 2s' insulin sensitivity.
As time went on, studies either verified or disputed this conclusion. One said it has no effect in type 1s (December 1998 Diabetes Care). Another demonstrated that in diabetic rats it "restored elevated blood glucose to normal."
John Walsh, PA, CDE, coauthor of "Stop the Rollercoaster," wants more long-term, human studies done, because vanadyl sulfate in high doses has also shown toxic side effects in animals, including kidney damage and oxidation of fats, leading to cardiovascular disease.
Walsh concludes, "Vanadium or one of its derivatives may someday help improve blood sugar..." but "too many unknowns surround this mineral today."
Scientists are working on different formulations of vanadium besides vanadyl sulfate for dietary supplementation. Natural Health magazine says 5 to 25 milligrams per day is a safe amount.
Other Supplements Linked to Diabetes Care
• Folic Acid
Brought to the limelight by its ability to reduce birth defects, folic acid also has been attributed to helping with vascular disease in people with diabetes.
Folic acid is said to act upon homocysteine levels in the body. Homocysteine is a substance normally metabolized into amino acids by the body but in high levels it can cause vascular problems and heart disease. Two groups are known to have problems metabolizing homocysteine: people with a rare genetic problem that causes early heart attacks and people with diabetes.
B vitamins, including folic acid, are known to counter the bad effects of high homocysteine levels, and folic acid has also been named as a homocysteine fighter. A Scandinavian journal, in 1997, reported that homocysteine concentrations in type 1 people "may at least partly be explained by a marginal deficiency of blood folate concentrations."
High homocysteine levels have been established as indicative of risk for cardiovascular disease in the general population but doctors need studies to see how homocysteine is relevant in diabetes.
In the June 1998 Diabetologia, a group of doctors in Barcelona explains its study of homocysteine and diabetes. "A high plasma homocysteine concentration is an independent risk factor for cardiovascular disease but information on its association with diabetes is limited," they begin. They also note that people with nephropathy, or kidney disease, have a particular tendency to cardiovascular disease.
To see if high homocysteine levels are a cardiovascular danger in people with diabetes as they are in the general population, the study looked at fasting homocysteine concentrations in type 1s, type 2s and people without diabetes. They found that 80 percent of the diabetic people with nephropathy had high homocysteine levels. The authors conclude that, particularly in type 2 diabetes, there is "a new link between microalbuminuria, diabetic nephropathy and kidney disease."
The November 1998 Diabetes Care found little evidence of homocysteine causing vascular disease in type 1s, so right now the evidence says lowering homocysteine is more crucial in people with type 2 diabetes.
Campbell takes 800 micrograms of folic acid per day, and believes that even 1600 micrograms is a safe level. He does caution that extreme doses of folic acid can mask symptoms of anemia, although this happens very rarely.
• Omega-3 Fatty Acids
Found in fish, flaxseed and canola oil, omega-3 fatty acids have been found to lower triglyceride levels, but the final word on their effect on glucose control still eludes researchers.
The latest word from Diabetes Care is that omega-3 fatty acids do help with triglycerides and don't alter glucose levels in the process. A study in the May 1998 issue reports that 6 grams of fish oil per day lowered triglycerides in type 2 men and had no effect on fasting glucose or HbA1c levels.
Three to five grams per day, in fish or flaxseed oil supplements, aid in diabetes management, according to Natural Health's consumer guide.
"The diet of many people with diabetes does not have a lot of magnesium," says Campbell. Nuts and shrimp have large magnesium amounts. Magnesium deficiency is a problem in diabetes, Campbell adds, contributing to complications, hypertension and heart disease.
Many people are unaware of a magnesium deficiency, according to Campbell. Often it is missed at the doctor's office.
"The magnesium amount looks okay in the cells, but it is the body stores of magnesium that are deficient," which doctors don't check.
This problem, says Campbell, "is a problem that has been well documented in the scientific literature and one that can result in potentially serious consequences for the individual with diabetes.'
He recommends 800 milligrams twice per day. One side effect is runny stools, says Campbell, but he points out that people with diabetes do often suffer constipation, so this can help.
Pill Versus Food
"Diabetics are no different from other Americans in that their diet isn't as good as it ought to be," says Blumberg.
"Although I find that diabetics happen to be a little smarter about their diets-they're a little more educated than the average American-we're still faced with issues of diets that are not following the dietary guidelines of more fruits and vegetables, less fats, more fiber," says Blumberg. "This is more important for a diabetic than for others."
Some health care professionals say that if you eat a proper diet you should not need extra vitamins or minerals. Campbell disagrees, saying that even people who eat enough fruits and veggies still need supplements.
Take an apple, for example, says Campbell. "People might be eating that apple a year after it's been picked, and by then so much of the nutrients are gone."
Water can be an enemy to nutrients. Boiling vegetables leaves some of the nutrients in the water and, says Campbell, "water softeners take the magnesium out of food."
Produce in America has suffered from chemicals in farming, says Haas. In his book, The Staying Healthy Shopper's Guide, he recommends produce grown organically. He cites a 1993 study in the Journal of Applied Nutrition that concludes that organic produce has 90 percent more, almost double, the amount of nutrients than commercially grown produce.
Andrew Weil, MD, alternative health author, emphasizes the importance of eating properly. "Although I don't think you can take too many antioxidants, I do think you can take too many pills...I much prefer that people look to food rather than pills for additional antioxidant benefits."
Over-antioxidizing may not be a big deal, but people can overdose on certain vitamins and actually damage the body. How much is too much? It depends on the substance.
Folic acid has been shown to help prevent cancer, but not if the daily dose is too high. Excess vitamin D has caused loss of bone mineral density and calcium deposits in the arteries. Scientists also warn that if you have high blood pressure or take blood clotting medicine, be careful with vitamin E. More is not necessarily better.
If you're considering taking supplements, check with your doctor, or a professional who knows about vitamins, to see if any harm from excess have been reported. In addition, there are agencies to consult.
The RDA, or Recommended Dietary Allowance, you see on food labels does not apply to supplementation. The RDA is only the amount needed to avoid deficiency. The RDAs were dictated before scientists discovered that taking large amounts of some substances can prevent disease. Thus, the government now must test how much is too much.
The National Academy of Sciences' Food and Nutrition department proposed new guidelines, the Dietary Reference Intakes (DRIs) in 1997, to turn vitamin experimenters into informed consumers of preventive medicine. The DRIs, currently being developed, will tell us not only the RDA, but also the "Tolerable Upper Intake Level." This is the maximum daily level for which no study has shown any harmful effects.
The National Academy of Sciences predicts the DRIs will be published by the year 2000.
Another source for avoiding excessive intake is a book, Vitamin and Mineral Safety, published by the Council for Responsible Nutrition, which is associated with the supplement industry. This book gives the "no observed adverse effect level," for certain vitamins and minerals; it is the highest daily level at which studies have shown no damage to be reported in humans.
George Blackburn, MD, associate editor of Health News, reports in a story on vitamins that "only healthy adults should take nutrient supplements without a doctor's guidance...anyone with a disease or chronic medical condition should take supplements only under medical supervision."
But, if doctors only study two hours of nutrition in medical school, and they haven't kept up on new developments, how can we know who to trust? Nutrition experts recommend getting the old, familiar second opinion, but make sure it is from a professional who has really studied nutritional medicine.
You can buy vitamins anywhere, from national chain stores to small health specialty stores. You don't need to pay a lot to get your daily dose, says Nutrition Action Health Letter, published by the Center for Science in the Public Interest. Store brands will do the trick.
And don't pay attention to the word "natural" on the label, either, say most experts. Your body does not know if a vitamin is natural or synthetic, with the exception of vitamin E.
"There is no difference between natural and synthetic vitamin C. Not true for vitamin E," says Blumberg.
"It comes in two different stereoisomers, which are sort of the equivalent of right and left hands. Your right and left hand are the same, five fingers, a thumb, but one cannot replace the other. The end result is that the natural source is more potent."
You can see this on the label. "It will say 'd-alpha-tocopherol,' which is natural, or 'dl-alpha-tocopherol,' which is synthetic."
"The natural source is more expensive, because it's more expensive to make," Blumberg continues. "They haven't been tested head to head. We do know that the natural form is more potent, but you can always just take more of the cheaper synthetic."
Blumberg offers some other shopping hints. "Go with a brand you trust. If you don't know any, talk to your pharmacist. Also, look for products that have expiration dates, or the sign of USP, the United States Pharmacopeia."
Campbell recommends looking at double-blind, controlled studies that have been conducted in humans with diabetes, not rats. "Also, I look for vitamins that have shown to be deficient in people with diabetes or one that has shown a benefit with supplementation."
"In general, I'm a believer in daily supplementation," he summarizes, "as long as no harm has been proven."
2 comments - Apr 1, 1999