The Dilemma of Vitamins and Herbal Supplements
By Dr. Kevin O'Neil
We all get bombarded daily with newspaper, magazine, radio, television, and Internet advertising for numerous vitamins, minerals, herbs, and nutritional supplements. In recent months, we have learned that saw palmetto performed no better than placebo for prostate symptoms and glucosamine did not fare any better than a placebo in relieving the pain of knee arthritis.
Does this mean these products did nothing? No—it means only that they did no better than placebo. So, if you are confused by the potential benefits and risks of vitamins and herbal supplements being promoted then you are certainly not alone.
For example, at one time, most physicians as well as the public thought vitamin E helped prevent heart disease. For years, many people erroneously thought vitamin C and Echinacea could prevent or treat the common cold. Most of us welcome simple measures that can help prevent common diseases, but we don’t want to spend our hard-earned money on remedies of questionable or unproven value.
Yet, the market for vitamins and nutritional supplements has become a multi-billion dollar industry, and often the “proof” is really nothing more than an opinion or someone’s “story” of how they thought the supplement helped.
In recent years, excitement was generated about a possible role of homocsyteine in causing strokes and heart attacks. Much experimental and clinical evidence points to the fact that homocysteine contributes to blockages in blood vessels (atherosclerosis). Scientists also learned that vitamin B6, vitamin B12, and folic acid in combination could lower homocysteine levels.
Therefore, it was logically assumed that lowering homocysteine levels with these vitamin supplements would lower the risk of heart attacks and strokes. Many doctors prescribed these supplements to their patients in order to give them the benefit of the doubt. After all, it was thought that anything that could be done to lower the risk of two very common and disabling conditions was the right thing to do.
Clinical research, however, often holds surprises. In the April issue, The New England Journal of Medicine published the results of two studies, the Norwegian Vitamin (NORVIT) trial and the Heart Outcomes Prevention Evaluation (HOPE) 2 trial, which demonstrate that supplementation with B vitamins and folic acid provided no benefit with regard to reduction of heart attacks and strokes.
In the Hope 2 trial, patients with known heart disease or diabetes, which is often associated with heart disease, were given vitamins or a placebo for five years. The group taking the vitamins had no significant difference in the incidence of heart attacks and strokes than the placebo group, despite the fact that homocysteine levels declined in the vitamin group.
In the NORVIT study, patients were given vitamins or placebo within a week of a heart attack and then followed for an average of three years. Although the group receiving the vitamins again had a reduction in their homocysteine levels, there was no reduction in the incidence of repeat heart attacks, stroke, or deaths from heart disease compared to the placebo group.
What can we learn from this? That we cannot jump to conclusions. Many of us think because these supplements are available over-the-counter that they must be harmless. But, one obvious conclusion is that we shouldn’t jump to use vitamins and supplements until they have been rigorously evaluated in well-designed clinical trials. Many adverse interactions have been reported between supplements and prescription medications.
In fact, a significant risk of post-surgical complications has been attributed to taking supplements that caused bleeding, heart rhythm disturbances, or other adverse events. Always make sure your doctor is aware of everything you are taking including non-prescription items. Bring a list or, better yet, bring all your medicines and over-the-counter vitamins and herbal supplements to your appointment so your doctor can review everything you are taking to ensure there are no interaction problems.
As for homocysteine, until more research suggests that vitamin supplements to lower homocysteine have any benefit whatsoever (and do not actually cause harm!), it is best to bypass it on the drugstore shelf.
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