Dietary supplement can cause trouble

Dear doctors: I have a friend, about 57 years old and in good health, who takes a lot of supplements, including yohimbine, horny goat weed, DHEA, vitamin E and amino acids.

My question is, What will this do to his body?

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One of the most frequent questions doctors get asked is about dietary supplements. People who believe in them say that supplements make them feel better and they're passionate about them.

I research what has been published in quality journals to try to shed some light on whether those supplements are truly effective. Although there is much more good-quality research than there used to be, often there isn't enough to make a judgment.

We'd like to make three important points about supplements.

First, anytime you take a medicine, there is a possibility that the medicine can improve the condition it is being taken for due to the placebo effect. That means that, as an individual, you can't ever tell whether a medicine is making you feel better due to its effect on your body or its effect on your mind.

Placebo effects always are taken into account in studies on pharmacologic medicines, and the Food and Drug Administration demands that a medicine be proven more effective than a placebo. Supplements seldom are subject to this same kind of study.

Second, supplements are not regulated. Nobody besides the manufacturer is saying that what is supposed to be in the bottle is in the bottle. Studies have shown that, after chemical analysis, many supplements contain none of the active ingredient they were supposed to contain. Some manufacturers are meticulous about quality; others are less scrupulous.

The FDA doesn't allow supplements to be promoted for a specific disease or condition, but manufacturers use language to get around this while making it clear what they want you to take it for.

Third, supplements, like all medicines, have side effects, and may have unknown effects when taken in combination with each other and with prescription medications.

A colleague of mine had a patient with catastrophic liver failure after taking supplements of echinacea and goldenseal, two of the better-known herbal medications that usually are considered to be safe.

Many supplements are touted as "natural." Just because something is natural does not mean it is safe for everybody.

If you are taking supplements, it's very important to make sure whoever is prescribing any medications for you knows what you are taking. In the case presented by the writer above, there were 11 supplements. The likelihood of a significant interaction just among them, let alone with any prescriptions taken, is very high.

A study published in 2012 suggested that, with the exception of vitamin D (which showed some benefit), vitamin supplementation either failed to help or seemed to cause harm for those taking them.

The study had some flaws, but it certainly made me less likely to recommend vitamins, at least for people who get good amounts of vitamins from their diet, meaning people who get the recommended amounts of fruits and vegetables.

My last comment is that yohimbine, at least, certainly has the potential for serious side effects.

I certainly have seen both elevated blood pressure and insomnia from this substance, which typically is used to treat erectile dysfunction in men.

Drs. Donohue and Roach regret that they are unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may write the doctors at P.O. Box 536475, Orlando, Florida, U.S.A. 32853-6475.

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