Recently I have heard a lot about ZMA, the nutritional supplement. Can you give me any guidance as to how you feel about its effectiveness? —Olan, West Hollywood, Calif.

ZMA is a combination of two essential dietary minerals (zinc and magnesium) and vitamin B6. Some sources indicate that zinc and magnesium are sometimes "not adequately supplied through normal dietary consumption" thus warranting its use. The zinc in ZMA is in the chemical form of zinc methionine and aspartate; and the magnesium in ZMA is in the aspartate form.

While you may have heard of ZMA as a popular new supplement that claims to increase anabolic hormones and strength in athletes, there is no scientific evidence for any claim that ZMA has any effects beyond those of taking equivalent amounts of zinc, magnesium and vitamin B6 in any other form.

Very few nutritional supplements undergo the strict double-blind placebo testing which can demonstrate (or negate) its true effectiveness in the field. Unlike many gyms and trainers, I specifically do not carry supplements in my studios because I feel it is important to maintain my objectivity about them. That's why, when I recommend a product, I do so without any financial tie to the supplement company or product. I feel I owe this to you, my clients and readers, as a fitness professional.

Therefore, I do not recommend use of ZMA at this time.