Cycling Nutrition with Monique Ryan: ZMA supplement

Dear Monique,

What is the scoop on ZMA? I have been trying to find out about this relatively new supplement. Is it safe? Is it effective? Isn’t ZMA essentially a mixture of vitamin B6, zinc, and magnesium?
DR

Dear Monique,
In papers worldwide, there has been concern over THG and its relationship to the Bay Area Laboratory Cooperative (BALCO). ZMA, a product related to BALCO and SNAC Systems is on the market. Is ZMA fuel safe and untainted by illegal substances and anabolic precursors? Can you provide a breakdown of the product? Are there any benefits to taking the product?

Thanks,
KG

Dear DR and KG,

ZMA which is sold as “ZMA Fuel” provides per serving for men (3 capsules): 1 gm protein, 10.5mg B6 (pyridoxine hydrochloride), 450mg magnesium (magnesiumaspartate), 30mg zinc (zinc monomethionine and zinc aspartate). The recommended serving for women is two capsules. The product is claimed to increase anabolichormones and strength in athletes. Both zinc and magnesium play a rolein maintain optimal levels of hormones including testosterone, among their many other functions in the body.

All of the ingredients in ZMA are safe and should be fine in the doses recommended (per serving), as long as the supplement is not overdosed by an overzealous athlete in hopes of achieving a greater effect. More than 50mg of zinc daily may not be safe and can upset both copper and iron balance. Over 100mg of zinc daily can be toxic. High doses of magnesiumat 1000mg daily may cause GI upset and diarrhea. Finally more than 200mg of vitamin B6 daily is not safe and may lead to nerve pain in the extremities, or peripheral neuropathy.

Clearly, like any other nutritional supplement providing essentially vitamins and minerals, ZMA needs to be taken properly and safely. Beyond supplement overdosing, as many cyclists and triathletes are aware, there still remains a risk of supplement contamination, even from what is essentially a supplement that contains two minerals, and a vitamin. For a review of what industry-related quality assurance programs are currently in place please see my column.

Of course the policy of US Antidoping is that even inadvertent ingestion of a banned substance is doping and the athlete is liable. To date one study (with BALCOfounder and president Victor Conte as co-author), which used university level football players as subjects, has been published on ZMA. Another is reported to be scheduled for publication. Subjects received the dose for men as described above, for seven weeks. Researchers reported an increase in muscle power measurements and an improvement in the anabolic hormone profile over the non-supplemented group.

It is also interesting to note that the supplement improved the blood zinc and magnesium levels of the treated athletes. Blood levels of these nutrients were low/borderline in both groups (supplement and non-supplemented), possibly reflecting a deficient diet. Diet was also not controlled in this study. In fact, blood levels of these nutrients dropped in the non-supplemented control group over the seven-week study period. The placebo group also had increases in strength and training during the study period.

Supplementing a diet low in specific nutrients when done in safe doses is acceptable. The diet can also be corrected with good food sources of nutrients and both zinc and magnesium have been reported to be low in the“typical” US diet. Any vitamin and mineral supplement recommendations should be provided in the context of the athletes diet, current dietary supplement profile, and training program. To date, there is not adequate scientific data to indicate that ZMA has beneficial anabolic and strength effects different or greater than taking equivalent amounts of zinc, magnesium, and B6 in other forms.
Monique

https://velo.outsideonline.com/2003/12/coaches-panel/the-feed-zone-nutrition-qa-with-monique-ryan-safely-supplementing_5358