Whey protein, creatine, beta-alanine — those are the shining stars of the supplement world, the ones that get all the attention and the positive press. Yes, it could be argued that their reputation is in direct proportion to their abilities to help build mass and strength, but there are other less-lauded supplements that nonetheless are mass-boosting powerhouses. Take, for example, the lowly minerals zinc and magnesium. The research on their ability to increase muscle strength and size is nothing short of extraordinary. And, conveniently, they come bundled together in a tidy little package called ZMA. But it’s not often that you see articles extolling ZMA’s benefits. That’s about to change.
ZMA is a patented compound that includes zinc, magnesium aspartate and vitamin B-6, which enhances absorption of the two minerals. When taken together as ZMA, the minerals demonstrate fairly astounding wide-ranging performance benefits. For example, a 2000 study performed by researchers at Western Washington University in Bellingham had NCAA football players take ZMA or a placebo nightly during an eight-week spring-training program. They reported that the athletes supplementing with ZMA had a greater than 30 percent increase in both free and total testosterone levels and a roughly 4 percent increase in insulin-like growth factor-I. The placebo group, on the other hand, had a 10 percent decrease in both free and total testosterone levels and a 22 percent decrease in IGF-I. In addition to those improvements in anabolic-hormone levels, the ZMA-supplemented athletes made significantly greater gains in strength and power and reported better sleep quality.
Initially, researchers thought that the athletes might not have been getting sufficient zinc, magnesium or vitamin B-6 from their diets and that supplementing with ZMA corrected an underlying dietary deficiency. But analysis of the athletes’ diets found that they were all consuming a lot more than the recommended intake for all three micronutrients. Instead, the insane gains can likely be attributed to the fact that athletes and others who train intensely are often found to be deficient in zinc and magnesium. This was illustrated by the placebo group, in which the subjects experienced decreased blood levels of zinc and magnesium over the course of the eight-week study.
Zinc and magnesium levels come under fire nearly constantly in the body. They are excreted by the body via sweat and urine, and they’re taken up by the body to be used for recovery and protein synthesis following training. In addition, consumption of refined sugars and white-flour products (such as white bread) lower blood levels of zinc and magnesium. Foods rich in calcium (such as dairy products) inhibit absorption of zinc and magnesium by the small intestines. And copper, as well as foods rich in phytates (phosphorous compounds found in whole-grain breads, cereals and legumes) also hinder the absorption of zinc by the small intestines. Now you should start to understand why supplementing with zinc and magnesium is so critical.
Minerals for Muscle
Bolstering the ZMA study, research done individually on zinc and magnesium show benefits for building bigger and stronger muscles. A 2007 study from Selçuk University in Turkey reported that four weeks of zinc supplementation in men increased both free and total testosterone levels at rest and after exercise. The same researchers found similar results in an earlier study on competitive wrestlers. And researchers from the U.S. Department of Agriculture reported that zinc depletion decreased muscle endurance, which means that maintaining zinc levels is critical to your ability to complete more reps with a given weight. In yet another study, Brazilian researchers found that subjects given a single dose of zinc experienced a significant drop in blood cortisol levels within two hours. Blunting cortisol can be critical for muscle growth and strength gains because cortisol increases muscle breakdown and competes with testosterone, decreasing its anabolic effects.
The Western Washington University researchers who did the ZMA study discovered in an earlier study that subjects taking a magnesium supplement while following a seven-week leg-training program increased their leg strength by 20 percent more than those taking a placebo. And a study by researchers at Justus-Liebig-University in Germany revealed that taking a magnesium supplement for four weeks led to significantly lower cortisol levels in athletes at rest and after a triathalon as compared to athletes taking a placebo. Plus, because magnesium has been shown to normalize and extend stages 3 and 4 slow-wave sleep, which results in deeper sleep, it may enhance growth-hormone levels at night.
ZMA also can aid fat loss, primarily because zinc is required to maintain thyroid hormone production. Those hormones keep metabolic rate up and increase the number of calories you burn per day. Research confirms that eating a diet low in zinc causes levels of thyroid hormones to fall and resting metabolic rate to drop. One study from the University of Massachusetts, Amherst, found that subjects placed on a low-zinc diet experienced a significant drop in metabolic rate. Yet when they later took a zinc supplement for 20 days, their metabolism jumped to a level even higher than before they followed the low-zinc diet. And the Selçuk University researchers also found that four weeks of zinc supplementation increased thyroid hormone levels in male wrestlers and sedentary men.
Zinc also appears to be important for maintaining levels of the hormone leptin, which plays a role in maintaining metabolic rate and blunting hunger. In fact, one study from Andong National University in South Korea showed that zinc deficiency significantly lowered leptin levels.
Anyone who has taken a natural cold remedy knows that zinc is involved in immune function. Research confirms that the incidence of acute lower-respiratory-tract infections decreases significantly following zinc supplementation. And even if you do manage to catch a cold, research from the Cleveland Clinic has shown that subjects receiving zinc at the onset of a cold had the length and severity of their colds cut in half. The researchers speculated that zinc may block the cold virus from combining with surface proteins that trigger symptoms. Zinc has also been found to significantly reduce the duration of fever and severity of pneumonia and other serious lower-respiratory infections. This can be of major importance, especially during the cold and flu season, because missed gym time leads to lost muscle and strength.
While it’s certainly possible to buy separate zinc and magnesium supplements, taking ZMA not only is more convenient but also can be more effective. ZMA offers chelated forms of zinc and magnesium and the addition of vitamin B-6, which both serve to enhance the absorption of these minerals. And ZMA provides the precise effective dose of all three micronutrients: 30 milligrams of zinc, 450 milligrams of magnesium and 10.5 milligrams of vitamin B-6.
Take ZMA on an empty stomach (to prevent interference with uptake) and within an hour of going to bed (to take advantage of magnesium’s effects on sleep quality).