Mention the word calcium, and just about everyone thinks about bones or teeth. It’s true that the majority of calcium is stored in bones, but the small amount that circulates in the blood—about 1 percent—is vital.
Calcium is required for proper nerve transmission and muscle contraction, including that of the heart. While an outright deficiency is rare in Western societies, the long-term effects of insufficient calcium can be apparent, particularly in older women who also lack estrogen. They often suffer from osteoporosis, a thinning of bone tissue. Osteoporosis begins at about age 30 but manifests to the greatest extent when women pass menopause: The lack of estrogen that ensues following menopause compounds the problem of a long-standing lack of calcium.
Another factor contributing to the problem is failure to do weight-bearing exercise—resistance training helps the bones retain calcium. Small, slight women are more prone to osteoporosis. Those who have more bodyfat have more protection because the enzyme aromatase, which is found in bodyfat, converts circulating androgens into estrogen. It’s also possible for men to get osteoporosis, particularly those who don’t exercise and who have low testosterone.
Some research has suggested that calcium may help with bodyfat loss. The theory is that dietary calcium suppresses calcitriol-based fat increases. Calcitriol, an activated form of vitamin D, suppresses thermogenic protein activity in fat cells and encourages an increase in fat deposition. The problem is, that kind of fat loss works only when the diet was previously lacking in calcium. More recent studies have found no fat-loss effects at all when calcium is added to the diets of subjects who are already getting plenty.
Bodybuilders’ precompetition diets may be short on calcium due to a lack of the best source of calcium—dairy foods, such as milk and cheese. You can easily remedy that deficiency, however, by taking supplemental calcium, preferably in the form of multimineral supplements, which provide the required nutrients without the unwanted calories.
A recent study found that athletes with a high-calcium intake, combined with intense training, have higher counts of both free and total testosterone. That would imply that calcium may provide anabolic effects. The subjects, 30 male athletes with an age range of 17 to 21, were divided into three groups of 10:
1) Athletes who took 35 milligrams of calcium gluconate per kilogram of bodyweight with no training.
2) Athletes who took the same dose of calcium and trained for 90 minutes a day, five days a week.
3) Athletes who trained for the same length of time but didn’t take any calcium.
The dose of calcium was three times the usual recommendation for the mineral, which is 800 milligrams daily—35 milligrams per kilogram of bodyweight amounts to 3,150 milligrams of calcium for a 200-pound athlete. The study lasted for one month.
As expected, the exercising groups had more free and total testosterone than the sedentary group. The hormone count was highest in group 2, where intense exercise was combined with the calcium supplement. The authors speculated that calcium pathways in the body that affect testosterone may have played a role. On the other hand, their credibility was dampened by their noting that a form of the amino acid by-product HMB contains calcium, and HMB has been linked to an increase in fat-free mass. In reality, HMB contains tiny amounts of calcium, and its mechanism has nothing to do with calcium. In fact, the studies showing the effectiveness of HMB are equivocal at best in regard to muscle size and strength.
Based on this preliminary study, I would not suggest that calcium is in any way an “anabolic” supplement, except perhaps in maintaining bone structure. Calcium is a vital mineral, but don’t count on it to build muscle or help you lose bodyfat, unless you’re deficient. Considering the widespread availability of calcium supplements, you shouldn’t be.
Cinar, V., et al. (2009). Testosterone levels in athletes at rest and exhaustion: Effects of calcium supplementation. Bio Trace Elem Res. In press.