For years, the medical community has advised women to take calcium supplements to prevent osteoporosis, or loss of bone density, in older age. For men, however, the evidence has been inconclusive. While intuitively one would think men should also supplement their calcium, the questions of whether and how much have lacked a research basis. Until now, that is. A paper published in the November 10 issue of the Archives of Internal Medicine by a team of New Zealand researchers indicates that men need calcium just as much as women—and they need a lot.
As the Auckland researchers point out, three out of 10 men will experience a fracture in older age due to fragile bones. But up to this point the role of calcium in preventing those incidents has been controversial. "There is no consistent evidence, to our knowledge, that calcium supplementation affects...BMD [bone mineral density] in men, despite male osteoporosis being a common clinical problem," write Dr. Ian R. Reid, MD, from University of Auckland in Auckland, New Zealand, and colleagues. "It is critically important to determine whether the widespread use of calcium supplements in older men is a worthwhile investment because 30 percent of older men experience a fragility fracture and men account for one-quarter of all hip fractures." The few studies that have examined calcium supplementation up to this point have had mixed results; and studies have suggested increased rates of cardiovascular incidents and kidney stones among men with high calcium intakes. So, the New Zealand study set out to discover not only the role of calcium in men, but how much calcium a man needs.
To investigate this question, Dr. Reid and his colleagues randomly assigned 323 men, aged 40 and over, to one of three groups: a control group on a placebo; a group supplemented with 600 mg of calcium per day; or a group supplemented with 1,200 mg of calcium per day (taken in two pills per day, a fact that the study authors feel may be an important contributing factor). These groups were then tracked for two years. The result was mixed. While supplementing calcium made a substantial difference to bone mineral density (BMD), it did so only in the heavily supplemented group. The 1,200 mg group also had fewer falls over the observed time period, though not fewer fractures. The conclusion is that supplementing calcium is important for older men, but only if they supplement with enough calcium.
How significant was the difference in the groups? Within six months, the 1,200 mg supplemented group had increased bone density by one to one-and-a-half percent over the placebo group at every measured site, an increase that persisted for the entire time of the study, though it was first perceived in the spine. The 600 mg group, by contrast, had no perceivable difference from the placebo group at any of the sites where BMD was measured. Falls were also different among the groups: the high supplementation group had fall rates of 45 per 100 person-years, versus 65 for the 600 mg group and 59 for the placebo group (with those last two not constituting a statistically significant difference). Reduced falls have also been observed in women who supplement calcium and Vitamin D, due to improved muscle function; this study implies the same kind of improvement may occur for men.
There is one disquieting outcome to the study that, the researchers acknowledge, will require further investigation. The question of the impact of calcium on cardiovascular health was re-opened by the study, which found an increased rate of cardiovascular incidents in both of the supplemented groups, though not to a statistically significant degree. Future research is likely to focus on this question, given the evident advantages of calcium supplementation for bone health. As Dr. Reid and his colleagues write, "Calcium, 1200 mg/d, has effects on BMD in men comparable with those found in postmenopausal women but a dosage of 600 mg/d is ineffective for treating BMD," the study authors write. "These findings provide a rationale for conducting randomized studies of the effect of calcium supplementation on fracture incidence in men. Such studies should also assess the incidence of cardiovascular events so that the balance of risk and benefit can be clearly determined."