Are Calcium Supplements Harmful?
Calcium is the fifth most commonly found element in the earth's crust and oceans. It's an essential component in building materials and in chemical reactions. In our bodies, calcium is also common and important; it's instrumental in our skeletal support system and in innumerable chemical reactions.
History has shown us the problems that the body can face when it is deprived of calcium. Malnourished children exhibiting the bowed legs of rickets serve as a stark reminder of the importance of calcium. For years now, doctors have been recommending adequate dietary calcium and calcium supplements for women after menopause. Recently, however, research has revealed potential harms to calcium supplementation.
This month, The British Medical Journal published the results of a large Swedish study which followed over 61,000 women over 19 years. The study looked at cardiovascular death (heart disease and stroke) as its endpoint. In a nutshell, the study showed that women with higher calcium intake (>1400 mg daily) had higher overall rates of cardiovascular death. This finding was boiled down, however, to reveal that the increased mortality was found in the group that achieved this higher intake with both diet and calcium supplements. While the "dietary only" group did not show increased mortality, a 2.5 fold increase in cardiovascular mortality was found in the "supplement-taking" group. Increases in cardiovascular mortality were also seen on some level in the group with low amounts of dietary calcium (<600 mg per day). Another study this month, sponsored by the National Institute of Health, showed increased mortality in calcium supplemented men but not women.
When women hit menopause, they are at risk for the development of osteoporosis, a weakening of the bones which can lead to fractures. As such, calcium supplementation is recommended to achieve adequate amounts of calcium to keep the bones strong. It's estimated by the National Institute of Health that 70% of older women take calcium supplements. Despite the known body's needs for calcium, no scientific studies have shown that taking calcium supplements decreases a person's risk for fracture.
While 99% of the body's calcium is utilized for bone structure and strength, the other 1% is utilized in reactions important for muscle functioning, nerve transmission, contraction/relaxation of blood vessels, and cellular signaling. These functions are never in any danger of suffering from low levels of calcium in the body.
What Does All of This Mean?
Calcium is a good thing for our body, but maybe too much of a good thing is a bad thing, at least in this regard. These recent findings are convincing, as this was a large-scale, quality study. My advice to patients is to stop supplementing calcium with pills. Examine dietary calcium intake with the goal of getting on the higher end of 600-1200 mg per day. For women after menopause, continue to supplement Vitamin D 800-2000 IU (international units) per day. The benefits of Vitamin D supplementation are well-supported in the scientific literature. Also, engage in weight-bearing exercise which has been shown to strengthen bones.