The promise is appealing: If you’re religious about taking calcium supplements, you can fend off the bone-thinning condition known as osteoporosis and prevent the debilitating fractures that often come with the condition. But recently the effectiveness of these supplements has been questioned. Sixteen randomized, controlled studies as well as 28 observational studies concluded that calcium (with vitamin D added) does not protect healthy post-menopausal women from experiencing fractures. And currently there isn’t evidence that calcium supplementation protects pre-menopausal women, but this is not yet a conclusion. What does this mean?


Why does your body need calcium and D? Bones seem solid, but their structures are continuously being broken down and renewed. During the breakdown phase, bone cells called osteoclasts dissolve old bones. In the renewal phase, cells called osteoblasts pull calcium and other minerals from the blood. These minerals join with collagen (a protein that provides structure) to re-form bone tissue. The activities of the osteoclasts and osteoblasts are balanced so that the right amount of bone is always being created and destroyed.


When we reach our thirties, however, that balance begins to shift.  The breaking-down process becomes dominant, and women lose slightly more tissue than they build.  That loss really accelerates for a few years after menopause.  But the bones aren’t the body’s only customer for calcium; the mineral is also essential to the functioning of the heart, muscles and nerves.   The body tries to maintain a constant level of calcium in the blood, so if you’re deficient, your body is going to take it from your skeleton, which is the biggest storage house for this mineral.  For this reason, an insufficient intake of calcium can speed up the weakening of bones.


The shortfall of vitamin D may be the bigger concern.  That’s because you need a derivative of vitamin D called calcitriol to facilitate the intestine’s absorption of calcium.  Since most people don’t get enough calcium and vitamin D, medical experts have urged the use of supplements to make up the difference.  It has been well-documented that sufficient calcium and vitamin D are necessary for strong bones.  Whether supplementation translates into fewer fractures is open to dispute.    However, not all experts are convinced that supplements are useless.  In most studies regarding supplementation, it’s difficult to control for compliance, and when interviewed, most subjects admitted to missing pills on more than several occasions.  When the Women’s Health Study was re-analyzed using only those subjects who reported compliance with vitamin D, the compliant group had a 30% reduction in hip fractures.  What’s more, vitamin D is important for muscle synthesis.  Among its good effects: boosting strength in the lower body and decreasing body sway and instability.  Perhaps for that reason, taking a vitamin D supplement can further reduce the risk of falling (which of course is a precursor to fractures).


Most experts agree that the safest and probably most effective source of calcium for strong bones and overall health is diet, not supplements.    The nutrients in our diets are like the instruments in a symphony orchestra.  They play together, and one depends upon the other for the total impact.  That said, the best sources of dietary calcium are fish and vegetables (yet another reason to increase your intake of these foods!).  Dairy products, which are viewed as good sources of calcium, are acidic, and therefore increase the acidity level in the blood.  The body responds by leaching calcium from the bones, NOT replenishing it.   Relying too much on dairy products may actually do more harm than good, and calcium supplements have been linked to the risk of heart attack in women.  In addition, most people take the wrong kind of calcium supplement because it’s cheaper and the pills aren’t as big so they’re easier to swallow.


We manufacture vitamin D when the ultraviolet rays from the sun strike our skin, which means many of us are deficient (sunscreen, anyone?).  Foods high in vitamin D are not plentiful in our diet, so supplementation with a D3 (cholecalciferol) gel-cap (not a solid pill), at least 1,000 IUs/day, is likely your best option for making sure that the calcium you do ingest from your food is well-absorbed and that your circulating levels of vitamin D are optimal.  Speak to your doctor about getting your vitamin D levels checked.  The best measure of your blood level of vitamin D is a form known as 25-hydroxy vitamin D.  Have the test done in April or May, when levels tend to be lower.


And remember: vitamins and minerals are only part of the story.  Engaging in weight-bearing activity (anything that forces your bones and muscles to work against gravity) is crucial to strengthening bones.  Exercise also helps maintain muscle strength, coordination and balance, which in turn help prevent falls and related fractures.


Adapted from an article by Leslie Pepper