Philip J. Goscienski, M.D.
If calcium is so important, how is it that in those countries where calcium intake is even lower than that in the United States, osteoporosis and hip fractures are rare? For example, Japanese women whose calcium intake is approximately one-half of our current recommendations have about half the rate of hip fracture of American women. Among population groups where calcium intake from dairy products is high the rate of hip fracture is also high.
Should we get our calcium from dairy products? Humans have drunk animal milk for only a tiny fraction of our history on this planet. Wild animals don't give up their milk without a battle and domestication of goats and cattle only began about 10,000 years ago. For a couple of million years before that no human beyond the age of weaning drank milk. That explains why most people in the world lose the ability to digest lactose, or milk sugar, by the time they're teenagers.
Throughout most of our existence we obtained plenty of calcium from plant sources, so early humans didn't need milk beyond infancy. The calcium in plants is absorbed better than the calcium in milk. Plants also contain potassium, magnesium and boron, all of which help to make bones stronger. Vegetables have very little sodium, a substance that is overabundant in our diet and that contributes to calcium loss and osteoporosis.
Americans' eating habits may contribute to osteoporosis because of our high intake of saturated fat, which interferes with calcium absorption from the intestines. This wasn't a factor during the Stone Age because wild game has almost no saturated fat.
There is one time in a person's life when calcium does matter. During adolescent years, when children should be reaching their peak bone mass their calcium intake is low. Ninety percent of adolescent girls fail to take in the recommended daily amount of calcium. In the 1970s teenagers drank twice as much milk as soft drinks. It's just the opposite now. And almost every parent knows how challenging it is to get children of any age to eat vegetables.
What's the real key to strong bones? A high level of physical activity. Walking or jogging does help to prevent bone loss but we need the kind of activity that puts real stress on bones. That means resistance exercise, or weight lifting. Stone Age kids grew up using their muscles for hours every day, which in turn caused their bones to become strong and thick-walled. Inactivity among children is the primary reason why they are becoming obese at an alarming rate. This lack of physical activity will have a tremendous impact on osteoporosis 4 or 5 decades from now. It will be too late then to pop a couple of calcium tablets at every meal.
It's possible to slow down osteoporosis at any age but that shouldn't be our first priority. Our primary goal should be to raise a generation of children that enters adult life with bone structure nearly as robust as that of our distant ancestors.
Philip J. Goscienski, M.D. is the author of Health Secrets of the Stone Age, Better Life Publishers 2005. Contact him at firstname.lastname@example.org.