At least every 5 years, the U.S. Department of Agriculture and the U.S. Department of Health and Human Services are required by federal law to issue Dietary Guidelines for Americans. According to the law, these guidelines are supposed to be based on the best available science. Yet some of their recommendations don’t seem to have any basis in science at all. In particular, I think that their recommendations about calcium intake will make the problem of osteoporosis worse, not better.
The USDA claims that Americans aren’t getting enough calcium in their diets and that they need to consume more cow’s milk and other dairy products. Yet why should I imagine that human beings need to drink any cow’s milk at all? Every other animal species on the face of the planet gets enough calcium from its food without drinking any milk at all from another species. Only mammals drink milk, and all they get is their mother’s milk during infancy. In fact, most human beings throughout most of the history of our species didn’t consume any dairy products at all. So why should I imagine that adult human beings need the equivalent of 3 glasses of skim milk every day? It makes no sense.
From what I’ve seen, it’s really hard to find any cases of anyone who got sick or had any problems with their bones or teeth because of a low-calcium diet. The human body is actually really good at adapting to a low calcium intake. A review of the literature found that there’s no consistent evidence that dairy products help children build stronger bones and teeth. Worse yet, we’ve known for more than 20 years that a high-protein, high-calcium diet probably causes osteoporosis. In other words, the USDA is making recommendations that aren’t based on the best available science. That is a serious violation of federal law.
Photo by robert.claypool 
Note: As I explain in my book Thin Diabetes, Fat Diabetes: Prevent Type 1, Cure Type 2, there is strong evidence that a protein in cow’s milk could be the underlying cause of most cases of type 1 diabetes.