By Larry Marsh, Kansas City Star Midwest Voices columnist 2009

In their new book "Building Bone Vitality" Amy Joy Lanou and Michael Castleman point to research suggesting that excessive consumption of high-protein foods produces too much acid in our blood that leaches calcium from our bones. Weak bones in men is a relatively new problem. Cavemen did not have this problem.

We all need to consume a reasonable quantity of protein for growth including bone growth. However, too much protein accompanied by too few green leafy vegetables can cause bone problems. Protein metabolizes as acid in our blood while fruits and vegetables generally metabolize as alkaline bicardonate. Too much acid without enough alkaline could lead to osteoporosis.

Michael Pollan in his 2008 book "In Defense of Food" deplores the fact that not only are we not eating enough unprocessed fruits and vegetables, but we are getting our protein from animals that got to eat very little, if any, grass and were fed mainly with grains. He points out that this doesn't generate the right nutrients in the meat we eat. It produces a quality of meat that is nutrient poor relative to what our ancestors ate. This change has not helped us in our struggle to maintain strong bones.

Our bodies are constantly working to break down old bone and replace it with new bone. Both protein and non-protein food sources are needed to get the right balance for this bone destruction and bone creation process to work smoothly. The missing ingredient that makes this all work properly is weight-bearing exercise. Heavy exercise triggers a burst of cytokine-6 production which tears down old bone which, in turn, triggers cytokine-10 production which builds up new bone.

A low-acid diet is not likely to be sufficient to maintain strong bones if not accompanied by weight-bearing exercise. Bones deteriorate naturally over time if left to themselves.

Our ancestors performed lots of hard physical labor. Until after the industrial revolution, there was no time to sit around and watch tv especially since there was no tv to watch anyway. People typically spent all day working in the fields.

In ancient times cavemen had to chase their sources of protein around the plain and through the forest. They also had to be able to run fast to avoid getting eaten themselves by ubiquitous predators. Cavemen didn't have to worry about developing weak bones. They never got to stop running long enough to develop them.

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Also see these health links:

Bone density and osteoporosis

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No-Eat-Day Diet: A good strategy or bad advice?

Kennedy's death reminds us that men in their 70s must be defensive players

Is calorie restriction a good defense against cancer?

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