Bone Mineral Content Of North Alaskan Eskimos (pdf)
... supports the substance of my last post, The More Protein You Eat, The More Calcium You Excrete.
The bone mineral content of arm bones in Eskimo natives of Alaska was measured.
"During the decade from 40 to 49, the Eskimos had 10% lower values than U.S. whites and the deficit increased to 14% in the succeeding two decades. During the seventies, the Eskimo males were 15% below comparable whites, but Eskimo females were almost 30% below."The authors excluded the following causes:
- Lack of physical activity.
- Vitamin D deficiency.
- Calcium deficiency.
"The acidic effect of a meat diet appears a more likely factor (ref. given). It has long been known that acidosis increases calcium excretion and causes bone dissolution (refs. given). ... In humans, a high protein diet, even with controlled intakes of calcium and phosphorous, greatly increases urinary calcium and causes negative balance (refs given)." "In addition, occasional periods of starvation or ketoacidosis from a total meat diet might also produce high calcium losses, as much as several hundred milligrams daily (ref. given)." "The high protein intake from the meat diet has sufficient potential effect to account for the observed bone loss even should there be long-term adjustment to the hypercalciuric effect of high protein."If a high-protein, high-meat diet leads to bone loss, what is the best amount of protein to consume? This study ... The Body's Negative Response To Excess Dietary Protein Consumption (pdf) ... says 30 grams:
"A clinical study of 100 patients reveals that persons who eat large quantities of dietary protein (more than 30g/day) generate high levels of acid which must be neutralized before being eliminated from the body."Actually, that 30 grams was a maximum:
"This clinic promotes that patients should ideally consume no more than 20g/protein/day with 30g/protein/day being the maximum acceptable level of dietary protein consumption."The article was published in 1998. It added:
"The idea that protein may be responsible for increasing urinary ammonia and acidosis is gaining in its base of support."