Their study, which appears in the American Journal of Physiology, shows how bones sacrifice themselves to compensate for the acid-producing foods we eat. These acids are ultimately excreted by the kidneys, but as we age, our kidneys don't function so well. If the kidneys can't keep up with our appetite, the bones step in and absorb the excess acid. That's good in the short term, but in the process the bones surrender calcium, phosphorus, sodium and everything they should be keeping to stay strong. Protein generates more acid than other foods, and the proteins in red meat generate more acid than those in fish or poultry.
Vegetable proteins give rise to the least amount of acid.
Scientists say older consumers should be wary of melatonin ads based on the premise that as we age, the hormone decreases in our system. Results of a new study fly in the face of this notion, they say. In the study, Dr. Charles Czeisler and colleagues at Harvard Medical School and Brigham and Women's Hospital in Boston studied 34 healthy men and women ranging in age from 65 to 81. They found their night-time melatonin levels did not differ significantly from those of 98 men in the 18 to 30 age range. The five- year study appears in the American Journal of Medicine.