**Study found with help of jboldman, Mod @ CEM, but this shows the importance of calcium when consuming large amounts of protein. We know high protein diets can pull calcium into the blood, potentially leading to kidney stones, but this also means your bones are lacking calcium. This is another argument for using a protein supplement in milk, other than post workout. Also, note the effects of protein on IGF-1, interesting.**
J Nutr 2003 Mar;133(3):852S-4S Related Articles, Links
Interaction of dietary calcium and protein in bone health in humans.
Calcium and Bone Metabolism Laboratory at the Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, MA.
Protein has both positive and negative effects on calcium balance, and the net effect of dietary protein on bone mass and fracture risk may be dependent on the dietary calcium intake. In addition to providing substrate for bone matrix, dietary protein stimulates the production of insulin-like growth factor-1 (IGF-1), a factor that promotes osteoblast-mediated bone formation. Protein also increases urinary calcium losses, by several proposed mechanisms. Increasing calcium intake may offset the negative impact of dietary protein on urinary calcium losses, allowing the favorable effect of protein on the IGF-1 axis to dominate. Several, although not all, studies are either compatible with or support this hypothesis. Protein supplements significantly reduced bone loss in elderly hip-fracture patients in a study in which both the protein and control groups received supplemental calcium. In an observational study, total protein intake was positively associated with favorable 3-y changes in femoral neck and total body bone mineral density in volunteers who received supplemental calcium citrate malate and vitamin D, but not in volunteers taking placebos. In conclusion, an adequate calcium intake may help promote a favorable effect of dietary protein on the skeleton in older individuals.