The supplement industry is required to follow several federal manufacturing and formulation standards. The study was designed to investigate only the effect of selenium supplementation on cancer. The study was performed on women only. The study was performed on a population that had low selenium intakes. The effect of dietary protein on bone calcium content is likely to be small.
Dietary protein decreases urinary calcium excretion.
Dietary protein decreases glomerular filtration rate. The current RDA for calcium may not off-set the effect of protein on calcium metabolism.