Phosphate in Health and Disease

Phosphate balance in adults is almost always zero, in contrast to calcium balance, which is usually negative, because of the effective action of PTH on renal tubules to block Pi reabsorption. In late life, however, intestinal phosphate absorption decreases and the serum phosphate concentration declines. These physiological decrements may contribute to disease, especially to increased bone loss and osteo-penia or more severe osteoporosis. Typically, these changes in Pi balance are also accompanied by similar changes in calcium balance. Too little dietary phosphorus and too little dietary calcium may be determinants of low bone mass and density and, hence, increased bone fragility. The usual scenario invoked to explain osteoporosis in old age, however, is that too little dietary calcium in the presence of adequate dietary phosphorus stimulates PTH release and bone loss (Figure 1).

Three human conditions that involve abnormal Pi homeostasis need explanation.

Gaining Weight 101

Gaining Weight 101

Find out why long exhausting workouts may do more harm than good. Most of the body-building workout and diet regimens out there are designed for the guys that gain muscle and fat easily. They focus on eating less and working out more in order to cut the excess fat from their bodies while adding needed muscle tone.

Get My Free Ebook


Post a comment