Acid diet (high-meat protein) effects on calcium metabolism and bone health.
OBJECTIVE
Update recent advancements regarding the effect of high-animal protein intakes on calcium utilization and bone health.


RESULTS
Increased potential renal acid load resulting from a high protein (intake above the current Recommended Dietary Allowance of 0.8 g protein/kg body weight) intake has been closely associated with increased urinary calcium excretion. However, recent findings do not support the assumption that bone is lost to provide the extra calcium found in urine. Neither whole body calcium balance is, nor are bone status indicators, negatively affected by the increased acid load. Contrary to the supposed detrimental effect of protein, the majority of epidemiological studies have shown that long-term high-protein intake increases bone mineral density and reduces bone fracture incidence. The beneficial effects of protein such as increasing intestinal calcium absorption and circulating IGF-I whereas lowering serum parathyroid hormone sufficiently offset any negative effects of the acid load of protein on bone health.


CONCLUSIONS
On the basis of recent findings, consuming protein (including that from meat) higher than current Recommended Dietary Allowance for protein is beneficial to calcium utilization and bone health, especially in the elderly. A high-protein diet with adequate calcium and fruits and vegetables is important for bone health and osteoporosis prevention.
Cao
Jay J
JJ
USDA, Agricultural Research Service, Grand Forks Human Nutrition Research Center, Grand Forks, North Dakota, USA. Jay.Cao@ars.usda.gov
Nielsen
Forrest H
FH
D000138:Acidosis / Q000150:complications* / Q000378:metabolism; D000818:Animals; D015519:Bone Density / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism*; D004044:Dietary Proteins / Q000009:adverse effects*; D050723:Fractures, Bone / Q000378:metabolism; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007408:Intestinal Absorption; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism; D008460:Meat / Q000009:adverse effects*; D018673:Nutrition Policy; D010281:Parathyroid Hormone / Q000097:blood
D004044:Dietary Proteins; D010281:Parathyroid Hormone; D007334:Insulin-Like Growth Factor I; D002118:Calcium