Saturday, March 24, 2012

High protein intake does NOT harm your bones or kidneys- new study reveals

Protein intake, calcium balance and health consequences

High-protein (HP) diets exert a hypercalciuric effect at constant levels of calcium intake, even though the effect may depend on the nature of the dietary protein. Lower urinary pH is also consistently observed for subjects consuming HP diets. The combination of these two effects was suspected to be associated with a dietary environment favorable for demineralization of the skeleton. However, increased calcium excretion due to HP diet does not seem to be linked to impaired calcium balance. In contrast, some data indicate that HP intakes induce an increase of intestinal calcium absorption. Moreover, no clinical data support the hypothesis of a detrimental effect of HP diet on bone health, except in a context of inadequate calcium supply. In addition, HP intake promotes bone growth and retards bone loss and low-protein diet is associated with higher risk of hip fractures. The increase of acid and calcium excretion due to HP diet is also accused of constituting a favorable environment for kidney stones and renal diseases. However, in healthy subjects, no damaging effect of HP diets on kidney has been found in either observational or interventional studies and it seems that HP diets might be deleterious only in patients with preexisting metabolic renal dysfunction. Thus, HP diet does not seem to lead to calcium bone loss, and the role of protein seems to be complex and probably dependent on other dietary factors and the presence of other nutrients in the diet.

J Calvez1, N Poupin1, C Chesneau2, C Lassale3 and D Tomé1

1AgroParisTech, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France
2Bongrain SA, 42 rue Rieussec, Viroflay, France
3Unité de Recherche en Epidémiologie Nutritionnelle, UMR U557 Inserm/U1125 Inra/Cnam/Paris 13, CRNH IdF, SMBH Paris 13, Bobigny Cedex, France

Correspondence: Professor D Tomé, Life Sciences and Health, AgroParisTech, 16 rue Claude Bernard, 75005 Paris, France. E-mail:

Received 27 April 2011; Revised 10 August 2011; Accepted 11 August 2011
Advance online publication 30 November 2011
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