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(skinnyman @ Aug. 21 2006,20:44)</div><div id="QUOTEHEAD">QUOTE</div><div id="QUOTE">uhm i bringing up this topic again.
i've read that a diet high in anirmal protein makes the body excretes 60% more calcium, making the urine acidic, which increases the risk of developing kidney stones.</div>
The body excretes more calcium on a high protein diet, including plant protiens.
But the balance of calcium is the same or better than a low protein diet, because raising the protein intake rasies calcium uptake.
Meat and soy protein affect calcium homeostasis in healthy women.Kerstetter JE, Wall DE, O'Brien KO, Caseria DM, Insogna KL.
Yale New Haven Hospital, New Haven, CT, USA.
jane.kerstetter@uconn.edu
We showed that increasing dietary protein from omnivorous sources increases intestinal calcium absorption and urinary calcium, whereas a low-protein diet decreases calcium absorption and lowers urinary calcium. To assess the effect of soy protein on this relation, we substituted soy for meat in high- and low-protein diets fed to healthy women. The study consisted of a 2-wk adjustment period followed by a 4-d experimental period in which 20 healthy women consumed, in random order, the following 4 diets: high-protein soy-based, low-protein soy-based, high-protein meat-based, low-protein meat-based. Measures of calcium homeostasis were evaluated at baseline and after 4 d of the experimental period.
At 24 h, net acid excretion was higher during the high- compared with the low-protein intervention (P < 0.05), and during the meat compared with the soy intervention (P < 0.05). The high-protein diets increased 24-h urinary calcium (P < 0.001), but urinary calcium did not differ due to the type of protein. Serum concentrations of parathyroid hormone and calcitriol, and urinary nephrogenous cAMP were higher during the low- compared with the high-protein intervention and during the soy compared with the meat protein (P < 0.05). In a subset of subjects, intestinal calcium absorption tended to be lower (P = 0.1) when they consumed the soy diets rather than the meat diets.
These data indicate that when soy protein is substituted for meat protein, there is an acute decline in dietary calcium bioavailability.