I'm wondering if anyone one here heard about meat and poultry leading to poor bone health from a loss of calcium? There are a number of studies showing animal protein causes a high excretion of calcium from the urine. I've spoken to another paleo advocate (I'm an advocate myself, just questioning some aspects) who said the calcium that is excreted is compensated by the calcium from the protein that's absorbed through the intestines. At first I was relieved, but I'm done further reading about phosphorus & calcium and seeing how most animal protein (and dairy) is roughly equal in these minerals, doesn't the phosphorus compete with absorption with the calcium? If this is true, not only is more calcium being excreted in the urine, but the calcium from the food isn't being absorbed that well either and therefore there is still a calcium deficit and a higher than adequate phosphorus intake.
I'm just worrying about this issue because my step mother has osteopenia and I'm trying to find a good diet for her. Are there other theories that challenges my conclusion? Am I mistaken?
asked byGena (40)
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on November 10, 2012
at 05:56 AM
Ok, so I've evaluated this theory before and found a bunch of studies confirming that meat protein is definitely not bad for your bones. Basically, meat protein increases the calcium lost in urine, but it also increases the calcium absorbed in your stomach and intestines ultimately improving or not negatively affecting calcium balance. The following are the studies I've found on this, so prepare for a data dump:
In a study on elderly people (3), the authors concluded that ???Increasing protein intake from 0.78 to 1.55 g/kg/d with meat supplements???when exchanged isocalorically for carbohydrates, may have a favorable impact on the skeleton in healthy older men and women???.
Another study (4) found that increasing protein calories from 12% to 20% using meat did not negatively affect bone status in post menopausal women.
In a series of studies by Jane Kerstetter et al. (2), increasing protein from low to moderate levels using mainly meat improved bone health and further increases did not adversely affect bone health.
One study found that (5) ???Under practical dietary conditions, increased dietary protein from animal sources was not detrimental to calcium balance or short-term indicators of bone health???.
An older study measuring the calcium needs of Peruvian Prisoners found that increasing meat in the diet from 100g to 300g brought about an more positive calcium balance (9)
Another study by Jane Kerstetter et al. (6) increased protein intake in women from 1 to 2.1 g/kg. The authors wrote ???These data directly demonstrate that, at least in the short term, high-protein diets are not detrimental to bone???. Meats such as fish and poultry were the main food sources used to increase protein.
A 6 month weight loss study fed overweight participants low and high protein diets (70.4 vs. 107.8 grams per day) and measured bone mineral loss (8). No adverse affects on bone loss were seen in the high protein group
A weight loss study on overweight individuals found that increasing protein in place of carbohydrates did not change urinary calcium levels or several markers of bone turnover (13). About half of the protein in the study was provided by meat.
Finally, a study which had women increase protein intake from 61 to 118 grams a day, provides more evidence that ???a high-protein diet has no adverse effects on bone health??? (7). The increase in protein in was achieved primarily by ???increasing portions of meat protein (mainly from beef)???.
There are some studies which show that protein might be bad for calcium balance???when the protein source is gluten and isolated dairy proteins (10,11,12). But protein from meat is not bad, and may even be good for your bones.