Too much meat not good for bone health in pre-pubertal girls

A study published in the March 2010 issue of British Journal of Nutrition suggests eating too much of protein, particularly animal protein may have a negative effect on bone mass accrual in pubertal girls with low intake of calcium.

Zhnag Q and colleagues from the Chinese Center for Disease Control and Prevention in Beijing China studied the effect of calcium and protein intakes on bone mass accrual in 757 pre-pubertal girls at an average age of 10.1 years in urban Beijing.

The researchers measured bone mass of the proximal, distal forearm and total body at baseline, 12, 24, 48 and 60 months during the follow-up.  Dietary intakes were assessed from food diaries.

They found calcium intake was positively associated with bone mineral content or BMC while protein intake was negatively associated with BMC, meaning high intake protein was linked to low BMC. 

They also found that animal protein, particularly meat protein, had significant negative effects on BMC accrual at proximal  and distal forearms. 

On average, these girls had intake of 432-675 mg of calcium per day and 55.9 to 51.0 grams of protein per day.

Dr. Colin T Campbell, a Cornell University nutrition professor, says in his book China Study that Americans eat an average of 15 to 16 percent of calories from protein, which he says is too high.

By David Liu

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