A recent American study analyzed the effects of a high-protein diet on the mineral content of bone in women who train or exercise regularly.
A portion of the medical community has hypothesized that a diet consisting of large amounts of protein can negatively affect health. Conditions such as bone demineralization and a loss of kidney function may be consequences of a high-protein diet. This hypothesis has been titled the acid-ash hypothesis. It claims that a high protein diet contains acid precursors that lead to bone demineralization. With no previous research of this sort targeted to exercise-trained women, a recent American study published by the Journal of the International Society of Sports Nutrition assessed the effect of a high-protein diet on the bone mineral content and bone density of exercise-trained females.
The study included24 female participants and spanned six months. The researchers assigned half of the women into the control group where they consumed an average diet. The remaining 12 women were on a diet that met or exceeded 2.2 grams of protein per kilogram of body weight daily. Diet was tracked through a food diary app while the resulting body composition was measured using dual-energy x-ray absorptiometry. All of the individuals maintained their habitual exercise levels.
High-Protein Diets Did Not Lead to Bone Loss
While the research instigated an increase in protein consumption with the experimental group, there was no significant change in the total caloric consumption or in the amount of carbohydrate and fat. Across both the control group and the high protein group, the bone mineral density of the whole body remained relatively constant. Similar trends were identified for lumbar bone mineral density with no significant reported changes. Lumbar T-scores and whole body T-scores remained constant as well. No changes in fat mass and lean body mass were identified either.
The study demonstrates that a high-protein diet may not have an impact on bone mineral density, lean body mass, or fat mass. These results contradict the hypothesis that an increase in protein consumption is harmful to bone health for exercise-trained women.
Further research incorporating a larger sample size may provide accuracy and increased reliability of the data presented. Since this study did not account for exercise levels, there is a possibility that they may impact the results. Further research that controls for more biological and environmental factors is required to further support this conclusion.
Written by Shrishti Ahuja, HBSc
Reference: Antonio, J., Ellerbroek, A., Evans, C., Silver, T., & Peacock, C. A. (2018). High protein consumption in trained women: bad to the bone? Journal of the International Society of Sports Nutrition, 15(1). doi:10.1186/s12970-018-0210-6