SYDNEY, Australia—Results from a recent study suggest vegetarian diets, particularly vegan diets, are associated with lower bone mineral density (BMD), but the magnitude of the association was clinically insignificant (Am J Clin Nutr. 2009; 90(4):943-950).
A systematic electronic literature search was conducted to identify all relevant articles on the association between vegetarian diet and BMD. Nine studies of 2,749 subjects (1,880 women and 869 men) were included in the analysis. Traditional and Bayesian methods of meta-analysis were applied to synthesize the data.
Overall, BMD was 4 percent lower in vegetarians than in omnivores at both the femoral neck and the lumbar spine. Compared with omnivores, vegans had a significantly lower lumbar spine, which was more pronounced than in lactoovovegetarians. The probability that BMD was 5 percent lower in vegetarians than in omnivores was 42 percent for the femoral neck and 32 percent for the lumbar spine. There was no evidence of publication bias. There was a moderate degree of between-study heterogeneity; the coefficient of heterogeneity varied between 46 percent and 51 percent.