Comparison of human bone mineral densities in subjects on plant-based and omnivorous diets: a systematic review and meta-analysis

Abstract

The increased consumption of plant-based diets has encouraged studies of bone mineral density (BMD). The present systematic review and meta-analysis compared the effects of plant-based and omnivorous diets on BMD. We searched the Cochrane Library, PubMed, EMBASE, and the Web of Science to July 1, 2020. We used the mean differences (MDs) with 95% CIs to compare group outcomes. We compared the lumbar spine, femoral neck, and whole-body BMDs of those on plant-based and omnivorous diets. We performed subgroup analyses by various clinical characteristics. Two reviewers independently assessed trial quality and extracted data. All statistical analyses were performed using Review Manager version 5.2. A total of 17 cross-sectional studies including 13,888 patients were identified. The pooled results indicated that those on plant-based diets (compared to omnivores) exhibited lower BMDs at the lumbar spine (MD - 0.04; 95% CI - 0.06 to - 0.02; P < 0.0001) and femoral neck (MD - 0.04; 95% CI - 0.05 to - 0.02; P < 0.00001), and a reduced whole-body BMD (MD - 0.03; 95% CI - 0.06 to - 0.01; P = 0.0009). Both vegetarians and vegans exhibited lower lumbar spine, femoral neck, and whole-body BMDs than omnivores. Plant-based diets were associated with lower BMDs than those of an omnivore population. Plant-based diets may compromise overall bone health; prospective research is required.