Summary:
Osteoporosis is characterised by the gradual weakening of bone tissue, often measured using bone mineral density (BMD) at key sites such as the lumbar spine and neck. It can lead to fractures, increased dependency, and higher mortality. Identifying dietary factors that may affect bone health is important for prevention. Plant-based diets, which limit or exclude animal products, are increasingly popular and have been linked to reduced risk of several chronic diseases. However, their relationship with bone health is less clear. While some studies suggest these diets can be healthy when they include enough calcium and vitamin D, concerns remain due to potential deficiencies in nutrients vital for bone strength, such as vitamin B12, high-quality protein, and omega-3 fatty acids. Research on this topic has produced mixed findings. Some studies suggest a higher risk of osteoporosis among those following plant-based diets, especially vegans, while others find no difference or even a protective effect. This study is a systematic review and meta-analysis using 20 observational studies, including over 243,000 participants. Compared to omnivores, those following a plant-based diet showed a significantly increased risk of osteoporosis at the lumbar spine. Risk was higher among vegans and individuals who had followed a plant-based diet for ten or more years. These findings suggest that long-term adherence to a plant-based diet, especially a strict vegan diet, may be linked to higher osteoporosis risk in certain populations. Further high-quality, long-term studies are needed to better understand this association and to explore whether nutrient supplementation can offset potential risks.
Abstract:Β
Background & aims: Plant-based diet is growing in popularity throughout the world for various reasons, yet its effect on bone health, especially osteoporosis, remains controversial. This systematic review and meta-analysis aim to investigate the association between plant-based diet and risk of osteoporosis. Methods: A systematic literature search of observational studies examining the relationship between plant-based diets and osteoporosis risk was performed across PubMed, Embase, Web of Science, Scopus, and ProQuest from inception to June 1, 2024. Two reviewers independently extracted data and assessed study quality using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies and the NewcastleβOttawa Scale. To synthesize effect estimates, a random-effects meta-analysis with inverse variance weighting was applied to pool odds ratios (ORs) and 95 % confidence intervals (CIs). Subgroup analysis and meta-regression were used to explore sources of heterogeneity. Results: This study encompassed 20 original observational studies collectively involving 243,366 participants. Primary analysis revealed that plant-based diet was associated with the risk of osteoporosis at the lumbar spine (OR = 2.44, 95%CI = 1.12β5.33, π = 0.02; π2 = 1.94; πΌ2 = 91.7 %), compared to omnivorous diet. The association remained directionally consistent although attenuated to non-significant at the femoral neck (OR = 1.91, 95%CI = 0.68β5.42, π = 0.22; π2 = 3.28; πΌ2 = 94.9 %). Subgroup analysis revealed vegans (FN: OR = 1.79, 95%CI = 0.94β3.54, π = 0.10; LS: OR = 1.45, 95%CI = 1.00β2.12, π = 0.05) and those who followed a plant-based diet for β₯10 y (FN: OR = 1.79, 95%CI = 1.29β2.49, π < 0.01; LS: OR = 1.35, 95%CI = 0.97β1.87, π = 0.07) to exhibit a more pronounced risk of osteoporosis. Heterogeneity was primarily driven by study design. Conclusions: This systematic review and meta-analysis indicate that adherence to plant-based diet may be associated with an elevated risk of osteoporosis, particularly at the lumbar spine, among individuals following a vegan diet or following a plant-based diet for β₯10 y. However, the heterogeneity observed across studies highlights the need for well-designed prospective studies in future, to clarify this relationship.
Article Publication Date: 2/6/2025
DOI: 10.1016/j.clnu.2025.05.023
