Risk of Bone Fracture on Vegetarian and Vegan Diets

Bone fractures can have a devastating effect on health, especially in the elderly, undermining their independence for daily activities, and increasing the risk of comorbidities and mortality. Nutrition is a key factor in maintaining an optimal bone health across the lifespan. The number of people that choose to avoid meat or even all animal products is increasing globally, for a diversity of reasons. Properly planned vegetarian and vegan diets are widely recognized as a healthy dietary pattern, but the long-term impact of these diets on bone health and more specifically risk of bone fractures is less clear. Classic studies have observed a slightly lower bone mineral density in vegetarians but have many limitations, including inadequate adjusting for relevant confounding factors, and cross-sectional design. The aim of this review is to summarize and put into context the current evidence on the effect of vegetarian and vegan diets on bone health, with a focus on fracture risk.

In recent years, results from many large prospective studies have emerged, which allowed us to assess the risk of incident bone fractures in vegetarians. In these studies, vegetarian and especially vegan diets were associated with an increased risk of bone fractures. In many recent prospective cohort studies, vegetarian and especially vegan diets were associated with an increased risk of bone fractures. At least part of this risk could be due to a lower body mass index and a lower intake of nutrients such as calcium, vitamin D, and protein. Some evidence suggests that combined vitamin D and calcium supplementation and other factors such as consumption of protein-rich foods may attenuate this risk. The eventual deleterious effect of vegetarian diets on bone health should be contextualized and balanced with its benefits, such as lower risk of cardiovascular disease and cancer.