Non-D vitamins and bone health in adults

Abstract

Osteoporosis is a major public health problem. Diet is an important modifiable risk factor for the prevention of osteoporosis. While vitamin D has received significant attention, emerging evidence indicates that other vitamins also play an important role in skeletal health. This Perspective highlights current understanding of the non-D vitamins (A, B, C, E, and K) and bone health in adults. Several studies of vitamin A (pre-formed retinol) have reported that excessive vitamin A has negative effects on bone. Yet, pro-vitamin A carotenoids, which can convert into retinol, have shown positive associations with bone mass, protection against bone loss and lower risk of hip fracture. Low levels of B vitamins may influence bone through homocysteine metabolism. While large observational studies have reported negative associations of homocysteine with bone mineral density (BMD) and positive associations with fracture, more controlled trials are needed to clarify the associations. Studies have shown mixed results for vitamin C and bone, indicating complex interactions of vitamin C with smoking, hormone replacement, calcium and vitamin E intake. Vitamin E affects bone formation and remodeling, and appears to be important for the skeleton. However, there is insufficient evidence to conclusively link vitamin E with bone health. Some vitamin K studies have shown that low level intakes increase hip fracture risk, however, intervention trials have been inconsistent. There is little research on multivitamin use and bone health. For most vitamins, prospective studies are needed to explore their mechanisms and pathways. Longer-term controlled trials are needed to determine whether treatment with specific vitamin supplements can improve bone health or reduce fracture risk. IBMS BoneKEy. 2010 December;7(12):431-446. 2010 International Bone & Mineral Society