Should adults take vitamin D supplements to prevent disease?

#### What you need to know The US Preventive Services Task Force recommends against vitamin D and calcium supplementation for fracture prevention in otherwise healthy postmenopausal women.1 However, despite high quality systematic reviews reporting ineffectiveness, many guideline groups continue to recommend vitamin D supplementation (with or without calcium) for fall or fracture prevention. Recently Public Health England recommended that everyone needs vitamin D equivalent to an average daily intake of 10 μg (400 IU) to protect bone and muscle health,2 and more than 30-50% of older people in some Western countries take vitamin D supplements.3 4 The role of vitamin D supplementation in individuals not at high risk of osteomalacia (box 1) has been extensively investigated in recent years, but some uncertainties remain. #### BOX 1: Vitamin D facts