Which vitamin D oral supplement is best for postmenopausal women?

Next to a healthy calcium and protein rich diet and exercise, vitamin D supplementation is a key pillar of osteoporosis prevention among postmenopausal women. This article reviews the recent recommendations on vitamin D by the IOF (2010), the Institute of Medicine (2010), and the US Endocrine Society (2011), including the evidence to support these recommendations for fracture and fall prevention. The recent recommendations agree that supplementation should be performed with vitamin D3 or vitamin D2, and that a minimal serum 25-hydroxyvitamin D threshold of 50 nmol/l (20 ng/ml)should be achieved to overcome vitamin D deficiency. In contrast to the Institute of Medicine, the IOF and the US Endocrine Society recommend vitamin D also for the prevention of falls, and state that for fracture prevention a higher serum 25-hydroxyvitamin D threshold of 75 nmol/l (30 ng/ml) should be targeted