Vitamin D is essential for efficient calcium absorption, however in minimal quantities. And, it is not always necessary to take vitamin D as we make vitamin D through our skin upon exposure to sunlight. About 800 units of vitamin D per day is advised to elderly patients (≥65 years)because of their minimal dietary vitamin D absorption, and their inefficiency in making vitamin D due to advancing age. For post-menopausal women between 50 and 65 years, a multi-vitamin supplementation containing 400 units of vitamin D is sufficient.