Adequate amounts of vitamin D, an essential, fat-soluble vitamin, come from consistent exposure to sunshine and are difficult to obtain from dietary sources. Postmenopausal women, older individuals, and those with malabsorption, limited sun exposure, or certain illnesses may need higher intakes of vitamin D. Vitamin D3, the naturally-occurring form, is supplied in high-potency amount of 5,000 I.U. per capsule for those most at risk of the effects of seasonal declines in vitamin D status or with existing vitamin D deficiency