TORONTO, CANADA. Dr. Reinhold Vieth, MD of the University of Toronto provides convincing evidence that vitamin D deficiency is widespread particularly in northern countries. He is also adamant that currently accepted RDAs (Recommended Daily Allowances) are totally inadequate to prevent osteoporosis and osteomalacia. He points out that total-body sun exposure easily provides the equivalent of 10,000 IU of vitamin D a day and that this amount is what the human race originating in Africa was originally accustomed to. With our current, officially-sanctioned phobia about sun exposure most people expose only their face and hands to the sun on a regular basis and as a result become woefully deficient. The use of sunscreens prevents the formation of any vitamin D at all and makes matters even worse. A vitamin D deficiency is not only heavily implicated in osteoporosis, but has also been linked to breast cancer, ovarian cancer, prostate cancer, and colon cancer. Recent research has shown that a vitamin D intake of 1300 to 3800 IU/day helps prevent multiple sclerosis and that MS is more prevalent among people deficient in vitamin-D. Dr. Vieth recommends a minimum vitamin D intake from supplements of 800-1000 IU/day and feels that a more optimum intake from sunlight and diet would be 4000 IU/day. He also states that numerous studies have shown that daily intakes as high as 10,000 IU are safe (in the absence of sunshine). Dr. Vieth also points out that the RDA for vitamin D (400 IU/day) used until 1997 was based on the amount of vitamin D found in a teaspoon of cod liver oil. The rationale being that one teaspoon of cod liver oil a day had been found over the years to protect children from rickets! (135 references)
Vieth, Reinhold. Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety. American Journal of Clinical Nutrition, Vol. 69, May 1999, pp. 842-56
Heaney, Robert P. Lessons for nutritional science from vitamin D. American Journal of Clinical Nutrition, Vol. 69, May 1999, p. 825 (editorial)