Scientists suggest daily intake of vitamin D helps to reduce disease frequency

University of California - RiversideAug 10 2010

Vitamin D is effective in reducing frequency of many diseases and cost of medical care, stresses UC Riverside's Anthony Norman

Anthony Norman, a leading international expert in vitamin D, proposes worldwide policy changes regarding people's vitamin D daily intake amount in order to maximize the vitamin's contribution to reducing the frequency of many diseases, including childhood rickets, adult osteomalacia, cancer, autoimmune type-1 diabetes, hypertension, cardiovascular disease, obesity and muscle weakness.

"A reduction in the frequency of these diseases would increase the quality and longevity of life and significantly reduce the cost of medical care worldwide," said Norman, a distinguished professor emeritus of biochemistry and biomedical sciences at the University of California, Riverside. "It is high time that worldwide vitamin D nutritional policy, now at a crossroads, reflects current scientific knowledge about the vitamin's many benefits and develops a sound vision for the future."

Currently, the recommended daily intake of vitamin D in the United States is 200 international units (IU) for people up to 50 years old; 400 IU for people 51 to 70 years old; and 600 IU for people over 70 years old. Today there is a wide consensus among scientists that the relative daily intake of vitamin D should be increased to 2,000 to 4,000 IU for most adults.

"Worldwide public health is best served by a recommendation of higher daily intakes of vitamin D," Norman said. "Currently, more than half the world's population gets insufficient amounts of this vitamin. At present about half of elderly North Americans and Western Europeans and probably also of the rest of the world are not receiving enough vitamin D to maintain healthy bone."

Reporting in a review paper in the July 28, 2010, issue of Experimental Biology and Medicine, Norman and Roger Bouillon of the Laboratory of Experimental Medicine and Endocrinology at the Katholieke Universiteit Leuven, Belgium, warn that if the current nutritional guidelines for vitamin D remain unchanged, rickets and osteomalacia, which could be easily prevented, will continue to occur.

They add that if the present guidelines for vitamin D intake are strictly implemented and applied worldwide to pregnant or lactating women, newborns and children, the occurrence of rickets in infants could be effectively eradicated.

Norman, the first author of the review paper, and Bouillon note that if the daily dietary intake of vitamin D is increased by 600-1000 IU in all adults above their present supply, it would bring beneficial effects on bone health in the elderly and on all major human diseases (e.g., cancer, cardiovascular, metabolic and immune diseases).

The researchers add, however, that if the vitamin D dietary intake were increased to 2000 IU per day and even more for subgroups of the world population with the poorest vitamin D status, it could favorably impact multiple sclerosis, type-1 diabetes, tuberculosis, metabolic syndrome, cardiovascular risk factors and most cancers.