Most Americans are not getting enough vitamin D, a fact that may put them at risk for developing cancer, according to a landmark study conducted at Creighton University School of Medicine.
The study followed older women for 4 years. During that time, the women who were taking vitamin D supplements had a dramatic reduction in risk for cancer when compared with women who did not get the vitamin.
Vitamin D enhances the body’s immune response to potential cancer cells, said Joan Lappe, PhD, RN, professor of medicine and the study’s director.
Study participants took 1,100 IU of vitamin D3 (an animal form of the vitamin that is more active and effective in humans than D2, made from plant sources). The dosage is also 2 to 3 times more than the current recommended daily requirement, which the researchers think should be increased for all. Supplements can be taken with or without meals and do not have to be spaced throughout the day. No side effects were noted.
There is a growing body of evidence that a higher intake of vitamin D for both men and women may be helpful in the prevention and treatment not only of cancer, but also high blood pressure, fibromyalgia, type 1 diabetes, multiple sclerosis, and rheumatoid arthritis and other diseases, the researchers said.
Humans make their own vitamin D3 when they are exposed to sunlight. In fact, only 10-15 minutes a day in a bright summer sun creates large amounts of the vitamin. But exercise caution because the sun’s ultraviolet B rays also can cause skin cancer. Sunscreen blocks most vitamin D production.
Also, the latitude at which you live and your ancestry also influence your body’s ability to convert sunlight into vitamin D. People with dark skin have more difficulty making the vitamin. People living at latitudes north of the 37th parallel – Omaha is near the 41st parallel – cannot get their vitamin D naturally during the winter months because of the sun’s angle.
The results of the study were reported in the online edition of the American Journal of Clinical Nutrition.