SAN DIEGO, Feb. 23 (UPI) -- Much higher levels of vitamin D than currently recommended may be needed to combat certain cancers and other diseases, U.S. researchers say.
Cedric Garland, professor of family and preventive medicine at University of California, San Diego School of Medicine, and colleagues at the Creighton University School of Medicine in Omaha, say the study involved several thousand volunteers who were taking vitamin D supplements of 1,000 to 10,000 International Units/day.
The study subjects were given blood tests to determine the level of 25-vitamin D -- the form in which almost all vitamin D circulates in the blood.
"We found that daily intakes of vitamin D by adults in the range of 4000-8000 IU are needed to maintain blood levels of vitamin D metabolites in the range needed to reduce by about half the risk of several diseases -- breast cancer, colon cancer, multiple sclerosis and type 1 diabetes," Garland says in a statement. "I was surprised to find that the intakes required to maintain vitamin D status for disease prevention were so high -- much higher than the minimal intake of vitamin D of 400 IU/day that was needed to defeat rickets in the 20th century."
Last December, a National Academy of Sciences Institute of Medicine committee identified 4000 IU/day of vitamin D as safe for everyday use by adults and children age 9 and older and 1000-3000 IU/day for infants and children through age 8.
The findings are published in Anticancer Research.
