Current government recommendations of 400 or 600 international units (IU) of vitamin D a day are insufficient to prevent serious diseases like breast cancer, a new study published in the journal Anticancer Research has found. Researchers from the University of California, San Diego (UCSD) School of Medicine and Creighton University (CU) School of Medicine discovered that when much higher doses of vitamin D are taken daily, the risks associated with developing several major diseases are reduced by about half.
"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," said Cedric Garland, DrPH, professor of family and preventive medicine at the UCSD Moores Cancer Center.
"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."
A review of several thousand volunteers taking between 1,000 and 10,000 IU/day of vitamin D revealed that much higher daily intakes of vitamin D are required to achieve blood serum levels of vitamin D in the healthy range of 40 to 60 nanograms per milliliter (ng/mL), or higher. And those who daily take such mega-doses of vitamin D in order to maintain these levels are much less likely to develop serious disease.
"Now that the results of this study are in, it will become common for almost every adult to take 4,000 IU/day," said Garland. "This is comfortably under the 10,000 IU/day that the Institute of Medicine (IOM) Committee Report considers as the lower limit of risk, and the benefits are substantial. Now is the time for virtually everyone to take more vitamin D to help prevent some major types of cancer, several other serious illnesses, and fractures."