A study that was recently published in the journal Anticancer Research suggests that current recommendations for vitamin D intake — about 600 international units (IU), according to the National Institutes of Health — are inadequate to prevent cancer.
Researchers from medical schools at the University of California (UC) and Creighton University have found that between 4,000 IU and 8,000 IU of the vitamin may be needed in order for cancer-preventing benefits to occur.
Authors noted that higher concentrations of vitamin D in the blood have been shown to stave off breast cancer, colon cancer, multiple sclerosis and type 1 diabetes.
"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 per day that was needed to defeat rickets in the 20th century," said Cedric Garland, professor of family and preventative medicine at UC San Diego Moores Cancer Center.
A team of scientists examined the vitamin D levels of thousands of volunteers for the study.
They also noted that only about 10 percent of Americans are getting adequate amounts of vitamin D.