Vitamin D reduced risk for cancer and type 1 diabetes, and most people were deficient in vitamin D, according to four new studies. Scientists have also recently discovered most tissues and cells have dedicated receptors that convert vitamin D to its active form, suggesting vitamin D is more important to overall health than doctors previously knew.
In the cancer study, researchers randomly recruited 1,179 healthy postmenopausal women aged 55 or older, living in rural Nebraska, who took 1,400 to 1,500 mg of calcium per day alone, this dose of calcium plus 1,100 IU of vitamin D3 per day, or a placebo for four years. Compared to placebo, those who took calcium alone were 47% less likely—and those who took calcium with vitamin D3 were 60% less likely—to have cancer. When doctors analyzed cancers diagnosed after the first 12 months, the calcium-vitamin D3 group was 77% less likely to have cancer.
In the diabetes study, doctors followed 10,821 children born in northern Finland for 30 years and found that the 8,577 children who received the recommended 2,000 IU dose of vitamin D per day in the first year of life were 80% less likely to have type 1 diabetes by age 30 than were those who received less vitamin D.
In a study of people with general muscle and bone pain, 93% of 150 participants were deficient in vitamin D, including 100% of African-Americans, American Indians, East Africans and Hispanics, 88% of Southeast Asians and 82% of Whites. Of the 28% overall who were severely deficient in vitamin D, 55% were 35 or younger.
In a sun-exposure study of 93 Hawaii residents who had an average of 11.1 hours of total body skin exposure per week without sunscreen, 51% had low blood fluid (serum) levels of vitamin D.
Scientists are calling for the U.S. government to raise its recommendation for vitamin D3—the more bioavailable form—from 200 IU for children and 400 IU for adults per day to at least 800 IU to 1,000 IU per day for both.