Three new studies from the Moores Cancer Center at the University of California, San Diego, have strongly linked vitamin D with lower risk for breast, colon, and kidney cancers.

In the breast cancer study, researchers analyzed the blood-fluid (serum) levels of vitamin D in 1,760 individuals and found that those who had the lowest levels of 25-hydroxyvitamin D had the highest rates of breast cancer, and that as the levels of vitamin D increased, breast cancer rates dropped.

In the colon cancer study, published in the February 2007 issue of the American Journal of Preventive Medicine, scientists reviewed findings from five different studies that took blood samples from healthy volunteer donors, and then followed up for 25 years. Researchers divided 1,448 participants into five equal groups according to the serum levels of vitamin D and found that those who had 34 nanograms of vitamin D per milliliter of blood (ng/ml) were 50 percent less likely to have colon or rectal (colorectal) cancer than were those with the lowest levels. In the studies, vitamin D levels ranged from below 13 ng/ml to 52 ng/ml. Doctors projected that those who get a total of 2,000 IU of vitamin D3 per day from diet, supplements, and sunshine will be 66 percent less likely to get colorectal cancer compared to those with the lowest vitamin D levels.

In the kidney cancer study, published in the International Journal of Cancer, researchers for the first time were able to use data from 175 countries and found that those who live closest to the equator—where sunlight is strongest—have the least kidney (renal) cancer.

Reference: Journal of Steroid Biochemistry and Molecular Biology; Feb., 2007, Vol. 103, No. 2.

     Those with higher levels of vitamin D had better physical performance and muscle strength than those with lower levels, according to results from a new study.

     Researchers from Wake Forest University School of Medicine, Winston-Salem, North Carolina, recruited 976 people, aged 65 or older, average age 74.8, from two towns in the Chianti area of Italy. Scientists measured physical performance including walking speed, ability to stand up from a seated position, maintain balance in several increasingly difficult postures, and hand grip strength. Those who had low levels of vitamin D scored 5% to 10% lower in physical performance tests and hand grip strength than those with higher levels. Research does not show that low vitamin D levels cause poor physical performance, but doctors noted that muscles need vitamin D to function properly.

     Separately, medical experts from Harvard Medical School, Boston, have recently concluded that the optimal level for vitamin D begins at 75 nanomoles per liter of blood (nmol/L). In the Chianti study, nearly 75% of women and 51% of men had insufficient levels of vitamin D, meaning 50 nmol/L or less. Approximately 29% of women and 14% of men were deficient in vitamin D, which doctors classified as 25 nmol/L or less. Harvard researchers stated that the average adult would require 560 IU of vitamin D per day to raise the level by 10 nmol/L.

     The U.S. Department of Agriculture currently recommends 200 IU of vitamin D per day for those under 50, 400 IU per day for those 50 to 70, and 600 IU per day for those over 70. There is a growing consensus in the medical community that vitamin D is safe at higher levels, that many people are deficient or insufficient in vitamin D, and that the government should raise its recommendations.

Reference: Journal of Gerontology: 2007; Vol. 62, 440-6.

     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 living in rural Nebraska, aged 55 or older, 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 most absorbable 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.

Reference: Journal of Clinical Endocrinology & Metabolism: 2007; Vol. 92, 2130-5.