Vitamin D lowers the risk of cancer, but exactly how much vitamin D do you need?
Higher levels of the sunshine vitamin have been linked to lower risks of diabetes, heart disease, multiple sclerosis and cancer. Researchers first discovered that vitamin D lowered the risk of colon cancer after linking higher prevalence of certain cancers to populations in higher latitudes, which had less exposure to sunlight. Since then, vitamin D has been linked to lower risks of breast, lung and bladder cancer.
Researchers have now discovered just how much vitamin D a person needs to enjoy it's cancer-combating effects.
"We have quantitated the ability of adequate amounts of vitamin D to prevent all types of invasive cancer combined, which had been terra incognita until publication of this paper," said Cedric Garland, researcher and adjunct professor at the UC San Diego School of Medicine Department of Family Medicine and Public Health.
To determine the quantity of vitamin D needed to protect against cancer, Garland and his team examined the levels of the serum 25-hydroxyvitamin D in blood samples.
The latest research included data from previous studies involving 2,304 women. The researchers found that cancer rates declined with increased levels of 25-hydroxyvitamin D. Further analysis revealed that women with 25-hydroxyvitamin D concentrations of 40ng/ml or more were 67 percent less likely than those with levels of 20 ng/ml or less to develop cancer.
The study did not reveal whether supplementation or sun exposure was the best way to obtain vitamin D.
However, the researchers concluded that vitamin D only starts protecting against cancer at 40 ng/ml. They noted that more health benefits were observed at higher levels of 25-hydroxyvitamin D.
"These findings support an inverse association between 25(OH)D and risk of cancer, and highlight the importance for cancer prevention of achieving a vitamin D blood serum concentration above 20 ng/ml, the concentration recommended by the IOM for bone health," Garland explained.
"Primary prevention of cancer, rather than expanding early detection or improving treatment, will be essential to reversing the current upward trend of cancer incidence worldwide," researchers wrote in the study. "This analysis suggests that improving vitamin D status is a key prevention tool."
The findings were published in the April 6 issue of the journal PLOS ONE.
