If you needed another good reason to play in the sun this summer, a new study has uncovered evidence that vitamin D can help protect against colorectal cancer. Previous studies looking at the link between vitamin D levels and colorectal cancer were inconclusive. However, this new study, led by the Harvard T.H. Chan School of Public Health, now adds evidence to the link between low vitamin D levels and colorectal cancer.
Researchers analyzed more than 5,700 colorectal cancer cases as well as 7,100 cases of people without the disease from around the world. Researchers found that the amount of vitamin D we need to prevent this type of cancer could be much higher than the current guidelines, which focused on preventing osteoporosis.
Colorectal cancer, also called colon or rectal cancer, is the third-leading cause of cancer death in men and women in the United States. However, the country’s aging population may increase that number. Adults in their 50’s experience more than double the rate of colorectal cancer compared to those in their 40’s. The American Cancer Society has even lowered their colorectal cancer screening recommendationto age 45 for people of average risk based on new data showingrising rates of colorectal cancer in people under age 50.
According to the new study, optimum bone health (which is strongly affected by vitamin D levels) was linked to a 22 percent lower risk of colorectal cancer. This link persisted, even after researchers adjusted for typical colorectal cancer risk factors. However, when compared to study participants with vitamin D levels considered high enough for optimum bone health, those that were deficient in vitamin D had a 31 percent higher risk of colorectal cancer five years later.
“Our study shows that having higher levels above bone health are associated with lower colorectal cancer,” Stephanie Smith-Warner, a Harvard epidemiologist and one of the senior authors of the study, told the Washington Post. Researchers concluded that although cancer risk was reduced in all groups, women benefited the most from maintaining vitamin D levels above those needed for optimum bone health.