Evidence Suggests Vitamin D May Aid in Cancer Prevention

Often called the "sunshine vitamin" for its link to sunlight exposure, vitamin D has long been associated with bone health. Within the past decade, it's also been suggested that vitamin can lower risks related to cardiovascular disease, depression, diabetes, and cognitive decline, the Endocrine Society reports.??

Now, a new research review adds to evidence that some cancers can be put on that list, too. Research published in Seminars in Cancer Biology notes that low vitamin D levels have been associated with increased risk of various cancers, such as colon, breast, and prostate.?? The evidence is strongest with colorectal cancer and in blood cancers like leukemia and lymphomas.

However, researchers add that despite this connection, supplementation for cancer patients in clinical trials hasn't been promising in lowering mortality rates. That led them to suggest the vitamin may be most effective for cancer prevention rather than part of treatment.

Better Immunity, More Prevention

Every vitamin plays a role in the body, so why would vitamin D stand out as a big player when it comes to cancer prevention, as well as other potential benefits? It probably has to do with how much the vitamin figures into immune function, according to Cristian Ilie, MD, PhD, of The Queen Elizabeth Hospital Foundation Trust in the UK.

Without that response, you'll have increased susceptibility to infection, and less protection when it comes to fighting off invaders such as cancer cells, he says.

You may also be at higher risk for the development of autoimmune diseases, according to a 2019 study in Frontiers in Immunology, which linked low levels of vitamin D to conditions like multiple sclerosis.??

Keep in mind, though, that vitamin D is not an immune-system panacea that cures all ills. Not all studies have shown beneficial effects, noted a 2018 study in Trends in Cancer Research.?? Although there are indications of better immune responses and lower inflammation, more research still needs to be done to resolve the variability among studies, those researchers concluded.

How Much Do You Need?

In terms of how much vitamin D you need daily to see benefits, that's still up for debate. The U.S. government recommended daily allowance is 600 IU, but the Endocrine Society suggests consuming potentially much higher levels of 1,500 to 2,000 IU daily to lower health risks.??

Although supplementation is always an option, you could also rely on that old standby: Sunshine. In general, you only need about 10 to 20 minutes of sun exposure per day to get your daily dose, according to Michael Holick, MD, Ph.D., director of the Bone Health Care Clinic at Boston University Medical Center.

"When you're getting vitamin D through exposure, you want to be smart, so you're not increasing skin cancer risk at the same time," he says, suggesting sunlight on the shoulders, arms, or legs instead of your back or face—the former increases cancer risk and the latter ups your wrinkle and blemish risk. Use sunscreen after you get your initial exposure, he adds.

In addition to sunshine, certain foods are also rich in vitamin D, such as:?

• Mushrooms
• Eggs
• Tuna
• Salmon
• Fortified dairy products