Vitamin D, also called the sunshine vitamin, is essential for supporting bone health and immune system function. However, researchers have also explored vitamin D to see if it can help prevent certain cancers, due to its role in controlling cell growth, division, and apoptosis.

Data published in the New England Journal of Medicine in 2019, based on the largest randomized clinical trials on the topic, show that vitamin D supplementation did not significantly reduce the overall incidence of invasive cancer in the general population compared to placebo. However, when researchers looked at specific cancer types, the VITAL study revealed a statistically significant 38% decrease in total cancer mortality (deaths from cancer) among participants who took vitamin D for at least two years. Of more than 25,000 men and women in the study, those who took 2,000 international units of vitamin D daily for an average of 5.3 years were nearly 20% less likely than the placebo group to develop advanced metastasized cancer. Still, researchers did not find a benefit in overweight or obese individuals.  

There is a strong association between colorectal cancer and vitamin D supplementation. Data published in JAMA Network Open showed that people who regularly took vitamin D had about a 17-25% lower risk of developing advanced colorectal adenomas or cancer, suggesting a potential benefit in protecting against gastrointestinal malignancies.

While vitamin D is important for overall health, it cannot be universally and definitively recommended as a cancer preventative, according to the National Cancer Institute and other medical organizations. However, due to the connection between vitamin D and cancer mortality, supplementing with vitamin D is a low-risk option that individuals can consider. It’s always best to consult a doctor for personalized advice on suitable supplementation doses and health strategies.