A new review of research indicates that vitamin D may help lower the risk of developing colorectal cancer. The findings come as rates of colon cancer are rising, particularly among younger adults.
Researchers analyzed data from 50 studies involving more than 1.3 million participants to understand the relationship between vitamin D and colorectal cancer prevention. They found that low levels of vitamin D are strongly linked to a higher risk of the disease.
A meta-analysis showed that people with higher vitamin D levels, measured by blood test, had a 39% lower risk of colorectal cancer compared to those with lower levels. When levels were tracked over time, those with higher levels had a 20% reduced risk.
A separate landmark study from 1996 found that women with the highest vitamin D intake were 58% less likely to develop colorectal cancer than those with the lowest intake. Other studies showed supplemental vitamin D and calcium were associated with reduced risk.
In a Canadian study, vitamin D supplements reduced the risk of polyps, which can develop into cancer, by 33% and the risk of high-risk polyps by 43%.
While the exact mechanisms are not fully confirmed by the review, laboratory and animal studies suggest the active form of vitamin D in the body may slow cancer cell growth, trigger cell death, support gut health, and reduce inflammation.
Despite potential benefits, many people have low levels of the vitamin. A 2025 study of over 5,600 U.S. adults found that 42% were vitamin D deficient and 37.6% had insufficient levels. This means nearly 80% of adults studied had low vitamin D.
Researchers emphasized the importance of maintaining blood levels in the range of 30 to 40 nanograms per milliliter, noting many could benefit from levels around 50 ng/mL.
Vitamin D is found naturally in some foods like cod liver oil, trout, and salmon, and in fortified foods like milk and eggs. For individuals with low levels, a daily supplement of vitamin D3, typically between 2,000 and 5,000 International Units, is often recommended, with levels improving within months.
Vitamin D status is one modifiable lifestyle factor connected to colorectal cancer risk. Regular health screenings, recommended starting at age 45, remain important for early detection and treatment.
The broader context of nutritional research continues to examine the role of vitamins in disease prevention. Studies on vitamin D often intersect with research on bone health, immune function, and other chronic conditions, highlighting its widespread importance in public health discussions.
