Vitamin D can lower the risk of THIS type of cancer

Colorectal cancer is one of the most common cancers worldwide. Over the years, conversations around prevention have shifted towards lifestyle, diet, and the role of certain vitamins. One nutrient that keeps cropping up in research is vitamin D. Quite commonly known as the “sunshine vitamin,” this compound is now being looked at for something more serious than bone health its potential to prevent or even slow down colorectal cancer (CRC).


Here’s all we need to know about what the science says, and what it really means.


A growing number of studies suggest that people with higher levels of vitamin D have a lower risk of developing colorectal cancer. In fact, a major meta-analysis found a 39% reduced risk in certain studies, and a 20% reduced risk in longer-term, prospective studies. This link first came to light when researchers noticed that areas with less sunlight (and therefore less vitamin D) had higher colorectal cancer death rates.



But is that the whole story?
Vitamin D doesn’t just float around in the bloodstream. Once it becomes calcitriol, its active form, it gets to work deep inside the body. Here's what calcitriol is known to do, especially when it comes to cancer cells:

Slows down the growth of cancer cells

Promotes the natural death of abnormal cells (apoptosis)

Helps healthy cells mature properly

Prevents tumors from building new blood vessels (antiangiogenesis)

That means vitamin D doesn't just “support” the body—it actively helps keep cancer cells in check.



The gut is where colorectal cancer begins and vitamin D plays an important role in keeping this area healthy. It helps maintain intestinal cell integrity, ensuring the cells lining the colon grow in an orderly fashion. It also has an important impact on the gut microbiome.


In people with CRC, the gut shows a clear shift: harmful bacteria like Fusobacterium nucleatum increase, while beneficial species like Akkermansia muciniphila go down. Low vitamin D levels make this imbalance worse, which can lead to inflammation and a higher risk of cancer.


A deficiency in vitamin D is now seen as a serious risk factor for colorectal cancer. People who don’t get enough sun, who have darker skin, or who follow a low-vitamin D diet may be at greater risk without even knowing it.


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This isn't just about long-term risk deficiency can also speed up disease progression in people already diagnosed with CRC. That’s why many oncologists are beginning to pay attention to vitamin D levels during treatment.


Still, the current body of evidence is strong enough that maintaining healthy vitamin D levels is now considered an important strategy, not just for bone health, but also for long-term protection against serious diseases like CRC.