Is higher dietary fiber intake associated with lower risk of colorectal cancer?

Dietary fiber refers to the parts of plant foods your body can’t digest, like those found in beans, whole grains, vegetables, and fruits. It passes through your digestive system mostly unchanged and may help move waste through your colon more efficiently. The studies we reviewed relied on detailed food records, which are considered a reliable way to track what people actually eat over time.

What we’ve found so far suggests a consistent link between higher fiber intake and reduced chances of colorectal cancer, but we cannot say fiber directly prevents it. The connection remains after adjusting for other habits, which makes the pattern harder to dismiss as coincidence. Still, we don’t know if fiber itself is the reason, or if people who eat more fiber also tend to eat fewer processed foods, drink less alcohol, or have other habits that might play a role.

Our current analysis shows no evidence against this association, but we also can’t rule out that other unmeasured factors might be involved. The evidence we’ve reviewed leans toward a protective relationship, but more research is always needed to understand the full picture.

In everyday terms: if you’re trying to lower your risk of colorectal cancer, eating more fiber-rich foods like oats, lentils, broccoli, and apples is a simple, safe choice that aligns with what we’ve seen so far.