Environmental Nutrition

Fitting fiber into your diet is a cancer-preventive strategy. Fiber most clearly protects against colorectal cancer (risk drops 10 percent for each 10-gram increase in fiber). Analysis combining 16 population studies also links higher fiber with lower breast cancer risk. Because fiber is a component of foods with nutrients and plant compounds (phytochemicals) that may help reduce cancer risk, it's difficult to isolate fiber-specific protection.

Fiber's multi-tasking protection

Dietary fiber may work in multiple ways to protect against cancer:

--Reduces intestinal exposure to toxins, dilutes concentration and speeds passage through the gut.

--Feeds healthy bacteria in your intestines that ferment fiber, forming substances that seem to promote colon cell health and fight inflammation as they circulate throughout the body.

--Lowers body estrogen levels by binding it in the colon, thus decreasing risk of estrogen-sensitive cancers.

--Reduces unhealthful levels of insulin, a hormone that seems to promote development of several types of cancer.

--Is linked with lower body weight and less tendency to gain weight, though fiber's specific role is controversial. Since overweight and obesity increase the risks of nine forms of cancer, this link has important cancer prevention potential.

Fiber's many forms

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