How A High-Fat Diet Can Increase Cancer Risk

The fact that our diets affect our risk for various diseases is not new–in fact, science has shown that what we eat is linked to everything from diabetes to dementia to cancer. Colon cancer is one that’s known to be especially dependent upon what we put in our bodies and to body weight. And now, a new study in Nature discovers more about why a high-fat diet is linked to colon cancer risk–it has to do with how stem cells in the gut accrue molecular damage over time. This is not at all a suggestion to cut out fat, but perhaps more a reminder to keep an eye on fats, and to choose the ones we do eat wisely.

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“We wanted to understand how a long-term high-fat diet influences the biology of stem cells, and how such diet-induced changes that occur in stem cells impact tumor initiation in the intestine,” says study author Omer Yilmaz.
To suss this out, he and his team fed mice diets that were 60% fat, for a period of nine to 12 months. The mice in this group gained a lot of weight–by the end, they weighed 30% to 50% more than their counterparts who ate a diet of regular lab chow. The mice eating the high-fat diet also developed more tumors in their intestines than control mice.
What seemed to underlie this difference, the researchers found, was the fact that intestinal stem cells proliferated in the obese mice–the cells were also able to operate more independently, without the usual cues from surrounding cells. The team discovered, too, that the stem cells’ “daughters,” progenitor cells, lived much longer in the obese mice, and started mimicking the behavior of stem cells.
“This is really important because it’s known that stem cells are often the cells in the intestine that acquire the mutations that go on to give rise to tumors,” Yilmaz says. “Not only do you have more of the traditional stem cells (on a high-fat diet), but now you have non-stem-cell populations that have the ability to acquire mutations that give rise to tumors.”