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Low-carb diet cuts risk of colon cancer, study finds

July 18, 2014

TORONTO, ON — Researchers at the Uni­ver­si­ty of Toron­to have found that gut bac­te­ria dri­ves a com­mon form of colon can­cer and that a low-car­bo­hy­drate diet can pre­vent the dis­ease.

Researchers found that microbes in the intes­tine con­vert car­bo­hy­drates into metabo­lites that spur can­cer growth. A low-car­bo­hy­drate diet shut down this process and led to a 75 per cent reduc­tion in can­cer inci­dence.

“Our results sug­gest that a diet low in car­bo­hy­drates could ben­e­fit those with a genet­ic pre­dis­po­si­tion to colon can­cer,” said Alber­to Mar­tin, a Pro­fes­sor in the Depart­ment of Immunol­o­gy at U of T who holds the Cana­da Research Chair in Anti­body Diver­si­fi­ca­tion.

“About 20 per cent of colon can­cers thrive on muta­tions in genes involved in DNA mis­match repair. For this type of can­cer, our study offers an expla­na­tion for the inter­play among genet­ics, diet and intesti­nal micro­bio­ta,” said Mar­tin.

No oth­er research has explained the inter­ac­tion of those three fac­tors in colon can­cer, although sev­er­al stud­ies have shown a link among them. As well, Mar­tin and his team found that inflam­ma­tion did not play a role in colon can­cer, despite evi­dence from oth­er stud­ies that it pro­motes the dis­ease.

The researchers did their study in mice, but with a low-car­bo­hy­drate, high-pro­tein diet that humans could repli­cate. The results also pro­vide a poten­tial expla­na­tion for many stud­ies in humans that have linked colon can­cer to the “West­ern diet,” which is gen­er­al­ly rich in com­plex car­bo­hy­drates such as pas­ta and bread, and in sat­u­rat­ed fats from red meat and cheese.

In the West­ern world, about one in 15 peo­ple will get colon can­cer. In Cana­da, the dis­ease is the sec­ond-lead­ing cause of can­cer-relat­ed death, claim­ing about 5,000 lives a year.

Mar­tin and his lab are now test­ing whether the low-carb diet could be an effec­tive treat­ment in mice with advanced colon can­cer, and are plan­ning work with clin­i­cal researchers to see if a dietary change can improve out­comes for peo­ple with colon can­cer.

The Mar­tin lab is also exper­i­ment­ing with antibi­otics as a poten­tial treat­ment for colon can­cer. “Our ear­ly research on this project showed that one metabo­lite in par­tic­u­lar — butyrate — is a key dri­ver of colon can­cer, so it’s con­ceiv­able that antibi­otics that lim­it butyrate could help pre­vent or con­trol colon can­cer,” said Mar­tin. The lab is also look­ing at whether butyrate could be a bio­mark­er for colon can­cer risk.

The jour­nal Cell pub­lished the study online today.

The research was fund­ed by the Cana­di­an Insti­tutes of Health Research, the Can­cer Research Soci­ety, the Lotte and John Hecht Memo­r­i­al Foun­da­tion grant of the Cana­di­an Can­cer Soci­ety, and the Cana­da Research Chairs pro­gram.


For more infor­ma­tion, please con­tact:

Hei­di Singer
Media Rela­tions Spe­cial­ist
Temer­ty Temer­ty Fac­ul­ty of Med­i­cine, Uni­ver­si­ty of Toron­to
Tel: 416–978-5811