July 26, 1996

Researcher’s work provides clues to link between dietary fiber, cancer

Researcher's work provides clues to link between dietary fiber, cancer

A VUMC researcher's investigation of short-chain fatty acids is enabling doctors to better understand the link between dietary fiber and cancer cell growth.

Dr. John Barnard, associate professor of Pediatrics and director of the division of Pediatric Gastroenterology and Nutrition, has studied butyrate, a short-chain fatty acid, on the molecular level for several years and has shown that it has the potential to fight cancer specifically by affecting cancer cell growth.

Barnard will present his work at the upcoming American Institute for Cancer Research (AICR) conference. His address, entitled "Regulation of Intestinal Gene Expression by Short Chain Fatty Acids," will be part of several lectures concerning dietary fat and gene expression.

Butyrate is found in small quantities in the average diet, but the majority of it is produced by the intestinal tract when bacteria ferments dietary fiber. Fiber has been recommended to prevent many diseases and recent studies have shown that a high-fiber diet decreases your chance of getting colon cancer.

"We have known for many years that butyrate has effects on cell growth and differentiation, so we are very interested in how butyrate accomplishes this. My lab has concentrated on understanding the molecular pathways and mechanisms by which butyrate controls intestinal cell growth."

The difference between butyrate and other short-chain fatty acids is the number of carbon atoms.

"The three and five carbon short-chain fatty acids do not affect growth. Butyrate's four carbon structure makes it unique," says Barnard.

Barnard's research has linked butyrate to the expression of c-myc, which is a key regulator of cellular growth. Understanding the relationship between butyrate and c-myc could mean that doctors could pinpoint the way cancer cells are affected by butyrate. This may someday provide a strategy to combat colon cancer on the cellular level.

"There may be some options for treatment as well as prevention," says Barnard. "For example, there is a branch of cancer therapy called "differentiation therapy" and it may be that this will be an important adjunctive treatment of cancer in the future."

Cloning techniques allowed Barnard to identify other genes that butyrate affects and there is hope that, in the long term, butyrate may yield some treatment options not only for cancer, but also for non-cancer related colon disease.

"Butyrate decreases expression of interferon-inducible genes, which may have relevance to inflammatory conditions of the colon, specifically ulcerative colitis, a common condition that gastroenterologists treat," says Barnard.

At the AICR research conference doctors from around the nation will gather to present their findings on the role of dietary fat on cancer cells. The conference, titled Dietary Fat and Cancer: Genetic and Molecular Interactions, will take place August 29-30 in Washington D.C.

"The goal of the conference is to gather investigators interested in the dietary factors that control cancer. It is a coming together of many people that work in a wide variety of areas that relate to dietary fat and cancer and it is an honor to be speaking there," says Barnard.