Researchers at the University of Colorado Cancer Center have shown that resistant starch may help in the prevention of IBD (inflammatory bowel disease) and colorectal cancer.
The team point out that, as the name suggests, resistant starch can’t be digested, so it ends up in the bowel in pretty much the same form it enters the mouth. Once in the bowel, this resistant starch decreases bowel pH and transit time, and increases the production of short-chain fatty acids. These effects promote the growth of good bacteria while minimising bad bacteria.
The review, published in Current Opinion in Gastroenterology, shows that resistant starch also helps the body resist colorectal cancer through mechanisms including killing pre-cancerous cells and reducing inflammation that can otherwise promote cancer.
“Resistant starch is found in peas, beans and other legumes, green bananas, and also in cooked and cooled starchy products like sushi rice and pasta salad,” said Janine Higgins, PhD, CU Cancer Center investigator and associate professor of Pediatrics at the University of Colorado School of Medicine. “You have to consume it at room temperature or below – as soon as you heat it, the resistant starch is gone. But consumed correctly, it appears to kill pre-cancerous cells in the bowel.”
Higgins describes studies showing that rats fed resistant starch show decreased numbers and sizes of lesions due to colorectal cancer, and an increased number of cells that express the protein IL-10, which acts to regulate the body’s inflammatory response.
”Resistant starch may also have implications for the prevention of breast cancer,” Higgins said. “For example, if you let rats get obese, get them to lose the weight, and then feed half of the rats a diet high in resistant starch – these rats don’t gain back the weight as fast as rats fed a regular, digestible starch diet. This effect on obesity may help to reduce breast cancer risk as well as having implications for the treatment of colorectal cancer.”
“There are a lot of things that feed into the same model of resistant starch as a cancer-protective agent,” Higgins concluded. “Much of this information currently comes from rodent models and small clinical trials but the evidence is encouraging.”