Resistant starch appears to reduce inflammation and kill off pre-cancerous cells in the lower gut, according to a new review appearing inCurrent Opinion in Gastroenterology.
Led by Janine Higgins from the University of Colorado Cancer Center, USA, the research team noted that once in the bowel, resistant starch has several important including decreasing bowel pH and transit time, and increasing the production of short-chain fatty acids.
These effects promote the growth of ‘good’ bacteria while keeping ‘bad’ ones at bay, all of which can help in the prevention of inflammatory bowel disease (IBD), they said.
However, Higgins and her colleagues also noted that the resistant starch could help to reduce the risk of developing colorectal cancer through mechanisms including killing pre-cancerous cells and reducing inflammation that can otherwise promote cancer.
“You have to consume it at room temperate or below – as soon as you heat it, the resistant starch is gone,” said Higgins. “But consumed correctly, it appears to kill pre-cancerous cells in the bowel."
"There are a lot of things that feed into the same model of resistant starch as a cancer-protective agent," she said.
"Much of this information currently comes from rodent models and small clinical trials but the evidence is encouraging."
Study details
The new review describes advances in research for the health benefits of resistant starch, highlighting gastrointestinal effects that are now being linked to systemic, whole body effects with clinical relevance.
Higgins and her team review 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.
These effects have important implications for overall health and the prevention or amelioration of various chronic diseases, they said.
"Resistant starch may also have implications for the prevention of breast cancer," added Higgins. "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,” she said.
Source: Current Opinion in Gastroenterology
Volume 29 - Issue 2 - p 190–194, doi: 10.1097/MOG.0b013e32835b9aa3
“Resistant starch: a promising dietary agent for the prevention/treatment of inflammatory bowel disease and bowel cancer”
Authors: Higgins, Janine A; Brown, Ian L.