Discovered which dietary supplement can reduce the risk of hereditary cancer by as much as 60 percent
A 20-year study involving nearly a thousand participants worldwide has made an important discovery – people with higher chances of developing certain types of cancer can reduce their risk of this disease by as much as 60 percent with a simple dietary supplement.
It is resistant starch, a special type of starch that passes through the small intestine and is then fermented in the large intestine, where it feeds the beneficial intestinal bacteria.
The results of the study were so convincing in reducing the risk of upper gastrointestinal (GI) cancer that researchers now want to repeat them to make sure they didn't miss anything.
"We found that resistant starch reduced many types of cancer by more than 60 percent. The effect was most evident in the upper intestine," says the lead researcher and nutritionist John Mathers one Newcastle University in great Britain.
Cancers of the upper digestive system include cancers of the esophagus, stomach, and pancreas.
"The results are exciting, but the magnitude of the protective effect was unexpected, so further research is needed to replicate these findings," adds one of the researchers, Tim Bishop, a genetic epidemiologist at The University in Leeds.
Resistant or resistant starch can be purchased as a fiber-like supplement and is found naturally in a range of foods, including light green bananas, oats, cooked and cooled pasta and rice, peas and beans.
The research was conducted between 1999 and 2005 and involved a group of 918 people with a condition known as Lynch syndrome. It is one of the most common genetic predispositions to cancer that we know of, with an estimated one in 300 people carrying the associated gene.
Those who inherit the genes for Lynch syndrome have a significantly increased risk of developing colorectal cancer, as well as cancer of the stomach, endometrium, ovaries, pancreas, prostate, urinary tract, kidneys, bile ducts, small intestine and brain.
To figure out how to reduce this risk, participants were randomly divided into two groups, where 463 of them unknowingly received a daily dose of 30 grams of resistant starch in powder form for two years – roughly equivalent to taking a not quite ripe banana a day.
The other 455 people with Lynch syndrome took a placebo in the form of starch powder every day, but which did not contain the active ingredients.
The groups of people were then followed for the next 10 years.
During the follow-up period, there were only 5 new cases of upper gastrointestinal (GI) cancer among 463 people taking resistant starch. Compared to 21 cases of upper digestive tract cancer in 455 people in the placebo group, that's a pretty significant reduction.
However, there was one area where resistant starch didn't make much of a difference, and that was the group of people with bowel cancer.
Although more detailed research is needed to understand exactly what is involved, the scientists said: "We think that resistant starch can reduce the development of cancer by changing the bacterial metabolism of bile acids and reducing those types of bile acids that can damage our DNA and eventually cause cancer," Mathers says, adding that further research needs to be done.
The trial was conducted on people already genetically predisposed to developing cancer and may not necessarily apply to the general public, but much can be learned by better understanding how resistant starch can help protect against cancer.