The trial, which lasted more than 20 years and included about 1,000 participants worldwide, had an important result – people with conditions that give them a greater chance of developing certain types of cancer can reduce the risk of some of these cancers by more than 60 percent. starch is more stable in their diet.
In fact, the results were so convincing when it came to reducing the risk of upper gastrointestinal (GI) cancers that researchers are now looking to replicate them to make sure nothing is lost.
“We found that resistant starch reduced the range of cancers by more than 60 percent. The effect was most pronounced in the upper part of the intestine,” says lead researcher and nutritionist John Mathers of Newcastle University in the UK.
Upper GI cancers include cancers of the esophagus, stomach, and pancreas.
“The results are interesting, but the magnitude of the protective effect in the upper GI tract was unexpected, so further studies are needed to replicate these findings,” adds one of the researchers, Tim Bishop, a genetic epidemiologist at the University of Leeds.
Resistant starch is a type of starch that passes through the small intestine and then ferments in the large intestine, where it feeds beneficial gut bacteria. It can be purchased as a fiber supplement and occurs naturally in a number of foods, including small amounts of green bananas, oats, cooked and chilled pasta and rice, beans and peas.
The double-blind trial was conducted from 1999 to 2005 and included 918 people with a condition called Lynch syndrome. Lynch syndrome is one of the most common genetic predispositions to cancer, with approximately one in 300 people carrying the gene for it.
People who inherit the Lynch syndrome gene have a significantly increased risk of developing colorectal cancer, as well as cancers of the stomach, endometrium, ovary, pancreas, prostate, urinary tract, kidney, bile duct, small intestine, and brain.
To find out how to reduce this risk, participants were randomly assigned to one of two groups, and 463 people were unknowingly given a daily dose of 30 grams of powdered resistant starch for two years. a banana every day.
Another 455 people with Lynch syndrome took a daily placebo that looked like powdered starch but did not contain the active ingredients.
Both groups were followed up after 10 years. The results of this study have just been published by the researchers.
During the follow-up period, there were only 5 new cases of upper gastrointestinal cancer among 463 people who received resistant starch. This compares with 21 upper GI cancers out of 455 people in the placebo group – a very remarkable reduction.
“This is important because upper GI tract cancers are difficult to detect and often go undetected early,” says Mathers.
However, there is one area where resistant starch doesn’t make much of a difference – the rate of bowel cancer.
Further work is needed to determine exactly what’s going on here, but the team has some ideas.
“We think that resistant starch may reduce the development of cancer by altering the bacterial metabolism of bile acids and may reduce the types of bile acids that damage DNA and ultimately cause cancer,” says Mathers.
“However, this requires further study.”
To be clear, this trial was conducted on people with a genetic predisposition to cancer and is not applicable to the general public. But we can learn a lot by better understanding how resistant starch helps protect against cancer.
The initial trial was called the CAPP2 study, and the team is now conducting a follow-up study, called CaPP3, involving more than 1,800 people with Lynch syndrome.
Colorectal cancer rates may seem unaffected by resistant starch, but don’t worry, research has some good news on that front as well.
The first trial also looked at whether taking daily aspirin could reduce the risk of cancer. In 2020, the team published results showing that aspirin reduced the risk of colon cancer by 50 percent in patients with Lynch syndrome.
“Patients with Lynch syndrome have a higher risk of developing cancer, so it is important to find that aspirin can halve the risk of colon cancer and other types of resistant starch,” said Sir John Burns, a geneticist at the University of Newcastle. Judge Mathers v.
“Based on our judgment, NICE [the UK’s National Institute for Health and Care Excellence] now we recommend Aspirin for people with a high genetic risk of cancer, the benefits are clear – aspirin and resistant starch work.
The study was published Cancer Prevention Research.