People with Lynch syndrome have an increased risk for various cancers, such as colorectal, endometrial,upper gastrointestinal (GI), pancreatic, bile duct and others. However, screening for upper GI, pancreatic and bile duct cancers can be challenging and the survival rate is lower than for other Lynch syndrome-associated cancers. Therefore, it’s important to find better prevention measures, particularly for non-colorectal GI cancers.
One promising preventive measure may be a simple dietary component - resistant starch. Resistant starch can be found in bananas, potatoes, grains, beans, peas, seeds and other foods. While most starch is broken down in the small intestine into sugar, resistant starch is not. Instead, resistant starch is partially broken down in the large intestine with the help of gut bacteria.
A recent study reports on 20 years of following people with Lynch syndrome who consumed resistant starch in their diets. Among participants, there were similar rates of colorectal cancer. Surprisingly, they saw fewer non-colorectal cancers associated with Lynch syndrome in the people who consumed resistant starch than in the placebo group. This indicates that resistant starch may lower risk of non-colorectal Lynch syndrome-associated cancers, especially upper GI cancers.
Since screening, diagnosis and management of these cancers are difficult, this finding could lead to a change in the standard of care for people with Lynch syndrome to help reduce their risk for upper GI cancers. It is important to continue to study this association with more people with Lynch syndrome as well as the general population to determine whether resistant starch and dietary fiber reduce the risk of GI cancers in the broader non-hereditary cancer population.