“We think that resistant starch may reduce cancer development by changing the bacterial metabolism of bile acids and to reduce those types of bile acids that can damage our DNA and eventually cause cancer. However, this needs further research,” said Professor John Mathers from Newcastle University. He is one of the co-authors of the latest study about the benefits of resistant starch in green bananas.
The 20-year study involved 900 patients with Lynch Syndrome (LS), formerly known as hereditary nonpolyposis colorectal cancer. Those afflicted by LS have a gene that causes cancer in their families. This condition increases their risk of developing colon cancer and other types of cancer.
Based on the findings of Prof. Mathers and his fellow researchers from the University of Leeds and Newcastle University, the resistant starch that green bananas contained provided a protective effect to the participants against non-colorectal LS cancers. The team used a dose that was equivalent to a green banana (before the fruit becomes too ripe and soft) eaten every day.
According to them, the effect of the resistant starch was especially evident for upper gastrointestinal (GI) cancers, which include the following:
- Stomach/gastric cancer: cancer in the stomach lining
- Bile tract cancer: cancer in the organs that are responsible for the production and storage of bile, which helps in the digestion of fats and elimination of wastes
- Pancreatic cancer: cancer in the pancreas, which is responsible for the production of enzymes and hormones
- Duodenal cancer: cancer in the first part of the small intestine, which is next to the stomach
The Johns Hopkins Patient Guide to Diabetes defines resistant starch as a carbohydrate that does not get digested in the small intestine and is fermented in the large intestine, which is beneficial.
“Gut health is improved as fermentation in the large intestine makes more good bacteria and less bad bacteria in the gut. Healthy gut bacteria can improve glycemic control,” stated their website.
However, further research is still needed to determine if resistant starch in green bananas will have the same protective effect against cancer in the general population.
“The biologic mechanisms underlying these specific cancers can be heterogeneous and therefore, the impact of resistant starch supplements may or may not be the same in those without LS. This could be done in trial testing resistant starch supplements in people without LS,” Corinne Joshu, a cancer researcher at the Johns Hopkins Kimmel Cancer Center and an epidemiologist at the Johns Hopkins Bloomberg School of Public Health, told Newsweek.Whizzco