Researchers at Newcastle University and the University of Leeds in the United Kingdom in a finding that appears in Cancer Prevention Research found that a Resistant starches(RS) powder supplement may help prevent cancer in people with Lynch syndrome.
Nearly 1,000 Lynch syndrome sufferers participated in the experts’ international CAPP2 experiment.
For an average of two years, they administered a 30g dosage of RS to the individuals. As anticipated, the supplements had no impact on colorectal malignancies. Unexpectedly, though, its preventive value was most pronounced in the upper digestive tract, where tumours are more likely to be severe and go undetected.
Dr. Anton Bilchik, surgical oncologist and division chair of general surgery at Providence Saint John’s Health Center and chief of medicine at Saint John’s Cancer Institute in Santa Monica, CA. who was not involved in the study, shared that Lynch syndrome(LS) is caused by a genetic mutation that stops the DNA from being able to correct itself after cell division as effectively as it should, which can give rise to cancers. It occurs in about 1% of patients with colorectal cancer.
The U.K.’s National Institute for Health and Care Excellence (NICE) recommends that people with LS take aspirin daily for at least two years to help prevent colorectal cancer. Until now, prophylactic surgery to remove noncancerous organs or glands was considered the only preventive measure against LS-related cancers outside the colon. The CAPP2 trial analyzed the long-term effects of aspirin and RS on cancer onset in patients with Lynch syndrome.
A total of 463 participants took 30 g of RS daily for up to four years, and 455 subjects took a placebo. Earlier research during the trial found that aspirin reduced colorectal cancer by 50%. A total of 463 participants took 30 g of RS daily for up to four years, and 455 subjects took a placebo.
The dose used was equivalent to eating one slightly unripe banana daily. Bananas at this stage resist breakdown in the small intestine, reaching the large intestine and feeding the microbiome there.
The researchers planned a 10-year follow-up and investigated data from the U.K.’s National Cancer Registry over 20 years. They found no difference in the number of colorectal cancer cases. However, fewer participants receiving the supplement developed non-colorectal LS cancers compared to those taking the placebo.
The study noted: “The reduction in non–colorectal cancer LS cancers was detectable in the first 10 years and continued in the next decade.” The researchers reported that “Dietary supplementation with RS for this limited period does not emulate the protective effect of diets rich in [dietary fiber] against colorectal cancer in the general population.”
Surprisingly, the participants taking RS were 60% less likely to be diagnosed with non-colorectal LS cancers. The protective effect was most evident with upper GI cancers, including stomach, bile duct, pancreatic, and duodenal cancers.
The researchers found five cancers in five participants on RS compared to 21 cancers in 17 of the control group.
Currently, the researchers are leading another multinational trial involving over 1,800 individuals with Lynch syndrome. The CaPP3 study aims to determine if smaller doses of aspirin can help reduce cancer risk. The present study’s authors have yet to determine exactly how RS reduces upper GI cancer risk. However, they are certain that the gut microbiota plays a part.
Gastrointestinal microbes produce a short-chain fatty acid called butyrate while breaking down RS. This compound helps stop the growth of cancer cells and might induce cancer cell death. According to Dr. Bilchik, one theory is that an increase in butyrate may contribute to reductions in upper GI cancers.
The study’s authors believe that RS’s effect on bile acids may also help explain the reduced LS cancer risk.
An unrelated 2022 Advance Science article reported that interactions between bile acids and the gut microbiome may be associated with GI cancer development.
The surgeon also noted that the study does not establish causality.
Overall, he found this research “very exciting, because the predominant causes of death in patients with Lynch syndrome are upper gastrointestinal cancers. So, those can be reduced [with RS], and that’s significant.”
The implications are impressive since these cancers are more challenging to diagnose and overcome than other LS cancers.
Dr. Michael Greger, a physician, author, and clinical nutritionist who was also not involved in the study, encourages the consumption of whole foods over supplements to fight and beat cancer.
Parvathy Sukumaran 
