What a cancer patient eats can affect the body's response to treatment as high-fiber diets may change gut microbes and make therapies more effective, a new study suggests.
According to data presented at the annual meeting of the American Association for Cancer Research (AACR), people with melanoma skin cancer who consumed a high-fiber diet responded five times better to immunotherapy treatment than those on poorer diets.
Diet has been found to be one way to change a person’s microbiome, the collection of bacteria, fungi and other microbes that live on and in the body.
In the experiment, researchers found that patients who consumed the highest amount of fiber in their diets, including fruits, vegetables and whole grains, had more of the bacteria associated with a response to the immune therapy. On the other hand, participants who ate processed meat and excess sugar had fewer of those bacteria, and their tumors were more likely to grow.
“We found that diet and supplements appear to have an effect on a patient’s ability to respond to cancer immunotherapy, most likely due to changes in their gut microbiome,” said Christine Spencer, a research scientist at the Parker Institute for Cancer Immunotherapy in San Francisco.
“We know from prior research that eating a higher-fiber diet has a lot of health benefits. But with this preliminary research on cancer patients and the microbiome, it appears that fiber is also linked to a better response to immunotherapy,” said Spencer.
“The gut microbiome plays a big role in moderating the immune system, so the idea that we could potentially change the microbiome—whether by diet or other means—to improve response to immunotherapy treatment is really exciting,” she explained.
However, the study found that probiotic supplements, whether pills or food supplements, actually reduced the diversity of microbes in cancer patients’ guts.