Serving Up Success

Immunotherapy as cancer treatment harnesses the power of a patient’s own immune system to fight cancer. This continues to be a cutting edge area of cancer research, with plenty of success stories, including immunotherapy medications such as Keytruda, Opdivo, and Tecentriq.

These medications do not have the exact same effectiveness in every patient, of course. Researchers have been keen to determine why these medications work better in some people – with the obvious goal to replicate the higher effectiveness. This remains an emerging area of scientific inquiry, but one interesting thread is starting to unravel: gut health.

Some research indicates that patients with a high-fiber diet respond better to immunotherapy treatment. The connection here is thought to relate to the gut microbiome; that is, the mix of bacteria that live in the intestinal tract. What one eats is a strong factor in determining the gut microbiome.

A high-fiber diet helps a healthy mix of bacteria thrive and ups the effectiveness of immunotherapy medications. Foods to focus on include whole grains, fruits and vegetables. In addition, research suggests that foods with added sugars and processed meats have an opposite effect: reducing the effectiveness of immunotherapy medications.

These food choices – foods high in fiber while avoiding sugary foods and processed meats – of course, are part of a healthy diet for many reasons, beyond a potential effect on immunotherapy. So there’s no reason not to focus on these aspects of a healthy diet while treating cancer.


Spencer CN, Gopalakrishnan V, McQuade J, et al. The gut microbiome (GM) and immunotherapy response are influenced by host lifestyle factors. AACR Annual Meeting 2019 Session PO.TB06.09

Gopalakrishnan V, Spencer CN, Nezi L, et al. Gut microbiome modulates response to anti–PD-1 immunotherapy in melanoma patients. Science 2018;359(6371):97-103.