by Ashleigh Feltham,  Accredited Practising Dietitian and Accredited Nutritionist

Approximately one in every seventeen Australians will be diagnosed with melanoma in their lifetime. It is the third most common form of cancer in Australia after prostate and colorectal cancer for men and breast and colorectal cancer for women. Melanoma is a type of skin cancer that affects the cells of your skin called melanocytes. Ultraviolet (UV) light and tanning beds play a major influence on the development of melanoma.

If you are diagnosed with melanoma you may need to undergo immunotherapy treatment. One such treatment is checkpoint inhibitor immunotherapy. Checkpoint inhibitors block the proteins that prevent the immune system from attacking cancer cells. Immunotherapy treatment restores the immune system to optimal levels to help fight cancer. The gut plays a major role in the immune system’s response; around 70% of the immune system is in the gut.

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A new study has provided insight into the powerful potential of a healthy gut in promoting a better response to immunotherapy in melanoma cancer patients. The observational study investigated the effects of dietary fibre and probiotics on 438 people diagnosed with melanoma most of whom were receiving immunotherapy treatment. Participants filled out a dietary questionnaire including their use of probiotics and antibiotics.

Researchers found that participants with prebiotic fibre in their diet responded better to checkpoint inhibitor immunotherapy compared to those on a low fibre diet. Prebiotic fibre feeds health promoting microbes in the gut. The best response to this form of immunotherapy was seen in patients on a high prebiotic fibre diet.

Researchers also investigated the effects a high-fibre diet in mice. They found that mice fed a diet rich in fibre had a better response to immunotherapy treatment.

Create a lifestyle approach by maintaining a primarily plant-based diet. This way, you will achieve a diet high in prebiotic fibre. This would include lots of foods like whole grains, nuts, seeds, legumes, vegetables and fruit. Aim to include these plant foods in each meal and snack. Variety is vital; different types of gut microbes require different types of prebiotic fuel. A good goal is to include 30 different plant foods each week to feed all of your health-promoting microbes.

An adult needs between 25g and 38g of dietary fibre each day
for good gut health.

Take home message:

Do not underestimate the power of your gut to promote health and wellbeing, especially in the case of optimising your immune system. This new research gives further insight into the importance your gut plays in optimising immunotherapy treatment response in melanoma patients.

References:

1. The Australian Melanoma Research Foundation.
2. Spencer CN, et al. Dietary fiber and probiotics influence the gut microbiome and melanoma immunotherapy response. Science. 2021 Dec 24;374(6575):1632-1640. doi: 10.1126/science.aaz7015. Epub 2021 Dec 23. PMID: 34941392.