A range of fruits and vegetables that are a typical part of a Mediterranean diet such as tomatoes, olives, and cucumbers cut up on a trayShare on Pinterest
Having a healthy diet may improve therapy outcomes for cancer patients, according to new research. Cameron Whitman/Stocksy
  • Immunotherapy is a type of biologic therapy used to treat melanoma, a serious type of skin cancer.
  • Researchers from the United Kingdom and the Netherlands observed the dietary intake of 91 patients with advanced melanoma receiving immune checkpoint inhibitors, a type of immunotherapy.
  • Their study suggests that there is an association between eating a Mediterranean diet and an improved immunotherapy response rate to melanoma.

Immunotherapy is used to treat various cancers. It involves the use of drugs to prime the immune system to recognize and attack cancer cells. Immune checkpoint inhibitors are a type of immunotherapy that blocks the actions of certain proteins.

In this new study, researchers asked patients with advanced melanoma receiving immune checkpoint inhibitors to document their dietary intake using questionnaires. The patients were also monitored using regular check-ups, including radiographic reviews.

Laura Bolte, study author and Ph.D. candidate at the University Medical Center Groningen, explained the objective of their study to Medical News Today:

“Importantly, this study was not a dietary intervention study. Patients were not put on a certain diet and followed-up but they filled in a dietary questionnaire prior to treatment through which we assessed their dietary habits.”

The researchers performed statistical analyses on the data obtained from the questionnaires to identify dietary patterns such as the Mediterranean dietary pattern.

They then associated these dietary patterns with treatment response and development of toxicity and found an association between the Mediterranean diet and the overall response rate.

“[P]atients who had a higher adherence to [a] Mediterranean diet, were more likely to respond to treatment with immune checkpoint inhibitors and to be progression-free at 12 months.”
— Laura Bolte, study author

The researchers highlighted that not all patients respond to treatment.

“Some patients develop drug-induced immune-related side effects such as colitis (inflammation of the gut). So the question is: How can we increase the response to immune checkpoint inhibitors to make more patients benefit? The relationship of immune checkpoint inhibitors with diet and the gut microbiome opens a promising and exciting opportunity to do so. Clinical trials investigating the effect of a high fiber diet, ketogenic diet and supplementation of omega-3 are underway,” Bolte said.

James Dobbyn, National Health Service senior research nurse and acute oncology clinical nurse specialist, who was not involved in this research, noted that a change in diet is “an empowering, non-pharmaceutical way for patients to help themselves through their cancer journey.”

Bolte pointed out that this study alone is not enough to make sweeping changes to melanoma patients’ treatment plans.

“Since this is an observational study, we do not derive causal relationships here, but show associations that need to be confirmed in clinical intervention studies,” she said.

Bolte told MNT that “while we need larger studies across multiple geographies, paired with higher resolution of food components to offer patient-tailored advise, we can already inform patients starting treatment with immune checkpoint inhibitors about the potential importance of their diet.”

“Rather than having a focus on energy and protein requirements solely, this dietary counseling could be extended to overall dietary quality and nutrient demands such as fiber and fatty acids,” she added.

“The traditional principles of [the] Mediterranean diet remain the most widely studied and recommended dietary guideline. This dietary advice is already provided in many other disease contexts such as for diabetes and immune-mediated diseases and in public health information aimed at disease prevention. Patients can be referred to these resources,” Bolte said.

“There are also dietary guidelines for cancer patients eg from the National Cancer Institute and American Cancer Society that overlap with the Mediterranean diet: emphasize consumption of fruits, vegetables, legumes, whole grains, nuts, and seeds, and pay attention to caloric and protein needs while limiting processed foods,” Bolte further explained.

“Dieticians could be involved in patient care as part of the multidisciplinary team of medical oncologists and other specialists.”
— Laura Bolte

James Dobbyn agreed.

“Dietary advice should be included in the patient information sheets for these drugs. This advice should also be routinely included in the patient counseling process prior to starting a course of treatment,” he said.

“In the real-world, healthier food is generally more expensive. Given the current cost of living crisis, we need to consider how patients can be supported in their healthier diet choices—if it is so important, the costs compared to the actual ICB drugs are minimal but likely highly significant for patients struggling in lower socio-economic groups and/or unemployed,” Dobbyn said.

“Oncology nurses will play a vital role in this aspect of patient, family, and carer education and support. They will also be able to signpost patients to financial support either through the benefits system or charitable support. The cancer charities will also need to be educated [on] the need for healthier lifestyle choices so that funding could be tailored to individual patient needs.”
— James Dobbyn

Finally, Bolte noted the importance of training all healthcare providers:

“An important way to implement dietary advice in clinical practice, in general, is by training doctors in important aspects of nutrition. All doctors should have a good answer on what is a healthy diet.”