Scientists at McGill University have uncovered an unexpected link between diet and cancer treatment efficacy, revealing that certain diets often considered unhealthy or fattening can boost the response to immunotherapy in mice. This discovery challenges conventional assumptions regarding nutrition and oncology, suggesting that the interaction between food and gut bacteria plays a critical role in strengthening the immune system's ability to fight cancer.
The research, led by Associate Professor Daniela Quail of the Rosalind & Morris Goodman Cancer Institute, highlights a synergistic relationship between the microbiome and diet. Quail explained that even with an optimal composition of gut bacteria, the specific foods consumed to nourish these populations can determine whether a patient responds to treatment. The study focused on immune checkpoint inhibitors, widely used drugs designed to help the immune system recognize and attack cancer cells.
One of the most surprising aspects of the findings was that diets associated with weight gain appeared to enhance immunotherapy effectiveness. Quail noted that this indicates the relationship between diet and cancer treatment is more complex than simple advice to eat healthy and exercise. However, the researchers strongly caution against interpreting these results as a recommendation for cancer patients to adopt obesogenic diets. They emphasize that excess weight carries established health risks and that the study does not prove such diets would improve outcomes in humans.
The investigation aimed to solve the "obesity paradox," a longstanding puzzle where obesity is generally linked to higher cancer risk, yet some studies show patients with higher body mass indices respond better to immune checkpoint inhibitors. To explore this contradiction, the team tested 12 different diets in mice and found that those associated with obesity improved treatment responses even when consumed for short periods. This suggests the apparent advantage may stem from diet-microbiome interactions rather than excess body weight itself.
The study, titled "Diet-microbiome synergy underlies obesity-associated immunotherapy efficacy," was published in Nature by McGill PhD graduate Lysanne Desharnais, Quail, and collaborators including Logan Walsh, Bertrand Routy, and Arielle Elkrief. The researchers hope that understanding these mechanisms will lead to safer strategies for enhancing immunotherapy without exposing patients to the dangers of obesity. Funding for the project was provided by organizations including the Canadian Institutes of Health Research, the Canadian Cancer Society, and the Terry Fox Research Institute.
Sources: ScienceDaily.