It is a universally acknowledged truth that vegetables are good for your health. We now learn, according to a study conducted by the Institut Curie and Inserm, that the presence of a compound found in cruciferous vegetables, indole-3-carbinol, is essential for making certain cancer treatments effective.
The researchers also highlight the biological mechanisms at play and explain how the absence of indole-3-carbinol induces a dysfunction in cytotoxic T lymphocytes and reduces the effectiveness of immunotherapy. Illustrating the importance of understanding the relationships between nutrition and immunity, these results were published in
Nature Communications on December 2, 2025.
The presence of a compound found in cruciferous vegetables, indole-3-carbinol, is essential for making certain cancer treatments effective.
© Photo by Monika Borys on Unsplash "
We now know that the response to anticancer treatments can be influenced by many environmental factors, such as nutrition. It has notably been shown that the composition of the gut microbiota, itself modulated by our diet, plays a role in the effectiveness of certain immunotherapy treatments (by anti-PD1 immune checkpoint inhibitors). And it is precisely this link between nutrition and anticancer treatments that we wanted to explore," explains Dr. Elodie Segura, Inserm research director at the Institut Curie (Immunity and Cancer unit).
The role of indole-3-carbinol in the effectiveness of anti-PD1 treatments
In a study conducted at the Institut Curie, the group of Dr. Elodie Segura, Inserm research director, focused on a specific nutrient: indole-3-carbinol, a molecule present in large quantities in cruciferous vegetables (cabbage, broccoli, cauliflower, watercress, turnip, arugula, radish...). To assess its role, the researchers compared the effectiveness of an immunotherapy in animals that received two different diets: one containing indole-3-carbinol and the other, not. With indole-3-carbinol, the anticancer treatment is effective in 50 to 60% of the animals. In contrast, when indole-3-carbinol is removed, the treatment's effectiveness drops to 20%.
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These results show us that when we remove this compound found in cabbage, there is a drastic decrease in the effectiveness of anti-PD1 immunotherapy" summarizes Dr. Elodie Segura.
Cytotoxic T lymphocytes, the keystone of the mechanism
It is known that cancer cells are capable of inactivating immune system cells, thus preventing the cancer from being attacked by cytotoxic or "killer" cells. However, immunotherapy treatments, by anti-PD1 immune checkpoint inhibitors, counteract the cancer's inhibition of cytotoxic T cells and allow them to reactivate. Thanks to this treatment, the cytotoxic T lymphocytes that are reactivated become capable of recognizing tumor cells and destroying them.
The researchers managed to identify the mechanisms of action of indole-3-carbinol at play in immunotherapy. They thus highlighted that indole-3-carbinol binds to a transcription factor called the
Aryl Hydrocarbon Receptor (AhR), which is notably expressed in cytotoxic T lymphocytes.
In the absence of indole-3-carbinol, cytotoxic T lymphocytes are incapable of responding to the treatment.
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Normally, during anti-PD1 immunotherapy, the lymphocytes are stimulated and reactivated to detect tumor cells. However, in the absence of indole-3-carbinol in the diet, the lymphocytes are not capable of recovering their functions," continues Elodie Segura.
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Our work helps us better understand the role of nutrients in antitumor immune responses. For patients, this data could help optimize diets to ensure treatment effectiveness."
While waiting for these results to be corroborated by specific clinical studies, cancer patients are encouraged to follow nutritional recommendations and their doctor's advice.