Scientists discovered that certain foods containing special compounds called AhR ligands can help your body’s immune system fight cancer more effectively when combined with a popular cancer treatment called anti-PD1 therapy. The research, published in Nature Communications, shows that when mice ate foods rich in these compounds (like broccoli and cabbage), their immune cells called CD8 T cells became much better at attacking cancer tumors. This suggests that what you eat might be just as important as the medicine itself when treating certain cancers, opening up new possibilities for improving cancer treatment by combining the right diet with immunotherapy.

The Quick Take

  • What they studied: Whether certain nutrients from food can improve how well a cancer immunotherapy drug (anti-PD1) works by activating a protein called the Aryl hydrocarbon receptor (AhR)
  • Who participated: Laboratory mice were divided into groups: some ate a normal diet low in AhR-activating compounds, while others ate the same diet supplemented with Indole-3-carbinol (a compound found in cruciferous vegetables like broccoli). Researchers also used genetically modified mice to understand which immune cells were involved
  • Key finding: Mice that consumed foods rich in AhR ligands showed significantly better tumor control when treated with anti-PD1 immunotherapy compared to mice on a diet lacking these compounds. The benefit specifically came from activating AhR in CD8 T cells (a type of immune cell), not in other immune cell types
  • What it means for you: Eating more cruciferous vegetables (broccoli, cabbage, Brussels sprouts) may help boost the effectiveness of certain cancer immunotherapies, though this research is still in early stages and human studies are needed before making treatment changes. Talk to your doctor before making any dietary changes during cancer treatment

The Research Details

This was a preclinical laboratory study using mouse models of cancer. Researchers created two groups of mice: one group ate a standard diet naturally low in compounds that activate the AhR protein, while another group ate the same diet supplemented with Indole-3-carbinol (found in vegetables like broccoli). Both groups were then treated with anti-PD1 immunotherapy, a drug that helps the immune system fight cancer. The researchers measured how well the therapy worked by tracking tumor growth and analyzing immune cell function. To understand which immune cells were responsible for the benefits, they used specially bred mice missing the AhR gene in specific cell types (CD8 T cells, NK cells, or myeloid cells) to see which ones were essential for the diet’s effect.

This research approach is important because it bridges the gap between nutrition and cancer treatment. Most cancer research focuses on the drug alone, but this study shows that what patients eat might be equally important. By using mouse models, scientists can carefully control all variables (diet, genetics, treatment timing) in ways that would be impossible in human studies, allowing them to identify the exact mechanisms involved. The use of genetically modified mice was particularly valuable because it pinpointed that CD8 T cells were the key players, not other immune cells, which helps explain how diet and immunotherapy work together.

This study was published in Nature Communications, a highly respected scientific journal, which indicates it underwent rigorous peer review. The research used multiple experimental approaches (different mouse strains, genetic modifications, tumor models) to confirm findings, which strengthens confidence in the results. However, this is preclinical research in mice, not humans, so results may not directly translate to people. The study was well-designed with appropriate controls, but human clinical trials would be needed to confirm these findings apply to cancer patients

What the Results Show

The main discovery was that mice fed a diet supplemented with Indole-3-carbinol (a compound from cruciferous vegetables) showed significantly better responses to anti-PD1 immunotherapy compared to mice on a diet lacking these compounds. Tumors grew more slowly and survival improved in the supplemented group. When researchers analyzed the immune system, they found that the diet enhanced the function of CD8 T cells—specialized immune cells that directly attack cancer. Specifically, the diet helped reinvigorate CD8 T cells that had become exhausted (worn out from fighting cancer), allowing them to work harder and longer against tumors. The AhR protein was essential for this benefit; when researchers removed the AhR gene from CD8 T cells, the dietary benefit disappeared entirely.

The study also revealed that AhR activation in other immune cell types (NK cells and myeloid cells) was not necessary for the diet’s anti-tumor effects, narrowing down the mechanism to CD8 T cells specifically. The researchers identified that AhR works through two main pathways: it helps restore the function of exhausted CD8 T cells and enables effector CD8 T cells (the active, tumor-fighting cells) to respond more effectively to the immunotherapy drug. This dual mechanism explains why the dietary intervention was so effective—it works on multiple levels to enhance immune function

This research builds on earlier work showing that the gut microbiome and diet influence cancer immunity, but it’s one of the first studies to specifically identify how a single nutrient pathway (AhR activation) directly impacts immunotherapy effectiveness. Previous research suggested that diet matters for cancer outcomes, but the exact mechanisms were unclear. This study provides a clear molecular explanation: specific food compounds activate a protein that enhances immune cell function. The findings align with observational studies suggesting that people eating more vegetables have better cancer outcomes, and now provides a biological mechanism to explain why

This research was conducted entirely in mice, and mouse biology doesn’t always match human biology. The study used laboratory tumor models that may not perfectly represent real human cancers. The researchers only tested one specific immunotherapy drug (anti-PD1), so results may not apply to other cancer treatments. The study didn’t test different doses of Indole-3-carbinol or compare it to other AhR-activating compounds, so optimal dietary amounts remain unknown. Additionally, the research didn’t account for how individual differences in gut bacteria (which also produce AhR ligands) might affect results in humans. Finally, this was a controlled laboratory setting where diet was precisely controlled—real-world human diets are much more complex and variable

The Bottom Line

Based on this research (moderate confidence level, as it’s preclinical): Consider increasing intake of cruciferous vegetables (broccoli, cabbage, Brussels sprouts, cauliflower, kale) if you’re undergoing anti-PD1 immunotherapy for cancer. These vegetables are rich in Indole-3-carbinol and other AhR-activating compounds. However, this should only be done under medical supervision and in consultation with your oncology team. Do not make dietary changes or supplement decisions without discussing them with your cancer care team first, as some dietary changes might interact with medications or affect treatment timing. This research suggests potential benefits, but human clinical trials are still needed to confirm effectiveness and determine optimal amounts

This research is most relevant to cancer patients currently receiving or considering anti-PD1 immunotherapy (drugs like nivolumab, pembrolizumab, or atezolizumab). It may also be relevant to people at high risk for certain cancers who want to optimize their diet preventatively. Oncologists and nutritionists specializing in cancer care should be aware of these findings. This research is NOT a substitute for standard cancer treatment and should not be used to delay or replace immunotherapy. People with certain medical conditions (like autoimmune diseases) should be cautious, as AhR activation might affect their condition—consult your doctor first

In the mouse studies, benefits appeared within weeks of dietary supplementation combined with immunotherapy. In humans, if similar effects occur, you might expect to see improvements in treatment response over several months, though this is speculative. The immune system changes triggered by AhR activation likely happen relatively quickly (days to weeks), but measurable improvements in tumor control would take longer. Realistic expectations: if you start eating more cruciferous vegetables now, don’t expect immediate results. Instead, view it as a long-term dietary strategy to support your cancer treatment over months

Want to Apply This Research?

  • Track daily servings of cruciferous vegetables (broccoli, cabbage, Brussels sprouts, cauliflower, kale) with a goal of 1-2 servings per day. Log the specific vegetable type, portion size (in cups or grams), and preparation method. Note any changes in energy levels, side effects, or treatment response markers (if available from your medical team)
  • Set a specific goal like ‘Add one serving of cruciferous vegetables to lunch and dinner’ or ‘Include broccoli in 5 meals per week.’ Start with vegetables you already enjoy to increase adherence. Use the app to set reminders for meal planning and grocery shopping for these vegetables. Track which preparation methods you prefer (raw, steamed, roasted) to maintain consistency
  • Create a weekly summary view showing total cruciferous vegetable intake. Correlate this with any available health metrics (energy levels, treatment side effects, medical test results if shared with the app). Set monthly goals to gradually increase intake. Share reports with your oncology team to discuss whether dietary changes correlate with treatment response. Monitor for any digestive changes or interactions with medications, and report these to your healthcare provider

This research is preclinical (conducted in mice) and has not yet been tested in human cancer patients. Do not make any changes to your cancer treatment, diet, or supplement regimen based on this information without first consulting your oncologist and medical team. While this study suggests that cruciferous vegetables may support immunotherapy effectiveness, it is not a substitute for standard cancer treatment. Some dietary changes or supplements may interact with cancer medications or affect treatment timing. If you are currently receiving cancer treatment, discuss any dietary modifications with your healthcare team before implementing them. This information is for educational purposes only and should not be used for self-diagnosis or self-treatment of cancer.