Researchers studied 630 colon cancer patients to see if eating certain healthy foods could improve their mood and overall well-being. They looked at two eating patterns: the MIND diet (which focuses on brain health) and a diet designed to support healthy gut bacteria. The study found that patients who followed these healthier eating patterns had less depression and anxiety, lower inflammation in their bodies, and healthier gut bacteria. This suggests that what cancer patients eat might be just as important for their mental health and quality of life as it is for their physical health.

The Quick Take

  • What they studied: Whether eating according to two specific healthy diet patterns (MIND diet and a gut-friendly diet) could help colon cancer patients feel less depressed and anxious, have less body inflammation, and maintain healthier gut bacteria.
  • Who participated: 630 colon cancer patients of various ages and backgrounds who completed surveys about their eating habits and answered questions about their mood and quality of life.
  • Key finding: Patients who scored higher on both healthy eating patterns reported significantly less depression and anxiety. For every point increase in the MIND diet score, depression symptoms dropped noticeably. The gut-friendly diet showed even stronger connections to reduced depression and lower inflammation markers in the blood.
  • What it means for you: If you or a loved one has colon cancer, eating more of the foods recommended in the MIND or gut-friendly diets may help improve mood, reduce anxiety, and support better overall well-being. However, this is one study showing associations, not proof that diet causes these improvements. Talk with your doctor or a dietitian before making major diet changes.

The Research Details

This was a cross-sectional study, which means researchers collected information from 630 colon cancer patients at one point in time rather than following them over months or years. Participants answered detailed questions about what they ate, their mood (including depression and anxiety), sleep quality, and quality of life. Researchers also measured inflammation markers in their blood and stool samples to check their gut bacteria composition.

The study compared two different eating score systems: the MIND diet (which emphasizes brain-healthy foods like leafy greens, berries, nuts, and fish) and the DI-GM diet (designed specifically to support beneficial gut bacteria through foods like whole grains, vegetables, and fermented foods). Researchers used statistical methods to see if higher scores on these diets were connected to better mental health outcomes and healthier gut bacteria, while accounting for other factors like age, medications, and overall health status.

This approach allowed researchers to identify associations between diet quality and health outcomes, though it cannot prove that the diet directly causes the improvements.

Understanding what cancer patients eat is important because depression and anxiety are common in cancer survivors and can affect their recovery and quality of life. If diet can help improve mood and reduce inflammation naturally, it offers a practical tool that patients can control. The focus on gut bacteria is particularly interesting because emerging research suggests that the bacteria in our digestive system may influence our mood and immune function.

This study has several strengths: it included a reasonably large number of participants (630), measured multiple health outcomes, and adjusted for many factors that could affect results. However, because it’s cross-sectional, we can’t determine cause-and-effect—we only know that healthier eating patterns are associated with better outcomes. The study relied on patients’ memory of what they ate, which can be imperfect. The results need to be confirmed by studies that follow patients over time to see if changing their diet actually improves their mental health.

What the Results Show

Patients who followed the MIND diet more closely showed significantly lower depression and anxiety scores. Specifically, for each one-point increase in their MIND diet score, depression symptoms decreased by about 1.16 points on the measurement scale, and anxiety decreased by about 2.48 points. These differences were statistically significant, meaning they’re unlikely to be due to chance.

The gut-friendly diet (DI-GM) showed even stronger associations with mental health improvements. Patients with higher DI-GM scores had notably lower depression and anxiety levels. Additionally, both diet patterns were associated with lower levels of inflammatory markers in the blood (CRP and IL-6) and in stool samples (fecal calprotectin), suggesting less inflammation throughout the body.

Interestingly, patients with higher scores on both diets also had lower levels of tumor biomarkers (CA19-9 and CEA), which are substances that can indicate cancer activity. The gut-friendly diet showed particularly strong associations with lower tumor biomarkers. This suggests that diet quality might be connected to cancer-related outcomes, though more research is needed to understand this relationship.

The study examined the gut bacteria composition and found that patients following these healthier eating patterns had more balanced and diverse gut bacteria communities. The ratio of two major types of bacteria (Firmicutes to Bacteroidetes) appeared to partially explain why diet was connected to better mental health outcomes. This suggests that diet may improve mood partly by supporting healthier gut bacteria, which can influence brain function through the gut-brain connection.

Previous research has shown that the MIND diet supports brain health in older adults and may reduce dementia risk. This study extends that finding to cancer patients and shows the diet may also help with depression and anxiety. The focus on the gut-friendly diet is newer, reflecting growing scientific interest in how diet shapes our gut bacteria and how those bacteria influence our mental health. The findings align with emerging research showing that gut health and mental health are closely connected.

This study has important limitations to consider. Because it’s cross-sectional, we can only say that healthy eating is associated with better outcomes—we cannot prove that changing diet will cause improvements. The study relied on patients remembering what they ate, which can be inaccurate. We don’t know if other factors not measured in the study (like exercise, social support, or medication use) might explain some of the connections found. The study included only colon cancer patients, so results may not apply to other cancer types. Finally, the study cannot determine whether people with better mental health naturally eat better, or whether eating better improves mental health.

The Bottom Line

Based on this research, colon cancer patients may benefit from eating more foods emphasized in the MIND diet (leafy greens, berries, nuts, fish, whole grains) and foods that support gut health (high-fiber vegetables, whole grains, fermented foods). These dietary changes appear to be associated with lower depression and anxiety, reduced inflammation, and better overall quality of life. However, this is preliminary evidence showing associations rather than proof of cause-and-effect. Confidence level: Moderate—the findings are promising but should be confirmed by studies that follow patients over time.

This research is most relevant to colon cancer patients and survivors dealing with depression, anxiety, or poor quality of life. It may also interest family members and caregivers looking for ways to support cancer patients’ well-being. Healthcare providers treating cancer patients may find this useful when discussing lifestyle factors that support mental health. People without cancer should note that while these diets are generally healthy, this study specifically examined cancer patients and may not apply the same way to the general population.

Based on similar nutrition research, dietary changes typically take 4-8 weeks to show noticeable effects on mood and inflammation markers. Gut bacteria composition may shift within 2-3 weeks of dietary changes. However, individual responses vary significantly, and some people may see benefits sooner while others take longer. Consistent adherence to the diet is important for seeing sustained benefits.

Want to Apply This Research?

  • Track daily servings of MIND diet foods (leafy greens, berries, nuts, fish, whole grains, olive oil) and gut-friendly foods (high-fiber vegetables, whole grains, legumes, fermented foods). Set a goal of 5+ servings daily and log actual intake. Simultaneously track mood using a simple 1-10 scale for depression and anxiety symptoms daily to see if patterns emerge over 4-8 weeks.
  • Start by adding one MIND diet food group per week: Week 1 add leafy greens to one meal daily, Week 2 add berries as a snack, Week 3 add fish once, Week 4 add nuts. Simultaneously, increase fiber intake gradually by choosing whole grain versions of bread and pasta. Use the app to set reminders for meal planning and shopping for these specific foods.
  • Create a weekly dashboard showing: (1) percentage of daily meals following MIND/gut-friendly guidelines, (2) mood and anxiety scores, (3) energy levels, and (4) digestive comfort. Review trends every 2 weeks to identify which foods correlate with best mood outcomes for that individual. Adjust recommendations based on personal response patterns rather than generic guidelines.

This research shows associations between diet and health outcomes in colon cancer patients but does not prove that diet changes will cause improvements. This information is educational and should not replace professional medical advice. Cancer patients should consult with their oncologist, primary care doctor, or registered dietitian before making significant dietary changes, especially if they are undergoing active cancer treatment, taking medications, or have other health conditions. Some dietary changes may interact with cancer treatments or medications. Individual responses to dietary changes vary, and what works for one person may not work for another. If you experience worsening depression, anxiety, or other mental health concerns, seek professional mental health support immediately.