Researchers in Brazil studied 470 adults to see if what people eat affects their mental health. They found that people with mental health challenges like anxiety or depression had different eating habits than others—they ate fewer vegetables but more fruits and fatty foods. The study was done during the COVID-19 pandemic when many people’s routines changed. While the researchers found some connections between diet and mental health, they warn that these links are very small and shouldn’t be seen as proof that food causes mental disorders. The findings suggest that diet and mental health are related, but more research is needed to understand exactly how.

The Quick Take

  • What they studied: Whether the foods people eat are connected to mental health problems like anxiety and depression
  • Who participated: 470 adults living in São Paulo, Brazil, ranging from young adults to older adults. The study was done online during the COVID-19 pandemic.
  • Key finding: People with mental health challenges ate fewer vegetables but more fruits and fatty foods compared to people without mental health challenges. However, the connection between diet and mental health was very weak.
  • What it means for you: Eating more vegetables might be helpful for mental health, but food alone doesn’t cause or cure mental disorders. If you’re struggling with anxiety or depression, talk to a doctor or counselor—diet can be one small part of feeling better, but it’s not a replacement for professional help.

The Research Details

This was a cross-sectional study, which means researchers took a snapshot of people’s eating habits and mental health at one point in time, rather than following people over months or years. The researchers recruited 470 adults online in São Paulo and asked them questions about their diet using a food frequency questionnaire (a list of foods with questions about how often they eat them). They also assessed mental health using a screening tool called the SRQ-20, which asks 20 questions about symptoms like feeling sad, anxious, or stressed.

The researchers collected information about people’s age, education level, relationship status, and whether they were getting help from a therapist or counselor. They then used statistical tests to see if there were patterns—for example, whether younger people had more mental health challenges, or whether people who ate more vegetables had fewer symptoms.

This approach is useful for spotting patterns and connections in large groups of people. However, because it’s a snapshot rather than following people over time, we can’t say for certain that diet causes mental health problems or vice versa. The study was also done during the pandemic, when people’s stress levels and eating habits were unusual, which is important context.

The study included a decent-sized group (470 people) and used established tools to measure mental health and diet. However, all the information was self-reported, meaning people answered questions about themselves rather than researchers directly measuring their food intake or mental health. People might not remember exactly what they ate or might answer questions differently based on how they’re feeling that day. The study was done online during COVID-19, so the results might not apply to people in other places or times.

What the Results Show

The researchers found that younger adults (ages 18-30) had higher rates of mental health challenges compared to older adults. Single people, people with a secondary school education, and people receiving therapy also showed higher rates of mental health symptoms. These differences were statistically significant, meaning they’re unlikely to be due to chance.

When looking at diet, people with mental health challenges ate fewer vegetables but more fruits and fatty foods. This was an interesting pattern, but the researchers emphasized that the actual connection between these foods and mental health was very small—so small that it might not matter in real life.

One surprising finding was that eating adequate amounts of healthy oils and fats was slightly associated with higher mental health symptom scores, but again, this connection was so weak that it’s hard to know what it really means. The researchers warned that just because something is statistically significant (meaning it’s probably real and not by chance) doesn’t mean it’s clinically significant (meaning it actually matters for people’s health).

The study found that sociodemographic factors—like age, education level, and relationship status—were more strongly connected to mental health than diet was. This suggests that life circumstances and social factors may play a bigger role in mental health than what people eat. The researchers also noted that the pandemic context was important, as stress and isolation during COVID-19 likely affected both eating habits and mental health.

Previous research has suggested that diet and mental health are connected, with some studies showing that diets rich in vegetables, fruits, and fish are associated with better mental health. This study’s findings partially support that idea (people with mental health challenges ate fewer vegetables), but the connections were much weaker than expected. The study adds to growing evidence that while diet may play a role in mental health, it’s just one piece of a much bigger picture that includes stress, social connections, sleep, and genetics.

The biggest limitation is that this study only took a snapshot in time—it can’t prove that diet causes mental health problems or that mental health problems cause people to eat differently. It’s also possible that both are caused by something else, like stress or poverty. All the information came from people’s own reports, which can be inaccurate. The study was done online during the pandemic, so the results might not apply to people in other situations. Finally, the connections found between diet and mental health were so small that they might not be meaningful in real life, even though they were statistically significant.

The Bottom Line

Eating more vegetables and maintaining a balanced diet may support overall health and could be one small part of managing mental health. However, this should never replace professional mental health care. If you’re experiencing anxiety, depression, or other mental health challenges, talk to a doctor, therapist, or counselor. Diet can be a helpful addition to treatment, but it’s not a cure. Confidence level: Low to moderate—the evidence suggests a connection, but it’s weak and needs more research.

Anyone interested in the connection between diet and mental health should know about this research. It’s especially relevant for people managing mental health challenges who want to understand all the factors that might help. However, people shouldn’t use this study as a reason to avoid professional mental health care or to think that changing their diet alone will fix mental health problems. This research is most useful for people looking for one more tool to support their overall wellness.

If you decide to eat more vegetables or change your diet, don’t expect immediate changes in your mental health. Any benefits would likely develop over weeks or months, and they would be small. Mental health improvements usually require a combination of approaches—like therapy, sometimes medication, exercise, sleep, social connection, and yes, healthy eating. Be patient and work with a healthcare provider.

Want to Apply This Research?

  • Track daily vegetable servings (aim for 3-5 servings per day) alongside a simple mood check-in (rate your mood 1-10 each evening). Over 4-8 weeks, look for patterns—do days with more vegetables correlate with better moods? Remember: correlation isn’t causation, but tracking can help you notice what works for you personally.
  • Start by adding one extra vegetable serving to one meal per day. For example, add spinach to breakfast eggs, carrots to lunch, or broccoli to dinner. Make it easy by buying pre-cut vegetables or frozen options. Track this change in the app and note how you feel, but remember this is just one small part of mental health care.
  • Use the app to log vegetables eaten and mood daily for 8 weeks. Create a simple chart showing the relationship between vegetable intake and mood. Share this with your doctor or therapist to discuss whether dietary changes might be helpful as part of your overall mental health plan. Don’t rely on this alone—continue professional mental health care.

This study found weak connections between diet and mental health symptoms, but it cannot prove that diet causes mental disorders or that changing diet will treat them. Mental health conditions are complex and involve many factors including genetics, stress, sleep, social connections, and life circumstances. If you’re experiencing symptoms of anxiety, depression, or other mental health challenges, please consult with a qualified healthcare provider, therapist, or counselor. Diet can be a supportive part of overall wellness, but it should never replace professional mental health treatment. This research is informational only and should not be used for self-diagnosis or as a substitute for medical advice.