Researchers looked at 38 scientific studies to see if special plant compounds called flavonoids—found in foods like blueberries, cocoa, and grapes—could help improve mood and mental health. These colorful compounds are natural chemicals that give fruits and vegetables their bright colors. The review found that eating flavonoid-rich foods regularly over weeks or months showed promise for boosting mood, while quick one-time doses had mixed results. While the evidence is encouraging, scientists say we need more research to understand exactly how these foods work and what amounts work best for different people.

The Quick Take

  • What they studied: Whether eating foods rich in flavonoids (natural plant compounds) could improve mood and mental health in healthy people of all ages
  • Who participated: The review analyzed 38 different scientific studies that tested flavonoid-rich foods on various groups of healthy people. Studies included people of different ages, genders, and backgrounds
  • Key finding: About half of the long-term studies (12 out of 25) showed that regularly eating flavonoid-rich foods improved mood and mental health. Quick, one-time doses were less effective, with only 5 out of 13 showing benefits
  • What it means for you: Eating flavonoid-rich foods like blueberries, dark chocolate, and tea regularly may help improve your mood over time. However, this isn’t a cure for mental health conditions, and you should talk to a doctor about any mood concerns

The Research Details

This was a systematic review, which means researchers searched through scientific databases (PubMed, Web of Science, and Scopus) to find all studies about flavonoids and mood. They looked for studies where people either took flavonoid supplements or ate flavonoid-rich foods and reported changes in their mood or mental health. The researchers included studies going back many years, up through October 2024.

The studies they found fell into two categories: acute studies (where people took flavonoids once and mood was measured shortly after) and chronic studies (where people ate flavonoid-rich foods regularly for weeks or months). Most studies used foods like cocoa, blueberries, grapes, cherries, and green tea as their flavonoid sources.

The researchers used a quality checklist to evaluate how well each study was designed and whether the results were trustworthy. This helps readers understand which findings are more reliable than others.

A systematic review is valuable because it combines information from many different studies instead of relying on just one. This gives us a better overall picture of what the research shows. By looking at 38 studies together, researchers can spot patterns and see which findings appear across multiple studies, making the conclusions stronger and more reliable than any single study alone.

This review was registered in advance (PROSPERO), which is a good sign that the researchers planned their work carefully. The researchers used a standard quality checklist to evaluate each study. However, the studies they reviewed varied quite a bit in their methods, the foods they tested, and how much flavonoid they used. This variation makes it harder to draw firm conclusions. The fact that only about half of the long-term studies showed benefits suggests the effects may be modest or work better for some people than others.

What the Results Show

When researchers looked at studies where people ate flavonoid-rich foods regularly over time (chronic studies), about half showed improvements in mood and mental health. The foods that showed the most promise were cocoa, blueberries, cherries, and green tea. Interestingly, quick one-time doses of flavonoid-rich foods were much less effective—only about 38% of those studies showed mood benefits.

The most commonly studied food was cocoa (chocolate), which appeared in 9 studies. Blueberries were the second most popular, appearing in multiple studies. The fact that different foods showed benefits suggests it’s not just one specific flavonoid that matters, but rather a group of related plant compounds.

The studies that showed positive results reported improvements in various mood measures, including general mood, anxiety levels, and overall mental well-being. However, the improvements were generally modest rather than dramatic.

The review found that the timing and duration of flavonoid consumption matters. Long-term regular consumption (weeks to months) appeared more effective than single doses. Different flavonoid-rich foods showed varying levels of effectiveness, suggesting that the specific type of food and its flavonoid content both play a role. The research also suggests that flavonoids may work through multiple pathways in the body, though the exact mechanisms aren’t fully understood yet.

This systematic review builds on growing evidence that diet significantly influences mental health and mood. Previous research has shown connections between overall diet quality and depression risk, and this review specifically focuses on one group of beneficial plant compounds. The findings align with emerging research suggesting that natural plant compounds have protective effects on brain health and mood regulation.

The biggest limitation is that the studies reviewed used different methods, different amounts of flavonoids, and measured mood in different ways. This makes it hard to say exactly how much flavonoid you need or which food works best. Many studies were small, and some had design issues that could affect reliability. Additionally, most studies were done in healthy people, so we don’t know if flavonoids would help people with diagnosed mood disorders. The researchers couldn’t do a statistical analysis combining all studies because they were too different from each other.

The Bottom Line

Based on this review, eating flavonoid-rich foods as part of a healthy diet may support mood and mental health, particularly with regular consumption over time. Good sources include dark chocolate (cocoa), blueberries, other berries, grapes, cherries, green tea, walnuts, and citrus fruits. Aim to include these foods regularly in your diet rather than expecting immediate effects from single servings. Confidence level: Moderate—the evidence is promising but not yet conclusive.

Everyone interested in supporting their mood and mental health through diet should know about these findings. This is particularly relevant for people looking for lifestyle approaches to complement other mental health strategies. However, these foods should not replace professional mental health treatment for diagnosed conditions like depression or anxiety. If you have a mental health condition, talk to your doctor before making major dietary changes.

Based on the studies reviewed, you’d likely need to eat flavonoid-rich foods regularly for several weeks to months to notice mood benefits. Don’t expect immediate changes from eating one serving of blueberries or chocolate. Think of it as a long-term lifestyle approach rather than a quick fix.

Want to Apply This Research?

  • Track daily consumption of flavonoid-rich foods (servings of berries, cocoa products, tea, grapes, cherries, walnuts, citrus) alongside a simple mood rating (1-10 scale) to see if patterns emerge over 4-8 weeks
  • Set a goal to include at least one flavonoid-rich food daily—such as a cup of berries, a cup of green tea, a small piece of dark chocolate, or a handful of walnuts. Log this in your app each day to build the habit
  • Use a weekly mood check-in combined with a flavonoid food log. After 4-6 weeks of consistent consumption, review whether your mood ratings have improved. Share this data with your healthcare provider if relevant

This review summarizes research on flavonoid-rich foods and mood in healthy populations. These findings should not be used to diagnose, treat, cure, or prevent any mental health condition. If you’re experiencing depression, anxiety, or other mental health concerns, please consult with a qualified healthcare provider or mental health professional. Dietary changes should complement, not replace, professional mental health treatment. Always talk to your doctor before making significant dietary changes, especially if you take medications or have existing health conditions.