Scientists reviewed dozens of studies to see how different foods affect brain health as we age. They found that eating certain foods—like green tea, fish, and vegetables—may help protect the brain from shrinking and damage. The research shows that some eating patterns are better for brain health than others, but scientists say we need more studies before making strong recommendations. The good news is that many of these brain-healthy foods are ones doctors already suggest eating for overall health.

The Quick Take

  • What they studied: How different foods and eating patterns affect brain structure and function as people age, using brain scans to measure changes
  • Who participated: The review looked at 51 different studies involving thousands of people from general populations. Some studies followed people over time, while others took snapshots of their eating habits and brain health at one point in time
  • Key finding: Eating green tea, fish, and foods rich in antioxidants appeared to slow brain shrinkage by small but measurable amounts over time. Foods that cause inflammation in the body seemed to increase the risk of small strokes in the brain
  • What it means for you: Your food choices may help protect your brain as you get older, but the effects are modest. This doesn’t mean any single food is a miracle cure—it’s about overall eating patterns. Talk to your doctor before making major diet changes, especially if you have health conditions

The Research Details

Scientists searched three major medical databases for all studies published through July 2024 that looked at how diet affects brain health using MRI brain scans. They found 51 studies total: 38 that looked at real-world eating patterns and brain scans, and 13 that tested whether changing someone’s diet actually changed their brain. Some studies took one snapshot of people’s diets and brains, while others followed people for years to see how changes happened over time.

The researchers carefully reviewed each study to see what foods or eating patterns were studied, how they measured brain health, and what they found. They looked for patterns across all the studies to see if certain foods consistently helped or hurt brain health. They also noted which studies were stronger (following people over time) versus weaker (just taking one picture in time).

This approach is important because no single study can give us the full answer. By combining results from many studies, scientists can see which findings show up again and again—those are more likely to be true. This helps separate real effects from lucky accidents. The review also helps identify which types of studies (long-term follow-ups versus one-time snapshots) give us more trustworthy answers.

The studies included were published in peer-reviewed journals, meaning other scientists checked the work. However, the review found that studies often disagreed with each other, suggesting the effects may be small or complicated. Most studies were observational (watching what people eat naturally) rather than experiments where scientists told people what to eat. The researchers noted that longer studies and intervention studies showed clearer patterns than one-time snapshots, which suggests those results are more reliable.

What the Results Show

When scientists looked at studies that followed people over time, they found more consistent patterns. Drinking green tea (about 100 milliliters or 3.4 ounces per day) appeared to slow the shrinking of the hippocampus—a brain part important for memory—by a tiny amount each year. People who ate a ‘prudent’ diet (lots of vegetables, fruits, whole grains, and fish) kept more brain volume in areas important for memory over 4 years compared to people eating less healthy diets.

Higher levels of carotenoids (natural pigments in colorful vegetables) in the blood were linked to less shrinking in the temporal lobe, another memory-related brain area. These effects were small but measurable—like the difference between a brain that shrinks 1% per year versus 0.98% per year.

When looking at inflammation markers in food (how much a diet causes inflammation in the body), eating patterns that caused more inflammation were linked to higher risk of silent strokes—small brain injuries that don’t cause obvious symptoms. The risk was about 77% higher for people eating the most inflammatory diets compared to the least inflammatory.

Some specific foods showed interesting patterns. Baked fish was linked to larger hippocampus size in one study. Oily fish, dairy products, and tofu showed mixed results—sometimes protective, sometimes not. Polyphenol-rich supplements (concentrated plant compounds) seemed to improve blood flow to the brain and how different brain areas communicate with each other, though this was tested in fewer studies.

Interestingly, when scientists did intervention studies (where they actually changed people’s diets), only 2 out of 6 studies that looked at brain structure showed benefits. This suggests that real-world eating patterns may matter more than short-term diet changes in studies.

These findings fit with what we already know about diet and brain health from other research. Studies on heart health and brain health often overlap—foods good for your heart tend to be good for your brain too. The anti-inflammatory eating patterns that helped brain health in this review are similar to Mediterranean and DASH diets that other research has praised. However, this review found smaller effects than some people might expect, suggesting brain health is complicated and diet is just one piece of the puzzle.

The biggest limitation is that most studies just observed what people naturally ate—they didn’t prove that food caused the brain changes. People who eat healthy diets often exercise more, sleep better, and have less stress, so it’s hard to know if the food itself or these other factors helped the brain. Studies often disagreed with each other, and many found no connection between diet and brain health at all. Most studies were done in wealthy countries with mostly older, white populations, so results might not apply to everyone. The brain changes found were very small—often less than 1% per year—so it’s unclear if they matter for how people actually feel or think. Finally, most intervention studies were short-term, so we don’t know if diet changes help the brain over many years.

The Bottom Line

Based on this research, eating patterns rich in vegetables, fruits, whole grains, fish, and green tea may help protect your brain as you age (moderate confidence). Reducing foods that cause inflammation in your body—like processed foods and sugary items—appears beneficial (moderate confidence). However, these effects are small, and diet is just one factor in brain health. Regular exercise, good sleep, managing stress, and staying mentally active are also important. Don’t expect dramatic changes from diet alone.

This research is most relevant for middle-aged and older adults concerned about brain aging and memory. If you have a family history of dementia or stroke, these findings may be especially interesting to discuss with your doctor. However, these findings don’t apply to people with specific medical conditions that require special diets—always follow your doctor’s advice. Young people should know that building healthy eating habits now may help brain health later, but this research doesn’t specifically address younger ages.

If you change your diet based on these findings, don’t expect to notice differences quickly. The studies that showed benefits followed people for years. Brain changes happen slowly—the protective effects found were measured in fractions of a percent per year. You might notice improved energy, mood, or thinking within weeks or months, but measurable brain protection likely takes years. This is a long-term investment in brain health, not a quick fix.

Want to Apply This Research?

  • Track daily servings of brain-healthy foods: green tea (cups), fish (servings), colorful vegetables (servings), and whole grains (servings). Aim for at least 2-3 servings of vegetables, 1-2 servings of fish per week, and 1 cup of green tea daily. Log these weekly to see patterns in your eating habits
  • Start with one small change: add one serving of colorful vegetables to lunch, or replace one sugary drink with green tea. After two weeks, add another change. This gradual approach is more sustainable than overhauling your diet overnight. Use the app to celebrate small wins and build momentum
  • Track your diet quality score weekly by logging the brain-healthy foods you eat. Set a goal to hit 80% of your targets most weeks. Every month, review your patterns to see which foods you’re eating consistently and which you struggle with. This helps identify realistic changes you can maintain long-term rather than chasing perfection

This research summary is for educational purposes only and should not replace professional medical advice. The findings show associations between diet and brain health, but do not prove that changing your diet will prevent brain aging or dementia. Brain health is complex and influenced by many factors including genetics, exercise, sleep, stress, and medical conditions. Before making significant dietary changes, especially if you have existing health conditions, take medications, or have concerns about cognitive health, consult with your doctor or a registered dietitian. This review notes that current evidence is not yet strong enough for definitive clinical recommendations, and more research is needed.