Researchers in China studied nearly 1,000 older adults to see if what they eat affects how well their brains work. They found that people who regularly ate shellfish (like shrimp, clams, and oysters) as part of their diet had better memory and thinking skills compared to those who didn’t eat much shellfish. The benefits were especially noticeable in women, people under 65, and those with a healthy weight. While this is promising news, the study only looked at one point in time, so more research is needed to confirm these findings.

The Quick Take

  • What they studied: Whether eating shellfish and other dietary patterns affects brain function and memory in older Chinese adults
  • Who participated: 964 people aged 50 and older living in Qingdao, China, most with lower levels of formal education
  • Key finding: People who ate more shellfish had about 40% lower odds of having thinking and memory problems compared to those who ate less shellfish
  • What it means for you: Adding more shellfish to your diet may help protect your brain health as you age, though this is one study and more research is needed. This is especially relevant if you’re a woman, under 65, or maintain a healthy weight.

The Research Details

Scientists looked at information collected in 2018 from older adults in China. They asked people detailed questions about what they ate and then tested their memory and thinking skills using a standard brain health test called the Montreal Cognitive Assessment. The researchers used a special statistical method to identify three main eating patterns: one focused on shellfish, one on fruits, and one on red meat. Then they looked at which eating patterns were connected to better or worse brain function.

This type of study is called ‘cross-sectional,’ which means researchers took a snapshot of people at one moment in time rather than following them over months or years. It’s like taking a photo instead of making a movie—it shows what’s happening right now but can’t prove one thing caused another.

This research approach is useful because it can identify patterns in what people eat and how their brains work. However, because it’s just a snapshot in time, we can’t be completely sure that eating shellfish directly causes better brain health. It could be that people who eat shellfish also do other healthy things. This is why scientists need to do follow-up studies to confirm the findings.

The study included a large number of people (964), which makes the results more reliable. The researchers used a recognized test for brain health and controlled for many other factors that might affect thinking skills. However, the study only looked at people in one city in China, so results might be different in other places. Also, people reported what they ate from memory, which can sometimes be inaccurate.

What the Results Show

The main finding was that people who ate the most shellfish had significantly better brain function than those who ate the least. Specifically, people in the highest shellfish-eating group had about 42% lower chances of having memory and thinking problems compared to the lowest group.

The benefits were even stronger in certain groups of people. Women who ate shellfish showed stronger protection against brain decline than men. People under age 65 also showed more benefit than older participants. People with a healthy weight (BMI under 25) showed the strongest connection between shellfish eating and better brain health.

The researchers also looked at two other eating patterns—one focused on fruits and another on red meat—but these didn’t show the same protective effect on brain health that shellfish did.

The study found that the shellfish pattern’s benefits didn’t significantly differ between men and women, or between different age groups, even though some groups showed stronger trends. This suggests that while the effect may be stronger in certain populations, shellfish consumption appears beneficial across different demographic groups.

Previous research has shown that seafood and shellfish contain important nutrients like omega-3 fatty acids, zinc, and selenium that support brain health. This study adds to that evidence by showing that in a real-world population of older Chinese adults, eating shellfish is connected to better brain function. However, most previous studies have been done in Western countries, so this research is valuable because it confirms the pattern in an Asian population.

The study has several important limitations. First, it only looked at people at one point in time, so we can’t prove that shellfish caused the better brain health—only that they’re connected. Second, people reported what they ate from memory, which can be inaccurate. Third, the study only included people from one city in China with lower education levels, so the results might not apply to everyone everywhere. Finally, the researchers couldn’t account for all possible factors that might affect brain health, like physical activity or sleep quality.

The Bottom Line

Based on this research, older adults may benefit from including more shellfish in their diet as part of a healthy eating pattern. Shellfish like shrimp, clams, oysters, and mussels are good sources of nutrients that support brain health. Aim to eat shellfish 2-3 times per week as part of a varied diet. However, this is one study, so it should be combined with other brain-healthy habits like staying mentally active, exercising, and eating plenty of fruits and vegetables. Confidence level: Moderate—this is promising evidence, but more research is needed.

This research is most relevant for older adults (especially those over 50) who want to protect their brain health and memory. It may be especially helpful for women and people under 65. People with shellfish allergies should not try to add shellfish to their diet. If you have concerns about cognitive decline or memory problems, talk to your doctor about all the ways you can protect your brain health.

Brain health benefits from dietary changes typically take weeks to months to become noticeable. You might not see dramatic changes in memory or thinking right away, but consistent eating habits over 2-3 months may support better brain function over time.

Want to Apply This Research?

  • Track shellfish consumption weekly: record the type (shrimp, clams, oysters, mussels), portion size, and frequency. Aim for 2-3 servings per week and monitor any changes in memory, focus, or mental clarity over 8-12 weeks.
  • Add one shellfish-based meal to your weekly meal plan. Start with easy options like shrimp stir-fry, clam pasta, or oyster soup. Use the app to set a weekly reminder to plan and prepare a shellfish dish, and log it when completed.
  • Create a monthly brain health check-in that includes: (1) shellfish servings eaten that month, (2) subjective memory and focus rating (1-10 scale), (3) other brain-healthy activities (exercise, mental games, social time). Review trends every 3 months to see if increased shellfish intake correlates with improved cognitive function.

This research suggests an association between shellfish consumption and better brain function in older adults, but it does not prove that shellfish directly causes improved cognition. This study was conducted in China and may not apply to all populations. If you have concerns about memory loss, cognitive decline, or other brain health issues, please consult with your healthcare provider for personalized medical advice. People with shellfish allergies should not consume shellfish. This information is for educational purposes and should not replace professional medical guidance.