Researchers wanted to know if eating peanuts could help older adults think better and have healthier brains. They had 31 healthy people over 60 eat about 2 ounces of roasted peanuts every day for 16 weeks, then compared them to a group that didn’t eat peanuts. The peanut eaters showed better blood flow to their brains and improved memory for recalling words. Their blood pressure also went down. While these results are promising, more research is needed to understand exactly how peanuts help the brain and whether these benefits apply to everyone.

The Quick Take

  • What they studied: Whether eating roasted peanuts every day for 4 months could improve how well blood flows to the brain and help with memory in older adults.
  • Who participated: 31 healthy men and women, average age 67 years old, with normal to slightly overweight body weights. All participants were mentally sharp at the start of the study.
  • Key finding: People who ate 60 grams (about 2 ounces) of peanuts daily had about 3.6% more blood flowing to their brains compared to those who didn’t eat peanuts. They also remembered about 1-2 more words correctly on memory tests, and their blood pressure dropped by about 5 points.
  • What it means for you: Eating a small handful of unsalted roasted peanuts daily may be a simple, tasty way to support brain health as you get older. However, this study was small and only looked at healthy older adults, so talk to your doctor before making major dietary changes, especially if you have allergies or health conditions.

The Research Details

This was a randomized controlled trial, which is one of the strongest types of research studies. Researchers randomly assigned 31 healthy older adults to two groups: one group ate 60 grams (about 2 ounces) of unsalted, skin-roasted peanuts every day, while the other group ate nothing special. After 16 weeks, the groups switched—the peanut eaters stopped eating peanuts, and the control group started eating them. This “crossover” design helps researchers see the real effects of peanuts by comparing each person to themselves.

The researchers measured brain blood flow using a special MRI machine that can see how much blood is reaching different parts of the brain. They also gave participants computer-based memory and thinking tests to check if their brain function improved. Blood pressure was measured at the beginning and end of each phase.

The study was “single-blind,” meaning the researchers knew who was eating peanuts and who wasn’t, but this didn’t affect the brain scans or memory tests since those were measured objectively by machines and computers.

This study design is important because it allows researchers to see cause-and-effect relationships more clearly than just observing people. By having each person serve as their own comparison (eating peanuts versus not eating peanuts), the researchers could rule out many other factors that might affect brain health. The use of advanced brain imaging (MRI) to measure blood flow is more precise than just asking people how they feel, making the results more reliable.

This study has several strengths: it used objective measurements (brain scans and computer tests rather than subjective reports), had excellent compliance (people stuck with eating the peanuts 99-100% of the time), and used a crossover design that’s scientifically rigorous. However, the sample size was relatively small (31 people), all participants were healthy, and the study only lasted 16 weeks. The results may not apply to people with memory problems, dementia, or other health conditions. Additionally, we don’t know if the benefits continue beyond 16 weeks or if different amounts of peanuts would work better or worse.

What the Results Show

When people ate peanuts daily for 16 weeks, the amount of blood flowing to their entire brain increased by 3.6% compared to when they didn’t eat peanuts. This might sound small, but even small improvements in brain blood flow can be meaningful for brain health. The increase was even larger in the gray matter (the thinking part of the brain), which showed a 4.5% improvement in blood flow.

Memory improved in a specific way: when people had to remember words they’d seen earlier in a test, they correctly recalled about 1-2 more words after eating peanuts for 16 weeks. This improvement was most noticeable when they had to remember words after a delay, suggesting that peanuts may help with longer-term memory storage.

Blood pressure also improved. Systolic blood pressure (the top number) dropped by about 5 points, and pulse pressure (the difference between the top and bottom numbers) dropped by about 4 points. These changes suggest that peanuts may help blood vessels stay flexible and healthy.

Interestingly, other types of thinking skills—like planning, problem-solving, and reaction time—didn’t show significant improvements. This suggests that peanuts may specifically help with memory rather than all types of brain function.

The study found that eating peanuts was very well-tolerated, with no reports of serious side effects. People had no trouble sticking to eating the peanuts every day (99-100% compliance), which suggests that this is a practical dietary change people can actually maintain. The blood pressure improvements are noteworthy because high blood pressure is a risk factor for brain problems as people age, so any reduction could be beneficial for long-term brain health.

Previous research has suggested that nuts, including peanuts, are good for heart and brain health because they contain healthy fats, antioxidants, and other protective compounds. This study adds to that evidence by showing a specific mechanism—improved blood flow to the brain—that might explain why peanuts help with memory. However, most previous studies looked at nuts in general or measured brain health indirectly. This is one of the first studies to directly measure brain blood flow using advanced imaging in response to peanut consumption.

This study was relatively small with only 31 participants, so the results may not apply to larger, more diverse populations. All participants were healthy older adults with normal thinking abilities, so we don’t know if peanuts would help people with memory problems or dementia. The study only lasted 16 weeks, so we don’t know if the benefits continue longer or if they fade over time. The study didn’t compare peanuts to other nuts or foods, so we can’t say whether peanuts are uniquely beneficial or if other nuts would work similarly. Additionally, the study used unsalted peanuts, so we don’t know if salted peanuts or peanut butter would have the same effects. Finally, the improvements in memory, while statistically significant, were modest in real-world terms (remembering 1-2 more words).

The Bottom Line

For healthy older adults, eating about 2 ounces (60 grams) of unsalted, roasted peanuts daily appears to be a safe and potentially beneficial addition to a healthy diet for brain health. This recommendation has moderate confidence because the study was well-designed but relatively small. If you enjoy peanuts and don’t have allergies, this is an easy dietary change to try. However, peanuts are calorie-dense, so you may need to reduce other foods to avoid weight gain. If you have a peanut allergy, tree nut allergy, or other health conditions, consult your doctor before making dietary changes.

This research is most relevant to healthy adults over 60 who want to support their brain health and memory as they age. It may also interest people concerned about age-related memory decline or those looking for simple dietary ways to maintain brain function. People with peanut allergies, those taking blood pressure medications, and people with existing memory problems or dementia should consult their healthcare provider before making changes based on this study. Younger adults may benefit too, but this study didn’t test that age group.

The study lasted 16 weeks to see benefits, so you shouldn’t expect immediate improvements. Give yourself at least 3-4 months of consistent peanut consumption to potentially notice changes in memory or brain function. Some benefits, like blood pressure reduction, might appear sooner (within weeks), but the brain blood flow improvements took the full 16 weeks to develop. Remember that brain health is built over time, and this is just one piece of a larger healthy lifestyle that includes exercise, sleep, social connection, and a balanced diet.

Want to Apply This Research?

  • Track daily peanut consumption (yes/no or grams consumed) and pair it with weekly memory checks using simple tests like recalling a list of 10 words after 5 minutes. Also track blood pressure if you have a home monitor, measuring it weekly at the same time of day.
  • Set a daily reminder to eat a small handful (about 2 ounces or 60 grams) of unsalted roasted peanuts at the same time each day—perhaps as a mid-morning snack or with lunch. Log it in the app immediately after eating to build the habit and track consistency. If you don’t like plain peanuts, try unsalted peanut butter (about 2 tablespoons) on whole grain toast or apple slices.
  • Track peanut intake daily for consistency, measure memory performance monthly using simple word-recall tests, and check blood pressure weekly if possible. After 12-16 weeks, compare your baseline memory and blood pressure to your current measurements to see if you notice improvements. Keep notes on how you feel mentally and any changes in energy or focus you might notice.

This research suggests potential benefits of peanut consumption for brain health in healthy older adults, but it is not medical advice. Individual results may vary, and this study was conducted on a small group of healthy people. If you have peanut allergies, are taking blood pressure medications, have existing memory problems, dementia, or other health conditions, consult your healthcare provider before significantly increasing peanut consumption or making other dietary changes. This study does not replace professional medical evaluation or treatment. Always speak with your doctor before starting new dietary interventions, especially if you have health concerns or take medications.