A 2021 study in Current Developments in Nutrition collected the food intake of almost 3,000 people between the ages of 60 and 80. The people also took part in certain tests of memory and cognitive function, such as naming as many animals as possible in 60 seconds. The people who ate peanut butter and peanuts were more likely to do better on the cognitive and memory tests than those who didn’t consume them.
It might be something about peanut butter’s effect on your gut health that could improve not only memory but also mood, according to a 2023 study in the Journal of Functional Foods. Researchers had younger adults eat either 25 grams of peanuts, 32 grams of peanut butter (about two tablespoons), or 32 grams of a control butter every day. After six months, the researchers found certain metabolites in the urine of those who ate peanuts and peanut butter. The peanut and peanut butter groups also improved their mood and memory. The researchers concluded that peanuts and peanut butter have certain polyphenols that are metabolized by the gut bacteria to produce substances that improve mood and brain function.