Albany, Ga. (September 23, 2021) – The University of Barcelona has released new research showing that consumption of peanuts and peanut butter may improve cognitive function and reduce stress in healthy young adults1. Researchers point to the polyphenols in peanuts that likely aided memory, executive function and processing speed and resulted in a reduction of cortisol, anxiety and depressive levels in a control group of mostly college students. The ARISTOTLE study was published online in Clinical Nutrition on September 22, 2021.
“The improvement of memory function and stress response after consuming regular peanuts and peanut butter seem to be related to the mental health effects of bioactive compounds such as resveratrol and p-coumaric acid found in peanuts, as well as the increased level of short chain fatty acids and very long chain saturated fatty acids in plasma and feces associated with peanut consumption,” says Dr. Rosa M. Lamuela-Raventós, the lead researcher from the University of Barcelona.
The three-arm, parallel-group randomized controlled trial was conducted from November 2019 to June 2020 with 63 healthy participants (44 females and 19 males) who were 18 to 33 years of age. The participants, who were mostly students, were from the University of Barcelona in Spain and consumed either 25 grams a day of roasted peanuts with skins or two tablespoons (32 grams) a day of peanut butter or two tablespoons (32 grams) a day of a control butter. The control had a similar macronutrient composition as the roasted peanuts and peanut butter but was free of phenolic compounds and fiber. Consumption of the peanut products began after a two-week, peanut-free period in advance of the study.
Study participants followed their regular diet and consumed the peanut products at any time of the day. Wine, grapes, dark chocolate with more than 70% cacao and berries were excluded from the participants’ diets due to their high levels of resveratrol, an antioxidant present in peanuts. In addition, other nuts were excluded from the diet.
“This new research involves a group of young participants and points to the possible cognitive and mental health benefits from a relatively small daily serving of peanuts or peanut butter,” says Dr. Samara Sterling, a nutrition scientist and research director for The Peanut Institute. “When you break down the nutritional structure of peanuts, they have a unique combination of vitamins, minerals and bioactive compounds, including resveratrol, niacin, vitamin E and coumaric acids, that can contribute to cognition and mental health.”
At the beginning and end of the study, trained personnel assessed the cognitive functions of participants, administering in a standard order a broad range of validated neuropsychological tests and mood disorder questionnaires. The tests evaluated the three main cognitive domains – memory, executive function and processing speed. The Hospital Anxiety and Depression Scale, validated for the Spanish population, was also used to detect anxious states and depressive states.
Biological samples (fasting blood, 24-hour urine and feces) were collected prior to the start of the study as a baseline and after six months of participation in the study. Participants were also contacted three months into the research to encourage their ongoing adherence to the study parameters.
“This is first-of-its-kind research that points to the potential ‘brain benefits’ of peanut and peanut butter consumption in a younger demographic,” explains Dr. Sterling. “The results show that a small addition to the diet can have a significant impact.”
The research was conducted by Dr. Rosa M. Lamuela-Raventós and her team at the University of Barcelona (Department of Nutrition, Food Sciences and Gastronomy, XIA, School of Pharmacy and Food Sciences, at the INSA-University of Barcelona and CIBEROBN).
Previous Research Supports Cognitive Benefits of Peanuts and Peanut Butter
While the ARISTOTLE study conducted by the University of Barcelona was among mostly college-age students, previous studies have focused on the benefits of peanut and peanut butter consumption among seniors.
A 2021 study published in the Journal of the Prevention of Alzheimer’s Disease found that adults 60 to 80 years of age who did not eat peanuts and peanut butter regularly were 30% to 50% more likely to do poorly on tests measuring learning, memory, language, processing motor speed (the time it takes to process and react to information) and attentiveness compared to those who did.2
In a separate 2018 study of adults 55 and older, higher cognitive scores were associated with consuming just one serving (10 grams) of nuts daily — as well as a 40% decreased likelihood of poor cognitive function.3
Researchers point to the polyphenols and various fatty acids in peanuts that likely contributed to these results. Additional vitamins, minerals and bioactive compounds found in peanuts that are beneficial for brain health include:
- Niacin: In a study of adults 65 and older, those who consumed more niacin showed a slower rate of cognitive decline and a 70% reduced risk for Alzheimer’s disease4 — peanuts are an excellent source of niacin.
- Vitamin E: Found to promote healthy brain aging and delay cognitive decline caused by Alzheimer’s disease.5 Peanuts are considered a “good source” of vitamin E.
- Resveratrol: A bioactive found in peanuts, resveratrol is believed to be beneficial in fighting against Alzheimer’s disease and other nerve degenerating diseases.6
- p-coumaric Acid: An antioxidant that appears to target the neurotransmitters in the brain that regulate mood, stress and anxiety. In 2014, authors of a study on p-coumaric acid noted that it may have similar effects for reducing stress as a leading anxiety-reducing drug, Diazepam.7
Even peanut skins have been found to deliver benefits. A 2016 randomized controlled trial found that peanuts eaten with skins improved both cerebrovascular and cognitive function in men and women.8
“This new research from the University of Barcelona supports the growing evidence of ‘food as medicine’ and the benefits that healthy food choices can have on both the young and old,” says Sterling. “Peanuts and peanut butter are an affordable and versatile way to load up on vitamins and minerals that can promote cognitive and mental health.”
This research has been supported by funding from The Peanut Institute 2019, CICYT [AGL2016- 75329-R], CIBEROBN from the Instituto de Salud Carlos III, ISCIII from the Ministerio de Ciencia, Innovación y Universidades, (AEI/FEDER, UE) and Generalitat de Catalunya (GC) [2017SGR 196]. None of the funders had a role in the study design, implementation, analysis or interpretation of the data, or the writing of the manuscript.
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Based in Albany, Ga., The Peanut Institute is a non-profit organization supporting nutrition research and developing educational programs to encourage healthful lifestyles that include peanuts and peanut products. The Peanut Institute pursues its mission through research programs, educational initiatives and the promotion of healthful lifestyles to consumers of all ages. As an independent forum, The Peanut Institute is uniquely positioned to work with all segments of the food industry, the research community, academia, consumer organizations and governmental institutions.