Background: Peanuts are rich in bioactive compounds that may have a positive impact on memory and stress response. Objective: To evaluate the effect of regular consumption of peanut products on cognitive functions and stress response in healthy young adults. Design: A three-arm parallel-group randomized controlled trial was conducted in 63 healthy young adults that consumed 25 g/day of skin roasted peanuts (SRP, n ¼ 21), 32 g/d of peanut butter (PB, n ¼ 23) or 32 g/d of a control butter made from peanut oil (free of phenolic compounds and fiber) (CB, n ¼ 19) for six months. Polyphenol intake, cognitive functions, and anxiety and depression scores were evaluated using validated tests. Fecal short-chain fatty acids (SCFAs) and plasma and fecal fatty acids were assessed by chromatographic methods. Urinary cortisol was quantified by an enzymatic method. Results: Comparing the two interventions with the control, a significant reduction in anxiety scores was observed in the SRP compared to the CB group. After the intervention, consumers of SRP and PB had an improved immediate memory (p ¼ 0.046 and p ¼ 0.011). Lower anxiety scores were associated with SRP and PB (p < 0.001 and p ¼ 0.002, respectively) and lower depression scores with SRP, PB and CB (p ¼ 0.007, p ¼ 0.003 and p ¼ 0.032, respectively). Memory functions and stress response were significantly correlated with polyphenol intake, fecal SCFAs, plasma and fecal very long chain saturated fatty acids (VLCSFAs). Conclusions: Regular peanut and peanut butter consumption may enhance memory function and stress response in a healthy young population. These effects seem to be associated with the intake of peanut polyphenols, increased levels of fecal SCFAs, and unexpectedly, VLCSFAs, which were also present in the control product.

Although numerous studies have reported the protective effect of nut consumption on cardiovascular risk, evidence for the role of peanuts in maintaining cardiometabolic health is inconclusive. Presented here are the results from the ARISTOTLE study, a parallel randomized controlled trial evaluating the impact of regular peanut intake on anthropometric, biochemical, and clinical measurements. The 63 healthy subjects that completed the study consumed their habitual diet plus either: a) 25 g/day of skin roasted peanuts (SRP, n = 21), b) two tablespoons (32 g)/day of peanut butter (PB, n = 23) or c) two tablespoons (32 g)/day of a control butter based on peanut oil (CB, n = 19) for 6 months. In addition, a meta-analysis of clinical trials, including data from the ARISTOTLE study, was carried out to update the evidence for the effects of consuming peanuts, including high-oleic peanuts, and peanut butter on healthy subjects and those at high cardiometabolic risk. After a systematic search on PubMed, Web of Science, Cochrane Library and Scopus databases up to July 2021, 11 studies were found to meet the eligibility criteria. In the ARISTOTLE study, lower total cholesterol/HDL-cholesterol and LDL-cholesterol/HDL-cholesterol ratios were found in the SRP group compared to the CB group (p = 0.019 and p = 0.008). The meta-analysis of clinical trials revealed that peanut consumption is associated with a decrease in triglycerides (MD: −0.13; 95% CI, −0.20 to −0.07; p &lt; 0.0001) and that healthy consumers had lower total cholesterol and LDL-cholesterol/HDL-cholesterol ratios compared to the control groups (MD: −0.40; 95% CI, −0.71 to −0.09; p = 0.01 and MD: −0.19; 95% CI, −0.36 to −0.01; p = 0.03, respectively). However, individuals at high cardiometabolic risk experienced an increase in body weight after the peanut interventions (MD: 0.97; 95% CI, 0.54 to 1.41; p &lt; 0.0001), although not in body fat or body mass index. According to the dose-response analyses, body weight increased slightly with higher doses of peanuts. In conclusion, a regular consumption of peanuts seems to modulate lipid metabolism, reducing triglyceride blood levels.Systematic Review Registrationhttps://osf.io/jx34y/, identifier: 10.17605/OSF.IO/MK35Y.