BARCELONA, Spain — It turns out that walnuts really are brain food! While adolescence and immaturity go hand-in-hand, but fascinating new research out of Spain suggests eating walnuts on a regular basis may help young children and teens’ brains develop — and even contributes to their psychological maturation.
These findings come from a new study led by the Institut d’Investigació Sanitària Pere Virgili (IISPV), in collaboration with the ISGlobal (a center promoted by “la Caixa” Foundation) and the Hospital del Mar Medical Research Institute (IMIM). Study authors believe their work is groundbreaking; while prior studies have focused on the effects of nuts on human health, scientists have not examined the specific impact of their consumption during the critical developmental stage of adolescence — until now.
Walnuts are naturally rich in alpha-linolenic fatty acid (ALA), a type of omega-3 known to play a key role in the development of the human brain, especially early in life.
“Adolescence is a time of great biological changes: hormonal transformation occurs, which in turn is responsible for stimulating the synaptic growth of the frontal lobe. This part of our brain is what enables neuropsychological maturation, i.e., more complex emotional and cognitive functions. Neurons that are well nourished with this type of fatty acids will be able to grow and form new, stronger synapses,” says Jordi Julvez, principal investigator and coordinator of the NeuroÈpia Research Group of the IISPV, in a media release.
Eating walnuts may even improve cases of ADHD
This project encompassed a total of 700 secondary school students between 11 and 16 years of age from 12 different high schools in Barcelona. Researchers randomly divided the participants into two groups; a control group, which received no intervention at all, and the experimental group, which received sachets holding 30 grams of walnut kernels. Young people in the experimental cohort could eat the walnuts on a daily basis for a period of six months.
Study authors report adolescents who consumed walnuts for at least 100 days (not necessarily every day of the trial) improved their attention functions. Those who had some symptoms of attention deficit hyperactivity disorder (ADHD) even experienced significant behavior improvements (less hyperactivity and paying more attention in class).
On the other hand, however, the team also noted an increase in functions related to fluid intelligence, which, according to Jordi Julvez, “is less influenced by learning; it is inherent to the person’s biology status. We assessed it with increasingly complex tests, such as having adolescents figure out what pattern a row of letters followed, for example.”
“Overall, no significant differences were found in the intervention group in relation to the control group,” Julvez adds, “but if the adherence factor is considered, then positive results are observed, since participants who most closely followed the guidelines – in terms of the recommended dose of walnuts and the number of days of consumption – did show improvements in the neuropsychological functions evaluated.”
How many walnuts should kids be eating?
All in all, this research suggests that adhering to a healthy diet on a consistent basis can benefit adolescents greatly at a pivotal time of brain development, both cognitively and psychologically.
“If boys and girls would heed these recommendations and actually eat a handful of walnuts a day, or at least three times a week, they would notice many substantial improvements in cognitive abilities, and it would help them face the challenges of adolescence and entering adulthood. Adolescence is a period of great brain development and complex behaviors that requires a significant amount of energy and nutrients,” concludes Ariadna Pinar, first author of the article.
This study received funding from the Instituto de Salud Carlos III through projects CP14/00108, PI16/00261 and PI21/00266 (co-funded by the European Union through the “A way to make Europe” program). The California Walnut Commission (CWC) also supported the study by providing the walnuts. None of the funding entities participated in the actual design or discussion of the results.
Moving forward, researchers plan to conduct an observational study (also supported by the CWC) aimed at determining whether the consumption of walnuts and nuts in general while pregnant influences the cognitive development and psychological maturation of infants.
The study findings appear in the journal EClinicalMedicine.