April 26, 2023 – Walnuts appear to be a tasty and nutritious way to boost attention and intelligence as well as psychological maturity in teenagers, according to new research.
Investigators studied 771 healthy adolescents attending 12 high schools in Spain. The youngsters ranged in age from 11 to 16, with an average age of 14.
The students were told to follow healthy eating recommendations and were divided randomly into two groups: 386 received 30 grams per day of raw California walnuts – about 14 walnut halves – to add to their diet, while 385 received no nuts and served as the control group.
They were tested before they entered the study and then again at 6 months, when the study ended. The analysis included tests of attention, working memory, and how quickly they think and reason, as well as behavioral strengths and difficulties. Some questionnaires, particularly those dealing with attention deficit hyperactivity disorder, were completed by teachers.
Adolescents who ate walnuts for at least 100 days were better able to think and reason on their feet, and they had fewer symptoms of ADHD – they paid more attention in class and were less hyperactive. But there were no significant changes between the groups in other cognitive areas, such as working memory.
Senior author Jordi Julvez, PhD, group leader at the Institute of Health Research Pere Virgili and an associate researcher at the Barcelona Institute for Global Health, said health care providers should advise teens “to eat a handful of walnuts three times a week for the rest of their lives; they may have a healthier brain with better cognitive function.”
Rich Source of Healthy Fatty Acids
Adolescence is a key time in brain development, when connections between the neurons and complex behaviors are being “refined,” the authors wrote.
Previous research suggests that polyunsaturated fatty acids (PUFAs) are key in helping the central nervous system to develop correctly, shaping its architecture and function during times of neural development.
Three of these acids play an “essential developmental role.” Two of them – the omega-3 fatty acids docosahexaenoic (DHA) and eicosapentaenoic (EPA ) – are polyunsaturated fatty acids that can only come through diet, mainly from seafood.
But seafood isn’t the only source of omega-3s. They can also come from plants. Walnuts are “among the richest sources” of plant-derived omega-3 fatty acids.
Food Is Medicine
Uma Naidoo, MD, director of nutritional and lifestyle psychiatry at Massachusetts General Hospital in Boston, said COVID “has left us with a huge mental health issue in the young: The rate of suicide in youth has increased and is very concerning.”
For this reason, Naidoo, a professional chef, nutritional biologist, and author of the book This Is Your Brain on Food, is “excited to see high-quality research being done on this vulnerable population, offering more solutions that are easier to implement, such as nutrition.”
She’s also excited that this type of research is “furthering functional nutrition for mental health,” as she believes that “food is medicine.”
The findings “align” with Naidoo’s own approach to nutritional psychiatry and are also in line with her clinical practice.
However, although these results are “promising,” more research is needed across more diverse populations to “make sure these results are truly generalizable,” says Naidoo, a faculty member at Harvard Medical School who was not involved with the study.
She “envisions a future where the research is so advanced that we can ‘dose’ these healthy whole foods for specific psychiatric symptoms and conditions.”