Food for thought: the best diets for your brain

As their children submit themselves to the ordeal of all-important end-of-year exams, parents of high school and university students may be wondering what they can do to help. One thing they ought to consider in particular is diet and its potential impact on academic outcomes.

Unfortunately, there’s relatively little research into the effect of nutrition on scholastic performance in young adults. But we do know that what we eat affects brain power.

Research findings

Let’s start with a brief overview of what the research says. Regular meals three times a day have been linked to higher academic performance in Korean adolescents, in a study from 2003.

In Norwegian teenagers, regular meals (lunch and dinner) were negatively associatedwith self-reported learning difficulties in mathematics. While foods reflecting a less healthy diet (including soft drinks, sweets, snacks, pizza, and hot dogs) were linked with learning difficulties in maths.

In the same 2013 Norwegian study, regular breakfast was associated with fewer learning difficulties, not only in maths but also in reading and writing.

In a 2008 Canadian study, higher academic achievement was reported in adolescents who consumed more fruits, vegetables and milk. Increased fish consumption positively influenced academic grades in Swedish teens, according to a paper published in 2010.

Another 2010 paper showed that, in Iceland, adolescents who had poor dietary habits (with higher consumption of chips, hamburgers and hot dogs) had lower academic achievement. In contrast, adolescents with higher fruit and vegetable consumption achieved higher academic scores.

In Australia, data from the long-running Western Australian Raine study have shown teenagers’ diet impacts cognitive performance, which is a significant predictor for academic achievement.

Specifically, my colleagues and I found a “Western” dietary pattern (high intake of take-away foods, red and processed meat, soft drinks and fried and refined food) at age 14 is associated negatively with 17-year-olds’ thinking abilities, especially reaction time and memory.

We also evaluated the school performance of teenagers in the Raine study. A higher intake of the kind of unhealthy food described above was linked to worse scholastic performance. The adolescents we looked at had poorer scores in mathematics, reading and writing, even after we had corrected for their body mass index and physical activity levels.

In contrast, we found a diet richer in fruit, yellow and red vegetables and whole grains was associated with better academic performance.

Diet and the brain

How exactly does diet affect mental performance? Adolescence is a sensitive time for the developing brain, particularly for the prefrontal cortex and other important brain structures, such as the hippocampus, which are critically involved in learning and memory. Research shows diet is likely to be a significant influence on brain capacity during this stage of life.

The Western dietary pattern appears to provide particular reason for concern at this critical time. This diet correlates with a high overall intake of total fat, saturated fat, refined sugar and sodium but lower levels of significant micronutrients, including folate and iron.

Folate has been positively linked to academic achievement in adolescents while iron deficiency has been associated with poorer mathematics scores in children and adolescents.

More generally, the Western dietary pattern is associated in young people with biological changes linked to metabolic syndrome, a term used to refer to a range of bodily changes associated with increased risk of cardiovascular disease and diabetes.

And this as well as high levels of fat and carbohydrate consumption are linked with impaired thinking skills through changes to key areas in the brain.

All these research findings are consistent with the idea that diet has impacts on teenagers’ thinking skills. In particular, they suggest the Western dietary pattern is a risk factor for poor academic performance.

Getting young people to take any advice from their parents is always challenging. But parents who can ensure their teenagers eat well may be conferring significant benefits on their academic performance.

Published in collaboration with The Conversation

Author: Jonathan Foster is a Curtin Senior Fellow, Professor & Clinical Neuropsychologist at Curtin University.

Image: Apples are displayed in a wheel barrow during an event promoting Polish apples in Warsaw August 6, 2014. REUTERS/Franciszek Mazur/Agencja Gazeta