The effect of dietary patterns and practices on the mental health of adults differ depending on an individual’s age, found researchers from Binghamton University, State University of New York.
Writing in Nutritional Neuroscience, the new data suggests the mood of young adults (YA) (18-29 years of age) appear to be driven by diet and lifestyle elements that increase availability of neurotransmitter precursors and their concentrations in the brain. A high meat intake and regular exercise may be responsible, suggest the scientists.
In mature adults (MA) over 30, the critical determinants of mood were the availability of antioxidants (obtained through fruit intake) and the avoidance of foods and dietary practices that activate the sympathetic nervous system (SNS). These include coffee, high-carbohydrate intake (particularly high glycaemic index carbs) and skipping breakfast.
"One of the major findings of this paper is that diet and dietary practices differentially affect mental health in young adults versus mature adults," commented first author Lina Begdache, assistant professor of health and wellness studies.
"Another noteworthy finding is that young adult mood appears to be sensitive to build-up of brain chemicals. Regular consumption of meat leads to build-up of two brain chemicals (serotonin and dopamine) known to promote mood. Regular exercise leads to build-up of these and other neurotransmitters as well.
In other words, young adults who ate meat (red or white) less than three times a week and exercised less than three times week showed a significant mental distress," Begdache continued.
"Conversely, mature adult mood seems to be more sensitive to regular consumption of sources of antioxidants and abstinence of food that inappropriately activates the innate fight-or-flight response (commonly known as the stress response)," added Begdache. "With ageing, there is an increase in free radical formation (oxidants), so our need for antioxidants increases.
“Free radicals cause disturbances in the brain, which increases the risk for mental distress. Also, our ability to regulate stress decreases, so if we consume food that activates the stress response (such as coffee and too much carbohydrates), we are more likely to experience mental distress."
The reason for the age-dependent response to different types of diet may be explained by brain maturity, suggested the researchers.
“The importance of the diet in modulating mental health is uncovering as many dietary factors have been described to alter brain chemistry. Brain maturation may not complete until the age of 30, which may explain the differential emotional control, mindset, and resilience between young adults and matured adults. As a result, dietary factors may influence mental health differently in these two populations.”
Study participants (463 aged under 18-29, and 100 aged over 30) completed electronic Food-Mood Questionnaires (FMQ). The FMQ included questions on food groups containing constituents known to be associated with neurochemistry and neurobiology. Mental distress was assessed using Kessler Psychological Distress Scale questionnaire.
The researchers examined the links between healthy diet (HD), healthy dietary practices (HDP), exercise and mental health. They also examined whether mental health could influence HD, HDP and exercise – to identify possible causal loops between mental wellbeing and dietary/lifestyle factors.
“In sum, our overall analysis suggests that the initial hypothesis regarding causal relationships and feedback loops around mental health and HD, HDP, and exercise bears certain validity,” said Begdache.
“Furthermore, our results show that mental well-being may not necessarily promote HD and HDP, but it is more likely to stimulate exercise in YA, but not in MA.”
As the study is observational, validation of causality would require replicating results in a randomised intervention trial. Nevertheless, a more detailed longitudinal study may help build the case for undertaking such a trial.
“Although the study revealed many interesting associations, further investigation of the effect of dietary components, individual dietary practices and type of exercise on mental well-being is needed at multiple time points,” Begdache concluded.
Source: Nutritional Neuroscience
Published online, doi: 10.1080/1028415X.2017.1411875
“Assessment of dietary factors, dietary practices and exercise on mental distress in young adults versus matured adults: A cross-sectional study”
Authors: Lina Begdache, Maher Chaar, Nasim Sabounchi and Hamed Kianmehr