However, there is growing scientific evidence that dietary factors may also affect mental health.
For instance, studies have found associations between the Mediterranean diet and a lower risk of depression.
To investigate the role of the diet in mental health, researchers from Binghamton University and Stony Brook University, both in New York, conducted an online survey of more than 2,600 participants from North America, Europe, the Middle East and North Africa (MENA), and Asia.
The survey spanned 5 years and included 1,147 young women, 628 mature women, 641 young men, and 207 mature men. For the purposes of the study, the researchers defined young as being between the ages of 18 and 29 years, while the mature participants were aged 30 years or over.
The study appears in the journal Nutrients.
Involvement in the survey was voluntary. All of the participants filled out a questionnaire after responding to a social media post advertising the study.
The scientists’ goal was to determine what foods and other factors, including exercise, geographical location, and time of year, were positively or negatively associated with mental health.
Young and mature women had a higher risk of mental distress during the spring season. The researchers also found negative mental health associations with high caffeine intake and moderate-to-high fast food consumption.
They also found that eating breakfast frequently and engaging in higher levels of exercise were linked to improved mental well-being among young women.
In contrast, for mature women, consuming breakfast frequently was linked to a higher rate of mental distress. However, as with young women, frequent exercise appeared to have a positive effect on well-being in mature women.
Additionally, mature women living in Asia or the MENA region reported more significant mental distress compared with those residing in North America.
Young men reported enhanced well-being in relation to frequent exercise, moderate consumption of dairy, and moderate-to-high meat intake. Conversely, high fast food and caffeine intake were both associated with poorer mental well-being.
As with mature women, mature men had a higher chance of mental distress if they lived in the MENA region. Higher education levels and moderate consumption of nuts were associated with positive mental health in mature men.
According to study coauthor Lina Begdache, Ph.D., an assistant professor of health and wellness studies at Binghamton University, scientists need to consider differences in brain maturity between young and mature adults.
She explains: “Young adults are still forming new connections between brain cells, as well as building structures; therefore, they need more energy and nutrients to do that.”
Taking age into consideration, she believes, will help us understand how diet and other factors play a role in mental health.
“We need to consider a spectrum of dietary and lifestyle changes based on different age groups and [sexes]. There is not one healthy diet that will work for everyone. There is not one fix.”
– Lina Begdache, Ph.D.
Begdache explains that there are critical differences in brain morphology and connectivity between men and women. Throughout her research, she has found that diet is less likely to affect men than women.
Men who adhere to even a “slightly healthy” diet tend to report good mental well-being, she explains. However, when their diet consists mostly of fast food, mental distress becomes more likely.
This study provides insight into the associations between diet, geographical regions, and exercise in people of different ages and sexes. However, limitations include the study’s cross-sectional nature, the nonrandom sampling, and the smaller sample size of mature men.
As most dietary research focuses on the relationship between diet and physical health, Begdache hopes that these findings will promote more research into the role that diet plays in mental well-being.
“I hope to see more people doing research in this area and publishing on the customization of diet based on age and [sex]. I hope that one day, institutions and governments will create dietary recommendations for brain health.”
— Lina Begdache, Ph.D.
It is worth noting, however, that the study was relatively small. In particular, the group of mature men numbered just 207.
Also, the study was cross-sectional, so the researchers only took a snapshot of each participant’s diet at one point in time. Diet can change significantly over the years.
Additionally, the scientists could not account for existing health conditions or environmental or genetic factors. The study of nutrition’s impact on mental health is challenging and, as ever, much more work is necessary.