Large study highlights link between diet and brain health

New research published in Nature revealed a strong link between diet and brain health. The study found that older adults who maintain a balanced diet have better mental health, higher cognitive functions and increased volume of gray matter in the brain, which is often associated with intelligence.

Researchers have long observed the profound impacts of food choices not only on physical health, but also on mental well-being and cognitive function. However, a detailed understanding of how specific dietary elements influence brain structure and function remained underexplored. The new study was based on the hypothesis that a more balanced and varied diet might be associated with better cognitive and mental health outcomes.

For their study, the researchers used a large dataset from the UK Biobank, a large-scale biomedical database containing in-depth genetic and health information from more than 500,000 UK residents. For this particular study, researchers analyzed data from 181,990 participants (average age 70.7 years) who completed detailed questionnaires online about their food preferences.

Participants’ food preferences were assessed using an online questionnaire classifying foods into 10 groups, such as fruits, meats and alcohol. This allowed the researchers to obtain detailed information on the participants’ usual consumption of different types of food.

Health assessments included cognitive function tests, blood metabolic biomarkers, brain imaging studies, and genetic analyses. These varied measures allowed researchers to comprehensively assess the impact of diet on brain health from several angles:

• Cognitive function tests assessed aspects such as memory, reasoning and attention.
• Blood biomarkers have provided information on metabolic health and other physiological aspects potentially influenced by diet.
• Brain imaging has offered direct insight into structural and functional aspects of the brain, allowing researchers to correlate eating habits with physical changes in the brain.
• Genetic analysis has helped to understand the genetic bases that could influence or be influenced by dietary habits.

Researchers leveraged advanced machine learning algorithms to manage and analyze the UK Biobank’s voluminous data. Machine learning techniques, such as principal component analysis (PCA) and hierarchical clustering, have been used to identify patterns in dietary data that may be linked to different health outcomes. This method allowed researchers to efficiently process large data sets and derive meaningful insights from them.

One of the most notable findings of the study was the clear association between a balanced diet and improved cognitive functions. Participants who reported eating a varied diet performed better on cognitive tests measuring aspects such as memory, reaction time and problem-solving skills. These results suggest that nutritional diversity is beneficial for maintaining and improving brain function, potentially contributing to the prevention of cognitive decline associated with aging.

In terms of mental health, the study found that people with a more balanced diet reported fewer symptoms of mental health disorders such as depression and anxiety. This connection highlights the potential for dietary choices to serve not only physical health, but also as an element of mental health management. A balanced nutrient intake can help moderate mood and emotional well-being, reinforcing the need for integrated dietary guidelines that consider mental and physical health outcomes.

Another important finding concerns the relationship between dietary habits and brain structure, particularly the volume of gray matter in the brain. Gray matter includes the regions of the brain involved in muscle control, sensory perception such as sight and hearing, memory, emotions, speech, decision-making, and self-control.

Participants with a varied diet showed increased gray matter volumes, suggesting that their eating habits could directly promote better brain function and structure. This finding is particularly relevant as greater gray matter volume is often associated with higher intelligence and cognitive reserve, which may contribute to delaying the onset of neurodegenerative diseases.

Lead author Jianfeng Feng, a professor at the University of Warwick, highlighted the importance of establishing healthy food preferences early in life. He said: “Developing a healthy, balanced diet from an early age is crucial for healthy growth. To promote the development of a healthy and balanced diet, families and schools should offer a diverse range of nutritious meals and cultivate an environment favorable to their physical and mental health.

Interestingly, researchers have also studied how genetic factors interact with food choices to influence brain health. It has been observed that genetic predispositions can either increase or moderate the impact of diet on brain health. For example, certain genetic profiles associated with poor eating habits could exacerbate the risk of cognitive decline or mental health problems, while beneficial genetic factors could amplify the positive effects of a healthy diet.

“Our findings highlight the associations between dietary habits and brain health, calling for concerted efforts to promote nutrition awareness and foster healthier eating habits among diverse populations,” said co-author Wei Cheng from Fudan University.

The researchers controlled for age, body mass index (BMI), education level and socioeconomic status using the Townsend deprivation index. These controls made it possible to isolate the specific effects of dietary habits on brain health by minimizing the impact of external confounding factors.

But even though the breadth and depth of the study provides compelling evidence, the researchers acknowledge some limitations. Food preference data relied on self-reported information, which may introduce bias or inaccuracies. The cross-sectional nature of the study makes it difficult to infer causality, whether better brain health leads to healthier eating habits or vice versa.

Future research should explore longitudinal data to track changes over time, helping to clarify the direction of observed relationships. Additionally, broadening the demographic scope beyond UK biobank participants could improve the generalizability of the results. Further studies could also look at the biological mechanisms by which diet influences brain structure and function, potentially guiding targeted interventions.

“Overall, our study provides systematic insights into understanding naturally developed eating habits in older adults and highlights the associations between a balanced diet and brain health,” the researchers concluded. “The implications of these findings highlight the potential benefits of dietary education from an early age, which could promote healthy food preferences and cultivate long-term brain health throughout life.” Future research is needed to fully understand the potential long-term associations between these dietary habits and brain structure and health, particularly in adolescent and middle-aged populations.

The study, “Associations of dietary habits with brain health from behavioral, neuroimaging, biochemical, and genetic analyses,” was authored by Ruohan Zhang, Bei Zhang, Chun Shen, Barbara J. Sahakian, Zeyu Li, Wei Zhang, Yujie Zhao, Yuzhu Li., Jianfeng Feng and Wei Cheng.