Summary: A new study finds that poor-quality diet can lead to brain changes associated with depression and anxiety. Researchers have found that poor eating habits reduce gray matter and change neurotransmitter levels in the brain.
These changes correlate with rumination, a symptom of mental health problems. The study highlights the importance of a healthy diet for mental well-being.
Highlights:
- Poor diet linked to a reduction in gray matter and an imbalance of neurotransmitters.
- Changes in brain chemistry correlate with symptoms of depression and anxiety.
- Study highlights circular relationship between diet, brain health and mental well-being.
Source: Reading University
A poor-quality diet can lead to brain changes associated with depression and anxiety. This is revealed by a unique study of brain chemistry and structure, as well as diet quality, conducted among 30 volunteers.
Brain scans show changes in neurotransmitters and gray matter volume in people with poor diets, compared to those adhering to a Mediterranean-style diet, considered very healthy.
Researchers also found that these changes are associated with rumination, which is part of the diagnostic criteria for conditions affecting mental health, such as depression and anxiety.
This research was carried out by the University of Reading, the University of Roehampton, FrieslandCampina (Netherlands) and Kings College London, and is published in Nutritional neuroscience.
When a person eats a poor-quality diet, there is a reduction in gamma-aminobutyric acid (GABA) and an increase in glutamate – both neurotransmitters, as well as a reduction in gray matter volume – in the frontal area of the brain. This could explain the association between what we eat and how we feel.
Dr Piril Hepsomali, from the University of Reading, said: “We can eat well ourselves! Ultimately, we find that people who eat unhealthy diets – high in sugar and saturated fat – have unbalanced excitatory and inhibitory neurotransmission, as well as reduced gray matter volume in the frontal part of the brain.
“This part of the brain is involved in mental health problems such as depression and anxiety. »
Exactly why diet affects the brain in this way is still being studied. It is possible that obesity and diets high in saturated fat cause changes in glutamate and GABA metabolism and neurotransmission, as shown in animal studies.
Distinct alterations in the gut microbiome, due to diets high in saturated fat, are thought to impact the cellular machinery that drives both GABA and glutamate production.
A diet high in saturated fat and sugar has also been shown to reduce the number of parvalbumin interneurons, which play the role of delivering GABA where it is needed.
An unhealthy diet also impacts blood sugar levels, thereby increasing blood sugar and insulin. This increases glutamate in the brain and plasma, thereby reducing the production and release of GABA.
A diet high in fat and cholesterol can lead to changes in cell membranes that also alter the release of neurotransmitters.
These changes in brain chemistry could lead to changes in brain gray matter volume, as observed in this study.
Dr. Hepsomali continued: “I would like to note that GABA and glutamate are also intimately involved in appetite and food intake. Decreased GABA and/or increased glutamate could also be a driving factor in unhealthy food choices.
“So there could be a circular relationship between eating well, having healthier brains and better mental well-being, and making better food choices to eat well. »
About this research news on diet and depression
Author: Nancy Mendoza
Source: Reading University
Contact: Nancy Mendoza – University of Reading
Picture: Image is credited to Neuroscience News
Original research: Free access.
“Adherence to unhealthy diets is associated with impaired frontal gamma-aminobutyric acid and glutamate concentrations and gray matter volume: preliminary results” by Piril Hepsomali et al. Nutritional neuroscience
Abstract
Adherence to unhealthy diets is associated with altered frontal gamma-aminobutyric acid and glutamate concentrations and gray matter volume: preliminary results
Goals
Common mental disorders (CMDs) are associated with impaired frontal excitatory/inhibitory (E/I) balance and reduced gray matter volume (GMV). Greater GMV (in areas implicated in CMD pathology) and improved CMD symptomatology were observed in individuals who adhered to a high-quality diet.
Furthermore, preclinical studies have shown an alteration of neurometabolites (mainly gamma-aminobutyric acid: GABA and glutamate: GLU) in relation to diet quality. However, the neurochemical correlates of diet quality and how these neurobiological changes are associated with CMD and its transdiagnostic factor, rumination, are unknown in humans.
Therefore, in this study, we examined the associations between diet quality and the neurochemistry and structure of the frontal cortex, as well as CMD and rumination in humans.
Methods
Thirty adults were categorized into high and low dietary quality groups and underwent 1H-MRS to measure medial prefrontal cortex (mPFC) metabolite concentrations and volumetric imaging to measure GMV.
Results
The low (vs. high) dietary quality group had reduced mPFC-GABA and high mPFC-GLU concentrations, as well as reduced GMV of the right precentral gyrus (rPCG). However, CMD and rumination were not associated with diet quality.
Notably, we observed a significant negative correlation between rumination and rPCG-GMV and a marginally significant association between rumination and mPFC-GLU concentrations. There was also a marginally significant association between mPFC-GLU concentrations and rPCG-GMV.
Discussion
Adherence to unhealthy eating habits may be associated with compromised E/I balance, which could affect GMV and, subsequently, rumination.