One promising area of research into depression involves diet. Studies show that Mediterranean-style diets, which emphasize eating fruits, vegetables, whole grains, and healthy fats, are associated with a lower risk of developing depression. This study shows that eating citrus fruits is associated with a lower risk of depression and changes in 15 different species of gut microorganisms.
Depression is a common and debilitating mental health condition that affects more than 280 million people worldwide. It is characterized by persistent feelings of sadness, loss of interest in previously enjoyable activities, and a host of other symptoms that can impair daily functioning.
Despite its prevalence, the exact causes of depression are still not fully understood, and many available treatments, such as antidepressant medications, are not always effective.
In fact, about 70% of patients who try treatment with these medications do not experience significant improvement and, in some cases, experience difficult-to-manage side effects. This highlights the urgent need to find new ways to approach and treat depression.
One promising area of research into depression involves diet. Studies have shown that Mediterranean-style diets, which emphasize eating fruits, vegetables, whole grains, and healthy fats, are associated with a lower risk of developing depression, with up to a 35% reduction in risk.
In addition, the Mediterranean diet appears to have a positive effect on mood symptoms. While it’s not entirely clear which specific foods are responsible for these benefits, eating citrus fruits, such as oranges and grapefruits, has recently been linked to a decreased risk of depression.
However, we still need to understand exactly how diet and depression are linked.
One important factor to consider in this relationship is the gut microbiome, which is the community of microorganisms that live in our digestive system. Research suggests that gut health may influence our mental health through a communication system called the “gut-brain axis.”
This axis involves the interaction between the gut’s nervous system and the brain, where chemicals produced in the gut can affect brain function. For example, the microbiome can produce substances that help in the production of neurotransmitters, such as serotonin, which is important for regulating mood.
Despite the extensive evidence for this connection, there are still few studies that investigate how the gut microbiome can affect the relationship between diet and depression.
To address these gaps in knowledge, researchers from Harvard Medical School, USA, conducted a study with more than 32,427 participants to examine how citrus fruit consumption can interact with the gut microbiome and influence the risk of depression.
This investigation analyzed citrus fruit intake over time, as well as the composition of the participants’ gut microbial communities.
This study is one of the first to explore in depth how the microbiome can affect the relationship between diet and depression, integrating a vast amount of data on diet, mental health and genetics.
To collect dietary data, they used food frequency questionnaires, where participants reported how often they consumed different types of foods, including citrus fruits. Data were collected every four years, allowing for careful analysis of changes in diet and mental health over time.
During follow-up, other dietary factors, such as energy intake, alcohol intake, and other types of fruits and vegetables, were also recorded to get a full picture of participants’ eating habits.
During the research, they observed that citrus fruit consumption was associated with a lower risk of depression and changes in 15 different species of gut microorganisms. One of these microorganisms, known as Faecalibacterium prausnitzii, was found to be more present in people who consumed more citrus fruits.
Faecalibacterium prausnitzii
On the other hand, those who presented symptoms of depression had lower levels of this microorganism. This bacteria is involved in metabolic processes that can influence the production of chemicals important for mental health.
In this analysis, they found that women who consumed more citrus fruits had a lower body mass index (BMI), practiced more physical activities and consumed more calories compared to those who ate less citrus fruits.
In addition, during the course of the research, they identified more than 2,173 cases of depression among participants who, initially, did not present symptoms of this condition.
Those in the highest citrus fruit intake group had a 22% lower risk of developing depression over time, even after adjusting for other factors that could influence this relationship.
These results emphasize the importance of diet in preventing depression and offer insights into how the gut microbiome may modulate the beneficial effects of citrus foods on mental health.
The research suggests that adopting a diet rich in citrus fruits may be a useful strategy for reducing the risk of depression and improving overall mental health.
READ MORE:
F. prausnitzii potentially modulates the association between citrus intake and depression
Chatpol Samuthpongtorn, Allison A. Chan, Wenjie Ma, Fenglei Wang, Long H. Nguyen, Dong D. Wang, Olivia I. Okereke, Curtis Huttenhower, Andrew T. Chan and Raaj S. Mehta
Microbiome, 14 November 2024DOI: 10.1186/s40168-024-01961-3
Abstract:
The gut microbiome modulates the effects of diet on host health, but it remains unclear which specific foods and microbial features interact to influence risk of depression. To understand this interplay, we leveraged decades of dietary and depression data from a longitudinal cohort of women (n = 32,427), along with fecal metagenomics and plasma metabolomics from a substudy (n = 207) nested in this cohort, as well as an independent validation cohort of men (n = 307). We report that citrus intake and its components are prospectively associated with a lower risk of depression and altered abundance of 15 gut microbial species, including enriched Faecalibacterium prausnitzii. In turn, we found a lower abundance of F. prausnitzii and its metabolic pathway, S-adenosyl-L-methionine (SAM) cycle I in participants with depression. To explore causality, we found that lower SAM production by F. prausnitzii may decrease intestinal monoamine oxidase A gene expression implicated in serotonin and dopamine synthesis. These data underscore the role of diet in the prevention of depression and offer a plausible explanation for how the intestinal microbiome modulates the influence of citrus on mental health.
Comments