THE Mediterranean diet is the traditional way of eating in Mediterranean countries, characterised primarily by vegetables, grains, legumes, herbs, nuts and spices. The primary source of fat is olive oil and protein consumption is moderate.
The health benefits of this diet have been proven by one of the most prolonged and rigorous diet and lifestyle studies yet conducted. In the 1950s, researchers implemented an ambitious plan to investigate diet, lifestyle and other risk factors for cardiovascular disease across various countries and cultures for an extended period.
The Seven Countries Study (SCS) was the first major attempt to scrutinise the diets and lifestyles of thousands of middle-aged men in the US, Europe and Japan and examine how those characteristics affected their risk of developing cardiovascular disease.
The SCS found associations between saturated fats, cholesterol levels and coronary heart disease. But the researchers also reported another notable result — that those who lived in and around the Mediterranean, in countries like Italy, Greece and Croatia — had lower rates of cardiovascular disease than participants who lived elsewhere and that the food they ate had a protective effect.
The study's key finding was that this diet had enormous benefits for heart health, and it was also linked to a lower risk of Type 2 diabetes, cognitive decline and certain types of cancer.
The Mediterranean diet focuses on whole, unprocessed foods with few or no additives, moderate quantities of omega-rich fish, and avoiding red meat.
A fascinating new study now suggests that a Mediterranean diet may also alleviate or prevent post-traumatic stress disorder (PTSD) symptoms.
While there is a vast body of credible research supporting the view that the condition of our gut microbiome has a significant impact on our physical health and influences the development and response of our emotions, this is the first study looking specifically at the connection between the gut microbiome and post-traumatic stress.
Compelling evidence increasingly points to the fact that the human gut microbiome, a complex community of microorganisms living in the gastrointestinal tract, plays a crucial role in the development and functioning of the nervous system, complex behaviours and brain circuits. Scientists refer to this as the “microbiota-gut-brain axis" and the concept of our gut being a “second brain” or a “hidden organ” is an emerging focus in scientific research. A previous study looking into the connection between our gut and mental health suggests that about 90% of the body’s serotonin is produced in the gut.
The latest study by the Brigham and Women’s Hospital and Harvard TH Chan School of Public Health found that participants who adhered to a Mediterranean diet experienced decreased PTSD symptoms. The study was published in Nature Mental Health on October 19, 2023.
One of the authors, Yang-Yu Liu, says: “We examined how factors like diet are associated with PTSD symptoms, [and] while further research is needed, we are closer to being able to provide dietary recommendations for PTSD prevention or amelioration.”
The team collected data from 191 participants who were assigned to three groups: probable PTSD, exposed to trauma but no PTSD and no trauma exposure. All the participants submitted two sets of four stool samples, once at the beginning of the study and again six months later. The samples were collected to provide microbial DNA information and to confirm that the participant’s gut microbiome was stable over six months.
The team found that participants who stuck to a Mediterranean diet experienced fewer PTSD symptoms. In particular, they found that the consumption of red and processed meats was “positively associated" with PTSD symptoms. In contrast, the consumption of plant-based foods was associated with decreased PTSD symptoms.
One of the elements of the study was to examine the link between PTSD symptoms and “gut microbiome signatures".
Eubacterium eligens, a specific anaerobic bacteria in the colon, seemed to be an important indicator of gut and mental health. Thriving colonies of the species were more common in people who ate healthier foods and the abundance of E. eligens was “highly consistent" with reduced PTSD symptoms.
They further demonstrated that E. eligens seemed to thrive on the enriched components of the Mediterranean diet (such as vegetables, fruits and fish) and that E. eligens was “negatively associated with red/processed meat", which people following a Mediterranean diet limit or avoid.
Lui says: “It’s exciting that our results imply that the Mediterranean diet may provide potential relief to individuals experiencing PTSD symptoms. We are eager to learn more about the relationship between PTSD, diet and the gut microbiome. In a future study, we will attempt to validate the efficacy of probiotics as a method to prevent PTSD.”
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Anneliese Burgess is co-editor of Vrye Weekblad. She was awarded the 2023 ATKV-Mediaveertjie for investigative journalism.
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