According to a recent study, higher consumption of fruits and vegetables is associated with a reduction in depressive symptoms over time. Individuals consuming the most fruits and vegetables had a lower risk of developing signs of depression compared to those with the lowest intake.
The study, conducted by researchers from the Centre for Healthy Brain Ageing (CHeBA) at the University of New South Wales, involved approximately 3,480 twins aged 45 and older from the United States, Australia, Denmark, and Sweden. They were monitored for up to 11 years, during which they reported their diet and mood, according to Scienze Notizie.
Twin studies are particularly useful for scientists because they allow researchers to isolate genetic influences from environmental ones, enhancing the reliability of conclusions regarding health outcomes like depression. "Twins share 50 to 100% of their genetic heritage and, when raised together, they also share the same family environment," said Karen Mather, a co-author of the study and geneticist at UNSW, according to T-Online.
"These results provide a new argument in favor of increasing fruit and vegetable consumption among adults over 45 years old," said Dr. Annabel Matison, the lead author of the study and a lecturer at the Centre for Healthy Brain Ageing (CHeBA), according to T-Online. The research found that individuals who consumed a greater number of vegetables reduced their risk of falling into depression.
The study found that individuals who consumed fewer fresh foods were more frequently affected by depression, with symptoms being more pronounced among those who consume few fruits and vegetables. Participants with high fruit intake averaged 2.1 servings per day, while those with low intake averaged 0.3 servings per day. Similarly, participants with high vegetable intake averaged 2.0 servings per day, while those with low intake averaged 0.5 servings per day.
The research group points out that the beneficial effects are seen at low "high intake" levels, far below the five to six servings a day recommended by WHO and the Danish dietary guidelines, according to Femme Actuelle. "Interestingly, total fruit and vegetable consumption, even in the high consumption category, still seems to be much lower than the dietary recommendations for most countries," the scientists observed.
The researchers suggest that the beneficial relationship between fruit and vegetable intake and depression is likely due to the high levels of dietary fibers, vitamins, and micronutrients they contain. Fruits and vegetables are recommended not only for cardiovascular and metabolic health but also for their protective effects on mental health, particularly due to their fiber content and benefits on the intestinal microbiome.
"The importance of the intestinal microbiome and its potential influence on depression, due to systemic and neuroinflammatory inflammation, is becoming better understood," said Matison. The researchers note that increasing consumption to the optimal level may enhance the identified effect, but further study of this hypothesis is required.
The study does not demonstrate a direct cause-and-effect relationship—partly due to the exclusion of variables like physical activity—the sample size and use of the twin model suggest a connection. While pharmacological and psychotherapeutic treatments remain essential in the fight against depression, more studies suggest that lifestyle changes, particularly in diet, could also play a role in the prevention of this disease, according to Femme Actuelle.
"The conclusion that we should eat more fruits and vegetables is good and sympathetic," said psychiatrist Poul Videbech. However, Videbech has reservations about the study's findings, emphasizing that the causal relationship between diet and depression is "extremely difficult to untangle."
"So when the initial joy has subsided, skepticism arises," he stated, according to Videnskab. He points out that a general weakness of observational studies is that they can only show a correlation between factors—here fruits and vegetables and depression symptoms—and cannot establish a certain causal relationship.
The article was written with the assistance of a news analysis system.