An analysis of 41 multi-country studies has found that a diet high in junk food raises the risk of developing depression, reports The Guardian. The study, published in the journal Molecular Psychiatry, took place in Britain, Spain, and Australia.
Researchers examined 41 studies attempting to uncover a link between diet and depression. The analysis revealed that processed foods high in fat and sugar lead to inflammation in the body, which in turn can directly affect the brain. Lead author of the study Dr. Camille Lassale, who works in the department of epidemiology and public health at University College London, commented on the link between inflammation and depression.
"A pro-inflammatory diet can induce systemic inflammation, and this can directly increase the risk for depression...[A] bad diet heightens the risk of depression to a significant extent."Lassale explained further that "Chronic inflammation can affect mental health by transporting pro-inflammatory molecules into the brain, it can also affect the molecules – neurotransmitters – responsible for mood regulation."
This systematic inflammation that Lassale refers to has similar effects on the body as pollution, obesity, and lack of exercise. The research showed that the link between poor diet and depression is more than correlative, and is, in fact, causal. Lassale stressed that participants were not already depressed prior to the study nor could the results be explained by depression causing people to eat lower quality food.
"Poor diet may increase the risk of depression as these are results from longitudinal studies which excluded people with depression at the beginning of the study. Therefore the studies looked at how diet at baseline is related to new cases of depression."
The conclusions of the study were made after analyzing five longitudinal studies looking at 32,908 adults from the U.K., France, Spain, Australia, and the U.S.
After reviewing the results, researchers are stressing how important it is for general physicians to talk to their patients about diet and properly inform them of the risks associated with poor diet.
Dr. Tasnime Akbaraly, the co-author of the research, expanded on this idea.
"Added to recent randomized trials showing beneficial effects of dietary improvement on depression outcomes, there are now strong arguments in favor of regarding diet as mainstream in psychiatric medicine. Our study findings support routine dietary counseling as part of a doctor's office visit, especially with mental health practitioners."Professor Helen Stokes-Lampard, the chair of the Royal College of GPs, spoke about the evidence that a healthy diet can have benefits for our mind and mood.
"This large-scale study provides further supportive evidence that eating a healthy diet can improve our mood and help give us more energy. It adds to the growing body of research which shows that what we eat may have an impact on our mental health. Increasingly, more GPs are recommending that their patients try to make sensible diet and lifestyle changes as part of a holistic approach to the management of chronic diseases because we know it may have a range of a positive effects on our patients' physical and mental health."