With antidepressant use on the rise globally, there is increasing interest in drug-free treatments for mental health.
Diet therapy and the ‘food is medicine’ movement promote diet as a low-cost option to improve psychological well-being.
However, a new systematic review of 25 randomised trials covering more than 57,000 people challenges the notion that you can eat your way out of depression and anxiety without a broader treatment approach.
Researchers at the Institute of Evidence-Based Healthcare at Bond University found that while some diets may offer modest mental health benefits, the overall picture is inconclusive.
The team, led by Assistant Professor Loai Albarqouni, analysed data from 25 randomised controlled trials that investigated various types of diets, including calorie restriction, low-fat diets, and Mediterranean-style diets.
They found calorie restriction and low-fat diets appeared to improve depressive symptoms, however the effect was small and mainly seen in people with cardiometabolic risk factors such as heart disease and type 2 diabetes.
The evidence regarding the impact of the popular Mediterranean diet was mixed or inconclusive, with a more pronounced effect among people with depression.
Previous studies have suggested dietary interventions—particularly those emphasising whole foods, fruits, vegetables, and healthy fats—can reduce depressive symptoms.
But Dr Albarqouni said the science isn't settled.
“While extensive research has demonstrated a link between nutrition and health, the evidence specifically connecting diet to mental health is still evolving,” he said.
“Poor nutrition can contribute to low mood, and improving diet may benefit both physical and mental health.
“However, much of the research is observational, meaning it shows associations but not causation. More controlled trials are needed to establish definitive links.”
Dr Albarqouni said diet was just one piece of the puzzle in finding effective treatments for depression and anxiety.
“Mental health is influenced by a combination of factors, including genetics, environment, and lifestyle.”
The quest to connect what’s on our plate with how we feel has grown more urgent as the mental health of Australians deteriorates—especially among younger generations.
More than 4.7 million prescriptions for the antidepressant Sertraline – branded as Zoloft - were issued between July 2019 and June 2020.
Dr Albarqouni said that for people with mild depression or anxiety, dietary changes can be a helpful part of a broader treatment plan – but it’s important to approach this holistically.
“It can be hard to eat well when you are feeling down,” he said.
“Understand that each step you take towards eating better is a step in the right direction for your mental health.
“Incorporate other healthy lifestyle practices, such as regular exercise, adequate sleep, and stress management.”