Adopting a healthy diet can ease depression
Studies have established that people who eat a low-quality diet are more likely to have depression — and thatthe lower the diet quality, the more severe the symptoms. So can improving diet quality in turn improve mental health?
Yes, asserts Australian-led research in the journal Psychosomatic Medicine, which determined that adopting a healthier diet is a promising strategy to reduce the symptoms of depression across the general population.
“Improving our diet can improve our mood,” said the study’s first author Dr Joseph Firth, a postdoctoral research fellow in the NICM Health Research Institute at Western Sydney University.
The study pooled data from 16 randomised controlled trials conducted around the world and canvassing almost 46,000 people, which measured the mental health outcomes of various dietary interventions.
The analysis suggested that any kind of dietary improvement eased depression, demonstrating similar benefits for:
● Weight-loss diets, which particularly benefited obese people — strengthening the emerging link between depression and obesity.
● Nutrient-boosting diets, such as the Mediterranean diet, or ones that swap foods high in refined carbohydrates and saturated fat (both abundant in processed, packaged foods) for ones high in vegetables, fruit, whole grains, legumes, and other core foods listed in the Australian Dietary Guidelines.
● Fat-reducing diets, specifically those that emphasised cutting saturated fat (the kind usually found in meat, dairy and other animal fats) rather than unsaturated fat (usually found in plant-based foods).
“All these types of healthy diets, regardless of the specific [eating] pattern adopted, have similar mental health benefits,” Firth noted in a briefing to the Australian Science Media Centre.
The analysis also found that women recorded stronger improvements in depressive symptoms than men.
It’s not clear why this is, though the researchers offer several possibilities: Women may have bodies that respond better to nutrients in food than men’s, and may also have different social beliefs about food and health that impact their health outcomes. Women are more likely to have depression than men, which could account for the greater effect.
It’s also not yet clear how an improved diet may improve symptoms of depression, though there are several possible pathways: the foods that make up a healthy diet are comprised of vitamins, minerals, fibre and other nutrients that benefit oxidative stress, inflammation, and the gut microbiome — all factors linked to mental health.
The researchers also tried to answer whether an improved diet affects symptoms of anxiety, though found no such link in the data.
Firth added that the results of the analysis apply to people with “subthreshold depression” — those who report low mood but haven’t been diagnosed with a depressive disorder.
More research is needed to establish how diet can help those with clinical depression, though he said preliminary investigations — such as Deakin University’s SMILES Trial, one of the 16 studies included in the new analysis — are promising.
He stressed that studies like this don’t imply that a healthy diet is a magic fix for depression, but rather than it’s just one of many ways to prevent and treat mental health conditions.
“There’s no need for anything extreme,” Firth said. “Just cutting back on junk food and improving your intake of nutrient-dense meals is effective for overall mental health outcomes.”
Depression affects millions of Australians in varying degrees, and has a massive individual, social and economic cost — so it’s encouraging that relatively straightforward and inexpensive lifestyle improvements can prevent and treat the condition.
A major study published in January affirmed that regular physical activity cuts the likelihood of depression, adding to a growing body of research into the mental health benefits of exercise.
MENTAL HEALTH RESOURCES:
If you need immediate support or are concerned about someone you know, please contact Lifeline Australia on 13 11 14 or via lifeline.org.au.