Tweaking your diet to improve nutrition could significantly reduce the symptoms of major depression.

Dietary approach to major depression shows promise

10 February, 2017

Changing the nutritional make-up of the diet may provide an effective strategy for treating major depression, according to a new study from Australia.

“We’ve known for some time that there is a clear association between the quality of people’s diets and their risk for depression,” said lead author Professor Felice Jacka Director of Deakin University’s Food and Mood Centre.

“This is the case across countries, cultures and age groups, with healthy diets associated with reduced risk, and unhealthy diets associated with increased risk for depression.

Her team’s findings, she said, offer up a possible new treatment approach to depression, one of the world’s most prevalent – and costly – medical disorders.

Focus on nutrition

What you need to know

» Previous research has suggested that diet has a role to play as a possible risk or protective factor for people with depression.

» In a new study from Australia people with major depression who followed a strict diet, with an emphasis on wholefoods foods and optimum nutrition, experienced significant improvement in depressive symptoms.

» Compared to those receiving dietary advice, at the end of the three month trial, 30% of those on the high quality diet met the criteria for remission of major depression.

The 12-week study, involving 67 adults with major depressive disorder, claims to be the first randomised controlled trial to directly test whether improving diet quality can actually treat clinical depression.

Participants were recruited and randomly assigned to receive either social support, which is known to be helpful for people with depression, or support from a clinical dietitian, over a three-month period.

The dietary group received information and assistance to improve the quality of their current diets.

For this groups the main focus was on increasing diet quality by supporting the consumption of the following 12 key food groups:

  • whole grains (5–8 servings per day)
  • vegetables (6 per day); fruit (3 per day)
  • legumes (3–4 per week)
  • low-fat and unsweetened dairy foods (2–3 per day)
  • raw and unsalted nuts (1 per day)
  • fish (at least 2 per week)
  • lean red meats (3–4 per week)
  • chicken (2–3 per week)
  • eggs (up to 6 per week)
  • olive oil (3 tablespoons per day)

The programme also included limits on certain ‘extra’ foods, such as sweets, refined cereals, fried food, fast-food, processed meats and sugary drinks (no more than 3 per week).

Red or white wine consumption beyond 2 standard drinks per day and all other alcohol (e.g. spirits, beer) were included within the ‘extras’ food group.

From depression to remission

Results, published in the international journal BMC Medicine, showed that participants in the dietary intervention group had a much greater reduction in their depressive symptoms over the three-month period, compared to those in the social support group.

At the end of the trial, a third of those in the dietary support group met criteria for remission of major depression, compared to 8 percent of those in the social support group.

“These results were not explained by changes in physical activity or body weight, but were closely related to the extent of dietary change,” Professor Jacka said.

“Those who adhered more closely to the dietary program experienced the greatest benefit to their depression symptoms.”

Professor Jacka, who is president of the International Society for Nutritional Psychiatry Research, said the findings offered an important new strategy for the treatment of depression.

“Mental disorders account for the leading cause of disability worldwide, with depression accounting for the large proportion of that burden,” she said.

“While approximately half of sufferers are helped by currently available medical and psychological therapies, new treatment options for depression are urgently needed.

Wider protection

“Importantly, depression also increases the risk of and, in turn, is also increased by common physical illnesses such as obesity, type 2 diabetes and heart disease. Successfully improving the quality of patients’ diets would also benefit these illnesses.”

The study suggests the new possibility of adding clinical dieticians to mental health care teams and making dietitian support available to those experiencing depression.

“It also supports the previous extensive research from human population studies and animal research suggesting that diet is a key determinant of mental and brain health,” Professor Jacka said.

Indeed a Mediterranean diet – strongly associated with the food components emphasised in this study – has been linked with a 30% reduced risk for depression as well as chronic disease.