A healthy diet may reduce the risk of severe depression, according to a prospective follow-up study of more than 2,000 men conducted at the University of Eastern Finland. In addition, weight loss in the context of a lifestyle intervention was associated with a reduction in depressive symptoms.
Access the freely available study here: Ruusunen A, 2013 - Diet and Depression: An Epidemiological Study
"The study reinforces the hypothesis that a healthy diet has potential not only in the warding off of depression, but also in its prevention," says Ms Anu Ruusunen, MSc, who presented the results in her doctoral thesis in the field of nutritional epidemiology.
Depressed individuals often have a poor quality of diet and decreased intake of nutrients. However, it has been unclear whether the diet and the intake of foods and nutrients are associated with the risk of depression in healthy individuals.
Those following a healthy diet are less at risk
A healthy diet characterized by vegetables, fruits, berries, whole-grains, poultry, fish and low-fat cheese was associated with a lower prevalence of depressive symptoms and a lower risk of depression during the follow-up period.
Increased intake of folate was also associated with a decreased risk of depression. Vegetables, fruits, berries, whole-grains, meat and liver are the most important dietary sources of folate. In addition, increased coffee consumption was non-linearly associated with a decreased risk of depression.
In addition, participation in a three-year lifestyle intervention study improved depression scores with no specific group effect. Furthermore, a reduction in the body weight was associated with a greater reduction in depressive symptoms.
Junk food, sugar and processed meats may increase depressive symptoms
Adherence to an unhealthy diet characterized by a high consumption of sausages, processed meats, sugar-containing desserts and snacks, sugary drinks, manufactured foods, French rolls and baked or processed potatoes was associated with an increased prevalence of elevated depressive symptoms.
Contrary to some earlier observations, vitamin B12 intake, serum concentrations of n-3 PUFAs, serum ratio of n-6 to n-3 PUFAs, tea drinking and total caffeine intake were not related to the risk of depression in this study.
The study was based on the population-based Kuopio Ischaemic Heart Disease Risk Factor (KIHD) Study. The participants, over 2,000 middle-aged or older Finnish men were followed-up for an average of 13-20 years.