Middle aged men whose diet is loaded with junk food – such as processed meat and sugary drinks – are at greater risk from depression, according to a new study.
However, researchers found eating plenty of fruit and vegetables wards off the blues.
A study of more than 2,000 men found a healthy diet reduced their risk of developing the mental illness which affects almost a fifth of British adults.
And shedding the pounds by improving diet and exercising more was associated with fewer cases of the condition.
Nutritionist Anu Ruusunen, of the University of Eastern Finland, said: ‘The study reinforces the hypothesis a healthy diet has potential not only in the warding off of depression, but also in its prevention.’
Patients with depression often eat poorly and consume fewer nutrients, but it has been unclear whether diet is linked with the risk in healthy people.
The new study found those who ate most vegetables, fruits, berries, whole grains, poultry, fish and low fat cheese suffered less symptoms and a lower risk of the condition during 13 years of follow up.
Increased intake of folate found in vegetables, fruits, berries, whole grains, meat and liver also had a beneficial affect, along with greater coffee consumption.
And participation in a three year lifestyle intervention programme involving a separate group of 140 middle aged men and women improved depression scores, with slimmer bodies leading to fewer symptoms.
But a junk food diet characterised by eating a lot of sausages, processed meats, sugary drinks, desserts and snacks, manufactured foods and baked or processed potatoes was associated with an increase in cases.
Contrary to some earlier observations, vitamin B12 intake, 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 Study and the participants were all middle aged or older Finnish men.
Their diet was measured by food records and food frequency questionnaires, and information on cases of depression was obtained from the National Hospital Discharge Register.
Depression is one of the leading health challenges in the world and its effects on public health, economics and quality of life are enormous.
Not only treatment of depression, but also prevention of depression needs new approaches. Diet and other lifestyle factors may be one possibility.
The research was published in Psychotherapy and Psychosomatics, European Journal of Nutrition, Public Health Nutrition and Diabetic Medicine.
In the UK, depression hits 19 per cent of people with 21 per cent of women reporting symptoms and 16 per cent of men. The highest rates occur among those aged between 50 and 54.