Healthy living * Mental wellbeing

Junk food link to depression

junk food Whole food diet lowers risk

People with diets high in processed and high-fat foods may be at a greater risk of depression, new research has found.

However, the results also showed that eating a ‘whole food’ diet with plenty of fresh vegetables, fruit and fish could help prevent depressive symptoms in middle age.

In the study, researchers from University College London analysed data from 3,486 civil servants with an average age of 55. All participants filled in questionnaires about their diet, and a report about any depressive symptoms five years later.

The researchers found that those who ate the most whole foods in their diet were 26% less likely to report depressive symptoms compared with those who ate the least.

And people who ate the most processed foods were 58% more likely to to report feeling depressed compared with those who ate the least.

The findings proved true after adjusting for other factors which could influence the results such as smoking, exercise and chronic health conditions.

The study, published in this month's British Journal of Psychiatry, is the first to examine the association between overall diet and depression – past studies have focused on the effect of individual nutrients.

The authors said: “Our results suggest that consuming fruits, vegetables and fish may afford protection against the onset of depressive symptoms, whereas a diet rich in processed meat, chocolates, sweetened desserts, fried food, refined cereals and high-fat dairy products would increase people’s vulnerability.”

There could be several reasons for the protective effect, the researchers said.

High levels of antioxidants found in foods such as fruits, vegetables and vegetables have been associated with a lower risk of depression in other studies. And folate, in vegetables such as broccoli, cabbage and spinach, and dried legumes such as lentils and chickpeas, may have a similar protective effect, they said.

In addition, fish contain high levels of long-chain polyunsaturated fatty acids, which are important components of brain membranes.

However, they also said the protective effect could be down to a combination of different nutrients rather than a single nutrient by itself.

A processed food diet is also associated with a higher risk of coronary heart disease and inflammation, which are known to be involved in the development of depression.

The researchers concluded: “The deleterious effect of a processed food diet on depression is a novel finding. Our research suggests that healthy eating policies will generate additional benefits to health and well-being, and that improving people’s diet should be considered as a potential target for preventing depressive disorders.”

This article was published on Mon 2 November 2009

Image © © Tomasz Trojanowski -

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