Processed Food Link To Depression

New research by a University of London team suggests the risk of depression is increased when one eats a diet that is high in processed food.

The British Journal of Psychiatry reports, comparing diet data of 3,500 middle-aged civil servants, average age 55-years, asked each participant to complete a questionnaire on their eating habits, including a self-report assessment for depression 5-years later. The study reveals eating plenty of vegetables, fruit and fish actually lowers the risk of depression.

The study, the first to look at the link between UK diet and depression, split the participants into two groups, with each group on separate diets, those that ate a diet whole foods diet, including loads of fruit, vegetables and fish. The other group ate a mainly processed food diet, consisting of sweetened desserts, processed meat, fried food, refined grains and high-fat dairy products.

Taking into account factors like gender, age, education, physical activity, smoking habits and chronic diseases, a significant difference was found in future risk of depression with the different diets.

Those eating mostly whole foods had a 26% lower risk of future depression, in comparison with those eating the least.

In contrast, people on a high in processed food diet had a 58% higher risk of depression, than those eating very few processed foods.

Researchers, without totally ruling out the possibility of people with depression eating a less healthy diet, they find it highly unlikely, since there was no association with diet and previous diagnosis of depression.

Dr Archana Singh-Manoux, author of the study points out, it is possible the findings could be explained by a lifestyle factor unaccounted for, saying: 'There was a paper showing a Mediterranean diet was associated with a lower risk of depression but the problem with that is if you live in Britain the likelihood of you eating a Mediterranean diet is not very high. So we wanted to look at bit differently at the link between diet and mental health'.

It is unclear why certain foods offer protection against or increase the risk of depression, however, scientists believe there could be a link between inflammation, as with conditions like heart disease.

The researchers suggested several reasons for the protective effects of a healthy diet against depression, from the high levels of anti-oxidants in fruits and vegetables, including folate found in broccoli, cabbage, spinach, lentils and chickpeas. Eating more fish may be protective due to high levels of polyunsaturated fatty acids, however, possibly the effect comes from a 'whole food' diet containing many nutrients from different food types, rather than one single nutrient.

Dr Brunner, a reader in epidemiology at UCL says, the reverse is also important like poor eating habits putting more of a strain on the body, such as: 'If, your diet is high in foods that make blood sugar levels go up and down like a yo-yo, then it is not good for your blood vessels and is bound to have an effect on the brain'.

Dr Andrew McCulloch, Chief Executive of the Mental Health Foundation adds: 'This study adds to an existing body of solid research that shows the strong links between what we eat and our mental health. Major studies like this are crucial because they hold the key to us better understanding mental illness'.

Further, he says, people's diets are increasingly becoming unhealthy, with the UK population consuming less nutritious, fresh produce and more of saturated fats and sugars.

Margaret Edwards, Head Of Strategy at the mental health charity SANE, said: 'Physical and mental health are closely related, so we should not be too surprised by these results, but we hope there will be further research which may help us to understand more fully the relationship between diet and mental health'.