November 2, 2009

Processed Food May Increase Depression

New research suggests that eating a diet high in processed food increases the risk of depression, BBC News reported.

A team of researchers from the University College London found that people who ate plenty of vegetables, fruit and fish actually had a lower risk of depression.

The British Journal of Psychiatry report compared dietary data on 3,500 middle-aged civil servants with depression data five years later.

The study is the first to look at the UK diet and depression.

Participants were split into two groups: those who ate a diet largely based on whole foods, which includes lots of fruit, vegetables and fish, and those who ate a mainly processed food diet, such as sweetened desserts, fried food, processed meat, refined grains and high-fat dairy products.

They found a significant difference in future depression risk with the different diets, after accounting for factors such as gender, age, education, physical activity, smoking habits and chronic diseases.

A 26 percent lower risk of future depression was noted for those who ate the most whole foods compared to those who ate the least whole foods. Also, those with a diet high in processed food had a 58 percent higher risk of depression than those who ate very few processed foods.

While there was no association with diet and previous diagnosis of depression, the researchers cannot totally rule out the possibility that people with depression may eat a less healthy diet.

There is a chance the finding could be explained by a lifestyle factor we had not accounted for, according to study author Dr. Archana Singh-Manoux.

"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," Singh-Manoux said.

Nutritionists are currently unable to explain why some foods may protect against or increase the risk of depression.  However, there may be a link with inflammation reminiscent to conditions like heart disease.

"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," said Dr. Andrew McCulloch, chief executive of the Mental Health Foundation.

He warned that people's diets are becoming increasingly unhealthy and said the UK population is consuming less nutritious, fresh produce and more saturated fats and sugars.

"We are particularly concerned about those who cannot access fresh produce easily or live in areas where there are a high number of fast food restaurants and takeaways," he 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," said Margaret Edwards, head of strategy at the mental health charity SANE.


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