Food and Behaviour Research

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06 March 2015 - Mail Online - Why FISH is nature's antidepressant: Mediterranean diet 'reduces the risk of stress, anxiety and mental illness'

Madlen Davies

People who adhered more strongly to Mediterranean diet were happier - 'Eating badly causes the depression in the first place,' researchers say.

  • [Mediterranean] Diet consists of vegetables, seeds, fruits, nuts, seeds and olive oil
  • It is low in processed foods, red meats and sweets and chocolate
  • These foods cause inflammation in the body which affects the brain
  • Mediterranean diet contains nutrients like omega-3, vitamins and fibre
  • These are crucial for a well-functioning brain, which staves off depression 

It is known to prevent against heart disease and is hailed as the secret to a long, healthy life. 

Now, researchers have found the Mediterranean diet can help people with depression, too.

A study found people who followed the diet were happier, less stressed and reported an improved quality of life compared to those who ate fewer Mediterranean foods.

The researchers said omega-3 in particular, a fatty acid found in fish, plays a vital role in maintaining and improving mental health and stability.

The diet consists of plant-based foods such as vegetables, legumes, fruit, nuts, seeds and olives, extra virgin olive oil, fish, with moderate red wine intake.

It also involves a low consumption of processed food, processed carbohydrates, sweets and chocolate and red meat.

As part of the study, Australian researchers recruited a total of 82 adults with depression, aged between 18 -65.

They assessed their mental health and quality of life using two official scales: the Depression Anxiety Stress Scales (DASS) and the Positive and Negative Affect Scale (PANAS).

They then assessed how strongly they followed the Mediterranean diet through a 14-item questionnaire.

The study’s lead author, Dr Natalie Parletta, of the University of South Australia, said there was a strong link between the Mediterranean diet and lower scores for mental illness.

This was despite the fact it was a study of people with depression, who tended to have poor diets in the first place.

She told MailOnline: ‘What we found is that poor diet is predicting the onset of depression.

‘We recruited people who had depression already. We screened out people who had good diet.

'It’s not that people are getting depressed and then eating badly, eating badly causes the depression in the first place'

‘So it was amazing that there was a significant correlation the Mediterranean diet and mental illness, even for people with low scores on the consumption of wholefoods.’

She said research shows there is an overlap between heart disease and depression, and scientists have begun to think there might be common underlying mechanisms.

Inflammation and insulin resistance which occurs in the body and causes heart disease could also cause depression in the brain, she said.

‘The brain is an organ like any other,’ she explained.

‘It has higher needs than other organs, from bloodflow to delivering oxygen, glucose and nutrients.

‘A lack of bloodflow and inflammation can affect the brain as much as any other organ.

A Mediterranean diet is high in nutrients such as omega-3, vitamin B, vitamin D, healthy fats and anti-oxidants, she said, which are all important for keeping the brain functioning well and staving off mental illness.

There has been a lot of research on how omega-3 fatty acids, found in fish, play a vital role in maintaining or improving mental health and stability. 

Deficiency in these nutrients can impair the brain’s functioning and lead to depression, she added.

She said: ‘There are many challenges in life, and factors that lead to depression. But by developing a strong foundation for our brain to function well through providing it with key nutrients, we’re better able to deal with life’s challenges.

‘And it’s not just the nutrients - the fibre is also beneficial. Highly fibrous foods means you’re not getting mood swings through sugar.

She continued: ‘Sometimes depression is biological. It could be a wheat allergy, it’s rarely known that an intolerance can lead to depression and even bipolar.

‘Depending on the person, a deficiency could be the key link to what is causing mental illness.’ 

On the other hand, a poor diet can lead to depression, stress and anxiety, she said.

She explained hat highly processed foods, red meat and confectionary increase our blood glucose levels, leading to sensitivity to insulin – the hormone that controls how much sugar is in our blood – and obesity.

This inflammation affects the brain, causing mental illness.