How to eat to reduce your likelihood of depression

Diet and Depression


The idea that you can prevent and treat mental illnesses like depression with diet is only something I’ve noticed gaining momentum over the last 5 years.

Whilst the data doesn’t support abandoning anti-depressants and psychological therapies, it is exciting that nutrition might become part of the arsenal we use in the fight against depression which affects an enormous number of people.

Our diet can impact on our mental health via a number of pathways: reduce inflammation, prevent insulin resistance, reduce impact or severity of disorders like diabetes, alter the mix of neurotransmitters in the brain, reduce stress hormones. Also we know that diet alters our gut bacteria, and we are only just starting to understand the psychological impacts of that.

An article recently came out in Molecular Psychiatry (where really small psychiatrists publish) that suggests adhering to a Mediterranean diet and/or avoiding a pro-inflammatory diet can protect against depression.

For those of you who have suffered with depression, or been affected by it in some way (e.g. a friend or family member), this is a pretty massive idea worthy of a little bit of reflection.

In this blog post, I reflect on the study in question and what it might mean in terms of the foods we eat.


What is depression?

Depression is not just feeling sad or moody from time to time, although it has almost become common parlance to say “I’m feeling depressed today”.

Instead, depression is a persistent and debilitating mental illness that affects all aspects of an individuals life – their relationships, their work, their hobbies, their life purpose and can lead to significant disability.

Sufferers experience a range of negative emotions (sadness, guilt, irritability, frustration, low confidence, disappointment, misery) that are both intense and relenting.

Their thinking becomes indecisive, self-critical, self-blaming, hopeless, and negative towards others, and the world.

They experience a range of physical symptoms such as feeling tired, sick, rundown. They report muscle problems, headaches, gut issues, sleep problems, changes in appetite, and changes in weight.

And their behaviour changes. They stop going out and doing things. They withdraw from everyday life. They struggle to get things done because they are unable to concentrate.

And this is just one type of depression (major depression). There are other types (melancholia, dysthymia, bipolar, cyclothymia, post-natal and seasonal affective disorder) that can add further complexity through additional symptoms and challenges.

Whilst it sounds severe and therefore you might assume quite rare, depression is actually quite common. In any given year, around 1 million Australians are struggling with depression. 1 in 8 men and 1 in 5 woman will experience depression in their lifetime. Across the world, depression is one of the leading causes of disease burden and disability. It is estimated to cost the global economy $1 trillion dollars a year.

Although our understanding of depression is constantly improving, and we have medical (e.g. medications), psychological (e.g. therapy) and lifestyle (e.g. exercise) interventions that can be used to treat depression, it remains a challenging illness to treat. For example, some people don’t respond to existing treatments. Others relapse.

That is why interesting developments in the area of nutrition and depression are so……interesting (#wordfail).


What did this ‘Molecular Psychiatry’ study find?

So the study in Molecular Psychiatry was a ‘systematic review and meta-analysis‘. That may or may not mean something to you depending on your area of study and level of knowledge.

Regardless, these types of studies are probably the best method we have of summarising the findings on any given health question. This is because these studies aggregate the data from lots of smaller studies to identify the average effect of interest across studies.

In the study the authors wanted to summarise the outcomes of studies that had looked at people’s diets and whether certain eating patterns were associated with lower rates of depression.

To do this they looked at 32 high quality studies that had measured both diet and risk of depression and looked at the strength of the relationship between these two.

What they found can be summarised quite simply:

  • Those who most strictly followed a ‘Mediterranean diet’ were 33% less likely to develop depression than those who had poor adherence.
  • Those who most strictly followed the ‘Healthy Eating Index’ were between 24-46% less likely to develop depression than those with poor adherence.
  • Those who had the least inflammatory diet were between 24 and 36% less likely to develop depression than those with the most inflammatory diet.


What does this mean in terms of how I should eat?

If you want to shift your diet towards one of the mentally healthier options identified in this study, there are a few simple guidelines.

  1. Eat more fruits, vegetables and nuts
  2. Eat small amounts of meat
    1. focus on fish and chicken
    2. eat less red and processed meats
  3. Eat whole grains and legumes
  4. Eat dairy but only small amounts
  5. Use olive oil instead of margarines or butters
  6. Minimise sugar sweetened beverages and foods
  7. Keep alcohol intake to a moderate level

To be honest, if you can get your diet to look like the current Australian Dietary Guidelines, you’ll be doing pretty well.

But if you want to explore further, you’ll find plenty of online resources and books about the Mediterranean Diet. This article is a good starting point.


What if I am already depressed?

So the Molecular Psychiatry article was focused on ‘preventing’ depression. But what about if you are already struggling with depression?

The good news is there is emerging evidence from Australian studies that the Mediterranean diet may be able to help as an adjunct to existing treatments and may even save you some money.

If you are struggling with depression, and you’d like to explore what options you have in addition to medication and psychological therapies, consider looking into diet.

Talk to your GP about a potential referral to a dietician, as making dietary changes can be challenging, especially if you are already struggling with depression.


Take-home message

Evidence is accumulating that how we eat impacts how we feel. This is in addition to the impact that other lifestyle factors can have: sleep, physical activity, drug and alcohol use.

It is why I recommend that anyone who struggles with mental health issues, in addition to pursuing the more traditional treatments (e.g. medication and therapy), also pursue healthy lifestyle changes.

I have, and my colleagues have witnessed some pretty amazing turnarounds of people who have dramatically improved their wellbeing through dietary or lifestyle means. I myself experienced a significant lift in wellbeing after having a dietary deficiency (in my case vitamin B12) diagnosed and treated.

Now it would be ill-advised of me to suggest that dietary changes will impact positively on your mental health, but any shifts you make towards a healthier diet will have positive impacts outside of mental health symptoms (e.g. reduced risk of cardiovascular disease or diabetes). It is worth a try.

As indicated before, if you are thinking of making significant changes to your diet, speak to your GP first, who might organise a dietician referral.

Have you had success altering your wellbeing through diet? I’d be interested to hear your story.

Take Care

Dr G


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