How Your Food Affects Your Mood

How Your Food Affects Your Mood

An explanation on the positive affects of a healthy diet on your mood, plus top tips of what mood-boosting foods to eat, from Marnie Nitschke, Accredited Practising Dietitian at Fork That Nutrition. (4 minutes reading.)

Have you ever wondered whether what you eat is affecting your mood?  

One in five Australians have experienced depression and anxiety. However, there is some good news.

Food can be a powerful tool in the treatment of mood disorders, and the best diets aren’t about expensive superfoods, restriction or calorie counting.

What does the research tell us?

Food and mood is an exploding field of research, and what is clear is that the quality of our diet has a huge effect on our mental health. This goes well beyond the concept of feeling bloated and tired if we overeat, or overdoing comfort foods like chocolate or chips when we feel sad.

Over the years, many studies have looked at the connection between food and mental health, and have overwhelmingly shown that people eating a higher quality diet (more fresh fruit and veggies, less processed and take away foods) tend to have less depression and anxiety.  Importantly, this association holds true, even when we account for other variables like physical activity levels, socioeconomic status and education. 

Until now, these studies have tended to be observational (observing what groups or populations eat, and relating this to their prevalence of mood disorders).  But more recently, an Australian trial incorporating a Mediterranean Diet model has proved that changing what you eat can significantly improve depression scores.

tomato brushcetta on a dining table with olive oil being dripped on with a spoon

The SMILES trial (Supporting the Modification of Lifestyle in Lowered Emotional States).

The ‘SMILES’ study was a 12-week, single blinded, randomised controlled trial (if you don’t have a scientific background, all you need to know is that this trial was rigorously designed).  The study was carried out by the Deakin Food and Mood Centre between 2012-2015, and results were published in 2017.

Investigators recruited 67 subjects who had been diagnosed with moderate to severe depression, and then randomised each subject to either the ‘intervention’ or ‘control’ arms of the study.

The intervention consisted of seven individual nutritional consulting sessions delivered by a clinical dietitian, teaching the subject how to improve the quality of their diet using a Mediterranean diet model. Importantly, subjects were not asked to change their physical activity, reduce food intake or lose weight.

Subjects in the control group also received one-on-one sessions, but instead of dietary advice, were given ‘social support’ (friendly chatting and engagement - to control for the possible placebo effect of positive social interaction).
And the results were pretty amazing. After 12 weeks, subjects in the diet support arm of the trial had a dramatic improvement in depressive symptoms compared to the control group.

The more they had changed their diet and improved their diet quality, the lower their depression score dropped. In fact, 1/3 subjects in the diet intervention group went on to have remission from their depression.
close up overhead picture of a healthy bowl of colourful food on a black bench
So how does the quality of our diet affect our mood?

The short answer is: it’s complicated.  But putting it simply, eating a high diversity of plant foods is the key, through its effect on our gut health and inflammation levels in our body. 

Many studies have shown that diets high in fast food and highly processed, packaged food can promote inflammation within our gut and brain.  The high level of saturated fats present in these foods can have a negative effect our production of neurotrophins (proteins that protect our brain from damage and help our neurones function at their best).

Conversely, plant foods like fruits, vegetables, legumes, whole grains, nuts and seeds perpetuate better gut health and a stronger gut barrier (70% of our immune system lives in and around our gut).  The big players in these ‘superfoods’ are the various types of fibre and antioxidants and polyphenols naturally present.

Polyphenols are plant compounds that you can think of as nature’s all natural ‘glow up’ pills.  While polyphenols are pretty tricky for us to absorb, they are a favourite food of our gut microbes – who cleverly convert these substances into fuel for gut cells, anti-inflammatory compounds and even signalling molecules that talk to our brain.

Want more polyphenols in your diet? Here’s some simple, delicious Mediterranean diet tips:
  • Cooking and dressing foods liberally with high quality, extra virgin olive oil
  • Drinking tea, coffee and even a glass or two of red wine (in moderation, with a meals)
  • Enjoying good quality dark chocolate / cacao products and nuts
  • Brightening up your plate with all the highly pigmented plant foods - berries, cherries, broccoli, tomatoes, capsicum, green leafies and olives
Where does olive oil come in here?

Extra Virgin Olive Oil is a good source of phenolic compounds which have been shown to reduce oxidative stress and inflammation levels in our body. Cheaper, refined olive oils do not contain these bioactive compounds in significant amounts. So in short, this is where spending a little more on a locally grown, organic Extra Virgin Olive Oil like Cockatoo Grove, is absolutely worth it.

Cockatoo Grove organic extra virgin olive oil bottle close up with hands dipping bread into a dish with olive oil

Other evidence based tips for the best diet quality for mental health:
  • Include fermented foods like sourdough bread, yoghurt, sauerkraut, kim chi and miso
  • Eat more whole grains like oats, barley, whole grain bread
  • Include legumes regularly in your diet, and try to eat more vegetarian meals
  • Eat a handful of nuts every day
  • Aim for 5+ serves of vegetables and at least two different fruits daily
  • Reduce highly processed foods high in sugar, additives and saturated fats
Final thoughts:
We now have great evidence that the quality of our diet is not only important for heart health and chronic disease prevention.  It’s also a key tool in managing our mood, energy levels and helping us think, function and feel better.  One of the best models we have for diet and optimal mental health is the Mediterranean diet -  it’s colourful, diverse, delicious, and Extra Virgin Olive Oil is a key part of it!

Here's a bit about Marnie ...