It probably comes as no surprise that we are a fast becoming a nation of stress heads. A 2017 study by Medibank found that over 5 million Australians are suffering from stress. A lack of sleep, work pressures, juggling too many things, housing affordability, finances and social media were reported as contributing factors. It is well known that people affected by stress are more likely to suffer from mental health conditions such as anxiety and depression.

In Australia, almost 1 in 2 Australians will experience a mental health condition such as depression or anxiety in their lifetime. It’s not all doom and gloom though. The great news is that there is plenty that we can do to help manage our stress, improve our mood and mental wellbeing and reduce our risk of anxiety and depression. In fact, your diet may very well be a great place to start with a growing body of research showing what you eat can improve your mood, affect your happiness and prevent depression and anxiety.  An unhealthy diet high in processed and refined foods can increase a person’s risk of depression, whereas a healthy diet- rich in vegetables, fruits, wholegrains, oily fish and lean red meat can prevent and potentially cure depression.

Neurotransmitters or brain chemicals are produced in our brain from the nutrients that come directly from the foods we eat. The quality of your diet can either impair or enhance the production of neurotransmitters. Variety in the diet is key as diets with a higher variety of fruits and vegetables have been shown to be more effective for improving mood. Eating more plant-based foods can have a positive effect on mood and mental health by calming down inflammation, clearing up oxidative stress and improving our gut microbiota which play a role in mood regulation and stress hormones. In fact a 2017 study called the SMILES trial showed that a modified Mediterranean diet- a form of a plant-based diet that contains smaller amounts of meat and dairy- could improve or even reverse depression in a small sample of people.

Read on to learn more about what nutrition strategies may help with balancing our moods and improving our risk of mental health conditions such as anxiety and depression.

1. Eat to nourish your gut bacteria

Our gut is home to a community of bugs collectively referred to as the gut microbiota. They weigh between 2-3kg and play an important role in maintaining our health including fermenting fibre and producing anti-inflammatory compounds called short-chain fatty acids (SCFAs). Our gut bacteria affect our brain and there are strong links between our gut bacteria and depression, anxiety and stress. For example 90% of our happy hormone called serotonin which plays a role in mood, sleep and memory is made in our gut. The gut and brain also chat back and forth via the gut brain axis and in animal studies we have seen that exposure to a significant stressor causes changes in the balance of gut bacteria as well as mood and behavior. Administering good bacteria called probiotics has also been shown to reduce levels of stress hormones and anxious and depressive behaviors.

Look after your gut health by avoiding;

• Large amounts of fat and saturated fat found in takeaway, snack foods and meat fat
• High amounts of added sugar found in sugar-sweetened beverages and snack foods as well as artificial chemical sweeteners
• Processed cereals such as white bread and refined breakfast cereals
• High intakes of red meat and processed meat  such as salami, bacon and sausages
• Excessive amounts of alcohol
• Low fibre diets

Improve and optimise your gut health by including these in your diet;

• Fibre: Aim for 30g per day from fruit and vegetables, legumes such as chickpeas, lentils and beans, wholegrains such as brown rice, quinoa, spelt, teff, wholegrain bread, rolled oats, bran, seedy crackers, barley, nuts and seeds
• Prebiotic foods also known as food for our probiotics. These include garlic, onion, oats, fruit, cabbage, kale and legumes
• Probiotic and fermented foods that contain live ‘friendly’ bacteria including yoghurt, yakult, kefir, tempeh, sauerkraut, miso and kombucha teas

2. Include high fibre, wholegrain and slow burning carbohydrates in your diet

Our brain exclusively runs off carbohydrates in the form of glucose so it makes sense to include good quality carbohydrates to provide our brain with a slow, steady supply of fuel. Low GI carbohydrates cause a nice gradual rise in blood sugar levels which has a positive effect on mood, memory and cognition.

Low GI foods include:

• Most fresh fruit
• Legumes e.g. chickpeas, beans, lentils
• Sweet potato, sweet corn and coles carisma potatoes
• Yoghurt and milk
• Seedy crackers such as vitaweats or ryvitas
• Pasta, rice noodles, quinoa, semolina, buckwheat, sourghum, teff
• Rolled oats, all bran, guardian cereal, weetbix, natural muesli and porridge
• Sourdough, spelt, wholegrain, light rye and wholemeal bread

3. Eat more fat

Fat makes up 60% of the brain’s dry weight and fatty acids found in food are involved in the growth and development of the brain and affect brain function. The type of fat we consume matters. A typical western diet consumed today throws out the balance of omega-3 and omega-6 fats. Tipping this balance causes inflammation in parts of the body, including the brain.

Consuming more omega-3 fatty acids has a positive effect on parts of the brain that play a role in mood and memory function and are anti-inflammatory. Omega-3 fatty acids increase the levels of healthful fats available to the brain and strengthen the protective layer around nerve cells.

The best dietary sources are;

• Oily fish (sardines, mackerel, tuna, anchovies)
• Cold water fish (herring, salmon, sardines)
• Algae
• Seafood
• Nuts such as almonds and walnuts
• Flaxseed, flaxseed oil and chia seeds

4. Include lean protein

Serotonin a neurotransmitter is produced by an amino acid called tryptophan that is found in protein-rich foods such as chicken, turkey, eggs, dairy products, legumes and tofu. Choline is important for producing neurotransmitters involved in memory, cognition and mental ability. Low levels of choline are also linked to depression and the best dietary source is egg yolk. Women consuming less (or more) than the recommended intake of red meat are more likely to have clinical depressive and/or anxiety disorders.

5. Load up on fruits and vegetables

Plant-based foods such as fruits and vegetables are high in a number of nutrients including a special group of antioxidants called phytochemicals as well as fibre. These are both some of the most health-promoting and disease-fighting nutrients which can only be found in plant foods. Plants contain thousands of phytochemicals which all have many beneficial roles in the body and for the brain as they help protect against oxidation and inflammation that may affect the brain and therefore our moods and mental health. We also know they have a positive impact on our gut bacteria which play an important role in our stress hormones.

6. What foods should be limited?

Unhealthy dietary patterns high in processed foods, red meat, processed meat, added sugars, sugar-sweetened beverages, trans fat and sodium and low in fruits, vegetables, wholegrains, nuts, seeds, fibre, omega-3 fatty acids and polyunsaturated fatty acids are associated with an increased risk for depression and often also anxiety. Many people argue that this link exists because many people with poor mental health turn to poor quality comfort foods such as chocolate and takeaway food but research shows that these foods cause depression in the first place.

Take home message

We are only really starting to scrape the surface when it comes to understanding the important role diet has on our mental health and wellbeing. Increasing our intake of plant-based foods such as fruit, vegetables and legumes, including high-fibre wholegrain foods and consuming foods rich in omega-3 fatty acids such as oily fish, nuts and seeds can have a positive effect on mood by calming down inflammation, clearing up oxidative stress and improving our gut health. Likewise limiting our intake of processed foods, added sugars and saturated fat is important for improving our moods and mental health and protecting against anxiety and depression.