Research shows your diet and mental health are linked

Topics Covered

• The SMILES Trial on diet and mental health
• The link between gut health and mental health
• What to eat to support your mental health?
• 5 simple diet tips to get you started

The link between diet and mental health is a topic that has been thoroughly studied, and it is now recognised that the food we consume does in fact influence our mental health and wellbeing. Research shows that consuming a healthy balanced diet is a protective factor against mental health conditions, whereas a poor-quality diet is a risk factor for common mental health disorders, such as depression.

The SMILES Trial on diet and mental health

One of the most well-known studies looking at diet and mental health was conducted by the Food & Mood Centre at Deakin University. The study was named the SMILES Trial (Supporting the Modification of Lifestyle in Lowered Emotional States), where participants were recruited from the community with symptoms of depression. They were separated into 2 groups, the ‘diet’ group who received dietary intervention with a Dietitian. This group received dietary education, support, and counselling as well as social support. The second group was the ‘befriending’ group also known as the control group. In this group, they only received social support. 

Long story short, the study found significantly greater improvements in mental health outcomes in the dietary support group compared to the control group. From these results, the researchers concluded that diet plays a significant role in mental health outcomes.

The link between gut health and mental health

The gut and the brain are connected by the Vagus Nerve which allows the brain and gut to send direct chemical messages to each other. Many important neurotransmitters such as melatonin, dopamine and about 90% of the body’s serotonin are produced in the gut, which is important for mood and sleep regulation. Having a healthy gut lined with trillions of bacteria is essential to the production of these neurotransmitters as well as stress regulation, immunity, mental health, and metabolic responses.

Eating well can also give you more energy, allow for a better night’s sleep, increase mental clarity, and reduce intense cravings for sugar or salt. All of these contribute towards increased moods and are why your diet and mental health are closely linked.

What to eat to support your diet and mental health?

As mentioned before, the gut and the brain are closely linked so what we eat can have a huge impact on our mental wellbeing. The SMILES trial used a modified version of the Mediterranean diet. 

If you haven’t heard of the Mediterranean diet before this is a diet that has extensive research behind it to support cognitive health, gut health, cardiovascular health and decreasing inflammation in the body. It incorporates a wide variety of fresh fruits and vegetables, wholegrains, legumes, nuts, fish, and healthy fats such as extra virgin olive oil. It is therefore rich in omegas, antioxidants, and protein. 

Of course, this isn’t the only diet that can lead to improvements in mental health conditions, but the overarching focus of all of these is the high consumption of whole, unprocessed plant foods.

The human brain is made of nearly 60% fat, which is why the dietary intake of essential fatty acids is crucial to mental and cognitive function. The Mediterranean diet focuses heavily on healthy fat consumption. 

Further studies in the field have found that inflammatory fats such as saturated and trans fats in meats, pastries and processed foods are related to depressive symptoms. On the flip sip, polyunsaturated and monounsaturated fats found in extra virgin olive oil and avocado were protective against the development of depression.

The Mediterranean diet also focuses on fibre. Fibre is what feeds the bacteria that live within our gastrointestinal tract, assists in bowel movement regularity, stabilises blood sugars and lowers cholesterol levels. Now, these bacteria are quite fussy, and each specific strain likes to feed on different fibres found in different foods. So, if we ate the same foods every day, our gut would be lacking diversity and some strains would begin to starve and die. 

Some studies have also shown that when the bacteria are starved of their preferred fibre, they begin to feed on the mucus lining of the gut, resulting in further gut disturbances. Therefore, for these bacteria (probiotics) to thrive in sufficient quantities, we need to feed them with a variety of fibres (prebiotics) from plant-based foods such as fruit, vegetables, beans, legumes, and grains.

5 simple diet tips to get you started

Below are 5 simple tips to help you support your diet and mental health.

• Start by making small changes that are easy to stick to – swap a processed snack to a piece of fruit or handful of nuts
• Try to have a serving of vegetables at every meal – get creative! 
• Opt for extra virgin olive oil over vegetable oils and coconut oil
• Limit red meat to 2-3 times a week and avoid processed deli meats
• A chocolate bar or pizza is okay every so often. You don’t have to be perfect. It’s what you do the majority of the time that counts!

All this evidence is extremely promising, and a few simple diet modifications could assist in alleviating low mood symptoms, increasing mental clarity and energy, and acting as a protective factor against mental health conditions. However, this does not replace medication where it’s necessary, and you should consult your health professional before making any changes.