Have you ever noticed that your emotions are often accompanied by a gut response? Like the feeling of butterflies in your stomach when you’re excited and nervous, or feeling a little nauseous when you’re stressed or anxious? Well there’s a good explanation for this phenomenon!
The gut-brain axis
The gut and the brain are thought to be closely linked with each other through the bi-directional communication of the gastrointestinal tract and the central nervous system, known as the gut-brain axis. The vagus nerve plays a key role in the gut-brain axis, but the gut and brain also communicate through our immune cells. This can help to explain why gut health is a key factor in overall health, and has been an area of interest in recent nutrition research to see if diet could be a modifiable risk factor in certain mental illnesses.
Current research indicates that diet has a key role in mental wellness, due to its impacts on gut structure and function, and therefore its link with overall health including brain health due to the gut-brain axis.
How food affects your mental health
The SMILES trial (2012-2015) was the first study in the world to demonstrate that dietary changes can improve symptoms in those with clinically diagnosed depression. In this study, 32% of participants achieved full remission (no longer considered depressed) after the 12-week intervention which involved individual consultations with an Accredited Dietitian, and following a modified Mediterranean diet (the ModiMed diet adapted from the PREDIMED study).
In 2017, the HELFIMED study findings supported the evidence from the SMILES trial. Study participants with self-reported depression were prescribed omega-3 supplements and participated in cooking classes with recommended dietary changes based on the Mediterranean diet. Participants reported significant reductions in depression and these improvements were sustained 6 months after the intervention was completed. Research in this area is still growing but so far, the results are promising.
Almost half (45%) of adult Australians will experience mental illness over their lifetime. Nutrition is a modifiable risk factor. Mental health exists on a continuum, so nutrition can play a role in stress and anxiety management, even if you are not experiencing chronic depression or mental illness.
How you can change your diet to improve your mental health
1. Add colour
Oxidative stress might play a key role in development of some mental illnesses. Colourful foods in the diet (fruit and vegetables) are full of antioxidants so are key for reducing oxidative stress.
2. Focus on gut health
Some neurotransmitters such as serotonin (the “happy” hormone) are produced in the gut. Gut health could be key in the number and uptake of these neurotransmitters that are involved in mood.
3. Up your intake of anti-inflammatory foods
Many mental illnesses are linked with inflammation, with chronic low-grade inflammation a risk factor for developing depression and possibly cognitive decline with older age. Mediterranean diets are associated with reduced inflammation so may support brain health and reducing risk of mental illness.
4. Increase dietary fibre
Diets high in fibre (such as the Mediterranean diet) have also been shown to support immune function. Fibre is used by the gut microbiota (bacteria in the gut) to produce metabolites such as short chain fatty acids that have a key role in inflammation regulation. Since the gut and brain also communicate via immune cells this could have a key role in mental health.
5. If in doubt, opt for the Mediterranean diet
Current trials looking at the link between food and mood have found positive results using the Mediterranean diet. Working one to one with an Accredited Practicing Dietitian is a useful strategy to assist making the dietary changes suggested to support mental wellness.