We all know a healthy diet can nourish our body and mind, but what constitutes a healthy diet may differ from country to culture, which can cause confusion when considering dietary changes. We explore the latest research on which foods can have the greatest impact on mental health as well as some simple tips you can start using today to support your mental wellbeing.
Food and Mood
Researchers at the Food and Mood Centre at Deakin University VIC are committed to conducting high-quality research to help us understand how diet and nutrition can impact our risk of mental health disorders and potentially how to treat them. Multiple observational studies have indicated that diet has a significant impact on depression: better quality diets are associated with reduced risk of depression and unhealthy diets containing highly processed food, saturated fats, refined sugar and refined carbohydrates are associated with depressive symptoms and often anxiety (1).
In 2017, a randomised controlled trial known as the ‘SMILES’ trial was conducted to investigate the efficacy of a dietary improvement program for the treatment of major depressive episodes (2). Participants were randomly assigned to receive ‘social support’ provided by trained personnel or ‘dietary support’ provided by an Accredited Practising Dietitian (APD) over a three-month period. Results showed that participants in the dietary support group following a modified Mediterranean diet had a much greater reduction in their depressive symptoms compared to those in the social support control group. Specifically, a third (33%) of those in the dietary support group met criteria for remission of major depression, compared to 8% of those in the social support control group. Results were related to the extent of dietary change and not attributed to physical activity or change in body weight i.e. those who improved the quality of their diet the most experienced the greatest benefit to their depression.
The Mediterranean Approach
In recent years the Mediterranean diet has been hailed as the world’s healthiest way of eating, largely due to the results of the PREDIMED study showing that the Mediterranean diet supplemented with olive oil and nuts had a significantly positive impact on the prevention of cardiovascular disease compared to a low-fat diet alone (3).
The general characteristics of a Mediterranean diet include:
- High intake of plant-based foods (vegetables, olive oil, fruit, nuts, whole grains and legumes)
- Fats principally from unsaturated sources like olive oil, nuts and seeds
- Moderate intake of fish and poultry
- Low intake of dairy products (mainly local cheese and yoghurt)
- Low intake of red meat, processed meats and sweets
- Red wine in moderation and consumed only with meals
Within this PREDIMED study, an observational study found a strong trend between those following the Mediterranean diet and preventing the onset of depression (4). This was statistically significant for participants who had type 2 diabetes. The results indicate the potentially beneficial role of adopting a Mediterranean-style diet for the prevention of depression, especially for those with diabetes.
Nourish your Gut
More and more we are hearing about new scientific developments in understanding our gut microbiome and the link between our gut and our brain. Often referred to as the gut-brain axis, this system works like a communication highway to and from our brain and our bowel, which means the emotional and cognitive centres of our brain have an impact on our intestinal function and vice versa.
Although there is much to be understood about our gut microbiome and its effect on our body systems, there is evidence pointing towards dysbiosis, a microbial imbalance or impairment, and several central nervous and neuropsychiatric disorders including autism, stress, schizophrenia, bipolar disorder, anxiety and depression (5,6), where researchers are comparing microbial markers from the gut to distinguish between affected patients and unaffected healthy individuals.
Simple dietary and lifestyle habits can have a substantial effect on your gut health. Here are our top three tips for improving your gut health:
1. Focus on fibre
Dietary fibre moves largely unchanged through our digestive system to our bowel where it can be utilised and fermented by microbes or ‘good bacteria’ (7). Fibre is found in plant-based foods such as vegetables, fruit, whole grains, legumes, lentils, nuts and seeds.
These organic chemical compounds are found naturally in plants and provide antioxidant and other beneficial functions when ingested by humans. Dietary polyphenols can modulate the gut microbial balance, enhance our ‘good bacteria’ and assist in inhibiting pathogens (8). Foods that are rich in polyphenols include berries, spices, cacao, dark chocolate, vegetables, tea and coffee.
3. Reduce stress
Acute or short-term stress can affect appetite, digestion and bowel motions; all components of good gut health. However, chronic or long-term stress is more detrimental to our health as it causes inflammation and can lower our immune system, so stress management strategies such as regular exercise, meditation, getting enough sleep, resolving conflict and making time for hobbies or things we enjoy, are key in our busy lives.
You can learn more about the gut microbiome via this link to our True Life Blog.
Cut back on Alcohol
One of the main reasons people choose to drink alcohol is to change their mood. Alcohol acts as a depressant and can temporarily reduce the feelings of anxiety through stress response dampening (9). However, regular and excessive alcohol consumption can impact brain chemistry which can cause changes in your mood, energy levels, immunity, sleep patterns, concentration and memory, often in a negative way.
According to Centers for Disease Control and Prevention (CDC) long-term, excessive alcohol consumption can lead to serious health conditions and chronic disease including:
- High blood pressure, heart disease, stroke, liver disease, and digestive problems
- Cancer of the breast, mouth, throat, oesophagus, liver, and colon
- Learning and memory problems, including dementia and poor school/work performance
- Mental health problems, including depression and anxiety
- Social problems, including lost productivity, family problems, and unemployment
Current Australian guidelines recommend for healthy men and women to drink no more than two standard drinks on any one day to reduce the lifetime risk of harm from alcohol-related disease or injury (10).
A Note on Emotional and Disordered Eating
There’s no question that our food choices can be influenced by our mood and how we’re feeling. The Food and Mood Centre has shown that stress and anxiety can increase the likelihood of choosing high carbohydrate, sugary or salty foods. Despite being ‘comforting’ at the time, regularly choosing nutrient-poor junk foods increases the risks of some mental health disorders. While a diet diverse in quality and nutrient-rich foods can improve our mood and be protective of our brain, as discussed above. Some scientific studies have explored mindfulness, mindful eating and mindful meditation to show a positive impact on cravings, weight management and other emotional eating behaviours (11).
It’s important not to confuse signs of emotional eating with an underlying eating disorder, which is a serious mental illness that has the highest mortality rate of any psychiatric illness. Many people who suffer from an eating disorder also suffer from anxiety and/or depression (12).
Eating disorders include anorexia nervosa, bulimia nervosa, binge eating disorder and disordered eating. You can learn more about these conditions and common myths surrounding them via this link to the Butterfly Foundation for Eating Disorders.
- The food and drink you choose to form your diet can have a positive or negative impact on your mental health and wellbeing
- Diets containing highly processed foods, saturated fats, refined sugar and refined carbohydrates are associated with depressive symptoms and often anxiety
- A diet diverse in quality and nutrient-rich foods can improve our mood and be protective of our brain
- The Mediterranean diet that is rich in plant-based foods, unsaturated fats and nuts has been associated with preventing the onset of depression, particularly in individuals with type 2 diabetes
- The gut-brain axis is the connection and communication between the emotional and cognitive centres of the brain and our gut microbiome, which means that improving your gut health can have a positive impact on your mental wellbeing
- Although alcohol may ‘lift’ your mood temporarily, in the long term, excessive consumption can cause serious conditions and disease including mental and social issues
- Various mindfulness techniques have been shown to positively impact cravings, weight management emotional eating behaviours
Eating disorders are serious mental illnesses and it’s important to understand and recognise the warning signs and symptoms. To learn more, visit the Butterfly Foundation for Eating Disorders
- Jacka et al. A randomised controlled trial of dietary improvement for adults with major depression (the ‘SMILES’ trial). BMC Medicine 2017;15:23
- Estruch et al 2018 NEJM 378:e34
- Sánchez-Villegas A, Martínez-González MA, Estruch R, et al. Mediterranean dietary pattern and depression: the PREDIMED randomized trial. BMC Med. 2013;11:208. Published 2013 Sep 20. doi:10.1186/1741-7015-11-208
- Marilia Carabotti, Annunziata Scirocco, Maria Antonietta Maselli and Carola Severi. The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems. Ann Gastroenterol 2015; 28 (2): 203-209
- Ting-Ting Huang, Jian-Bo Lai, Yan-Li Du, Yi Xu, Lie-Min Ruan and Shao-Hua Hu. Current Understanding of Gut Microbiota in Mood Disorders: An Update of Human Studies. Front Genet. 2019; 10: 98. Published online 2019 Feb 19. doi: 10.3389/fgene.2019.00098
- Stefania Filosa, Francesco Di Meo and Stefania Crispi. Polyphenols-gut microbiota interplay and brain neuromodulation. Neural Regen Res. 2018 Dec; 13(12): 2055–2059. doi: 10.4103/1673-5374.241429
- Sher, K. J., & Walitzer, K. S. (1986). Individual differences in the stress-response-dampening effect of alcohol: A dose-response study. Journal of Abnormal Psychology, 95(2), 159-167.
- Janet Warren, Nicola Smith and Margaret Ashwell. A structured literature review on the role of mindfulness, mindful eating and intuitive eating in changing eating behaviours: effectiveness and associated potential mechanisms. Nutrition Research Reviews (2017), 30, 272–283