Globally, it's estimated that 1 in 8 people live with a mental disorder, with depressive disorders accounting for the largest amount of disability-adjusted life years (DALYs) among mental disorders [1]. While mental disorders are complex and multi-factorial, there is emerging research that nutrition may play an important role in both the prevention and treatment of depression [2].
Learn more about food and mood in the HealthCert Professional Diploma program in Medical Nutrition Management – online nutrition training for GPs.
The SMILES (Supporting the Modification of Lifestyle in Lowered Emotional States) trial was a randomised controlled trial that explored whether dietary quality could improve symptoms of depression [3]. In the study, the participants either followed a modified Mediterranean diet under guidance from a dietitian or were assigned a social support group. It was found that after 12 weeks, those following the healthy dietary pattern had a greater reduction in depressive symptoms than those in the social support group. Interestingly, those who had greater improvements in their diet were also found to have the biggest reduction in depressive symptoms.
The diversity of the gut microbiome has also been associated with the development of depression, with findings that the gut microbiota profile of patients with depression differ significantly from those without depression [4, 5]. However, causation is yet to be established. Metabolites produced by gut microbiota can also influence the body's neurotransmitters, such as by stimulating the release of serotonin. This suggests that a gut-healthy diet consisting of probiotics and prebiotics may be a therapeutic approach for mental health disorders, but further research is needed [6].
Omega-3 fatty acid supplementation may help to treat depression, with promising findings from a meta-analysis showing a benefit in anti-depressant treatment [7, 8]. Foods high in antioxidants such as polyphenols and isoflavonoids have also been shown to be inversely associated with depressive symptoms [9].
Poor quality diets, such as typical Western diets high in ultra-processed foods and saturated fats, may lead to deficiencies in nutrients that are needed to produce neurotransmitters (including B vitamins, vitamin D, zinc, magnesium, and essential fatty acids) and may contribute to the underlying pathology of behavioural disorders [10]. Identifying and correcting nutrient deficiencies may be helpful in managing mental health disorders as well.
The Mediterranean diet and other healthy dietary patterns which emphasise plenty of vegetables, fruit, plant-based sources of protein, fish, and olive oil may help to decrease the risk of developing depression and depressive symptoms and help to manage these illnesses.
It's important to note that mental disorders are multi-factorial, but there is growing evidence that nutritional management should be part of standard care when it comes to mental health treatment [10]. Understanding nutritional management can help GPs further support patients with mental health disorders to improve health outcomes.
Learn more about food and mood with the online HealthCert Professional Diploma program in Medical Nutrition Management.
– Sarah Marko, Accredited Practising Dietitian
References
[1] Global, regional, and national burden of 12 mental disorders in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019. The Lancet Psychiatry 2022. https://doi.org/10.1016/S2215-0366(21)00395-3.
[3] Opie RS, O'Neil A, Jacka FN, Pizzinga J, Itsiopoulos C. A modified Mediterranean dietary intervention for adults with major depression: Dietary protocol and feasibility data from the SMILES trial. Nutr Neurosci 2018. https://doi.org/10.1080/1028415X.2017.1312841
[4] Alli, SR, Gorbovskaya I, Liu JCW, Kolla NJ, Brown L, MĂĽller DJ. The Gut Microbiome in Depression and Potential Benefit of Prebiotics, Probiotics and Synbiotics: A Systematic Review of Clinical Trials and Observational Studies. Int. J. Mol. Sci. 2022.. https://doi.org/10.3390/ijms23094494
[5] Amirkhanzadeh Barandouzi Z, Starkweather AR, Henderson WA, Gyamfi A, Cong XS. Altered composition of gut microbiota in depression: A systematic review. Front Psychiatry 2020. https://doi.org/10.3389/fpsyt.2020.00541.
[6] Limbana T, Khan F, Eskander N. Gut Microbiome and Depression: How Microbes Affect the Way We Think. Cureus 2020. https://doi.org/10.7759/cureus.9966.
[7] Schefft C, Kilarski LL, Bschor T, Köhler S. Efficacy of adding nutritional supplements in unipolar depression: A systematic review and meta-analysis. Eur Neuropsychopharmacol 2017. https://doi.org/10.1016/j.euroneuro.2017.07.004.
[8] Guu TW, Mischoulon D, Sarris J, Hibbeln J, McNamara RK, Hamazaki K, et al. International Society for Nutritional Psychiatry Research Practice Guidelines for Omega-3 Fatty Acids in the Treatment of Major Depressive Disorder. Psychother Psychosom 2019. https://doi.org/10.1159/000502652.
[9] Huang Q, Liu H, Suzuki K, Ma S, Liu C. Linking what we eat to our mood: A review of diet, dietary antioxidants, and depression. Antioxidants 2019. https://doi.org/10.3390/antiox8090376.
[10] Kris-Etherton PM, Petersen KS, Hibbeln JR, Hurley D, Kolick V, Peoples S, et al. Nutrition and behavioral health disorders: Depression and anxiety. Nutr Rev 2021. https://doi.org/10.1093/nutrit/nuaa025.