Updated: Nov 26, 2020
Nutrition should be one of the first things brought up in the discussion about mental health due to its far-reaching impacts on the body and mind. Poor diet and mental disorders are the leading health issues of the 21st century, and the two most important factors contributing to death and disability across the globe.
New and recent evidence indicates that poor diet and mental and brain health are linked and have profound implications for the health of individuals and societies (1, 2, 5). Research also suggests the possibility of being able to reduce the risk of and even prevent at least some of the burden of mental disorders (3, 4).
Optimising our mental health starts with optimising our body first.
This 3-part Mental Health Series will discuss the link between diet and mental and brain health and offer insights and suggestions for what we can do to improve mental health using nutritional interventions.
Can Nutrition Make You Feel Better?
Mental health disorders are complex. So is the brain. And so are the foods we eat, and the ways our bodies interact with those foods and nutrients. Your brain needs a lot of energy to work properly and to create neurotransmitters - those chemicals that send signals through the nervous system.
We are still new to this field of figuring out exactly how the brain works, and exactly how nutrients may improve brain health. Still, there are some promising possibilities.
Without enough energy or the right nutrients, your brain won’t get what it needs. One study suggests that eating a lot of processed foods could increase depression by 60 percent (6). Other research has shown that nutrient deficiencies often look like mental health problems (7-10).
Here are some pathways by which a healthy diet might protect your brain.
1. Nutrition may reduce inflammation
Chronic inflammation occurs when your immune system gets set permanently to “on”, and remains a constant low-level physiological response. Chronic inflammation becomes problematic because the body struggles to turn off the inflammatory response and it can start damaging healthy tissues as well.
The resulting damage is linked to all manner of health problems, including cancer, heart disease, neurodegenerative disorders like Alzheimer’s and depression. One theory is that pro-inflammatory cytokines – which are markers of inflammation - may interact with other proteins in the brain, promoting changes that contribute to depressive illness (11, 12).
2. Nutrition may improve your gut health
Your gastrointestinal tract (GI) does more than move food from one end to the other. It is responsible for absorbing the nutrients for your organs - including the brain - need to function properly. To do these important jobs, your gut relies on healthy intestinal cells and beneficial bacteria, which help manufacture vitamins, absorb minerals, and digest food.
The organisms that exist within your gut are responsible for bodily functions including immune health, detoxification, nutrient absorption, and neurotransmitter and vitamin production. Dysbiosis can occur in the gut, which is a disruption of the gut bacteria by various stressors, such as an unhealthy diet. Dysbiosis promotes gut inflammation, and, if left unchecked, contributes to the development of chronic diseases such as inflammatory bowel disease (IBD), obesity, brain fog, depression, asthma and psoriasis (13, 14).
Did you know that most serotonin — the happy-making neurotransmitter — is made in the gut, not the brain. Poor GI health could prevent its production.
3. Nutrition may promote neuroplasticity
The brain uses nutrients to produce brain-derived neurotrophic factor (BDNF), a protein that is essential to the central nervous system and which strengthens neural connections, particularly in areas involved in memory and learning.
Some research suggests that BDNF could support neuroplasticity — the brain’s ability to adapt, rewire itself, and grow. This would be especially beneficial in recovery from depression and trauma (15).
Over the next couple of weeks, we will dive deeper into these pathways and provide you with practical helpful tips on how to improve your mental health through nutritional interventions!
It is important to remember the bigger picture. While nutrition is essential for building optimal mental health, it is but one piece of the puzzle. Lifestyle factors such as sleep, stress management, and exercise are also critical contributors to mental health.
1) Health effects of dietary risks in 195 countries, 1990–2017: a systematic analysis for the Global Burden of Disease Study 2017. Lancet. 393, 10184, p1958-1972
2) Whiteford H A et al. (2013). Global burden of disease attributable to mental and substance use disorders: findings from the Global Burden of Disease Study 2010. Lancet. 382 (9904):1575-86.
3) Jacka, F.N., O’Neil, A., Opie, R. et al. A randomised controlled trial of dietary improvement for adults with major depression (the ‘SMILES’ trial). BMC Med 15, 23 (2017). https://doi.org/10.1186/s12916-017-0791-y
4) Le Port A, Gueguen A, Kesse-Guyot E, Melchior M, Lemogne C, Nabi H, et al. Association between dietary patterns and depressive symptoms over time: a 10-year follow-up study of the GAZEL cohort. PLoS One (2012) 7(12):e51593.
5) Jacka FN, Kremer PJ, Berk M, de Silva-Sanigorski AM, Moodie M, Leslie ER, et al. A prospective study of diet quality and mental health in adolescents. PLoS One (2011) 6(9):e24805. doi: 10.1371/journal.pone.0024805
6) Ruusunen, A. Diet and depression – an epidemiological study. University of Eastern Finland. 2013.
7) Wang J, Um P, Dickerman BA, Liu J. Zinc, magnesium, selenium and depression: a review of the evidence, potential mechanisms and implications. Nutrients. 2018;10(5):584.
8) Rosanoff A, Dai Q, Shapses SA. Essential nutrient interactions: does low or suboptimal magnesium status interact with vitamin D and/or calcium status? Adv Nutr. 2016;7(1):25-43
9) Tarleton EK, Kennedy AG, Rose GL, Crocker A, Littenberg B. The association between serum magnesium levels and depression in an adult primary care population. Nutrients. 2019;11(7):1475. doi:10.3390/nu11071475
10) Boyle NB, Lawton C, Dye L. The effects of magnesium supplementation on subjective anxiety and stress—a systematic review. Nutrients. 2017;9(5):429.
11) Milaneschi Y, Bandinelli S, Penninx B, Vogelzangs N, Corsi A, Lauretani F, et al. Depressive symptoms and inflammation increase in a prospective study of older adults: a protective effect of a healthy (Mediterranean-style) diet. Molec Psychiatry (2011) 16(6):589. doi: 10. 1038/mp.2010.113
12) Firth, J., Veronese, N., Cotter, J., Shivappa, N., Hebert, J. R., Ee, C., … Sarris, J. (2019). What Is the Role of Dietary Inflammation in Severe Mental Illness? A Review of Observational and Experimental Findings. Frontiers in psychiatry, 10, 350.
13) Giorgia Caspani, Sidney Kennedy, Jane Foster and Jonathan Swann (2019). Gut microbial metabolites in depression: understanding the biochemical mechanisms. Microbial Cell 6(10): 454-481.
14) Appleton J. (2018). The Gut-Brain Axis: Influence of Microbiota on Mood and Mental Health. Integrative medicine (Encinitas, Calif.), 17(4), 28–32.
15) Tao Tang et al. (2020). The Role of BDNF on Neural Plasticity in Depression. Front. Cell. Neurosci.