“…in the context of urbanization, cultural and technological changes and the global industrialization and ultraprocessing of food, the findings related to nutrition and mental health are connected to some of the most pressing issues of our time.” (17)
Nutrition is important for a healthy body, that’s undeniable, but it’s also super important for the health of your mind. So much so, that scientists coined the term ‘nutritional psychiatry’ to promote a field of research dedicated to studying the role of diet in mental health.
The brain is always ‘on’ – even working hard while we sleep – and so it needs a huge chunk of the body’s energy and nutrient intake. Despite it’s relative small size, the brain uses more energy than any other organ in the human body, using up 20 percent of total energy intake! So what we eat has a direct impact on how our brain functions - and ultimately, how we feel. It also impacts several other body systems.
How nutrition impacts mental health:
Neurotransmitters are chemical messengers in the body that allow for communication between nerve, muscle and gland cells. Serotonin is a neurotransmitter that helps regulate sleep, appetite, mediate mood and inhibit pain – aka. it’s really important when it comes to happiness. About 95% of serotonin is produced in your gut, which is lined with millions of nerve cells. So, you know how you get butterflies in your stomach, or how it can feel like your stomach is in knots under stress, or how you can feel nauseous when you’re really emotional – it all makes sense because of how closely your gut and nervous system are linked.
The function of the nervous cells in the gut are strongly influenced by the billions of bacteria that make up the intestinal microbiome. When we eat less fruit and vegetables, less fibre, and more processed, non-organic foods (like we do in North America), we compromise the health of our microbiome, the nervous systems and integrity of our gut, and subsequently, mental health. Eating a high-fat Western diet may negatively impact the microbiome and cause inflammation in the gut, leading to gaps between cells (intestinal permeability) and ultimately inflammation throughout the whole body, even impacting the brain.
When we’re stressed, we actually use nutrients differently. Stress places an additional demand on the body when it comes to nutrition. Under stress, our adrenal glands amp up, and we use more vitamins and minerals (especially vitamin C, vitamin E, magnesium, potassium, which further increases metabolism of proteins, fats and carbohydrates – to provide quick energy to overcome stress) to fight or to flee. While all of this is occurring, there's increased oxidation occurring, resulting in increased inflammation and eventually cell damage.
Antioxidants from our diet – including vitamins A, C, E, minerals, and trace elements like zinc – are critical for dealing with oxidation in the body. Our immune system is also really important to mental health and is strongly influenced by diet and other lifestyle factors. Nutrition is also important in early life, impacting nervous system development and repair. Early life nutrition is especially important as we are seeing children with higher rates of obesity, diets that are high in calories but low in nutrients with a coinciding increase in depression, anxiety, and suicide among children and youth.
- Studies have linked eating a healthy diet to lowered risk of anxiety and/or depression. This suggests that ample nutrition can provide protection against depression and anxiety! (1-7)
- Healthy dietary patterns (high intakes of vegetables, fruits, potatoes, soy products, mushrooms, seaweed, and fish) was associated with a decreased risk of suicide (8)
- Adherence to a Mediterranean diet results in better cognitive outcomes (mental capacity) and a reduced risk for dementia (9 – 10)
- Studies suggest that omega-3 oils can help improve outcomes in disorders including, but not limited to, bipolar depression, post-traumatic stress disorder, major depression, and the indicated prevention of psychosis (11 – 14)
- Adoption of the Mediterranean diet for 10 days has been found to result in significantly increased vigor, alertness and contentment among participants vs controls (15)
- Consumption of energy-dense, high-fat, high-sugar, and sodium-rich foods may be a form of self-medication, a recent study suggested that (in healthy university students) consumption of such foods increases negative mood 48 hours after consumption(16)
Eating for mental health:
With all of the conflicting messages about nutrition out there, it’s no doubt that we are all a bit confused (hell, I have a degree and a diploma in Nutrition and I still get confused sometimes). I would love to tell you that there is a magic pill to promote mental health, but, there isn’t – it’s gonna take some commitment. Given the brain’s constant use of such a wide variety of nutrients, and the potential errors in metabolism that may be at play in mental disorders, focussing on a single nutrient is likely not the answer.
We need to shift the way that we eat. The research shows us that following a more traditional diet, like the Mediterranean diet – high in fruits and vegetables, whole grains, fish and other seafood, and nuts and seeds, and limiting or avoiding processed foods – is linked with improved mental health and happiness.
What to eat for happiness:
- whole foods: the closer it is to how it was harvested, the better
- local foods: when they aren’t transported over a long distance and picked before they’re ripe, nutrient levels are higher
- eat A LOT of fruits and vegetables: high in fibre, vitamins and minerals
- eat organic: many insecticides and pesticides are neurotoxins. There are claims that the science isn’t settled about their health risks, but we also said that cigarettes and margarine were perfectly fine when they first hit the market, and the research is starting to support that conventional farming is damaging to our health and our environment
- limit or avoid processed foods: processed food tends to be high in calories, low in nutrients, and contain several compounds that have been shown to negatively impact our health
- eat fish and other seafood and other healthy fats (avocado, nuts and seeds, grass-fed, organic meat)
PS. If you don’t know where to start, I've developed a program that can help – 28 Days Happier is a guide to living a happier, healthier, more vibrant life and includes 4 weeks of meals plans (with over 90 recipes and weekly grocery lists) that focus on foods that make you happy!
1. Jacka FN, Mykletun A, Bjelland I, Tell GS. The association between habitual diet quality and the common mental disorders in community-dwelling adults: the Hordaland Health Study. Psychom Med 2011.
2. Jacka FN, Pasco JA, Mykletun A, Williams LJ, Hodge AM, O’Reilly SL, Nicholson GC, Kotoicz MA, Berk M. Association of western and traditional diets with depression and anxiety in women. Am J Psychiatry 2010.
3. Sanches-Villegas A, Delgado-Rodriguez M, Alonso A, Schlatter J, Lahortiga F, Serra Majem L, Martinez-Gonzalez MA. Association of the Mediterranean dietary patters with the incidence of depression: the Seguimiento Universidad de Navarra/University of Navarra follow-up (SUN) cohort. Arch Gen Psychiatry 2009.
4. Skarupski KA, Tangney CC, Li H, Evans DA, Morris MC. Mediterranean diet and depressive symptoms among older adults over time. J Nutr Health Aging 2013.
5. Rienks J, Dobson AJ, Mishra GD. Mediterranean dietary pattern and prevalence and incidence of depressive symptoms in mid-aged women: results from a large community-based prospective study. Eur J Clin Nutr 2013.
6. Lai JS, Hiles S, Bisquera A, Hure AJ, McEvoy M, Attia J. A systemic review and meta-analysis of dietary patterns and depression in community-dwelling adults. Am J Clin Nutr 2014.
7. Psaltopoulou T, Sergentanis TN, Panagiotakos DB, Sergentanis IN, Kosti R, Scarmeas N. Mediterranean diet, stroke, cognitive impairment, and depression: a meta-analysis. Ann Neurol 2013.
8. Nanri A, Mizoue T, Poudel-Tandukar K, Noda M, Kato M, Kurotani K, Goto A, Oba S, Inoue M, Tsugane S, Japan Public Health Centre-based Prospective Study Group. Dietary patterns and suicide in Japanese adults: the Japan Public Health Center-based Prospective Study. Br J Psychiatry 2013.
9. Solfrizzi V, Panza F. Mediterranean diet and cognitive decline. A lesson from the whole-diet approach: what challenges lie ahead? J Alzheimers Dis 2014.
10. Martinez-Lapiscina EH, Clavero P, Toledo E, Estruch R, Salas-Salvado J, San Julian B, Sanchez-Tainta A, Ros E, Valls-Pedret C, Martinez- Gonzalez MA. Mediterranean diet improves cognition: the PERIMED_NAVARRA randomised trial. J Neurol Neurosurg Psychiatry 2013.
11. Balanza-Martinez V, Fries GR, Colpo GD, Colpo GD, Silveira PP, Portella AK, Tabares-Seisdedos R, Kapczinski F. Therapeutic use of omega-3 fatty acids in bipolar disorder. Expert Rev Neurother 2011.
12. Matsuoka Y, Nishi D, Yonemoto N, Hamazaki K, Hashimoto K, Hamazaki T. Omega-3 fatty acids for secondary prevention of posttraumatic stress disorder after accidental injury: an open-label pilot study. J Clin Psychopharmacol 2010.
13. Su KP, Wang SM, Pae CU. Omega-3 polyunsaturated fatty acids for major depressive disorder. Expert Opin Investig Drugs 2013.
14. Amminger GP, Schafer MR, Papageorgiou K, Klier CM, Cotton SM, Harrigan SM, Mackinnon A, McGorry PD, Berger GE. Long-chain omega-3 acids for indicated prevention of psychotic disorders: a randomized, placebo-controlled trial. Arch Gen Psychiatry 2010.
15. McMillan L, Owen L, Kras M, Scholey A. Behavioural effects of a 10-day Mediterranean diet: results from a pilot study evaluating mood and cognitive performance. Appetite 2011.
16. Hendy HM. Which comes first in food-mood relationships, foods or moods? Appetite 2012.
17. Logan, AC, Jacka, FN. Nutritional psychiatry research: an emerging discipline and its intersection with global urbanization, environmental challenges and the evolutionary mismatch. Journal of Physiological Anthropology 2014.