[5 min read] Happy meals: The link between diet and depression

Did you know that depression and anxiety are the most common mental health conditions worldwide (1)? While treatment for patients with depression in primary care typically involves medications and therapy, current evidence suggests that nutrition and mental health are highly intertwined. 

Whether we’re shopping for it, reading about it, preparing it, or eating it, food is a big part of our daily lives. Many of us intuitively sense a food-mood connection (think a celebratory dinner or comfort food), but it is in the last decade that scientific evidence has started to catch up to conventional wisdom.

Research examining dietary quality and dietary patterns suggests that nutrient-dense dietary patterns (filled with colourful fruits and vegetables, whole grains, unprocessed meat, and fish) can reduce the risk of developing depression and anxiety disorders (2). Unfortunately, the reverse also appears to be true: a dietary pattern characterised by large amounts of red and/or processed meat, refined grains and sugar, and low intakes of fruit and vegetables is associated with an increased risk of depression or symptoms of depression (3).

How is food linked to mood?

The connection between diet and emotions stems from the connection between the brain and the gastrointestinal (GI) tract, often called the “gut-brain axis”. The GI tract harbours billions of microbes that influence the production of neurotransmitters, chemicals that carry messages between the gut and the brain (4). Eating nutrient-rich food promotes the growth of bacteria that positively affects neurotransmitter production; on the other hand, highly processed junk food can cause inflammation that hampers production.

Beneficial brain foods

So what foods are recommended in medical nutrition interventions for patients with depression or depressive symptoms? Here is a quick overview of what they can include at mealtime:

  • Omega-3s: Did you know that the brain is comprised of about 70% fat? Good-fat diets, not low-fat diets, are important for mental health (5). Omega-3s are inflammation fighters found in oily fish like salmon, flax and chia seeds, and walnuts.
  • Polyphenol-rich foods: Polyphenols are plant chemicals found in cocoa, blueberries, olive oil, and coffee. They have been strongly associated with better mood, higher cognition, and protective effects against brain diseases (6). Thumbs up for dark chocolate!
  • Fermented foods: Foods like yogurt, kefir, kimchi, and sauerkraut contain lots of beneficial microbes that boost gut health, and hence brain health. Find out more in this previous article.
  • High-fibre foods: Legumes, whole grains, nuts, seeds, fruits and vegetables are high in fibre, which promotes a happy gut microbiome and hence a happy mind (7).

The bottom line

Eating a varied and colourful diet with lots of plants promotes gut health, and by extension, brain health. If patients need extra support, consider referring them to see an Accredited Practising Dietitian.

Learn more on the link between diet and depression in the online Professional Diploma Program in Medical Nutrition.

 

Lynette Law, Provisional Accredited Practising Dietitian (Provisional)

See more recent research.


References

  1. Friedrich MJ. Depression is the leading cause of disability around the world. Jama. 2017;317(15):1517-.
  2. Lassale C, Batty GD, Baghdadli A, Jacka F, Sánchez-Villegas A, Kivimäki M, et al. Healthy dietary indices and risk of depressive outcomes: a systematic review and meta-analysis of observational studies. Molecular psychiatry. 2019;24(7):965-86.
  3. Li Y, Lv M-R, Wei Y-J, Sun L, Zhang J-X, Zhang H-G, et al. Dietary patterns and depression risk: A meta-analysis. Psychiatry Research. 2017;253:373-82.
  4. Strandwitz P. Neurotransmitter modulation by the gut microbiota. Brain Res. 2018;1693(Pt B):128-33.
  5. Dyall SC. Long-chain omega-3 fatty acids and the brain: a review of the independent and shared effects of EPA, DPA and DHA. Front Aging Neurosci. 2015;7:52-.
  6. Gomez-Pinilla F, Nguyen TTJ. Natural mood foods: the actions of polyphenols against psychiatric and cognitive disorders. Nutr Neurosci. 2012;15(3):127-33.
  7. Berding K, Carbia C, Cryan JF. Going with the grain: Fiber, cognition, and the microbiota-gut-brain-axis. Experimental Biology and Medicine. 2021;246(7):796-811.

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