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References: Food and Mood

  1. A randomised controlled trial of dietary improvement for adults with major depression (the "SMILES" trial). Jacka FN, et al. BMC Medicine, 2017. The trial analyzed in this chapter's claim box: 67 adults with depression, 12 weeks, remission 32.3% vs 8.0%. The free full text explains the diet, the blinding, and the funding. (A correction was published in 2018.)

  2. The Effects of Dietary Improvement on Symptoms of Depression and Anxiety: A Meta-Analysis of Randomized Controlled Trials. Firth J, et al. Psychosomatic Medicine, 2019. Combines 16 trials with 45,826 participants and finds a small effect on depressive symptoms and no significant effect on anxiety. Useful for seeing how one exciting trial fits into the bigger picture.

  3. Mediterranean dietary pattern and depression: the PREDIMED randomized trial. Sánchez-Villegas A, et al. BMC Medicine, 2013. A large trial in older Spanish adults at high heart risk that found no significant overall effect on new depression. A good reminder that bigger trials sometimes give more modest answers.

  4. Ultra-Processed Food Consumption and Mental Health: A Systematic Review and Meta-Analysis of Observational Studies. Lane MM, et al. Nutrients, 2022. Pools 17 observational studies of 385,541 people, explains the NOVA classification, and notes that the link appears to run in both directions.

  5. Ultra-processed food exposure and adverse health outcomes: umbrella review of epidemiological meta-analyses. Lane MM, et al. BMJ, 2024. The umbrella review covering nearly 10 million people. Shows how evidence can be "convincing" as an association yet "low" in quality.

  6. Food and mood: how do diet and nutrition affect mental wellbeing?. Firth J, Gangwisch JE, Borisini A, Wootton RE, Mayer EA. BMJ, 2020. A readable overview of nutritional psychiatry and the possible pathways, including the gut microbiome, with an honest discussion of what is still unknown.

  7. Gut-microbiota-targeted diets modulate human immune status. Wastyk HC, et al. Cell, 2021. The Stanford trial in which 36 healthy adults ate more fermented foods or more fiber for 17 weeks; the fermented-food group had higher microbe diversity and lower inflammation markers. It did not measure mood.

  8. Dietary Guidelines for Americans, 2020-2025. US Department of Agriculture and US Department of Health and Human Services. Source for the teen fiber amounts (about 25 g for girls and 31 g for boys aged 14 to 18) and the share of Americans who don't meet them.

  9. Dietary Guidelines for Americans, 2025-2030. US Department of Agriculture and US Department of Health and Human Services. The current federal guidelines. Their "Gut Health" box says fermented and high-fiber foods support a diverse microbiome; they give no gram target for fiber.

  10. Food Security in the U.S.: Key Statistics and Graphics. USDA Economic Research Service. Official 2024 numbers on food insecurity (13.7% of households; 18.4% of households with children) and the definition used in this chapter.

  11. Eating Disorders. National Institute of Mental Health (NIMH). Explains what eating disorders are, that they are serious, and that they can be treated successfully, with early help being important. A trustworthy place to start if food worries are affecting you or someone you know.