Thomas Jefferson acknowledged our pursuit of happiness as an inalienable right that every man should be free to pursue. My intention with these articles is to help you in that pursuit as I have observed that we often bark up the wrong tree in our hunt for happiness. We began this series acknowledging our use of favorite food as a happy trigger but asked the question; Are these foods really making us happier? The short answer is no. In fact, research is revealing that our SAD (Standard American Diet) way of eating may actually be contributing to depression and anxiety.
In an Australian randomized control trial 76 college students age 17-35, completed a 21-day trial. At the beginning of the study all participants rated high on the depression score and had poor diets. Half of the participants were put on a healthier diet that emphasized increase intake of vegetables, fruits, whole grains, lean protein that included lean meat: poultry, eggs, tofu, beans, nuts and seeds, and other ingredients in the diet such as olive oil, etc. They were also instructed to decrease refined carbohydrate, sugar, fatty or processed meats and soft-drinks. The other half of the participants did not change their diet. Using a well-established scoring system the diet change group went from a being scored at moderate severity depression score to a score in normal range. The control group that did not change their diet remained in the moderate severity depressed state.1
A meta-analysis of 41 studies also revealed an association between dietary patterns and depression. Based on their observations, the study’s lead author Dr. Camille Lassale stated, “A pro-inflammatory diet can induce systemic inflammation, and this can directly increase the risk for depression. . . . Bad diet heightens the risk of depression to a significant extent.”2
Inflammation seems to be at the foundation of varying chronic health concerns, including depression. A link between our diet and systemic inflammation is the gut microbiota/microbiome, the combination of microbes residing in the lining of our gut. “The gut microorganisms community is emerging as a key mechanism for modulating mental well-being. In fact, emotional disorders—such as depression and anxiety—are frequently accompanied by functional gastrointestinal disorders, suggesting an association between gut function and psychiatric diseases.”3 In fact, when the gut microbiome from depressed humans is transferred to rodents via fecal transplants, the rats start manifesting depressed, anxious behavior.4
Like any community, the gut microbiome is composed of different families and clans that have unique contributions to our health. Certain categories of bacteria appear to be more implicated in depression while others appear to be associated with positive mood. What seems to pop up quite a bit in the medical literature is the value of diversity. “Gut microbiome diversity has been strongly associated with mood-relating behaviours, including major depressive disorder.”5 I think of the Amazon forest when I think of a diverse ecosystem, which thrives in the context of the abundant diversity of plant and animal species. Similarly, diversity and abundance in the human microbiota is considered to be a marker of resilience and optimal physical and mental health.
One of the best ways to support a healthy, diverse, flourishing microbiome is by feeding on a healthy and diverse diet. While the SAD way of eating is associated with lower diversity, consuming a whole food plant based diet is associated with much greater diversity. This is because whole plant-based foods contain a variety of indigestible substances, which commonly refer to as fiber that “feed” the beneficial microbes, enabling them to thrive and work for our health and happiness.
Learning about the role of the microscopic friends that we didn’t know we had, points us in the direction of truly happy trails. The Bible says, “Blessed is the one who finds wisdom, and the one who gets understanding . . . her ways are ways of pleasantness” Proverbs 3:13, 17.
- Francis HM, Stevenson RJ, Chambers JR, Gupta D, Newey B, et al. (2019) A brief diet intervention can reduce symptoms of depression in young adults – A randomised controlled trial. PLOS ONE 14(10): e0222768. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0222768
- https://www.theguardian.com/society/2018/sep/26/eating-junk-food-raises-risk-of-depression-says-multi-country-study
- Winter, G., Hart, R. A., Charlesworth, R., & Sharpley, C. F. (2018). Gut microbiome and depression: what we know and what we need to know. Reviews in the neurosciences, 29(6), 629–643. https://www.degruyter.com/document/doi/10.1515/revneuro-2017-0072/html
- Kelly, J. R., Borre, Y., O’ Brien, C., Patterson, E., El Aidy, S., Deane, J., Kennedy, P. J., Beers, S., Scott, K., Moloney, G., Hoban, A. E., Scott, L., Fitzgerald, P., Ross, P., Stanton, C., Clarke, G., Cryan, J. F., & Dinan, T. G. (2016). Transferring the blues: Depression-associated gut microbiota induces neurobehavioural changes in the rat. Journal of psychiatric research, 82, 109–118. https://pubmed.ncbi.nlm.nih.gov/27491067/#:~:text=Fecal%20microbiota%20transplantation%20from%20depressed%20patients%20to%20microbiota-depleted,behaviours%2C%20as%20well%20as%20alterations%20in%20tryptophan%20metabolism.
- Winter, G., Hart, R. A., Charlesworth, R., & Sharpley, C. F. (2018). Gut microbiome and depression: what we know and what we need to know. Reviews in the neurosciences, 29(6), 629–643. https://www.degruyter.com/document/doi/10.1515/revneuro-2017-0072/html
