In the last decade, research on the human microbiome and its impact on various aspects of our health has shed light on the importance of maintaining a healthy balance of bacteria in our gut. More specifically, this research demonstrates how gut health, or lack thereof, can play a large part in disease development. A disruption to the gut bacteria has been linked to depression, cancer, allergies, and more recently, immune reactions.
What is the microbiome and what does our “gut” have to do with it?
Our skin, organs, and intestines all contain millions of microorganisms that make up the microbiome. The bacteria that live in our gut have the ability to “communicate” with our brains and other organs. These bacteria are commonly referred to as “good” or “bad” and a balance between the two is desirable. When the “bad” bacteria are dominant, they can alter the breakdown of certain nutrients which can cause disease and other health issues. For example, the amino acid tryptophan breaks down to form serotonin, a natural mood stabilizer. When levels of “good” bacteria are down, it can trigger an alternate breakdown that creates quinolinic acid instead. The hypothesis for this particular example is that decreased serotonin and increased quinolinic acid may lead to depression.
Dietary Impact on Gut Bacteria?
Common gut bacteria are Bifidobacterium and Lactobacillus. Both of which you can impact by what you eat. Diets high in animal protein, saturated fat and trans-fat have been shown to disrupt the balance, while diets rich in plant proteins and unsaturated fats have been shown to maintain the balance. Refined carbohydrates and artificial sugars are disrupters while complex carbohydrates, like whole grains, can act as prebiotics and support the growth of “good” bacteria. Polyphenols, which are found in fruits, vegetables, seeds, and tea have also been shown to benefit the gut microbiota. Interestingly, a diet made up of high levels of unsaturated fats, polyphenols, and fiber and low levels of animal protein, saturated fat, and refined carbs is the Mediterranean diet. A diet that has been hypothesized by numerous studies to prevent diet-related diseases.
Dysbiosis of the gut can occur through poor diet, early or frequent use of antibiotics, and other environmental factors. To help bring balance to the gut microbiota, many people turn to probiotics. In fact, probiotic use in the USA quadrupled between 2007 and 2012. Dietary examples of probiotics are yogurt and fermented foods and drinks. Supplements also exist, but with all the hype it is important to do your research or consult with a health professional first. There is still a lot to learn about the microbiome and our health.
Sources
Hansen CHF, Nielsen DS, Kverka M, Zakostelska Z, Klimesova K, Hudcovic T, et al. (2012) Patterns of Early Gut Colonization Shape Future Immune Responses of the Host. PLoS ONE 7(3): e34043. https://doi.org/10.1371/journal.pone.0034043
Singh, R. K., Chang, H. W., Yan, D., Lee, K. M., Ucmak, D., Wong, K., Abrouk, M., Farahnik, B., Nakamura, M., Zhu, T. H., Bhutani, T., & Liao, W. (2017). Influence of diet on the gut microbiome and implications for human health. Journal of translational medicine, 15(1), 73. https://doi.org/10.1186/s12967-017-1175-y
Waclawiková, B., & El Aidy, S. (2018). Role of Microbiota and Tryptophan Metabolites in the Remote Effect of Intestinal Inflammation on Brain and Depression. Pharmaceuticals (Basel, Switzerland), 11(3), 63. https://doi.org/10.3390/ph11030063
Zheng, D., Liwinski, T. & Elinav, E. Interaction between microbiota and immunity in health and disease. Cell Res 30, 492–506 (2020). https://doi.org/10.1038/s41422-020-0332-7
https://www.nccih.nih.gov/health/probiotics-what-you-need-to-know
