You might have read the title and thought “there is no way that works” but, I am here to tell you otherwise. In my undergrad years, I worked in a lab where we studied a soil dwelling bacterium, Mycobacterium vaccae, and it’s relation of stress. These are beneficial microbes in soil and the environment that we have long lived alongside but, as humans have moved away from farms and an agricultural or hunter-gatherer existence into cities, we have lost contact with organisms that served to regulate our immune system and suppress inappropriate inflammation. That has put us at higher risk for inflammatory disease and stress-related psychiatric disorders. A study has shown children raised in a rural environment, surrounded by animals and bacteria-laden dust, grow up to have more stress-resilient immune systems and might be at lower risk of mental illness than pet-free city dwellers (Hackle et al., 2018).
Stress-related disorders, such as posttraumatic stress disorder (PTSD), are highly prevalent and often difficult to treat. In rodents, stress-related, anxiety-like defensive behavioral responses may be characterized by social avoidance, exacerbated inflammation, and altered metabolic states. In the lab, we have shown that, in rodents, subcutaneous injections of a heat-killed preparation of the soil-derived bacterium Mycobacterium vaccae promotes stress resilience effects that are associated with immunoregulatory signaling in the periphery and the brain (Loupy et al., 2020). This brings us one step closer to developing a microbe-based “stress vaccine” which could be given to first responders, soldiers and others in high-stress jobs to help them fend off the psychological damage of stress. This finding should also encourage us to spend more time in nature for better quality of life.
Böbel TS, Hackl SB, Langgartner D, et al. Less immune activation following social stress in rural vs. urban participants raised with regular or no animal contact, respectively. Proc Natl Acad Sci U S A. 2018;115(20):5259-5264. doi:10.1073/pnas.1719866115
Loupy, K. M., Cler, K. E., Marquart, B. M., Yifru, T. W., D'Angelo, H. M., Arnold, M. R., Elsayed, A. I., Gebert, M. J., Fierer, N., Fonken, L. K., Frank, M. G., Zambrano, C. A., Maier, S. F., & Lowry, C. A. (2020). Comparing the effects of two different strains of mycobacteria, Mycobacterium vaccae NCTC 11659 and M. vaccae ATCC 15483, on stress-resilient behaviors and lipid-immune signaling in rats. Brain, behavior, and immunity, S0889-1591(20)31363-5. Advance online publication. https://doi.org/10.1016/j.bbi.2020.09.030
Hi Tumim! Awesome post. This is so interesting! It makes me wonder how many health benefits we are missing out on due to modern day living... This post reminded me of something I learned about when I was younger.
ReplyDeleteIn Hindu culture, many of us choose to be vegetarian or at minimum, not eat beef. As a result, many Hindu women have low iron levels due to this diet and menstruation. Low iron levels can also result from low consumption of poultry, which again coincides with their diet (Moschonis et al., 2013). I found out later that many Hindus chose to cook their food in specifically iron cast skillets back in the day to make up for this deficiency and ingest higher amounts of dietary iron. Pretty interesting that they were able to catch and come up with solutions to these things, even so long back!!
Overall, it seems that old is gold!!
Moschonis, G., Papandreou, D., Mavrogianni, C., Giannopoulou, A., Damianidi, L., Malindretos, P., Lionis, C., Chrousos, G. P., & Manios, Y. (2013). Association of iron depletion with menstruation and dietary intake indices in pubertal girls: the healthy growth study. BioMed research international, 2013, 423263. https://doi.org/10.1155/2013/423263