The changing microbial landscape of Western society: Diet, dwellings and discordance

Abstract

BackgroundThe last 50–100 years has been marked by a sharp rise in so-called “Western-diseases” in those countries that have experienced major industrial advances and shifts towards urbanized living. These diseases include obesity, type 2 diabetes, inflammatory bowel diseases, and food allergies in which chronic dysregulation of metabolic and/or immune processes appear to be involved, and are likely a byproduct of new environmental influences on our ancient genome. What we now appreciate is that this genome consists of both human and co-evolved microbial genes of the trillions of microbes residing in our body. Together, host–microbe interactions may be determined by the changing diets and behaviors of the Western lifestyle, influencing the etiopathogenesis of “new-age” diseases.Scope of reviewThis review takes an anthropological approach to the potential interplay of the host and its gut microbiome in the post-industrialization rise in chronic inflammatory and metabolic diseases. The discussion highlights both the changes in diet and the physical environment that have co-occurred with these diseases and the latest evidence demonstrating the role of host–microbe interactions in understanding biological responses to the changing environment.Major conclusionsTechnological advances that have led to changes in agriculture and engineering have altered our eating and living behaviors in ways never before possible in human history. These changes also have altered the bacterial communities within the human body in ways that are seemingly linked with the rise of many intestinal and systemic metabolic and inflammatory diseases. Insights into the mechanisms of this reciprocal exchange between the environment and the human gut microbiome may offer potential to attenuate the chronic health conditions that derail quality of life. This article is part of a special issue on microbiota.

Gut microbiota and glucometabolic alterations in response to recurrent partial sleep deprivation in normal-weight young individuals

“…The last two decades have revealed an increasingly important role of the gut microbiome for human health [1], [2], [3]. Differences in intestinal microbiota composition have been uncovered between healthy controls and those suffering from various diseases, including metabolic pathologies such as obesity, the metabolic syndrome and type-2 diabetes mellitus (T2DM) [4], [5], [6].…”

The role of the brain–gut–microbiota axis in psychology: The importance of considering gut microbiota in the development, perpetuation, and treatment of psychological disorders

“…When discussing the role of GM in behavior, health, and disease, it is important to pay respect to the intertwined coevolution between humans and our resident microbes. It is suggested that the sharp increase in various disease states over the last 50–100 years (Campell, ; Linneberg et al, ) can be, at least in part, explained by relatively recent dietary and lifestyle changes in the context of human evolution (Broussard & Devkota, ). Currently, humans, particularly those in industrialized countries, are living in an environment to which they have not adaptively evolved (Gluckman, Low, Buklijas, Hanson, & Beedle, ).…”

“…Currently, humans, particularly those in industrialized countries, are living in an environment to which they have not adaptively evolved (Gluckman, Low, Buklijas, Hanson, & Beedle, ). An unintended consequence of industrialization, these changes are putting the GM under evolutionary pressure to shift from a previously mutualistic relationship with their human host to a more antagonistic one (Broussard & Devkota, ; Quercia et al, ). This is due to human evolution requiring significantly more time (Uyeda, Hansen, Arnold, & Pienaar, ) compared to single‐celled organisms such as GM that evolve and adapt to environmental and internal states much more rapidly (within as little as 24 hr; David et al, ; Wu et al, ).…”

“…A continued loss of fiber from the Western diet will inevitably lead to continued depletion of short‐chain fatty acids (SCFAs; Broussard & Devkota, ) with downstream effects on the development and perpetuation of psychological illnesses through their immunoregulatory effects (Rogers et al, ). SCFAs (acetic, butyric, and propionic acids in particular) are one of the main metabolites of GM (Carabotti et al, ; Smith et al, ).…”

“…changes are putting the GM under evolutionary pressure to shift from a previously mutualistic relationship with their human host to a more antagonistic one (Broussard & Devkota, 2016;Quercia et al, 2014). This is due to human evolution requiring significantly more time (Uyeda, Hansen, Arnold, & Pienaar, 2011) compared to singlecelled organisms such as GM that evolve and adapt to environmental and internal states much more rapidly (within as little as 24 hr ;David et al, 2014;Wu et al, 2011).…”