A Catastrophic Biodiversity Loss in the Environment Is Being Replicated on the Skin Microbiome: Is This a Major Contributor to the Chronic Disease Epidemic?

Abstract

There has been a catastrophic loss of biodiversity in ecosystems across the world. A similar crisis has been observed in the human gut microbiome, which has been linked to "all human diseases affecting westernized countries". This is of great importance because chronic diseases are the leading cause of death worldwide and make up 90% of America's healthcare costs. Disease development is complex and multifactorial, but there is one part of the body's interlinked ecosystem that is often overlooked in discussions about whole-body health, and that is the skin microbiome. This is despite it being a crucial part of the immune, endocrine, and nervous systems and being continuously exposed to environmental stressors. Here we show that a parallel biodiversity loss of 30-84% has occurred on the skin of people in the developed world compared to our ancestors. Research has shown that dysbiosis of the skin microbiome has been linked to many common skin diseases and, more recently, that it could even play an active role in the development of a growing number of whole-body health problems, such as food allergies, asthma, cardiovascular diseases, and Parkinson's, traditionally thought unrelated to the skin. Damaged skin is now known to induce systemic inflammation, which is involved in many chronic diseases. We highlight that biodiversity loss is not only a common finding in dysbiotic ecosystems but also a type of dysbiosis. As a result, we make the case that biodiversity loss in the skin microbiome is a major contributor to the chronic disease epidemic. The link between biodiversity loss and dysbiosis forms the basis of this paper's focus on the subject. The key to understanding why biodiversity loss creates an unhealthy system could be highlighted by complex physics. We introduce entropy to help understand why biodiversity has been linked with ecosystem health and stability. Meanwhile, we also introduce ecosystems as being governed by "non-linear physics" principles-including chaos theory-which suggests that every individual part of any system is intrinsically linked and implies any disruption to a small part of the system (skin) could have a significant and unknown effect on overall system health (whole-body health). Recognizing the link between ecosystem health and human health allows us to understand how crucial it could be to maintain biodiversity across systems everywhere, from the macro-environment we inhabit right down to our body's microbiome. Further, in-depth research is needed so we can aid in the treatment of chronic diseases and potentially change how we think about our health. With millions of people currently suffering, research to help mitigate the crisis is of vital importance.

Keywords: biodiversity; butterfly effect; catastrophic biodiversity loss; chaos theory; chronic disease epidemic; entropy; microbiome; skin allergy epidemic; skin microbiome.

Figure 1

A graph showing the comparative biodiversity benchmarks for different skin health states taken from previous work [55]. For an in-depth explanation and background on each, please refer to the original study. The skin of individuals in basic settlements with limited urbanized practices is reduced in biodiversity by 25% compared to Amerindians, and even individuals with the healthiest skin in Western environments, labeled “Western-Healthy,” exhibit a 30% reduction in biodiversity compared to the “Agrarian-Healthy” skin of Amerindians. The decrease falls further to 51% for individuals with diabetes but without skin lesions, 64% for diabetic individuals with skin wounds, and an alarming 84% reduction in biodiversity for individuals with skin diseases in the Western world.

Figure 2

A comparison of biodiversity loss as percentages for the gut and skin microbiome.

Figure 3

Factors thought to be contributing to the large reduction in biodiversity in the skin microbiome of people in the urbanized, developed world.

Figure 4

Global causes of death from 1990 to 2016. (A) shows that 57% of global deaths in 1990 were from chronic or “communicable” diseases, compared to 33% for “communicable”, maternal, neonatal, and nutritional diseases, and 10% for injuries. (B) shows that these percentages for the same categories in 2016 were 72%, 19%, and 9%, respectively. (C) shows that these percentages for the same categories in 2016 were 74% and 26% for the combined last two categories, as the data was unclear. The data to make (A,B) was taken from Anderson and Durstine, 2019 [139], and (C) from the 2022 report from the World Health Organization (WHO) called “Noncommunicable Diseases: Progress Monitor 2022” [4].

Figure 5

Health statistics graphs for the USA created from data collated in the report “Health, United States 2019” [140]. Graph (A) shows the infant mortality rate in the USA, measured in deaths per one thousand infants. It decreased from 29.2% in 1950 to 5.7% in 2018. Graph (B) shows the life expectancy at birth for people living in the USA, split into male and female numbers, as well as an overall average. It increased from 47.3% in 1900 to 78.7% in 2018. Graph (C) shows the total healthcare expenditure per person in the USA, which increased from $2009 in 2008 to $3076 in 2018.

Figure 6

Graph (A) shows childhood reported eczema prevalence rates in the United Kingdom, which rose from 5.1% in 1946 to 20% in 2012. Data was taken from three sources [141,143,149]. Graph (B) shows the percentage of children aged 0–17 years who reported an allergic condition in the past 12 months from 1997–2011 in the USA. It shows a significant linear increase for food and skin allergies; however, skin allergies seem to be accelerating at a faster rate. Graph (B) was adapted from SOURCE: CDC/NCHS, Health Data Interactive, National Health Interview Survey, https://www.cdc.gov/nchs/data/databriefs/db121.pdf (accessed on 26 June 2023) [150]. Graph (C) shows the percentage of adults with a diagnosed seasonal allergy (25.7%), eczema (7.3%), food allergy (6.2%), or any allergic condition (31.8%) in the United States in 2021 [151]. The criteria for adults counted as having an allergic condition included being diagnosed with one or more of the three conditions shown in the graph. There is some overlap between the three conditions, and the estimated percentages are taken from interviews with a sample of the civilian population in America.

Figure 7

(A) shows a simplified version of the potential outcomes associated with biodiversity loss in the skin microbiome. It is important to note that more work needs to be conducted to establish causality and that many outcomes may affect each other. (B) shows a map of the diseases associated with reduced biodiversity in the skin microbiome, along with the potential mechanisms of disease development, and finally the diseases in which the literature describes the skin microbiome as potentially playing an active role in their development.

Figure 8

The stable system shown in (a) (here representing an ecosystem with increased biodiversity) needs a much larger energy input to move from its current state. Stability refers to the resilience of a system against external factors and changes that impact the system. For the unstable system shown in (b) (here representing an ecosystem with reduced biodiversity), a smaller external energy input is needed for it to be able to move from its current state to another state.