The modernization of our society has changed many aspects
of how we live our day to day lives—but it’s safe to say that once we change the
external, the internal can change too! The earth is experiencing what we now classify
as an Anthropocene; the global time period from which humans have taken over
the Earth. From damaging our ecosystems with the industrialization of cities,
to the destruction of the ozone layer, our activities have altered natural
processes such as climate change and the “way nutrients move in our ecosystem,
such as nitrogen and phosphorus”. Over the past few centuries, humans have
fought an ongoing battle to defeat germs and bacteria. Despite our pronounced
efforts to improve sanitation and free ourselves from disease—medical establishments
have seen the contrary—”A staggering increase in allergies and autoimmune
diseases in the industrialized world.” While some like to blame that we were
once deprived of the necessary bacteria to develop our immune systems as
children—this theory lacks hard evidence between the exposure to pathogens and
immunological response systems. With our growing knowledge on microbial health
and the numerous studies conducted, researchers have come up with a better
theory that does not blame one factor to the rise of allergy and disease but all factors—the “disappearing
microbiota” theory. This theory takes into account all the ways we have
modernized our society and how it has potentially affected the health of our
microbiomes. Pollution, modern birth practices, exposure to antibiotics and modern
dietary patterns are a few of the many factors that have contributed to
altering our microbial systems. When our gut health suffers, our bodies are not
properly equipped with enough of the healthy microbes to fight off whatever
wants to attack. External factors in the environment (such as the ones
previously listed) have also been accounted for in altering the composition of
our microbes. This in turn, depletes us from reaping the benefits of what once
was a symbiotic relationship between the human and its gut microflora.
According to a CDC publication made in 2016 in reference to data
from the Journal of American Health Association (JAMA), at least 30 percent of
antibiotics prescribed in the United States are unnecessary.
Even more surprisingly, a recent publication made by the WHO (World Health
Organization) on January 29th, 2018 revealed a study that demonstrated
high levels of antibiotic resistance worldwide.
Resistance was found in 500,000 people amongst 22 countries. If this still
doesn’t surprise you, most of these new resistant strains of bacteria are
amongst the most common and potentially dangerous such as Escherichia coli, Staphylococcus aureus, and
does this indicate?
misusing and overusing antibiotics. As a result, our microbiomes are getting
weaker, the bacterial infections are getting stronger, and we are now more
prone to infection—infection that will be a lot harder to fight off than before.
Recovery of the gut microflora from antibiotic treatment can take an extensive
amount of time depending on the type of antibiotic being used. Conclusively, antibiotics
should only be used when necessary to avoid the further deterioration of our
gut microflora and the development of more antibiotic-resistant strains of
Epidemic with Diet patterns
Our society has experienced a large spike in obesity worldwide along
with its associated disorders. While sedentary lifestyles and excess calorie
intake have gotten must of the bad wrap, our microbiota hasn’t been getting any!
The truth is, studies have shown a strong link between obesogenic diets and the
negactive impact it plays on our microbiomes. “Changes in diet can account for
57% of the variations in microbiota.” A study was conducted by Turnbaugh et al.
on mice gavaged with human feces to study the correlation between diet and the
human microbiota. The study consisted of two groups of mice—one group fed a
vegetarian diet and the other a western diet consisting of high-fatty foods.
Results proved that the mice fed with the western diet had increased numbers of
bacteria associated with the Firmicutes
phyla and a large decrease in one of the four most dominant bacterial phyla in the
human gut–Bacteroides spp. The shift
in gut community for mice being fed the Western diet was evident, so much so,
scientists were able to notice within a day.
So what? We get a new phyla of gut bacteria with a new diet—but what
harm can the change of composition of a microbe do to our bodies?
It’s important to really consolidate the fact that gut bacteria
such as the Bacteroides spp. are dominant for a reason, they are meant to regulate
certain processes in the body and any change in composition to the natural
order in which our body is meant to run can mean serious implications on our
health. Here’s why….
The Bacteroides spp. is responsible for producing GLP-2, an
intestinal peptide that prevents lipopolysaccharide (LPS) from entering our
plasma by protecting the gut and making sure food is digested properly. With
decreased levels of GLP-2 caused by the Firmicutes
phyla, we are likelier to get higher levels of LPS plasma concentration and
what we now know as a “leaky gut”. A
leaky gut can translate to serious health complications, as the increased
permeability of the gut (the “leakiness”) may permit toxins to flow out of our
intestines and into our blood stream!
It is important we keep ourselves properly informed on how
obesogenic diets affect not just our weight and energy levels but also our
microbiomes. A simple change in the composition of our microbes can be one of
the leading resulting causes of disease in obese individuals.
births—Modern day birth and its effect on our microbiome
New research has also demonstrated how modern birth practices are
depriving offspring of necessary microbes normally obtained through vaginal
births. “The necessary microbes destined for the gut microbiota originate from
the maternal birth canal and rectum.” A newborn conceived through Caesarean
section will miss out on these microbes and will instead receive its gut
microbes from the mother’s skin and hospital environment. Consequently, hours
and days after the newborn is conceived, a newborn conceived through Caesarean
section is likelier to be exposed to unfamiliar possibly even harmful bacteria
that can pose a threat to the newborn’s undeveloped immune system. The newborn
will also be deprived of healthy probiotic bacteria normally obtained after
conception through traditional birth practices that is critical to the
development of the immune system. These critters won’t arrive until much later
and in smaller quantities for caesarean section babies. Conclusively, modern
birth practices can pose a real threat to the immune system of newborns due to
the deprivation of important gut bacteria obtained through traditional birth
Finally, we have pollution—one of the most obvious of the four. It
is pretty obvious to see the effects on how industrialization has done its
collateral damage–from carbon emissions to industrial waste to harming the ozone
layer, not only are we polluting the external world but also our internal worlds.
Our microbiomes have been greatly affected by the pollution of our Earth. For
purposes of keeping things short, I will only focus on air pollution,
specifically a key component which has done a great deal of harm to our
microbiomes. “Air pollution consists of a heterogenous mixture of different
substances, including gases.” This key pollutant that has greatly affected our
microbiomes has been the exposure to Particulate matter (PM). Studies have
shown that the inhalation of Particulate matter is discarded from the lungs and
into the intestine. PM has also polluted our food and water supply, causing
even more damage to our intestine. Ingestion of PM has also demonstrated its
effects on changing the composition of gut bacteria—a study conducted on mice
resulted in dereased amounts of of Bacteroidetes, Firmicutes, and Verrucomicrobia as well as changes
in the short chain fatty acid production. Not only does it change our microbes but studies
on Particulate matter have reported to have significant effects on increasing
intestinal permeability—this can lead to inflammation of the gut and result in
diseases such as IBD.