THE MICROBIOME AND DISEASE, SERIES #7

Skylar Steinberg

Sabine Hazan

Globalization, which is the fusing of disparate
trade agreements, communications,
economies, technologies, and cultures,1 has
significantly changed humans’ environments, diets,
and overall health. The term “globesity” refers
to the shift from traditional, localized diets to a
Western diet, known as “nutrition transition.”2
Research has shown that increasing globalization
by one standard deviation often results in a 23.8%
increase in obesity and a 4.3% rise in calorie
intake.3 Integrating Western habits alters lifestyles,
demographics, and economic conditions in ways
that promote obesogenic environments. Global
trade agreements facilitate the consumption of
highly-processed foods in lieu of traditional fare,
such as fruits, vegetables, and raw foods. As a
result, communities across the world are eating
more high-fat, high-sugar foods, as well as larger
quantities of meat than before.4
Historically, the digestive tract’s microbial
ecosystem was tailored for a specific geographic
area, much as the flora and fauna of an ecosystem
are geographically distinct.5 However, the rise of

globalization has spurred a mass transition of the
European and American microbiome worldwide,
altering the unique digestive patterns and processes
of other nations, which has, arguably, caused a
global rise in obesity.6 For example, Western
microbiomes consist of 15% to 30% fewer species
than non-Western microbiomes7 and research
shows that lower gut microbiome diversity is
associated with weight gain.8 Therefore, it is fair
to partially attribute our global obesity epidemic
to the decrease in microbial diversity because of
a larger adaptation of a Western diet.
The “disappearing microbiome hypothesis”
has been used to describe how technological and
cultural changes accompanying industrialization
has lead to a “disappearing microbiome”.9 Bacteria
in the genus Treponema, which appears in the
stool of numerous non-Western populations, for
example, does not appear in the microbiomes of
those in Western civilizations.10
Additionally, Western microbiomes generally
bear a greater amount of Bacteroides, while non–
Western microbiomes generally contain greater
amounts of Firmicutes and Proteobacteria,11 and
the ratio of these phyla has been associated with
the development of obesity.12
After the age of three, the adult microbiome
develops and becomes highly-resistant to changes

on a short-term basis. However, long-term dietary
shifts can result in significant impacts and can
potentially harm future generations. As we age and
our health deteriorates, the stability and diversity of
the gut microbiota declines, which major changes
to diet can exacerbate and accelerate.13
Long-term diet studies have shown that humans
can alter the ratio of Bacteroidetes and Firmicutes
by consistently consuming different foods
abnormal to our environments.14 Additionally,
evidence shows that our diet shapes the relative
abundance of dominant phyla in our systems and
the composition of macronutrients that we consume
influence specific bacterial groups.15
This Western dietary shift can significantly
impact developing nations, which are more
susceptible to obesity and other diseases. Low-cost,
easily-accessible packaged food also decreases the
need for physical activity and as these populations
start eating differently, it can significantly harm their
gut biome and lead to other health complications.16
While more research is needed to better assess
how globalization causes the microbiome to shift,
it’s evident that people in developing areas lack
the necessary resources and education to inform
them how consuming these processed, high-fat,
and high-sugar Westernized foods can compromise
their overall health.

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