THE MICROBIOME AND DISEASE
Globalization, which is the fusing of disparatetrade agreements, communications,economies, technologies, and cultures,1 hassignificantly changed humans’ environments, diets,and overall health. The term “globesity” refersto the shift from traditional, localized diets to aWestern diet, known as “nutrition transition.”2Research has shown that increasing globalizationby one standard deviation often results in a 23.8%increase in obesity and a 4.3% rise in calorieintake.3 Integrating Western habits alters lifestyles,demographics, and economic conditions in waysthat promote obesogenic environments. Globaltrade agreements facilitate the consumption ofhighly-processed foods in lieu of traditional fare,such as fruits, vegetables, and raw foods.
As aresult, communities across the world are eatingmore high-fat, high-sugar foods, as well as largerquantities of meat than before.4Historically, the digestive tract’s microbialecosystem was tailored for a specific geographicarea, much as the flora and fauna of an ecosystemare geographically distinct.5 However, the rise ofglobalization has spurred a mass transition of theEuropean and American microbiome worldwide,altering the unique digestive patterns and processesof other nations, which has, arguably, caused aglobal rise in obesity.6 For example, Westernmicrobiomes consist of 15% to 30% fewer speciesthan non-Western microbiomes7 and researchshows that lower gut microbiome diversity isassociated with weight gain.
8 Therefore, it is fairto partially attribute our global obesity epidemicto the decrease in microbial diversity because ofa larger adaptation of a Western diet.The “disappearing microbiome hypothesis”has been used to describe how technological andcultural changes accompanying industrializationhas lead to a “disappearing microbiome”.
9 Bacteriain the genus Treponema, which appears in thestool of numerous non-Western populations, forexample, does not appear in the microbiomes ofthose in Western civilizations.10Additionally, Western microbiomes generallybear a greater amount of Bacteroides, while non–Western microbiomes generally contain greateramounts of Firmicutes and Proteobacteria,11 andthe ratio of these phyla has been associated withthe development of obesity.12After the age of three, the adult microbiomedevelops and becomes highly-resistant to changeson a short-term basis.
However, long-term dietaryshifts can result in significant impacts and canpotentially harm future generations. As we age andour health deteriorates, the stability and diversity ofthe gut microbiota declines, which major changesto diet can exacerbate and accelerate.13Long-term diet studies have shown that humanscan alter the ratio of Bacteroidetes and Firmicutesby consistently consuming different foodsabnormal to our environments.
14 Additionally,evidence shows that our diet shapes the relativeabundance of dominant phyla in our systems andthe composition of macronutrients that we consumeinfluence specific bacterial groups.15This Western dietary shift can significantlyimpact developing nations, which are moresusceptible to obesity and other diseases.
Low-cost,easily-accessible packaged food also decreases theneed for physical activity and as these populationsstart eating differently, it can significantly harm theirgut biome and lead to other health complications.16While more research is needed to better assesshow globalization causes the microbiome to shift,it’s evident that people in developing areas lackthe necessary resources and education to informthem how consuming these processed, high-fat,and high-sugar Westernized foods can compromisetheir overall health.