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Modern Diet and the Evolutionary Process
Modern diet and our eating habits have made a considerable impact on our evolution. A recent study conducted by scientists to examine the evolution of our teeth over the past 7500 years shows that modern day human beings have less diverse oral bacteria than our predecessors. Scientists believe this to be the cause for the high prevalence of chronic oral diseases in the current era.
The study was conducted by researchers from the University of Adelaide, Australia, University of Aberdeen, Scotland, and the Wellcome Trust Sanger Institute, Cambridge, England and was published in Nature Genetics. As part of the study, the researchers analyzed the DNA of calcified bacteria found in the teeth of humans ranging from prehistoric times to the modern day. This has helped them analyze the diet evolution and behavior of human beings.
The study was led by Professor Alan Cooper who pointed out that this was the first study spanning 7500 years which analyzes the evolution and changes in bacteria and their health consequences.
To study the effect of changes in diet pattern of humans, 34 European skeletons, ranging between the ages of 20 and 60 and dating from Mesolithic to Medieval times were analyzed. The ancient microbial DNA present in the calcified dental plaque was examined. The researchers also sequenced the currently known form of oral pathogens, namely Streptococcus mutans and Porphyromonas gingivalis.
When human beings transitioned from the hunter-gatherer stage to farming, consumption of more barley, wheat, and sugar started to change the oral ecosystem, and more of gum-disease causing bacterial species started to flourish.
With the beginning of the Industrial Revolution, when humans started eating processed sugar and flour, the oral ecosystem changed once again and more of decay-causing bacterial species started to flourish in our mouths.
With each major change in eating habits, the diversity of oral ecosystem declined dramatically. A greater diversity of ecosystem signifies a more resilient and healthy ecosystem. Therefore, a gradually declining oral biodiversity can explain the high prevalence of dental diseases in modern human beings. The study further highlights the mismatch between our modern diets and the rate of gum diseases and tooth decay. It also highlights the point that our bodies are more adapted to our evolutionary lineage and have not completed adapted to this changed environment that we have ended up creating for ourselves.