Impact of Chewing Betel Nut on the Oral Microbiome

Consumption of betel nut products dates back thousands of years, and is current common practice across South Asia and Oceania. In recent years, the World Health Organization (WHO) has publicly stated that betel quid products pose a substantial health threat to the populations that consume them. The International Agency for Research on Cancer has long determined that betel quid without tobacco is carcinogenic to humans, and areca nut is carcinogenic to humans. Conclusions were drawn from strong evidence of betel nut causing precancerous oral submucosal fibrosis (OSF) conditions, as well as sufficient evidence of carcinogenicity in animals. Importance of local microbiome composition and its contribution to disease status in humans has become a topic of increased investigation, specifically with regard to gastrointestinal cancer. The effects of chewing betel nut on the composition of the oral microbiome have not been studied. Due to recent advancements in technology, oral microbiomes can be analyzed effectively with a combination of the Polymerase Chain Reaction (PCR) technique and next-generation sequencing hardware and software. This study assessed the microbiome diversity within samples taken from betel nut chewers and controls, and additionally compared microbial composition between samples. The initial results of α-diversity tests indicate that chewing betel quid appears to increase the species diversity in the oral microbiome. Comparisons between samples for β-diversity analysis indicated that the control samples contained oral microbiomes that were much more closely related than the samples taken from betel quid chewers. Early findings suggest chewing betel quid does correlate with a microbial composition shift, which may play a role in development of oral cancer.