The Oral, Gut Microbiota and Cardiometabolic Health of Indigenous Orang Asli Communities

Abstract

The Orang Asli (OA) of Malaysia have been relatively understudied where little is known about their oral and gut microbiomes. As human health is closely intertwined with the human microbiome, this study first assessed the cardiometabolic health in four OA communities ranging from urban, rural to semi-nomadic hunter-gatherers. The urban Temuan suffered from poorer cardiometabolic health while rural OA communities were undergoing epidemiological transition. The oral microbiota of the OA were characterised by sequencing the V4 region of the 16S rRNA gene. The OA oral microbiota were unexpectedly homogenous, with comparably low alpha diversity across all four communities. The rural Jehai and Temiar PP oral microbiota were enriched for uncharacterised bacteria, exhibiting potential for discoveries. This finding also highlights the importance of including under-represented populations in large cohort studies. The Temuan oral microbiota were also elevated in opportunistic pathogens such as Corynebacterium, Prevotella, and Mogibacterium, suggesting possible oral dysbiosis in these urban settlers. The semi-nomadic Jehai gut microbiota had the highest alpha diversity, while urban Temuan exhibited the lowest. Rural OA gut microbiota were distinct from urban-like microbiota and were elevated in bacteria genera such as Prevotella 2, Prevotella 9, Lachnospiraceae ND3007, and Solobacterium. Urban Temuan microbiota were enriched in Odoribacter, Blautia, Parabacetroides, Bacteroides and Ruminococcacecae UCG-013. This study brings to light the current health trend of these indigenous people who have minimal access to healthcare and lays the groundwork for future, in-depth studies in these populations.

Understanding the Diversity of Human Gut Microbes in Indigenous Populations Across the World

“…Under the same geopolitical boundaries, hunter-gatherer Jehai and agricultural Temiar have similar microbial taxa abundance (Fig. 3), similar results as suggested by the previous study 72 , and show distinctness from the African and North American hunter-gatherers (Fig. 6B).…”

“…This thing might be happened due to the different dietary practices. This assumption resolved by the previously published article 72 , the Temiar frequently consume rice, meat, sh, and plants that they grew such as sweet potato leaves which is more or less similar to the Jehai, on the contrary the Temuan consume a diet with lacking plant ber closely resembled urban Malaysians. The results also suggest that Jakun community of Malaysia exhibit high abundance of Prevotella within their gut microbial composition due to frequent consumption of 'Ulam' (a type of vegetable).…”

“…FASTQ le of 16S rRNA amplicon sequences data of human gut microbiome were downloaded and processed to understand the Gut microbiota diversity and composition of the indigenous populations around the world. The data comprise twenty-one indigenous populations from Southern Africa 49 , Central Africa 48 , East Africa 49 , North America 73 , West Asia 75 , East Asia 78 and Southeast Asia 77,72 with different traditional livelihood practices. Information regarding the geographical location, age, sex, and subsistence pattern of each individual is available in Supplementary Table.…”

Ectopic colonization by oral bacteria as an emerging theme in health and disease

“…For that reason, the composition of the oral microbiota has been widely studied across different geographic areas and life stages and information on its taxonomy and ecology have been summarized and made freely accessible on the Human Oral Microbiome Database website (Dewhirst et al 2010 ) and the Oral Microbiome Bank of China database (Xian et al 2018 ). Nevertheless, it is undeniable that so far, oral microbiome studies have neglected populations from nonindustrialized countries: to date, there are only a few studies on African, Asian, or Indigenous cohorts (Yang et al 2019 , Nath et al 2021 , Yeo et al 2022 , Araújo et al 2023 ). Recent research has clearly shown that the oral bacterial community structures of healthy individuals is distinct from individuals suffering from diseases such as periodontitis, dental caries, oral cancer, IBDs, colonic cancer, and preterm birth (reviewed by Peng et al 2022 ).…”

Nepali oral microbiomes reflect a gradient of lifestyles from traditional to industrialized

“…These studies report that oral microbial diversity decreases with industrialization, with microbiome composition exhibiting differences based on lifestyle as well. More specifically, relative abundances of Neisseria , Haemophilus, Prevotella, and Streptococcus tend to decrease with industrialization [30, 31, 33, 35, 36]. However, several potential confounding factors may underlie the reported differences.…”