Maladaptation to modern diets has been implicated in several chronic disorders.Given the higher prevalence of disease such as dental caries and chronic gum diseases in industrialized societies, we sought to investigate the impact of different subsistence strategies on oral health and physiology, as documented by the oral microbiome. To control for confounding variables such as environment and host genetics, we sampled saliva from three pairs of populations of hunter-gatherers and traditional farmers living in close proximity in the Philippines. Deep shotgun sequencing of salivary DNA generated high-coverage microbiomes along with human genomes. Comparing these microbiomes with publicly available data from individuals living on a Western diet revealed that abundance ratios of core species were significantly correlated with subsistence strategy, with hunter-gatherers and Westerners occupying either end of a gradient of Neisseria against Haemophilus, and traditional farmers falling in between. Species found preferentially in hunter-gatherers included microbes often considered as oral pathogens, despite their hosts' apparent good oral health. Discriminant analysis of gene functions revealed vitamin B5 autotrophy and urease-mediated pH regulation as candidate adaptations of the microbiome to the hunter-gatherer and Western diets, respectively. These results suggest that major transitions in diet selected for different communities of commensals and likely played a role in the emergence of modern oral pathogens.
K E Y W O R D Sdiet, hunter-gatherers, metagenomics, oral microbiome, Philippines
Body checking includes any behavior aimed at global or specific evaluations of appearance characteristics. Men and women are believed to express these behaviors differently, possibly reflecting different socialization. However, there has been no empirical test of the impact of gender on body checking. A total of 1024 male and female college students completed two measures of body checking, the Body Checking Questionnaire and the Male Body Checking Questionnaire. Using multiple group confirmatory factor analysis, differential item functioning (DIF) was explored in a composite of these measures. Two global latent factors were identified (female and male body checking severity), and there were expected gender differences in these factors even after controlling for DIF. Ten items were found to be unbiased by gender and provide a suitable brief measure of body checking for mixed gender research. Practical applications for body checking assessment and theoretical implications are discussed.
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