Lower BMI equals fewer nasal bacteria in men

Researchers from the University of Wroclaw have found a link between body mass index (BMI) and the number of bacteria colonising noses. Their study has been published in the American Journal of Human Biology.

“According to an evolutionary point of view, traits related to attractiveness are supposed to be honest signals of biological quality,” said Dr Boguslaw Pawlowski. “We analysed whether nasal and throat colonisation with potentially pathogenic bacteria is related to body height and BMI in both sexes.”

103 healthy females and 90 healthy males participated in the study, which Dr Pawlowski believes is “the first attempt to study body morphology traits related to physical attractiveness in relation to bacterial colonisation in young people”. Six potentially pathogenic species of bacteria, the most common being Staphylococcus aureus, were isolated and identified from nasal and throat swabs.

The results showed that ‘colonised’ men were found to have a higher BMI than non-colonised males, while colonised women had lower waist-to-hip ratios. The researchers thus concluded that their hypothesis was confirmed, but only for BMI in males.

“This result and a higher WHR in non-colonised females indicate higher immunocompetence of those who bear the costs of higher levels of testosterone, which according to previous studies is correlated negatively to BMI in males and positively to WHR in females,” they said.