New research suggests individuals considered ‘physically attractive’ may boast stronger immune systems.
In the US study, individuals rated as attractive had:
- higher rates of phagocytosis of E. coli bioparticles (when certain types of white blood cells destroy microbes and damaged host cells);
- higher basophil white blood cells counts;
- lower neutrophil white blood cells counts.
Female participants rated photos of males with high functioning natural killer (NK) cells – immune cells that defend against viral infections and cancer – as more attractive, suggesting ‘females may prefer males who are well suited to combat viral threats and neoplastic growth’.
Male participants rated photos of females with slower rates of Staphylococcus aureas (S. aureus) growth in their plasma as more attractive than females with faster rates of S. aureas growth; S. aureus is a common bacterium that lives on the skin and in some people’s noses – golden staph can cause a range of mild-to-severe infections.
Noting that scientists who study human evolution have long postulated that individuals considered the most ‘good looking’ may also be healthier, study lead author Summer Mengelkoch told medicalnewstoday.com: ‘It’s long been theorised that this relationship should exist, but no one’s really studied it very directly before.’
Previously researchers have suggested those with ‘faces considered attractive across cultural groups’ may also possess traits linked to being better reproductive partners ‘because they’re healthy with strong immune function’.
For this study, researchers at Texas Christian University recruited 159 participants aged from 17-30 who needed: to be free of chronic medical conditions; have a body mass index (BMI) less than 30; have not suffered acute illness for 2 weeks before the study; not to be taking hormonal contraceptives; be willing to abstain from steroids and anti-inflammatory medicines, exercise and alcohol for 2 days prior to the study; and be willing to fast on the morning of the study.
In addition, females participated during the early follicular phase of their ovulatory cycle, to control the impact of sex steroid hormones on immune function and inflammatory processes.
Participants were photographed from the neck up, while wearing neutral facial expressions and after removing any cosmetics, and then gave a blood sample – which was tested for several factors, including how their peripheral blood mononuclear cells (PBMCs) responded to various immunological stimulants, the functional level of their NK cells, and S. aureus growth in plasma to identify their antibacterial defences.
Then the researchers collected ‘facial attractiveness’ ratings from 492 viewers (259 females, 233 males) aged 18-29 (60% white, 20% black, 12% hispanic, 9% asian).
The viewers rated 25 randomly selected photos of members of the opposite sex on characteristics which included factors such as attractiveness and health.
The study, published in Proceedings of the Royal Society B: Biological Sciences, reported participants identified as ‘attractive’ had higher rates of phagocytosis of E. coli bioparticles – the process by which certain types of white blood cells destroy microbes and damaged host cells.
Those with higher levels of phagocytosis are thought to be less likely to experience microbial infections, and Mengelkoch said this result implies that ‘we might find people who can efficiently deal with bacterial threats to be really attractive’. AMP
