Scientists test ‘grandma hypothesis’ and reveal these two places on the body are germ-filled
Maybe Grandma was right all along when she warned you to clean behind your ears and between your toes.
Scientists at George Washington University in Washington DC theorized that these areas could be a haven for bacteria because they are not washed as often as other parts of the body, such as arms and legs.
Keith Crandall, a professor of genomics at the university, recalled that his own grandmother used to tell him to “scrub behind the ears, between the toes and in the belly button.”
Under Professor Crandall, 129 graduate and undergraduate students swabbed themselves behind the ears, toes and in their navels.
Scientists at George Washington University in Washington DC thought that behind the ears, between the toes and in the belly button would be a haven for bacteria because they are not washed as often as other parts of the body.
They did this every January in 2019, 2020, 2022 and 2023, skipping 2021 due to the Covid pandemic.
The team also wiped their forearms and calves as control areas.
They extracted and sequenced the DNA from the skin samples to compare it with microbes, microorganisms such as bacteria, that live in the so-called hotspots compared to the control areas.
Researchers found that there was greater diversity and therefore potentially a healthier collection of microbes on the forearms and calves, compared to the other areas.
A healthier collection could indicate more bacterial species that are less likely to cause disease.
Behind the ears, between the toes and in the belly button it is often moister and warmer, giving bacteria the perfect place to thrive.
When certain bacteria take over the microbiome – the collection of bacteria, fungi and viruses throughout the body – they can shift the balance of health, Professor Crandall said.
If the microbiome shifts in favor of harmful microbes, it can lead to skin diseases such as eczema or acne.
The microbiome varies throughout the body and will consist of bacteria that are both beneficial and potentially harmful.
However, this can be avoided if the areas are thoroughly cleaned, as your grandmother always instructed.
The research was published in the journal last month Frontiers in microbiology.