Strictly speaking, there are many reasons to listen to what your grandparents have to say – they’ve been around the block, after all.

That said, if you’ve been tempted to dismiss their advice on hygiene, this study says you might want to think again.

A team of scientists from George Washington University Computational Biology Institute was looking into the skin microbiome of healthy individuals.

They were focusing on the variations between different areas, like places your normally would wash (arms, shoulders, etc) and those you might forget, like your belly button or behind your ears.

Keith Crandall, a director there, recalled his own grandmother’s advice in a statement.

“She always told me to scrube behind the ears, between the toes, and in the belly button.”

The 129 graduate and undergraduate students in their study turned over samples from their calves and forearms, behind their ears, between their toes, and in their navels.

They compared the oily, neglected area samples to those collected from dry, cleaner areas.

Crandall’s grandma (and probably yours) was right – the cleaner, drier areas contained a healthier collection of microbes than the neglected ones.

“Dry skin regions were more even, richer, and functionally distinct than the sebaceous and moist regions. Within skin regions, bacterial alpha- and beta-diversity also varied significantly for some of the years compared, suggesting that skin bacterial stability may be region and subject dependent.”

Microbes are important to our health, so a shift toward more harmful bacteria could cause things like eczema or acne.

This is one of many studies looking into the relationship we have with our microbiome and how much it affects all areas of our health.