Listen, I don’t know about you, but my grandma was right about a lot of things.

I’m lucky mine was around long enough for me to realize that and realize soak up all she had to say.

And when she told you to focus on some key areas while washing up, well?

She was right about that, too.

The “Grandmother Hypothesis” is the theory that people tend to miss several key areas while washing, which leaves their microbiome lacking.

Recently, a team from the George Washington University Computational Biology Institute was investigating the skin microbiome of healthy people. They focused on variations across skin areas, like between the often washed arms, and often ignored navel and behind the ears.

Keith Crandall, who was part of a statement.

“My grandmother always told me to scrub behind the ears, between the toes, and in the belly button.”

He wondered whether or not these areas might contain different types of bacteria, since they are more often neglected.

129 graduate and undergraduate students collected samples for the study, focusing on their calves and forearms, behind their ears, between their toes, and in their navels.

The same students were taught to sequence the DNA in these samples and to compare them.

Crandall’s grandma – and everyone else’s – was right.

“Dry skin regions (forearms and calves) were more even, richer, and functionally distinct than sebaceous (behind the ears) and moist (belly button and between the toes) regions.”

They did not find any significant differences in gender, ages, or ethnicities.

“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.”

Your skin microbiome is important, and when the balance is off, diseases like eczema or acne could result.

So listen to your granny, y’all.

She knows what she’s talking about, even if she doesn’t know why.

If you thought that was interesting, you might like to read about why we should be worried about the leak in the bottom of the ocean.