Today I have fallen down a hand-washing rabbit hole. What I both love and hate about microbial research is that it is far from straight-forward. And the topic of microbes and hand-washing is no exception. Read on for more detail.
In the past, the approach to hand hygiene has been to kill as many bacteria as possible in an indiscriminate fashion in order to prevent us spreading the disease-causing bacteria (pathogens). But with our growing understanding of just how important microbes are for health, we now know that a blanket approach to ridding our hands of bacteria is not a good plan. Our skin is an incredible interface with bacteria. It is literally covered in them, all sorts of them. Our immune system interacts with these bacteria and the substances that they produce. Our skin bacteria are an important part of having healthy skin and of having a healthy immune system.
I now think of my skin as ending at the outer edge of my microbial covering, even though this is invisible to me. This applies to the skin on every part of my body – in every nook and cranny. But today I am concentrating on hands.
Our hands support the greatest bacterial diversity and the most dynamically changing community of any other body site and our left hand differs greatly from our right. They are separate and distinct microbial ecosystems.
In light of this dawning of microbial understanding, the aim now, at a scientific level, is to reduce the speed of transmission of pathogenic bacteria between humans in order to reduce disease rather than just trying to KILL THEM ALL. A targeted approach. I am hoping our cultural view will catch up soon, for the sake of our skin health and our general health.
But whether certain bacteria are helpful or harmful is not clear-cut. Many varying circumstances can influence whether a bacterium is helpful, harmful or simply commensal (doing no harm). And often, it can be the presence of other bacteria that prevent helpful or commensal bacteria taking an opportunity to become harmful. There is a synergy between bacteria. A complex inter-relationship that we are only just starting to learn about. Which means that trying to get rid of them all can actually create opportunities for pathogenic domination. This knowledge also means it is going to be a complex process designing soaps/washes that only kill the genuinely harmful ones because it is not always entirely clear which ones those are. Despite this, a number of organisations are on the case.
So where does this leave us in terms of washing our hands? Well, it is still a good idea to do so after going to the loo and before eating food – ideally with soap and water. The anti-bacterial solutions, to me, are a step too far unless you are about to conduct surgery. And too much hand washing can affect skin health – by upsetting microbial balance but also through lotions and potions and water affecting the skin itself.
How well we dry our hands also appears to be very influential in terms of passing on bacteria. We need to dry our hands. The WHO and CDC recommend using paper towels. Of course, paper towels aren’t sterile. Hand driers are supposed to be designed to reduce the risk of redistribution of microbes to hands but there is concern that such rapid air movement may be acting as a microbial aerosol, spraying hand and environment microbes towards us at force. Which may or may not turn out to matter, but it doesn’t sound appealing to me. As I said at the outset, the research isn’t straight-forward but when out and about, I avoid the soggy well-used fabric towels, tend not to use hand driers and prefer paper towels or loo roll for hand drying.
Wash your hands, but not too often. Always wash them thoroughly before eating and after going to the toilet. And dry your hands but not on the tea towel! Change your hand towels regularly at home. And remember that our microbes are an integral part of us and should be treated as such.
Cleanliness In Context: Reconciling Hygiene With A Modern Microbial Perspective: Roo Vandegrift et al 14 July 2017 Microbiome 20175:76