Tegan Taylor (1:50)

And so what Ingrid doesn't tell us is what age she is, because if she was 15 or 16, that would work, but I suspect she isn't.

Norman Swan (1:57)

Well, she does say that this does not apply to teenage boys, people doing extreme exercise, or a hot summer's day. But she's asking if you've had a solitary day indoors, is it necessary?

Tegan Taylor (2:09)

Well, this is up your alley, so to speak. There's a history here, isn't there?

Norman Swan (2:12)

There's a cultural lens here. And I think it's interesting to kind of ask ourselves what we're trying to do when we wash ourselves, because when I think about it, I think about wanting to appear groomed, which is a cultural thing. Wanting to not smell, which is a social thing, wanting to feel clean, which I think is something that we're probably conditioned to. And then like, pretty low down on the list is any true health motivation. I think most of it is about how you're perceived by other people.

Tegan Taylor (2:43)

You think? I don't know. I think it's partly health too. But then I'm an obsessive compulsive.

Norman Swan (2:48)

I know that you love brushing your teeth multiple times a day and no shade. I don't think there's anything wrong with showering a lot. I just wonder whether.

Tegan Taylor (2:54)

Well, some people think there is.

Norman Swan (2:56)

Well, yes, there are. And there have been some people who've done some n equals 1 experiments on this. And they're always very like, oh, I did it and I don't smell anymore. And I just wonder whether having gone.

Tegan Taylor (3:07)

Through three years of losing all your.

Norman Swan (3:09)

Friends, everyone else is sort of just taking a couple of steps back from them.

Tegan Taylor (3:13)

Yeah. Well, you should tell us, because you're the history buff on this. What's the history of hygiene? And we should separate this out from what one microbiologist, late Professor Nancy Millison, University of Melbourne, used to say, the project of separating the mouth from the anus. We're not talking about that. In other words, sanitation. We're talking about personal hygiene here. What's the history here? How long.

Norman Swan (3:35)

Oh, gosh, how long do you have? Like, how far back in evolutionary history do we go? Because we've got evidence of microorganisms like single celled organisms back in the beginning of life. We have waste removal systems even in these small organisms. And you see other species having really quite fastidious hygiene habits. Like anyone who owns a cat knows how carefully they groom themselves. You see birds preening themselves, we see apes cleaning each other. And humans have kept ourselves clean in all sorts of different ways over the years. But again, like I say, it's a cultural thing. And so depending on the time or the place that you lived, a lot of the sort of history around this that I could find is very Eurocentric. But a lot of it involves wiping yourself down, maybe with a cloth or a dry cloth, like rubbing yourself down, or perhaps just washing your face and hands and maybe your feet relatively frequently, but hardly ever immersing yourself in a body of water. And apart from cultures like, you know, the Romans who have their baths or the hammams or something like that in the Middle east, getting naked, A, very frowned upon by lots of cultures until very, very recently, and B, the idea of getting your whole body wet all at once is a resource thing that most people didn't have the time or energy for and also was a health risk if you were using dirty water or if you lived somewhere really cold.

Tegan Taylor (5:03)

Yes, but the Roman baths and the hammams, they had other purposes. So the Roman baths is where you did business, it was a social occasion and so on. But we too easily ignore in a sense the ancient wisdom of non Anglo, non Christian traditions. So for example, if the west had accepted smallpox inoculation, which had been done for centuries in places like China and the Middle east, then we would have been spared major smallpox outbreaks. But because it came from the east, it was considered superstition and not effective. And the thing about Haman's is that it was about cleanliness, scrubbing you down, but also about this physiological thing about water. So I'm not sure the hygiene thing is just something about Christian morality, which is what some of the historians argue, that it emerged in the United States in particular that there was some moral superiority about being clean and smelling clean.

Norman Swan (6:00)

Well, even that, even that quote. So it's kind of attributed to John Wesley, but I don't know if it originated with him, this idea of cleanliness being next to godliness. But at that time people weren't bathing full body immersion as the Baptists would say. They were just, they were keeping a clean home and they had clean hands and that sort of thing. So I'm interested, interested to call out the fact that in the more recent history, a lot of the hygiene trends that we've seen in sort of the 20th century are a product of, well, people working more closely together in offices and perhaps having a bit more self consciousness that you really are going to be sitting in quite close quarters with the same people again and again. And capitalism. You can sell soap, you can sell mouthwash. If you make people feel self conscious about something, you can sell them a product.

Tegan Taylor (6:49)

Yeah, and there was a. Peasant classes felt that dirt was protective, sweat was cleansing, and if you had a strong body odor, that was a sign that you were healthy and virile.

Norman Swan (7:01)

I do like that idea that your body odour is somehow connected to your sexual power.

Tegan Taylor (7:06)

Friday night at the nightclub, I'm not sure it was going to work too well. But then you have religious orders, particularly nuns, who did not wash their entire body because it was considered unclean or immoral to do so. So it is a relatively recent phenomenon where we wash ourselves in such a regular way with substances which emulsify the fat on our skin and wash it off so that you are taking the natural fat and organisms off your skin. And dermatologists decry that.

Norman Swan (7:39)

Yeah, I think it's good to remind people how soap actually works. So you think about having an oily fry pan and you put some detergent in it, and you can sort of see the oil kind of run away from it, and as you scrub it, it turns into a sudsy foam, and that's the oil bubbles kind of breaking down because of this detergent. And soap is kind of just a milder form of that. And of course, our skin's covered in protective oils, like you say. But then also the membranes of a lot of microorganisms are a fatty, oily layer as well, which is why washing your hands can be so effective in killing things like bacteria and viruses. But like you say, Norman, it can kill ones that maybe you want to keep part of your natural microbiome.

Tegan Taylor (8:21)

So there are organisms called commensals, and those are the ones, the natural ones that don't cause disease. And then there are pathological organisms, fungi and other organisms on your skin, like streptococcus and staphylococcus, which can cause disease. So, for example, skin infections, which then go on to cause rheumatic fever, eye infections, which go on to cause blindness, trachoma and so on. I mean, there are. We can get too romantic about this because there are, particularly in warm climates, there are organisms which grow on our bodies which actually cause disease. And washing our bodies helps to get rid of them and prevent those diseases from occurring because of the pathological organisms that are around. So it's very hard to generalize about it. And what you've got at the moment are people living in New York or famously, Steve Jobs was one of these people who never washed or rarely washed, who say, well, we get away with it. We can change our clothes every day, we change our bed linen regularly. Our clothes that smell, it's not us. And eventually that smell goes away. That's fine, because we're living in a relatively clean environment. But when you're not necessarily living in a clean environment, it can cause disease.

Norman Swan (9:31)

Yeah. So I think what's interesting is we've got a spectrum here. On one end of the spectrum, you have people who perhaps never have the opportunity to wash in safe ways and so are at risk of serious infections, like you say. And at the other end of the spectrum, we've got this fetishisation of everything being clean and smelling like a flower. And perhaps you're showering multiple times a day using lots of different products, a lot of deodorizing products, perhaps antibacterials or antimicrobials. Somewhere in the middle of those two is probably the sweet spot in terms of health. I guess the question from Ingrid is, where is that?

Tegan Taylor (10:05)

Well, let's start with dermatologists, skin specialists. They would argue we shouldn't be using soap, we should be using non soap cleansers to preserve that fatty layer in our skin, to preserve the commensals, reduce the risk of conditions like eczema and itching, which might lead to skin damage and skin infections.

Norman Swan (10:26)

Alright, so you've got itchy skin, you scratch it, you open that skin layer up and then an infection can get in.

Tegan Taylor (10:31)

That's right. So dermatologists strongly argue that you should use non soap cleansers. And in fact some would argue that you can use something like sorboline to clean yourself, which is a very cheap moisturizer which helps to cleanse the skin. But there are others as well. And not to shower too often, but it's pretty hard in a country like Australia where you're getting very hot, very sweaty and you feel uncomfortable.

Norman Swan (10:55)

Yeah. So there was a really useful article that we found in the Atlantic, basically charting how many showers a week on average people had in different countries. And it varies quite a lot. Some of it's cultural, but I do think some of it is definitely climate based, like you say. So at the lower end of the spectrum, in terms of weekly showers and weekly shampoos, Japan, China and the UK were down around about 5 a week and then Brazil was up at around 12 a week. And so you've got to think, at least in part, there is a climate thing at play because Brazil's a country that's pretty hot in most of the country for most of the year, versus somewhere like the UK or Japan, which for a large part of the year it's very cold.

Tegan Taylor (11:40)

When I was a wee boy, we had two baths a week, there was no shower in the house. When I went away from home to university and went into digs, we were allowed one bath a week.

Norman Swan (11:52)

What?

Tegan Taylor (11:54)

Which is why visiting Australians would say, oh, I understand that one. And it was extraordinary. Compare that to now, I will sometimes shower twice a day and I'll certainly wash my hair every day. I mean, people who'd be horrified by that. I mean, there's interesting stories about people who haven't showered for years and say they. The acceptability of it is cultural as well, that if you look clean, people think you are clean.

Norman Swan (12:18)

Part of the narrative around the people who do say that they've sworn off showering or they don't use soap or shampoo anymore is that they'll often talk about there being a period of time that's like a deconditioning period where your body kind of freaks out. And maybe you do smell and maybe you are kind of have oily skin or oily hair.

Tegan Taylor (12:33)

Let's be best. They probably stink to high heaven.

Norman Swan (12:36)

But I'm interested to know whether there is a kind of your body reaches an equilibrium after time when you're not using those products anymore or if that is part of their propaganda.

Tegan Taylor (12:47)

Well, some people swear by that, that they reach this equilibrium where they no longer smell and they've got this natural smell about them. The anecdotes about Steve Jobs was he was always pretty unpleasant to be around environmentally. So who knows, it may be different for different people. But look, I think the basic thing is true here, which is that if you use soap a lot, you are actually destroying the natural surface of your skin and you probably are removing handy bacteria as well as others. Although there have been studies suggesting that when you look at the skin of people who've washed in plain soap, there's not that much difference in their microbiomes compared to people who've just washed with water. So like many of these things, they're not incredibly well studied.

Norman Swan (13:33)

The other thing I would like to call out here, if we are taking a health lens to this, is that there are bigger health impacts of regular showering and regular use of commercial soaps and that sort of thing than just my own personal health of protecting myself from infection. Such as, well, we're using water. You're putting products down the drain that have conditioners and they've got fragrances in them. There's been a lot of concern in the past about microplastics in say, an exfoliating scrub that's not in Australia anymore. The resources that are used to produce those products, the resources that are used to treat that water has an environmental impact. So I'm not saying that us all not showering twice a day is going to save the planet, but it's not a zero impact habit.

Tegan Taylor (14:16)

I mean, I think that for the good of the planet, probably once is enough in terms of when you're in.

Norman Swan (14:21)

The shower once a year.

Tegan Taylor (14:23)

That's right. But you know, having grown up in Scotland with two baths a week, I've flipped to the other end of the scale. There's just no way cleanliness is in.

Norman Swan (14:33)

The nose of the beholder. Near you.

Tegan Taylor (14:36)

That's right.

Norman Swan (14:37)

But for health reasons, I'm guessing that skipping the odd day every now and again isn't going to do Ingrid too much harm.

Tegan Taylor (14:42)

No, it's not. Ingrid can cut back if she likes. Probably from the advice we've seen around the place, you want to wash your clothes regularly because it's your clothes that do carry the smell to a significant extent. And all of us should be washing our hands before cooking and after being to the bathroom.

Norman Swan (15:01)

Absolutely. Wash your hands, you filthy animals. If you are like Ingrid and you have a question for us, you can email us. We are thatrashvc.netau and no question, it's.

Tegan Taylor (15:10)

Too personal for Tegan and I.

Norman Swan (15:13)

And we've also been receiving your feedback at the same email address. A couple of people, Norman, have been seeking some more information about yours and my favourite diet, the Mediterranean diet, and specifically about the IG Nobel Prize winner that came out a couple of months ago, which was all about a related phenomenon called the Blue Zones, which are basically parts of the world that seemed to have a lot of people who lived beyond 100. And so the Ig Nobel Prize was awarded to a scientist who actually had an Australian connection who basically debunked it. And Libby has accused us of not talking about it. And you. And I said, well, we did. And then I remembered that we actually talked about it on other podcast, the Health Report. Right.

Tegan Taylor (15:57)

So the question is, some of these Blue Zones are places where they eat a Mediterranean style of diet. Even in Japan, where the Japanese diet and the Southeast Asian diet in Vietnam can look a bit like the Mediterranean diet when you analyze fruit, vegetables, amount of red meat and so on. So just to go back over the Blue Zone myth, most blue Zones were where poor people lived. And it goes against all the evidence from around the world that poverty is associated with a shorter lifespan. And it turns out that people were lying about their age to get pensions. The recording of births accurately was not done, therefore you never actually knew the age of people. It doesn't actually necessarily call into question the idea of the Mediterranean diet. The Mediterranean diet's actually been studied quite a lot. There's been even some randomized trials of it. So the evidence around the Mediterranean diet is pretty solid, but the evidence around the Blue zones is far from solid.

Norman Swan (16:54)

I think part of the problem here is that a lot of the imagery that's used when talking about either of these things are beautiful Mediterranean islands of old people sitting on these islands being old and healthy. But two different kind of data sets that have gone into this in the Mediterranean diet is still out on top. Well, thank you so much to everyone who sent in questions about the Blue Zone diet. Of course, if you want to send us a line, you can do so at thatrash@abc.net au in the meantime, happy eating. Happy eating. And we'll see you next week.