Minnesota scientist says ‘man flu’ may be more than a punchline

CATHY WURZER: Chances are you've heard a woman poking fun at a man in her life when he has a cold, and let's just say he's not handling it very well. It's been parodied hundreds of times in stand-up performances and internet comedy sketches.

NURSE: Wake up!

DR. BOYCE: [GROANS]

NURSE: Quick! There's a man!

DR. BOYCE: What is it, nurse?

NURSE: He has the flu.

DR. BOYCE: My god. Not the man flu.

NURSE: That's right.

DR. BOYCE: What's the status?

NURSE: Jonah, male in his 30s. Girlfriend called 111 this morning when he woke up complaining of a sore throat and wouldn't stop talking about it.

DR. BOYCE: How long has he been sick?

NURSE: Only since this morning, but he's been acting like it's been an entire week. He could barely get off the couch when we arrived.

DR. BOYCE: Jonah, I'm Dr. Boyce. How are you feeling?

JONAH: Terrible. I've got a runny nose.

[BLOWS NOSE]

CATHY WURZER: [LAUGHS] But research shows there may be some biological and evolutionary factors that indeed make male and female experiences of having a common cold feel different. A University of Minnesota professor of ecology, evolution, and behavior says there is evidence that many men may suffer effects of infection more than women, and that researcher is Professor Marlene Zuk. She's here to talk about it. Thanks for taking the time, Professor.

MARLENE ZUK: Thanks for having me. I had not heard that clip before. That's arresting.

[LAUGHTER]

CATHY WURZER: What do you make of some of the jokes?

MARLENE ZUK: Oh, everybody loves a good sexism joke. I think people have been interested in this for a long time. But certainly, I'm not going to stand up for the oh, yes, men are just all big babies routine, because that's really not very well-founded. [CHUCKLES]

CATHY WURZER: Let's talk about the, quote, "man flu." And many of us, of course, have rolled our eyes when dealing with a person in our lives, a brother or husband, being extra dramatic about their cold or sore throat or runny nose. But you have said that men can experience a different immunological response to getting a cold, so let's unpack that.

MARLENE ZUK: Sure. And it's not really meant-- so I should hasten to add here that I am not-- this is my disclaimer that I'm not a medical doctor. I'm not a medical person of any stripe. I'm a biologist who's interested in the ways that males and females, mostly in animals, evolve to be different. And of course people are animals so they fit right into this.

And what evolution tells us is that males and females differ in lots of ways in their physiology. And in many, many species, though not all, men or males tend to be more susceptible to disease, and they have generally not as strongly functioning immune systems. So OK, if you want to carry on from that to why men complain a lot when they have the flu, that's a possibility. But it is really interesting to think about where that sex difference could have come from.

CATHY WURZER: That is, actually. What are some of the theories?

MARLENE ZUK: So the idea is that at a at a really proximate level, just the physiology of it, is that men have higher levels of testosterone. Male mammals have higher levels of testosterone, generally speaking, and testosterone is associated with a suppressed immune system. Lots of examples of ways in which males get diseases more severely or are more likely to get them exist.

And my interest in it as an evolutionary biologist is, well, why is that? Is that just some random effect or is there some reason why it occurs? Is there some way in which it could be adaptive? So I've spent some time investigating, mostly looking at the literature in this. I actually also tried to mess around looking at sex differences in disease susceptibility in insects.

And a lot of it seems to have to do with males having a more generally-- what is crudely referred to as a live hard, die young strategy in evolution. That if you throw it all into trying to get mates and sire a lot of offspring, then you're going to do better than if you just wait around and don't. Therefore, if your body exacts a price by making you more susceptible to disease, but in the meantime, you end up able to sire more offspring and compete better as a male, then you're going to do really well. So it's the price you pay for a lot of attributes that make a male successful.

From the female perspective, though, you don't want to go for broke until you've managed to give birth to the offspring, raise them, make sure they're doing OK, and so forth. So there's more of a bet-hedging strategy there. And again, let me emphasize-- before people start getting irate that these are wild generalizations-- I am not saying that male humans, for instance, never invest in their offspring. We all know that they do. But from an evolutionary perspective, you start thinking, well, what could the roots of this be? And I think that basic difference in sexual strategy is one of them.

CATHY WURZER: I wonder, too, you mentioned testosterone, and I'm wondering if there's something about estrogen that is almost a protectant in terms of how a female might have a different immunological response to infection versus, say, more testosterone on the male side. Does that make sense?

MARLENE ZUK: Yeah, it does, and people have certainly looked at it, and the answer is the perpetual thing you will get from a scientist, which is it's complicated. [LAUGHS] So estrogen is not-- and this is part of the problem that people run into when they think that, oh, if I'm an older man I should just raise my testosterone levels and all will be well, and I will have the body, libido, and mind of a 25-year-old, which perhaps gratefully is not the case. It doesn't work that way.

And similarly, estrogen has lots and lots of different effects on the body, not just on your immunological responses. So yeah, estrogen is not, strictly speaking, comparable that way. And also again, disclaimer, of course both males and females, in mammals that have estrogen and testosterone, have both estrogen and testosterone. So humans, both males and females, have both. So it's not this elixir of youth or elixir of protection.

But see, an interesting thing in here, for instance, is think about pregnancy in mammals. Well, one of the things that pregnancy needs-- pregnancy is great in a sense that it protects-- from an evolutionary perspective, I'm not making any personal judgments here. But pregnancy is great from an evolutionary perspective, because it protects the offspring. It keeps them from being harmed. It makes sure they have enough food. I mean, it's just awesome.

However, from a female body perspective, that fetus is a foreign object. How do you overcome not just rejecting it as though it were something, a disease that had been introduced into the body? So lots and lots of people look at how females immunosuppress during pregnancy, because that's necessary.

So women, for instance, with autoimmune diseases like lupus or rheumatoid arthritis often find that their symptoms are better during pregnancy, because autoimmune diseases mean your immune system is in overdrive, right? It's acting so strong that it's reacting against things it really shouldn't be reacting against. Well, during pregnancy that's tamped down, and so women with those autoimmune diseases sometimes find that their symptoms are better during pregnancy, because their immune system's been ramped down so that they can tolerate this little foreign invader inside of them and not react to it like it's a disease.

CATHY WURZER: Hmm. I didn't know that. That is really interesting. Wow.

MARLENE ZUK: I mean, I don't know if it's any consolation to experiencing other things about pregnancy. But yeah, the immune system is this constant balance between, OK, is this an OK thing to admit? Or no, this is a terrible thing, I should get rid of it. Because you can't just get rid of everything or you end up with allergies and autoimmune diseases and your nose freaking out because, pollen! But seriously, nose, there is nothing wrong with pollen. But your immune system is in overdrive going, pollen!

CATHY WURZER: [LAUGHS] Like many people's immune systems right now are actually doing that very same thing, yes.

MARLENE ZUK: Right now, yes. That is probably why it was topmost in my mind. So anyway, one of the things I really like to think about is exactly how that immunity changes, depending on how evolution's acted on the body.

CATHY WURZER: So the advice, I think, moving forward, the next time our male loved ones get sick, is--

MARLENE ZUK: [LAUGHS]

CATHY WURZER: --instead of just rolling your eyes, maybe listening to them. A little sympathy, maybe.

MARLENE ZUK: You know, a little sympathy probably goes a long way in both directions. Although, I would also, as a woman, like to argue for the recognition of the, and remember, I also brought you soup for the last five days, and perhaps I could get a little bit of sympathy for that.

[LAUGHTER]

CATHY WURZER: Professor, it was fun talking to you. Thank you so much.

MARLENE ZUK: Yes, always a pleasure. Always a pleasure. You're very welcome. Thanks.

CATHY WURZER: We've been talking to University of Minnesota professor of ecology, evolution, and behavior Marlene Zuk.