Heatshock in a Bottle

Scientists this week discovered just exactly how bleach kills germs. You would think we would’ve known for ages, but sometimes what seems the simplest question is actually quite complicated at the molecular level. And, as is often the case in science, the researchers weren’t even looking for the answer to this question when they stumbled upon it. Here’s the backstory (with practical heath tips included) to our interesting science bleach mystery:

When you get a fever, it kills many types of germs. Just that two or three degree change in your body’s temperature can be lethal to some germs, or at least prevent the germs from reproducing (which gives your body a break in the battle and a chance to wipe the germs out). You may be thinking that just a tiny difference in temperature shouldn’t make that big a difference in outcome. To me, it’s like the difference, for humans, between a 100 degree day and a 110 degree day. That’s only a ten percent difference (on the Fahrenheit scale – even less on the Celsius scale), but those ten degrees make a huge difference in human survival and the incidence of heat-stroke (and let’s not even discuss decreased human reproduction at 110 degrees…). The fever-related germ-death situation has practical implications for us all: putting heat (especially wet heat) on an early infection 3 times a day gives your body a big advantage in wiping it out. Hot soaks (or hot packs) are a great tool to use for early skin infections (but be sure you don’t burn yourself) – it’s like giving your body a fever only in that one spot, and rushing your blood to it with germ-fighting cells. So why, on a molecular level, do germs die at slightly higher temperature? That’s the question these scientists were asking. The answer? Heat-shock proteins, that’s why.

As the article states, “‘Many of the proteins that hypochlorite [bleach] attacks are essential for bacterial growth, so inactivating those proteins likely kills the bacteria,’ Marianne Ilbert, a postdoctoral fellow in Jakob’s lab, said in a statement.”

Go here for a really nice, user-friendly description of all the phenomenal work your own heat-shock proteins do for you each day (you can skip their last, marketing paragraph).

One of the nice things about heat-shock-related germ death is that it’s really hard for the germ to become resistant to it. And here’s the final plot twist to this story: it turns out you actually make bleach inside your body as a weapon in your battles against germs! – But at a price…

“The researchers said the human immune system produces hypochlorous acid [bleach] in response to infection but the substance does not kill only the bacterial invaders. It kills human cells too, which may explain how tissue is destroyed in chronic inflammation.”

So does this new information mean that you should grit your teeth and put bleach on your infections? Hey, wasn’t that what the dad did in My Big Fat Greek Wedding by spraying glass-cleaner on everything? The answer is (drum-roll please)…um, NO. The reason? Some disinfectants (bleach and hydrogen peroxide, for example) kill not only the germs, but also your body’s cells – as these researchers pointed out. That’s why, for example, it’s really important you don’t put hydrogen peroxide on a cut everyday (once is all you’re allowed).

My Big Fat Greek Wedding

Image via Wikipedia

You can end up with a chronically poor-healing (or not-at-all healing) ulcer by applying bleach/hydrogen peroxide over and over. So then why does applying, for example, hot soaks (which also use heat-shock proteins) work better? The reason hot soaks are safe and effective is purely because of that difference in temperature between what kills a germ versus what kills a human cell – we tolerate temperatures that little naked isolated germs just can’t take – but that’s also why you need to make sure your hot soak isn’t so hot it burns. Nowadays we have lots of great, safe disinfectants to use, so when it comes to cuts don’t reach for the (ouch) bleach. The bottom line from our new heat-shock in a bottle discovery and how it relates to your everyday life?

1) Apply hot soaks to early infection 3 times a day.

2) Use the bleach only on countertops….or that tomato stain. Not humans.

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