You may have heard that being “too clean” can damage your immune system, but is it true and what should you do?
The reality of immunity is very different from the “too clean” myth, and it’s important to understand how to protect yourself from infection.
Exposure can give specific immunity
It’s true that becoming ill with specific diseases, such as chicken pox or measles, conveys lasting immunity to that specific disease, but it doesn’t make you more resistant to unrelated infections like salmonella, flu or athlete’s foot.
Even with flu, catching flu one year only gives limited immunity to next year’s strain.
Infection doesn’t boost overall immunity
There’s no known mechanism through which repeated infections would strengthen the immune system in some general way.
If that were the case, then instead of enjoying constantly increasing levels of health and life expectancy as we’ve improved our defences against infectious disease over the last century, we’d have started to slip backwards as our immune systems broke down and common infections became rampant.
There’s no evidence we’re any more susceptible to common infections now than we ever were.
Confusion over the “hygiene hypothesis”
This idea is fundamentally a confusion arising from the “hygiene hypothesis” — the idea that allergies have increased because our contact with microbes has changed over the last century.
Most experts in the field of infection and diseases now believe the rise in allergies has nothing to do with hygiene. Instead, evidence indicates that exposure to a diverse range of “friendly” microbes at an early age helps to train our immune system. For example, playing in mud or sand will expose the system to these microbes, which do not necessarily lead to an infection.