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Module 9 - Do we need germ exposure to keep our immune system strong?

Immunity to infectious diseases

A quite separate issue from the Old Friends Mechanism (so-called hygiene hypothesis) and allergies etc. is the popular notion that clean modern lifestyles may be weakening the immune system, making us more susceptible to infectious diseases.

If this were the case, infectious disease statistics – particularly respiratory infections like coughs, colds and flu – would be rising rapidly, but they are not.

Although acquiring a normal body microbiota during, and in the first months after, birth is critical to developing the immune system, there is currently no evidence that “regular” infections during childhood and adulthood are important to keep our immune system “strong”  and boost our immunity to infection.

People tend to  assume that regular exposure to dirt and germs is important so children build up a strong immune system to fight infection despite the fact that there is no evidence for this

How do we build immunity to infection?

The way  to develop specific immunity to  a particular diseases (e.g. chicken pox, measles, flu)  is to catch that disease or be vaccinated against it. We are also probably exposed to small doses of various pathogens in our daily lives - large enough to develop immunity but too small to overwhelm the immune system and  make us ill.

However, catching a dose of flu or a cold does nothing for immunity to Campylobacter or E. coli, or vice versa. So it’s not true that catching lots of infections boosts our general immunity against all infections.

Factors which reduce our general immunity to infection are poor lifestyle and poor health – poor nutrition, malnutrition, excessive alcohol consumption, drug abuse, stress, etc

The best way to build general immunity to infection is through a healthy balanced lifestyle

Read more about the immune system by clicking here