Excessive Hygiene and the Immune System: How Clean Is Too Clean?

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Particularly in the era of COVID-19, people have become extra conscious of their personal hygiene. You’ve probably never paid so close attention to how often you touch your face. But there’s another concern too—can excessive hygiene affect the immune system in a bad way?

According to the “hygiene hypothesis,” being too clean can cause allergies, asthma and other health problems. This hygiene theory says immunity is learned when people’s immune systems are exposed to environmental triggers. However, it’s not entirely true. Learn how cleanliness and the immune system are related and how clean you need to be to stay healthy.

The Hygiene Hypothesis and Disease

The theory behind the hygiene hypothesis is that when babies are born, their immune system is undeveloped and must be “turned on” by environmental factors. Scientists have hypothesized that when homes are too clean, newborns don’t have the opportunity to begin developing their own antibodies.

It is true that before birth, a fetus’s immune system must be muted so the body doesn’t reject maternal material and antibodies. After birth, the baby’s immune system must begin the work of protecting against disease. When the immune system doesn’t learn which antigens are truly harmful and which aren’t harmful, it can react too aggressively to triggers that are no big deal. This can cause inflammation and, according to the hygiene hypothesis, lead to autoimmune diseases, asthma and allergies. Scientists have found that in some societies and countries other than the United States, children have a lower incidence of these diseases, possibly because they are exposed to more antigens at a young age.

However, there’s still scientific debate about whether this evidence means that being too clean causes allergies or autoimmune diseases.

Hygiene and Disease Prevention

Scientists know that handwashing and disinfecting frequently touched surfaces can prevent the spread of infectious diseases. Not only does it keep you safe, it keeps other people healthy, too. There’s no convincing evidence that washing your hands frequently will harm your immune system, so don’t be afraid to lather up with soap and water regularly.

But scientists also think that kids playing on the playground and in the mud is a good thing. It’s not crucial to completely insulate children from every single germ they could come into contact with—their immune systems do need to learn what germs to fight off later in life. The key is finding a balance between good hygiene and being overly cautious.

Keep Your Immune System Strong

So, while you shouldn’t be overly concerned about frequent handwashing, there are plenty of other ways to keep your immune system functioning well, such as:

  • Keep your vaccinations up to date, which teaches your body to prevent these diseases even though it has not already experienced them. Vaccines are only developed for diseases that have the potential for serious illness, disability, or death (or all three), such as measles, hepatitis B, polio, and COVID-19.
  • Eat a healthy diet with plenty of fiber and good fats to reduce inflammation.
  • Keep stress under control, since stress can lead to inflammation over time.
  • Get some physical activity and plenty of sleep, which keeps the immune system strong.
  • Drink alcohol in moderation and don’t smoke, since smoking and too much alcohol can weaken your immune system.
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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Mar 11
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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