How Poor Hygiene Habits of the Past Evolved Into Modern Allergies

The incredibly insightful animated video series Kurzgesagt looks at the history of humankind and its lack of hygiene to explain why allergies are so prevalent in modern times. It turns out that people then had to deal with worms on a daily basis and human bodies adapted to deal with them.

Allergies are more than just overreactions – they might be an evolutionary relic from a time when worms invaded our bodies daily.

However, once bathrooms, disinfection, and soap entered the picture, the worms went away but the physiological responses did not. This means that anything that can be construed as a worm is attacked by the well-armed human immune system.

The people who escaped these conditions now face an interesting problem an immune system without a major enemy that had kept it down for millions of years. It could very well be that our immune system still operates assuming that worms are making it weaker and that it has to be overly aggressive because of that.