WATCH: Nail biters and thumbsuckers have fewer allergies as adults

- Nail biting and thumb sucking may be nasty habits, but new research published in the journal Pediatrics shows that kids who habitually stick their fingers in their mouths actually grow up to have fewer allergies. Hmm. Gross.

Of the participants tracked, 50% of those with good manners developed allergies to a variety of things, including pets and mites. Children who did one or the other were 40% less likely to test positive for allergies. And the little imps who did both had only a 31% rate of allergic reaction as adults.

Children (and adults) are widely discouraged from nail biting and thumb sucking because our hands are teeming with bacteria. But researchers think that childhood exposure to germs may actually boost health later in life. It's called "the hygiene hypothesis." Coming into contact with viruses, allergens- and the family dog- somehow primes the immune system to fight microbial attacks.

More research is needed as to how exactly the dirt helps- but in the meantime you can stop over-sanitizing- and give the chronic nail biter in your family a break. Now, the authors of the study do NOT recommend that either habit be encouraged as a way to prevent allergies- but they also say their findings proves that a little dirt don't hurt.

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