Narrator: This is Science Today. Images of growing up on a farm are often associated with robust health - and now there's scientific evidence supporting this old association. Preventive medicine specialist, Mark Schenker, of the University of California, Davis, says studies have shown that children who grew up on a farm are less likely to suffer from allergies and asthma, thanks to exposure to allergens, or antigens, found on the farm.
Schenker: Exposure to a number of antigens that exist on the farm protects against subsequent development of allergies and probably asthma.
Narrator: Schenker says this so-called 'hygienic hypothesis' may also explain why children in urban environments have higher rates of allergies and asthma.
Schenker: As we move to more hygienic environments without exposure to a number of antigens in early life, we make ourselves at increased risk for allergic, asthmatic reactions as adults.
Narrator: For Science Today, I'm Larissa Branin.