Does too much hygiene cause diabetes?

The incidence of auto-immune diseases like type 1 diabetes and allergies has risen dramatically in developed countries over the past fifty years. The reasons for this trend are not fully understood but a theory known as the 'hygiene hypothesis' links it to a rise in hygiene standards. According to this theory, eliminating bacteria in food and the environment of infants may be depriving the immune system of the stimulus it needs to develop adequately, especially during the first critical years of childhood.