Can we be too careful when it comes to allergies?

Cleanliness is next to godliness, right?

They say plumbers have probably done as much as doctors to extend modern life spans, but can cleanliness go too far?

According to the so-called hygiene hypotheses, allergies and autoimmune disorders are caused by the ultra-sterile environment made possible by antibacterial soap, disinfectants and other common cleansers.

In fact, a study published Monday in the journal Pediatrics found that children whose families used dishwashing machines were more likely to have allergies than kids whose plates were washed by hand.

The theory is that too much cleanliness prevents the immune system from developing resistance to germs and other substances commonly encountered in every day life.

The headline that caught our attention involved peanut allergies.

The American Academy of Pediatrics advised parents 15 years ago to keep peanuts far away from infants and toddlers who might have a life-threatening reaction to them.

We can't argue with that advice; anyone who has experience with a peanut allergy or allergy to another food knows they will do anything to avoid a recurrence.

But results of a study released this week show that children who avoided peanuts for the first five years of their lives were up to seven times more likely to wind up with a peanut allergy than kids who ate peanuts at least three times a week.

Because peanut allergies are so dangerous, peanuts have been baned from many schools, airlines and other venues.

At the same time, however, the rate of peanut allergies has tripled over in the last two decades in the United States.

A study of Jewish children, some of whom lived in Britain and some who lived in Israel, found that the ones who lived in Britain were 10 times more likely to have peanut allergies than their counterparts in Israel, where children start eating foods made with peanuts when they are seven months old. Children in Britain don't eat peanuts until they are at least a year old.

In a more structured text, 640 infants who were deemed at risk of developing peanut allergies -- they were already allergic to eggs or had severe eczema, a skin condition that can be caused by allergies -- were divided into two groups.

Half of the kids, all 7 to 11 months old at the start of the study, avoided peanuts and the other half given smooth peanut butter or a peanut snack.

Results showed that of those with no sign of peanut allergy at the start of the trial, 13.7 percent of those who avoided peanuts became allergic by the time they were five.

Of those who ate peanuts regularly, only 1.9 percent became allergic. That amounted to an 86 percent relative reduction in peanut allergy risk.

Kids who already showed sensitivity to peanuts also showed improvement, a 70 reduction in peanut allergies for those who at the food.

Of course, peanut allergies are a serious condition, and no one should experiment without benefit of medical supervision. And, schools, churches and other organizations should be careful to avoid endangering any children who have such an allergy.

But the study reinforces the idea that letting immunities build up through natural activities may be better than taking things too far in the other direction.