The theory that children are developing allergies due to a lack of exposure to common germs and childhood infection is being threatened by new research.

The “hygiene theory” says that children are more prone to allergies because modern life is too clean and germ free. The idea was that being exposed to germs makes the immune system stronger and properly orients it against truly foreign intruders. This idea was supported by studies that showed young children exposed to illnesses by older siblings or daycare attendance cut their chances of allergies.

However, new research shows that it might not be that straightforward.

A Dutch study, published by the American Thoracic Society, showed that even though children attended daycare and contracted more infections, there was no advantage in their development of allergies or asthma with other children by age 8. In fact new studies on the risk of wheezing before age 3 actually show that frequent chest infections may actually predispose children to asthma. So, parents who hope that sending kids to daycare will give them a health advantage may be actually increasing their child’s asthma risk.

The hygiene hypothesis is not dead though. While some experts question whether we need dirt and germs to develop a healthy, well-balanced immune system, we can still see that children that grow up in “less hygienic” environments like farms are also less likely to end up with asthma or allergies.

What parents can do to help their child avoid allergies are the same things that also promote healthy children:

1. Moms should breastfeed. Many studies show that breastfeeding reduces the incidence of both allergies and asthma. It is also the best infant nutrition, bar none. The World Health Organization says that exclusive breastfeeding should continue to at least 6 months, with breastfeeding itself to continue to 2 years and beyond.
2. Ensure that your children are getting good nutrition. When they are old enough, begin a broad-spectrum multi-vitamin / multi-mineral supplement that includes at least the RDA of B vitamins. It has been found that B12 in particular can help to prevent allergic symptoms.
3. There are other things that can help reduce your child’s chances of allergies, including making sure that a pregnant mom eats at least one apple a day and that she also take cod liver oil in her third trimester.

Sources: WHO, BBC, BeAllergyWise