If you made it through childhood without developing an allergy that doesn’t mean you’re home free. According to a new study, 45 percent of adults develop an intolerance to a foodstuff after they got older.

This picture is enough to make some people swell. Credit: Pixabay.

An allergy is the response of the body’s immune system to normally harmless substances, such as pollen, foods, or house dust mite. This hypersensitivity causes the body to overreact by producing a disproportionate immune response when contacting an allergen. In some cases, the response can be so strong that the body enters anaphylactic shock, with potentially fatal consequences.

It’s not clear what causes allergies or why some people are more predisposed than others. Studies so far have linked both genetic and environmental factors to allergies. What’s certain, it seems, is that allergies are on the rise regardless of gender or ethnic background. According to findings presented at the American College of Allergy, Asthma, and Immunology conference, the incidence of shellfish allergy has grown by 7 percent, tree nuts by 18 percent, and peanuts by 21 percent. Shellfish and peanuts are also among the most common food allergies overall. The results are based on a survey of 53,575 U.S. adults.

The survey also shows that adults are far more susceptible to developing allergies than previously thought. Another surprising finding was that ethnic minorities are more predisposed to developing allergies in adulthood. According to co-author Christopher Warren, among black, Asian, and Hispanic adults, the risk of developing a food allergy to certain foods is higher than for whites.

There are two likely candidates that can explain the upward trend in allergies across the US. One deals with hygiene — too much of it, to be precise. Children nowadays are too locked up at home for their own good. Since their bodies haven’t accustomed to various substances, the immune system simply doesn’t have enough experience to differentiate between harmless and potentially dangerous substances, or so the theory goes. Secondly, misuse of antibiotics is throwing the immune system out of wack, besides generating antibiotic resistance, which is a way worse problem. Vitamin D deficiency (not enough sunlight) and obesity have also been linked to allergies.