Food allergies have largely been found to be a major health issue in developed and western countries. Data suggest that food allergies are less common in developing regions of the world, but there may be limited information. It also may be that allergies will start increasing everywhere, following the trend in the U.S. More studies are needed to determine prevalence rates, types of allergens affecting children in other countries, and how allergies are diagnosed and managed in vulnerable children.
Why Allergies are More Common in Developed Countries
Unfortunately, no one really knows why this is true, although there are many hypotheses. One idea is called the hygiene hypothesis: children in developed countries are more often exposed to pathogens that help their immune systems develop in a way that minimizes allergies. Deficiency in vitamin D in children in developing urban areas may also be a factor. Some researchers have also found that allergies are underreported in developing nations.
Prevalence of Allergens Around the World
The lack of information about allergies in developing countries, as compared to the number of studies conducted in the U.S., Canada, Europe, Japan and other developed nations, makes it challenging to come up with good prevalence numbers. It has long been assumed that there are fewer allergies in developing countries, but it is still hard to say this is definitely true.
There are food allergies present in children around the world, and while prevalence may vary, so too can the types of allergens. For instance, while nut and peanut allergies are most prevalent in the U.S., in Asian countries fish and shellfish cause most allergies. In some countries, overall prevalence seems to be very low. For example, in Mexico estimates are at about 2.7 percent, as compared to up to four percent in the U.S.
Food Allergies vs. Malnutrition
A major issue with identifying food allergies in developing countries is the ability to accurately diagnose them. Symptoms of malnutrition, which is not uncommon in these regions, are similar to those of food allergies. This makes it challenging to identify and diagnose true food allergies. When a child does have a food allergy, this can then lead to malnutrition. Even in developed economies, restricted diets due to food allergies can cause malnutrition. The problem is exacerbated in developing countries. Many food aid programs rely on staple foods that cause some of the more common allergies: milk, soy, fish, wheat and peanuts. If a child has to rely on food aid and has a food allergy malnutrition can become a serious problem.
What is needed most to help children in developing countries who may be living with food allergies is more research. It is hard to know for sure if the assumption that these children have fewer allergies is really true. Only accurate and abundant information will allow health professionals and advocates in developing regions to provide better allergy testing, education and management strategies. That information will also prove useful in determining why some areas may have more food allergies than others, which ultimately will help children everywhere.