The American Academy of Allergy Asthma and Immunology (AAAAI) reports that as of 2010, 8 percent of children have a food allergy. The AAAAI also reports that all allergies worldwide have been on the rise for the last 50 years. However, that’s mostly in the developed world. In rural areas and undeveloped nations, there are significantly fewer cases of food allergies. So what is causing the rise in food allergies? These are some of the leading theories, based on research, as to why food allergies are on the rise.
The Hygiene Hypothesis
Many studies have contributed to the hygiene hypothesis. From those studies, it’s known that people living in rural areas and on farms in both developed and undeveloped nations have fewer allergies in general. They are however, exposed to more bacteria and even parasites in their environment. That increase risk for other health problems may be providing protection from allergies. The hypothesis is that if the immune system is busy doing its job of protecting the body from invaders, it won’t malfunction and attack or react to things, such as food, that should be benign to humans.
Diets in the developed nations included more processed foods, fats, and sugars. Diets in tribal cultures, where there are few if any food allergies, include more fresh plant material. These dietary differences can lead to changes in the gut, including to the amount and types of bacteria found in the gut. In a study reported in the Proceedings of the National Academy of Sciences, children in an African village had a more types of bacteria living in their gut than compared to children living inItaly. The kinds of and the number of bacteria that can survive in the gut may be dependent on diet.
Late Exposure to Allergens
Many doctors for years have told parents to wait until a child is a year or older to introduce foods known to cause allergic reactions, such as eggs, peanuts, or strawberries. However, no study has shown this helps prevent food allergies. Now some studies suggest it may increase the risk for food allergies. The idea is that children need early exposure to these foods to teach the immune system that they are harmless and not something to attack. The AAAAI reports that, “Delaying the introduction of potentially allergenic foods, even in infants at risk for food allergy, has not been clearly shown to be beneficial.”
What’s not Contributing to the Rise in Cases
It’s not believed that an increased awareness is leading to significantly more food allergy diagnosis. This makes sense because parents generally can make the connection between eating the food and the allergic reaction and hives or anaphylactic shock are well-known symptoms of allergies.
The many studies in the last few years have contributed greatly towards better understanding the rise in food allergies. However, there is still not a clear understanding of how to change that pattern because none of the leading hypothesizes have been proven without a doubt to be the cause of the development of food allergies. In all likelihood, a combination of factors is responsible for the increase.
According to Strategies to prevent or reduce allergic disease published in 2011 in the Annuals of Nutrition and Metabolism, “Current evidence-based guidelines for allergy prevention remain limited to avoidance of cigarette smoke, promotion of breastfeeding and the use of hydrolyzed formula when breastfeeding is not possible.” It also mentions that, “Allergen avoidance strategies have been largely removed from most guidelines.” Hopefully with the recent studies offering clues to the causes of food allergies, soon doctors will be able to give parents proven methods to prevent the development to these allergies.
CNN Health: Why are food allergies on the rise?
PubMed: Strategies to prevent or reduce allergic disease.
AAAAI: Allergy Statistics
AAAAI: Prevention of Allergies and Asthma in Children: Tips to Remember
AAAAI: Infant feeding guidelines may help to promote the incidence of food allergy
Allergic Child: Possible Causes of Food Allergies
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Guest post by: Guest post contributed by Robert Anders, on behalf of Manhattan Ortho. Robert is an experienced health specialist and freelance writer. In his spare time he enjoys passing on helpful dental tips.