Food Allergies: When Your Body Attacks Itself
By Lil Mixins Research Staff
If you ask an allergist what a food allergy is, they might tell you something like “it's an IgE mediated immune response to a protein.”
Of course, this probably doesn’t mean much to you.
Luckily, we’re here to help explain allergies a bit more clearly.
A baby with hives, a common symptom of food allergy.
Your Immune System
First things first: Your immune system is a complex series of reactions designed to fight off threats and keep you healthy. The immune response starts when scouts, or IgE antibodies, see something and recognize it as a threat.
The scouts then shout “THREAT!” real loud, and that wakes up the fighter, or mast cells. Those guys respond to the “attack” by releasing a bunch of chemicals like histamine. These chemicals perform tricks like heating up the body, giving you a runny nose, making your eyes water, building up mucus and making you cough.
Generally, the immune system is really helpful and keeps all of us safe everyday. We can even teach the immune system to react to a virus with vaccines, which is pretty cool.
So what’s the deal with food allergies? Well, the problem here is that those same scout antibodies decide to treat something simple and generally harmless like peanuts, dust, dog dander, or milk, like a threat, just like they treat a virus.
You’re probably wondering - why do some people’s bodies suddenly mistake something like peanuts or cat fur for a threat?
Luckily, we have an illustrative example from the New York Times on hand.
Ticks & Sharks
The article explains that a lone-star tick bite contains a sugar, alpha-gal, which is released into the body along with the tick *venom*. When the body fights off this tick bite, it mistakenly learns that alpha-gal sugar in the tick bite is also a threat. The next time that person eats red meat, which contains alpha-gal sugar, the body attacks like it’s been bitten by a tick again.
Another way to think about it is like this: Imagine for a moment that a little boy is taught that sharks are in water and sharks can hurt you. The next time that little boy is brought to a lake, he might refuse to go in because he mistakenly *knows* there will be sharks - even though we all know sharks do not live in lakes.
What Scientists Think
To connect all this together, here’s what scientists think happens with nuts: one theory is that the body learns to fear a peanut because of a bacteria or mold that was present one time peanuts were eaten. The body mistakenly thinks BOTH the mold and the peanut are a threat. So the next time you eat a peanut it summons a threat response...aka an allergic reaction.
Another theory, called the Dual Exposure Hypothesis, is that peanut dust enters the body through a cut in the skin, and the body flags it as a threat by mistake. Then, the next time you eat a peanut, your body recognizes the proteins in the peanut as ones it has seen before (on it’s “dangerous threats” list), and once again, causes an allergic reaction to “deal” with the threat.
What We Don’t Know
Whether the exact mechanism by which food allergies are created is one of these or some entirely other reason, one thing is clear: the body’s immune system is very powerful, and an allergic reaction can be life-threatening.
Unfortunately, we do not yet know how to un-teach the immune system, which has a long memory. In the case of vaccines, this memory means we only have to get treated as kids, but maintain the benefits of protection our whole lives. With food allergy, it can mean a life-long condition, and playing Russian roulette with every meal.
What We Do Know
Fortunately, recent scientific studies have helped us begin to better understand ways to possibly prevent food allergy. The ground-breaking LEAP (Learning Early About Peanuts) study showed conclusively that early introduction (at 4-12 months of age) of peanuts significantly decreased the likelihood of developing allergies later.
Prevention is Key
This raises the important point that sometimes prevention can be more important than treatment. If you take steps to avoid getting allergies in the first place, you won’t have to worry about treating them later on.
So, while we may not completely understand exactly how allergies work, we are learning more every year about how to stop them from developing. And that itself is promising for all those who suffer from allergies.
If you are pregnant or have a newborn, it is important to ask your doctor about early introduction of allergens. Since the guidelines have only changed in the past couple of years, many people still don’t know about the importance of starting to expose your 4-7 months old to peanuts and other common allergens.
Pediatricians will typically go over early introduction with you at the standard 4-month well visit for your baby. But if they don’t, you should bring it up and ask them. Early introduction is the best way we currently know of to lower the risk of children developing peanut allergies.
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