There are now new guidelines in the US about the introduction of peanuts into babies’ diets, with the idea that early exposure decreases the chances of developing a peanut allergy later.
This is essentially the opposite of the approach for many years, where parents were encouraged to hold off on peanut introduction until kids are older. But the new guidelines make sense if you understand how the human immune system works.
Knowing What’s “You”, and What Isn’t
The immune system is meant to be reactive to proteins that are not “us”.
Bacteria and viruses, for example, are made up of proteins that do not look like our own proteins. When our immune system sees them, it recognizes them as an invader that needs to be ousted. To do that, your immune system creates all kinds of inflammation – coughing, sneezing, fever congestion, loose stool, etc. We think of these things as the bad parts of being sick, but they’re all an effort to kick those little critters out. That’s why sometimes suppressing fevers and other symptoms can inhibit your body’s ability to do its job.
But there are many proteins in our world that aren’t part of our own bodies but are also not infectious or dangerous to us–things like food proteins, for example. Your body has a complicated, amazing system for knowing that those things are good for us, even though they’re foreign.
Occasionally, though, your body makes a mistake. It confuses a food protein–like peanuts, say–for a dangerous invader, and fires up the defences. That’s when we see the signs that we call an “allergic reaction”.
Learning Good From Bad
How does your body know what’s dangerous and what isn’t? There are many complicated mechanisms that determine how tolerant we are, but they include a healthy gut flora (microbiome) and gut immune system and the exposure of the flora and immune system to potential allergens. In other words, your immune system needs to learn.
It’s typically been suggested that peanuts, gluten, eggs and other foods that have an increased chance of creating allergy be avoided until a child is three years old. The idea is that the immune system is more mature and therefore may not react. However, if the gut never gets a chance to experience those proteins and realize they are not allergenic when it is developing its ability to be tolerant, then it may be making a bigger deal out of a food protein then it should be.
The new guidelines are, essentially, a way to “teach” the immune system sooner, rather than later.
Remember: allergies can be serious business. It is a good idea to talk to your primary health provider before you get started with early introductions, especially if you have a history of food allergies in your family.