Remember the birthday dinner scene in Mrs. Doubtfire, when Pierce Brosnan’s character Stu tastes the cayenne-laden jambalaya? Okay, didn’t think so, but here’s the point: He’s immediately coughing, wheezing, and then choking—all classic signs of a severe, whole-body allergic reaction.
This is not what happens when someone on a trendy fad diet eats gluten, is it? That’s because there’s a big difference between a food allergy, a food intolerance, and what we’ve now come to call a food sensitivity. Here’s when it’s typically not an allergic reaction:
Your symptoms are all in your stomach…
An allergic reaction is governed by the immune system, so it looks pretty similar no matter what you’re allergic to. The immune system controls a variety of blood proteins called antibodies, which seek out invaders such as bacteria and viruses. “When a person has a food allergy, her body mistakenly identifies a food protein as being dangerous,” says Bruce Lanser, MD, a faculty food allergist at National Jewish Health in Denver. The antibody immunoglobin E (IgE) essentially attacks that protein, he says, with an onslaught of chemicals that lead to the symptoms Stu so adeptly displayed. (Solve the hidden cause of many chronic health issues and lose weight with The Good Gut Diet.)
Because of this standard immune system reaction, a legit food allergy will result in things such as hives, swelling, difficulty breathing, wheezing, sneezing, and trouble swallowing, says Amy Shah, MD, an asthma, allergy, and immunology specialist at Valley E.N.T. in Glendale, AZ.
Sensitivities and intolerances don’t have the same type of immune system response and instead result mostly in GI complaints, she says, such as diarrhea, constipation, gas, or bloating. An intolerance means a person lacks an enzyme required to break down a part of the food; people with lactose intolerance are short on the enzyme lactase, which breaks down the sugar lactose in milk, for example. A food sensitivity is less well defined, Lanser says, but typically involves mild abdominal pain and an upset stomach after eating certain foods. It doesn’t seem to be determined by the immune system or any specific deficiency.
…or primarily in your head.
If your only or biggest symptom after eating is a headache, it’s not an allergy, Lanser says, because it’s not one of the classic responses dictated by your immune system. Headaches and brain fog are most likely signs of a sensitivity, he says. (Here’s what else your brain fog could mean.) Same goes for behavior changes. Worried parents have long associated allergies with hyperactive little ones, but a true allergic reaction probably wouldn’t send a kid bouncing off the walls. Instead, an allergy is more likely to make a child clingy, withdrawn, and quieter than usual, Lanser says.
Your symptoms come on gradually.
After that big pasta and pizza fest, it might take you an hour or so to really feel your worst if you’re sensitive or intolerant. Allergic reactions, on the other hand, happen nearly instantaneously. “The whole reaction usually peaks and ends around 30 minutes after exposure,” Shah says.
You don’t feel the same every time you eat the same food.
You might feel bloated and headachy when you eat pizza, bagels, or toast and assume you’ve got a wheat allergy—until there’s a day when a little slip-up doesn’t bother you whatsoever. With an intolerance or a sensitivity, you’ll probably have symptoms when you eat that problematic food, but you might not necessarily have them every time. Whereas “with food allergies, the reaction happens every time, and it’s not subtle,” Shah says.
You can handle a bit of the food or prepare it a safer way.
It follows, then, that sometimes a little bit might be fine. “Most people can tolerate small amounts of foods they’re sensitive to,” Shah says. No such luxury with an allergy; not even a crumb will do. “If you have a peanut allergy, you’re never going to not have a reaction,” Lanser says.
You’re only concerned because a friend/coworker/mother is concerned.
If we haven’t made this clear enough yet, true allergy symptoms are life-threatening and raise serious red flags. Yes, a sensitivity or intolerance can cause discomfort, but if you never noticed anything before someone planted the idea in your head, you probably don’t have a food allergy.
You’ll be in the bathroom for hours if you drink milk, but not after eating a hard cheese like Cheddar.
That’s not a dairy allergy; it’s lactose intolerance. In fact, many of us lose the ability to digest lactose after childhood, Shah says, so milk can be particularly problematic. But because the bacteria that makes cheese feeds on lactose, most of the problematic enzyme is eliminated in hard, aged cheeses, so you do still have some intolerance-friendly dairy options. And if almond, soy, cashew, or coconut milk won’t cut it, you can conveniently get your missing enzyme in the form of an over-the-counter pill.
Still think it’s a food allergy?
Then it’s time to get tested by a qualified allergy specialist. You’ve probably heard of the classic skin test used to figure out if you’re allergic to things such as pollen and puppies. The same test works for food: Microscopic amounts of common allergens (e.g., wheat, soy, eggs, tree nuts) are placed under the first layer of skin, and if you’re allergic, you’ll see a mosquito bite–like bump within 15 to 30 minutes.
The gold standard, Lanser says, is the skin test and a blood test, which measures the levels of IgE antibodies in your body after eating certain foods. There’s currently no test to diagnose a sensitivity, Lanser says. If it seems more likely that’s your issue, your best bet is to keep a detailed diary of everything you eat and all the stomach rumblings, headaches, and wooziness you feel afterward. Slowly but surely, you’ll see a pattern in your reactions, he says. Shah recommends avoiding the culprit for 4 to 6 weeks, then reintroducing it into your diet. The reaction should be pretty obvious after staying away from the trigger for so long, she says.