What to Do If You Think You Have a Food Sensitivity

McKenna Princing Fact Checked
A woman holds a cactus in an ice cream cone.
© Thais Varela / Stocksy United

Maybe you’ve noticed your stomach gets a little wonky after eating gluten. Or you saw an advertisement on Facebook for an at-home food sensitivity test kit and thought it could help you figure out why you’ve been so gassy lately.

Many of us have stomachs that don’t approve of certain foods. But is it an intolerance? Maybe an allergy? Can an at-home test help you figure out what the problem is and what to do about it?

Here’s what you need to know about food sensitivities, those at-home tests and how to get your stomach back on the right track. 

Food sensitivity vs. food allergy

First, it’s important to clear up one major misconception: food allergies and food intolerances or sensitivities are not the same thing.

“People get really confused between the three. I always ask every patient if they have any intolerances or allergies, and they’ll often give me a list of seven things and say, ‘I can’t eat soy, dairy, gluten, pineapple, eggs, etc.,’” says Judy Simon, a registered dietitian nutritionist who sees patients at UW Medical Center – Roosevelt. 

A food allergy is an immune response, whereas a food intolerance is often a digestive issue, Simon explains. 

With an allergy, your body mistakes a specific food, such as peanuts or eggs, as an invader and ramps up its immune response. This causes potentially life-threatening symptoms such as severe hives, breathing problems or anaphylactic shock

In contrast, most food intolerances are (thankfully) not dangerous but can be extremely uncomfortable. (Not-so-fun fact: Irritable bowel syndrome (IBS) is often connected to having food intolerances, according to Simon.)

Take lactose intolerance, which Simon says impacts around two-thirds of the worldwide population to some degree. With this condition, your body lacks enough of an enzyme called lactase, used to digest foods that have lactose in them, such as milk, cheese and other dairy products. Because of this, the bacteria in lactose ferments in the gut instead of broken down in the digestive tract normally. This causes bloating, diarrhea and other unpleasant symptoms. 

In some cases, people may get reflux-like symptoms from a food sensitivity, such as heartburn, phlegm or even irritation in the skin around the mouth. Symptoms like these are often caused by acidic foods and drinks such as citrus fruits or coffee.

People can have food intolerances to all kinds of things, such as caffeine, sulfites or FODMAPs, which stand for fermentable oligosaccharides, disaccharides, monosaccharides and polyols, which are all types of carbs.

There are other diseases that can cause digestive issues, such as celiac disease, which is an autoimmune disorder that causes an immune reaction to gluten. People with celiac disease won’t go into anaphylactic shock, but they still shouldn’t eat gluten because it damages their small intestine, leading to other health issues.  

Why at-home food intolerance tests don’t work

Before you buy that at-home test kit for food sensitivities, there’s something you should know: it’s not testing what you think it is, which means it won’t give you the results you’re looking for.

It all comes down to antibodies. To detect a true food allergy, doctors will do a test to see how much of the IgE (which stands for immunoglobin E) antibody your body produces. This is the antibody that triggers an allergic reaction. 

At-home food sensitivity test kits, however, don’t test for IgE; they test for IgG, a different antibody that our body produces naturally after eating, well, lots of different things.

“When we eat foods, we develop antibodies in response to certain foods. Producing those IgG antibodies is what our body is supposed to do,” Simon explains.

Which means the at-home tests are measuring a normal immune response, not an abnormal one caused by any food intolerances. 

“What happens is — and I see this all the time — people think they’re allergic to 25 foods after one of these tests. If you did four different tests, you could get four different results,” Simon says.

Thus far, Simon has not come across any clinical benefits of testing for IgG antibodies, she says. 

Additionally, at-home food sensitivity test kits are not regulated by the Food and Drug Administration (FDA). 

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How to deal with food sensitivities

So, if at-home tests are off the table, what other options do you have for diagnosing and treating food intolerances? Here are some strategies Simon recommends. 

Get tested by a doctor

There are reliable, science-backed tests that can diagnose some food allergies or sensitivities. For example, there’s a blood test for celiac disease and breath tests to check for things like lactose intolerance or fructose intolerance.

One caveat of these types of tests is that you need to still be eating the disruptive food in order for the test to work, says Simon. So, if you think you have celiac disease, you need to keep eating gluten until after you’ve been tested. 

If you’re interested in getting a test, talk with your doctor.

Keep a food diary

If you’ve worked with your doctor to get tested for food sensitivities and allergies and haven’t had any luck getting results, the next step might be food journaling. 

“If someone doesn’t have easily diagnosable symptoms, I’ll tell them to eat as simply as possible, keep a food diary for a few weeks, and try to find connections,” says Simon.

Keeping a food diary means writing down all of the food you eat each day and noting if you have any stomach problems. After keeping track of your eating and symptoms for some time, you can go back and look at what you wrote and see if there were any foods that caused distress several times. 

Try an elimination diet

Elimination diets involve eliminating foods that may bother you and then slowly adding them back in to see how your stomach reacts. Elimination diets take time to be done properly, and it’s usually best to try one with the guidance of a dietitian or doctor, says Simon. 

At first, elimination diets may seem restrictive, but the goal is to figure out which foods bother you so you can continue eating all the foods that don’t bother you with peace of mind. 

One example of a proven elimination diet is the low-FODMAP diet, which helps many people who have IBS, says Simon. 

Check in with your mental health

“When someone comes to me, I listen to their discomfort and treat them as a whole person, not just what’s going on with their gut,” says Simon.

This approach is important for many people who are experiencing stomach problems, since the gut and brain are linked: literally. Your stomach and brain talk to each other, and one often influences the other. 

That’s not to say that abdominal distress is all in someone’s head, because it’s obviously not. But for people who do experience anxiety or other mental stress along with stomach problems, working to better their mental health may also help their stomach. 

If you’re seeking help for possible food intolerances, the most important thing is that you find a dietitian or doctor you feel comfortable with, says Simon. They should listen to your concerns and take your discomfort seriously, while working with you to find the best approaches to treatment.