Think You Have Food Intolerance? Test It

Only 3 to 4 percent of adults have true food allergies. If you experience bloating after consuming a plate of pasta, or gassiness after enjoying an ice-cream sundae, you most likely have a more common condition: Food intolerance.

While it's confusing to tell the difference between a food allergy and food intolerance, the main difference is that an allergy to an offending food is an immune system reaction.

Allergy or Intolerance?

Food intolerance may produce symptoms such as:

  • Nausea
  • Vomiting
  • Gas
  • Cramps
  • Bloating
  • Stomach pain
  • Diarrhea
  • Headaches
  • Irritability
  • Nervousness

Reactions due to food intolerance are generally of a digestive nature, but can affect the nervous system as well. The symptoms may be uncomfortable, and may lead to serious health consequences, but are rarely life-threatening. On the other hand, a food allergy may produce anaphylaxis, a life-threatening response to the allergen. 

According to the American Gastroenterological Association, an allergic reaction to food can take place within a few minutes to an hour. Reactions can begin with itching in the mouth, progressing to vomiting, diarrhea, and abdominal pain, and even lead to asthma, hives, eczema, and a drop in blood pressure.

Common food intolerances include:

  • Gluten—found primarily in grains such as wheat, barley, and rye.
  • Fructose—a sugar naturally found in fruits and honey, but is also present in some soft drinks and fruit beverages.
  • Lactose—found in cow's milk and dairy products.
  • Corn products.

Testing Different Food Intolerances

Fructose Intolerance. Your doctor will most likely order a breath test that checks for hydrogen. According to the AGA, "when hydrogen is detected within one hour after eating a food containing fructose, the person is regarded as being fructose intolerant."

Lactose Intolerance. A lactose tolerance test first measures fasting blood sugar. Then, after consuming liquid containing lactose, blood samples are taken over a two-hour period to determine glucose levels. This allows doctors to see how well the body is able to digest the sugar.

The doctor may also order a hydrogen breath test to help determine if you have an inability to digest lactose.

Gluten Intolerance. A blood test looks for gluten autoantibodies. If the test is positive, an intestinal biopsy may be conducted to look for damage to the intestinal lining that may point to Celiac disease, an autoimmune disorder that affects about 1 in 130 people.

And lastly, if symptoms disappear after eliminating gluten from your diet, chances are you are sensitive to gluten.

About Elimination Diets

An elimination diet-avoiding the suspected food for a period of time then reintroducing the food to see if the food really does create an adverse reaction-is helpful in determining if you have a food intolerance.   

However, do not omit foods from your diet before talking to your doctor.  It's important to work with your doctor to be sure you're completely eliminating the culprit (gluten, for example, can be found in vitamins, cold cuts, and soy sauce).




Food Allergy. The Mayo Clinic. Web.

Understanding Food Allergies and Intolerances. American Gastroenterological Association. Web.

Is It a Food Allergy or Intolerance? WebMD. Web.