Unexpected Signs You May Have a Food Intolerance


Food intolerance can be tricky. You may get this confused with a true allergy, or you may wonder if you have celiac disease or just intolerance to wheat. Most people associate digestive issues with food intolerance, but there are other sneaker symptoms too. If you struggle with some mysterious symptoms and you aren’t sure what is causing them, consider the possibility that you are sensitive to certain foods.

Food Intolerance vs. Food Allergy

A true allergy is a response to an allergen, like proteins in peanuts, that is mediated by the immune system. The allergen triggers an immune response that leads to inflammation and characteristic symptoms, like inflammation or hives.

Intolerance to a food is not related to the immune system. It is an issue of digestion. One of the most common intolerances is related to lactose. Some people lack the enzyme needed to digest this sugar found in milk, so if they eat it they experience diarrhea, upset stomach and other symptoms. Other common intolerances are to sulfites, dyes and other food additives.

Common Symptoms of Food Intolerance

Intolerance is most often a digestive issue, so the characteristic and most common symptoms are related to digestion, including:

  • Abdominal discomfort or pain

  • Bloating

  • Gas

  • Diarrhea

  • Nausea and vomiting

  • Heartburn


If you are intolerant to a food and have trouble digesting it, these are the symptoms you may experience. Everyone is different and may have one or two, or even all of these symptoms from an intolerance.

Less Common Signs of Food Intolerance

Food intolerance largely causes digestive symptoms, but there can be other signs that one or more foods just don’t agree with you. These may be directly caused by the food, or they may be consequences of the indigestion and stomach upset the food causes:

  • Headaches and migraines may be triggered by foods, or more often by food additives. Some people report headaches from eating MSG, for instance, a flavor additive.

  • If you are intolerant of sulfites, which are common food additives, you may experience asthma or wheezing.

  • Hives and itchy skin are more commonly associated with true allergies, but not all skin reactions are triggered by allergens. A sensitivity to a food or additive could impact your skin.

  • Fatigue and unexplained tiredness can also be triggered by certain foods. If you are tired but feel as if you get enough sleep, look to what you’re eating.


Do You Have a Food Intolerance?

While intolerances to foods or additives is generally less serious than true allergic reactions, they are also less well understood. Aside from some very specific intolerances, like sulfites or lactose, the cause of most of these reactions are not known, nor are there definitive tests for them. If you think you may be sensitive to a food, you may want to try an elimination diet. This involves cutting out a lot of different foods and then adding them back in to determine what is causing your symptoms.

It’s a good idea to work with your doctor or a nutritionist if you want to try an elimination diet so you don’t miss out on important nutrients. You should also talk to your doctor about allergies and being tested to eliminate allergens as a possibility. If you do go through an elimination diet, once you pinpoint what triggers symptoms, it should be fairly simple to avoid it in the future.