Symptoms of a food intolerance

The symptoms of food intolerance are often compared to those of food allergies, which involve the immune system. Food intolerance symptoms tend to be less severe; anaphylaxis, a life-threatening reaction, may occur with food allergies but is much less common with intolerances. In general, the symptoms of food intolerance tend to be milder than those of true food allergies. They may appear within minutes of consuming the trigger food, or up to 48 hours later, making it more difficult to tie the symptoms to the trigger food.

The symptoms of food intolerance tend to be gastrointestinal. Most of those with a food intolerance will experience at least one of the following symptoms: upset stomach, bloating, cramping, gas, diarrhea, and constipation. For many of those with a food intolerance, these symptoms are the only signs of the food intolerance. If you have irritable bowel disease, it may also be a sign of food intolerance.

In addition to gastrointestinal symptoms, food intolerance may affect many other areas of the body. Other potential symptoms include headaches, dizziness, chills, irritability, or fatigue. A food intolerance can also affect the respiratory system, with congestion, watery eyes, a runny nose, or symptoms mimicking those of asthma. You may also experience skin symptoms including rashes, hives, and eczema.

How do you know if these symptoms indicate a food intolerance or something else? Visit your doctor for food intolerance blood tests and advice on whether an elimination diet or food diary could help pinpoint the cause.