Food allergies happen when an ingredient in food is mistaken as something harmful by the body. As you ingest a food that you’re allergic to, the body mistakenly believes it has to defend itself from this ‘attacker’. Much as the body defends itself from pollen, the body’s own immune system will start releasing antibodies to fight off this ‘harmful’ invader.
A food intolerance is different. A food intolerance is caused by the digestive system itself responding to an irritating food, as opposed to the response of the whole immune system as happens with an allergy. In the case of intolerance, the digestive system is simply unable to properly digest or breakdown the food. Many people who say they have a milk allergy are actually lactose intolerant – their body has an inability to process the lactose in milk.
Symptoms of a wheat or gluten allergy can include itchy skin – sometimes with rashes or hives, nausea, stomach pain, diarrhea, eczema, joint and muscle aches and pains, shortness of breath and respiratory distress, chest pain, swelling of the airways, and anaphylaxis. Allergic reactions to food can be life threatening, and may require immediate medical care and treatment with antihistimines.
On the other hand, symptoms of wheat or gluten intolerance may include stomach pain, nausea, cramps, bloating, gas, vomiting, heartburn, diarrhea, headaches, irritability, and an unexplained runny nose or itchy eyes. A food intolerance is not usually considered life threatening, although the digestive disorders can cause problems with child growth and development by preventing proper absorption of nutrients.
Apart from the severity of symptoms, another difference between a food allergy and a food intolerance is the amount of food needed to trigger a reaction. Allergies can be triggered by very small amounts of the food allergen. Food intolerance, on the other hand, is affected by the quantity of the food consumed. Eating the occasional small amount of the offending food might not cause a problem, but eating a large amount or eating it frequently may produce symptoms.
And how about Celiac Disease; how does it figure into all this? Celiac (or coeliac) is symptom to a gluten intolerance, however the outcome is more severe. In CD, the small intestine reacts badly to gluten, which is present in wheat and some other grains. The small intestine becomes inflamed which leads to reduced absorption of nutrients passing through during digestion. Eventually, signs of malnourishment can appear as a result of the nutrients not being properly absorbed by the small intestine.