As a registered dietitian, I have encountered many clients who are confused about the difference between food allergies and food intolerances. While both can cause unpleasant symptoms after consuming certain foods, they are actually two distinct conditions with different underlying mechanisms.
What is a Food Allergy?
A food allergy is an immune system response to a specific food protein. When someone with a food allergy consumes that particular food, their immune system mistakenly identifies it as a threat and produces antibodies to fight it off. This triggers the release of histamine and other chemicals, which can cause a range of symptoms such as hives, swelling, difficulty breathing, and even anaphylaxis in severe cases. Food allergies are relatively common, affecting about 4-6% of children and 4% of adults in the United States.The most common food allergens include peanuts, tree nuts, milk, eggs, soy, wheat, fish, and shellfish. These eight foods account for about 90% of all food allergies.
What is a Food Intolerance?
Food intolerance, on the other hand, is a non-immune reaction to certain foods or food components. It occurs when the body has difficulty digesting or metabolizing a particular food or ingredient. Unlike food allergies, food intolerances do not involve the immune system and are not life-threatening.However, they can still cause uncomfortable symptoms such as bloating, gas, diarrhea, and abdominal pain. The most common food intolerances include lactose intolerance (inability to digest lactose in dairy products), gluten intolerance (inability to digest gluten in wheat and other grains), and histamine intolerance (inability to break down histamine in certain foods).
What Causes Food Allergies and Intolerances?
The exact cause of food allergies and intolerances is still not fully understood. However, research suggests that both genetic and environmental factors play a role.Food allergies
tend to run in families, which suggests a genetic predisposition. If one or both parents have a food allergy, their child is more likely to develop one as well. Exposure to certain allergens early in life may also increase the risk of developing food allergies.Food intolerances
, on the other hand, are often caused by an enzyme deficiency or sensitivity to certain food components.For example, lactose intolerance occurs when the body does not produce enough lactase enzyme to break down lactose, the sugar found in dairy products. Gluten intolerance, also known as celiac disease, is an autoimmune disorder triggered by the ingestion of gluten.
Diagnosing Food Allergies and Intolerances
The first step in diagnosing a food allergy is to undergo an allergy test, which can be done through a skin prick test or a blood test. These tests measure the levels of IgE antibodies in the blood, which are produced in response to allergens. If the results show high levels of IgE antibodies to a specific food, it is likely that the person has a food allergy.Food intolerances
, on the other hand, are more challenging to diagnose.There is no specific test for food intolerances, and symptoms can vary widely from person to person. The best way to identify a food intolerance is through an elimination diet, where suspected trigger foods are removed from the diet for a period of time and then gradually reintroduced to see if symptoms reappear.
Managing Food Allergies and Intolerances
The only way to prevent a food allergy reaction is to avoid the trigger food altogether. This can be challenging, especially when eating out or traveling. People with severe food allergies should always carry an epinephrine auto-injector (such as an EpiPen) with them in case of accidental exposure.Food intolerances
, on the other hand, may not require complete avoidance of the trigger food.For example, someone with lactose intolerance may be able to tolerate small amounts of dairy products without experiencing symptoms. In some cases, taking enzyme supplements or avoiding certain food combinations may help manage symptoms.
