Food intolerances arise if the body is unable to digest a certain food. This impairment may be due to a lack of digestive enzymes or a sensitivity to certain chemicals.
While a food allergy results from an immune system reaction to a specific food, food intolerances usually involve the digestive system, not the immune system.
A person with a food intolerance will often experience discomfort soon after eating certain foods. The symptoms are varied and usually involve the digestive system.
Common symptoms of food intolerance include:
- excess gas
- stomach pain
- a runny nose
- malaise, which is a general feeling of being under the weather
In people with a food intolerance, the amount of the food that the person eats determines the severity of their symptoms.
The symptoms of food intolerances can take a while to emerge. The onset may occur several hours after ingesting a food, and the symptoms may persist for several hours or days.
It can be difficult to determine whether someone has a food intolerance or an allergy because the signs and symptoms of these conditions overlap.
These conditions have some symptoms in common. However, food intolerance symptoms tend to take longer to appear than food allergy symptoms.
While a food allergy results from an immune system reaction to a specific food, a food intolerance involves the digestive system rather than the immune system.
With a food intolerance, the amount of the food the person eats is related to the severity of their symptoms. On the other hand, with a food allergy, even a small amount of food can trigger a severe allergic reaction.