Another cause of food intolerance that is confused with a food allergy is lactose intolerance, or lactase deficiency. This common food intolerance affects at least 1 out of 10 people. The following information provides a basic overview of lactose intolerance:
- Lactase is an enzyme that is in the lining of the gut
- Lactase breaks down lactose, a sugar found in milk and most milk products
- When a person is lactase-deficient, there is not enough lactase in the gut to digest lactose
- Lactose, instead, is used by bacteria to form gas, which causes bloating, abdominal pain, and sometimes diarrhea.
There are tests your healthcare provider can use to find out whether your body can digest lactose.
Another type of food intolerance is a reaction to certain products that are added to food to enhance taste, provide color, or protect against the growth of microbes. Several compounds, such as MSG (monosodium glutamate) and sulfites, are tied to reactions that can be confused with food allergy.
MSG is a flavor enhancer that, when taken in large amounts, can cause some of the following signs:
- Sensations of warmth
- Chest discomfort
- Feelings of detachment.
These passing reactions occur rapidly after eating large amounts of food to which MSG has been added.
Sulfites occur naturally in foods or may be added to increase crispness or prevent mold growth. Sulfites in high concentrations sometimes pose problems for people with severe asthma. Sulfites can give off a gas (sulfur dioxide) that the person with asthma inhales while eating the sulfited food. This irritates the lungs and can send a person with asthma into severe bronchospasm, a tightening of the lungs.
The Food and Drug Administration (FDA) has banned sulfites as spray-on preservatives for fresh fruits and vegetables. Sulfites are still used in some foods, however, and occur naturally during the fermentation of wine.