Expert Q&A: Eating With Food Allergies
An interview with Stanley Cohen, MD.
What is the difference between an intolerance and an allergy?
Most people think the terms "food allergy" and "food intolerance" mean the same thing. Yet a food intolerance or reaction does not involve the immune system and can involve components of the food other than proteins. Milk or dairy is a good example in which many people confuse an allergy with intolerance. A milk allergy can only occur if the individual is allergic to the milk proteins (casein, whey, or lactalbumin). Intolerance to milk is caused by an inability or reduced ability to digest the milk carbohydrate (lactose), and results in diarrhea, bloating, gas, pain but no vomiting or rash.
Other common food intolerances are to wheat and corn products. Approximately 33% of adults and 6%-8% of children have had some kind of intolerance or adverse food reaction.
Can intolerances be diagnosed with a medical laboratory test?
If you suspect you are lactose-intolerant, your doctor can give you a hydrogen breath test to verify the condition. Blood tests can confirm a gluten intolerance. Eliminating suspected foods, then reintroducing them in a planned way, helps confirm a diagnosis of food intolerance.
Is it true that people with lactose intolerance can tolerate some dairy products?
Yes, but they need to proceed cautiously to determine that it is an intolerance, and not an allergy. If you have some degree of tolerance to dairy, test your limits by consuming small portions at meals and watch for symptoms. Good choices for this kind of testing are aged cheeses and yogurts with active cultures, which have less lactose. Other options are to drink milk that contains predigested lactose, or take an enzyme that aids in lactose digestion. Keep in mind that dairy is sometimes not well-tolerated immediately following a bout of gastroenteritis, but this is only temporary.
If you suspect your child has an allergy, what should you do?
For a few weeks, keep a diary of everything your child eats and at what time, any symptoms, and what time symptoms appear. Keeping a symptom diary will help you and your physician identify food triggers or patterns. Take into consideration any emotional factors in your child's life, such as stress, or whether the symptoms only occur on school days, or every time he has a baseball game or a visit with a stepparent.