Expert Q&A: Eating With Food Allergies

Expert Q&A: Eating With Food Allergies


An interview with Stanley Cohen, MD.


An estimated 12 million Americans suffer from food allergies. Dairy
and wheat are just a few of the foods that can cause reactions and
allergies in adults and children.
Food allergies and
reactions can be confusing. Often, it's not easy to figure out which
foods contain ingredients that may trigger a reaction. Further, many
people who think they are allergic to a food may actually be confusing
a food reaction for an allergy -- and may not need to eliminate certain
foods.
WebMD turned to Stanley Cohen, MD, for answers to common questions
about food allergies. He's a specialist in pediatric gastroenterology
and nutrition, and author of Healthy Babies, Happy Kids: a Common Sense Guide to Nutrition for Growing Years.
What is a food allergy?


A food allergy is a predictable reaction to a specific food or food group. An allergy is caused by an immune reaction to the protein in a food, which brings about a sudden release of chemicals that cause the symptoms.
Symptoms
typically appear within a few minutes to two hours of consuming the
food. They can range from mild -- like a rash, itching, or swelling --
to life-threatening, including breathing difficulties and swelling of
the throat or tongue. Many people with severe allergies carry an
epinephrine pen, a self-injectable device to help counteract the
allergic reaction and give them time to get emergency medical attention.
Many
children and adults will start with a single allergy, and then develop
others. Some even "lose" their allergy over time. If you are allergic
to milk protein, you may also be allergic to other kinds of milk
protein, like goats' milk and soy beverages.
What are the most common food allergies?


Eight foods account for 90% of all food allergy reactions: milk, eggs, peanuts, tree nuts, soy, wheat, shellfish, and fish.
In
older children and adults, fish, peanuts, shellfish, and tree nuts are
the most common allergies. These allergies are also considered the most
serious, because they can be life-threatening.
If you are trying to avoid allergenic foods, what should you look for on food labels?


It
is essential that you become an avid label reader. Start at the list of
ingredients, which is where you will find the clues to what is
contained within the product.
Become familiar with all the
food terms for your specific allergy. For example, if you are allergic
to milk protein, you need to avoid all foods made from milk, including
cheese, yogurt, half-and-half, and cream. Avoid all foods that contain
whey, casein, caseinate, nonfat milk solids, lactoglobulin, cow's milk
protein, nougat, curds, sodium caseinate, or lactalbumin. Look
carefully at butter, margarine, ice cream, cakes, puddings, sorbet,
breads, soups, vegetables with sauces, and more.
People
with allergies would benefit from a diet that is less processed and
closer to natural foods, because there are fewer additives in these
foods that could cause problems.

How are allergies diagnosed?


There are several ways to
confirm an allergy. First is the old-fashioned prick test, where the
skin is scratched with the allergen and observed for reactions. The
second is the patch test, which is similar to the prick test, and the
last are specific food allergy blood tests. In all of these tests,
there is a possibility for false positives and negatives, so physicians
usually try an elimination diet, in which the suspected food is
avoided. This is followed by a food challenge in which the suspected
food is reintroduced under careful observation on three separate
occasions to confirm the allergy.
How do you treat allergies?


At
this time, there are no medications that cure food allergies. The most
important treatment is the elimination of the allergy-causing food.
Careful reading of ingredient labels is essential to avoiding all foods
with the allergy-causing ingredient. For example, milk may be listed by
its components casein or whey, and eggs can be labeled as albumin. If
you have an allergy to a certain food, you must become familiar with
all related ingredients that could potentially cause a reaction. A good
rule of thumb is, when in doubt, don't eat it.
Evolving
research suggests that certain probiotics ("friendly" bacteria) may
help to prevent or moderate the effects of some allergies. Consult your
physician to determine if you might benefit from including probiotics
in your diet.
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.
Is there anything parents can do to keep children from developing allergies?


The
cause of food allergies is not fully understood, yet there appears to
be a hereditary association. Children are 20% more likely to develop
allergies if one of their parents has the allergy, and 40% more likely
if both parents are allergic.
Breastfeeding may help prevent the onset of allergies, especially if the infant is breastfed for an extended period of time.
Some
experts think an early introduction to the highly allergic foods may be
beneficial in breastfed babies. Introduction should occur slowly,
between 4 and 6 months of age, with only one new food a week, and
parents must be vigilant in watching for symptoms. It's recommended
that you check with your doctor before introducing these foods.
What precautions should allergic moms take when feeding their newborns?


Breastfeeding
is best. Protein hydrolysate infant formulas are the recommended
formula for allergic infants. When you start introducing foods, only
introduce one new food a week, starting with rice cereal or vegetables
and ending with eggs. Be very cautious with egg whites, since they are
highly allergenic in infants. Preferably, introduce them in the
presence of your physician.
Can children outgrow food allergies?


Most
allergies start in childhood, but not all. What is fascinating is that
some kids outgrow their allergies and begin tolerating the protein by 5
years old if they avoid the offending foods when they are young. In
the case of milk allergy, this occurs primarily in infants and
toddlers, and many outgrow it by the age of 3.
However, allergies to peanuts, tree nuts, fish, and shellfish tend to be lifelong.
Why are wheat allergies and gluten intolerance on the rise?


More
cases are being identified because we have better screening tools. It
is now estimated that one in 133 people have a wheat allergy to the
gluten (protein); previously we thought only one in 5,000 had the
allergy.

What precautions should you take if you suspect you are gluten-intolerant?


Gluten
is a combination of starch and protein found primarily in wheat,
barley, rye, and spelt. It is used extensively in our food supply as a
thickening agent and filler, and can be found in minute amounts in
foods ranging from ketchup to ice cream.
A growing number
of people feel they have difficulty digesting gluten, or blame gluten
for other conditions. Grains that are well-tolerated for
gluten-sensitive individuals are corn, rice, potatoes, buckwheat,
amaranth, quinoa, and sorghum. Legumes are a high-fiber, high-protein
option that can be used as a grain substitute.
If you feel
you are not tolerating gluten, read labels carefully to avoid products
made from wheat, barley, bulgur, matzo, rye, spelt, graham flour,
semolina, farina, triticale, durum, gluten, gliadin, and couscous and
everything that is made from these products.
Any suggestions for eating out with allergies?


Eating
out is a challenge when you have allergies, because you don't know
exactly what is in the food you order. Ask lots of questions of the
server to better understand the contents of your favorite dishes, and
frequent those restaurants where you find foods that are prepared
without offending foods.
In general, ordering simply
prepared foods is your best bet. Go for grilled or roasted meats, and
fish or chicken without flour coatings. Steamed vegetables, baked
potatoes, plain rice, and fruit are other dishes that should be
well-tolerated.
Can you develop an allergy to a food that you once tolerated?


Yes,
but perhaps more commonly, you may have been allergic but because of a
limited exposure to the food you may have not recognized the food
reaction symptoms. For example you may not have linked a skin rash to
your diet, but it could be a symptom of an allergy. Or, if you
typically don't eat much shellfish, you might not know you have an
allergy until you eat a large portion.
If you are
eliminate certain foods or food groups due to allergies or
intolerances, should you be concerned about missing nutrients?


Absolutely.
All of my patients work with a registered dietitian to ensure the
missing nutrients from the eliminated food is supplied by other foods
or dietary supplements. This is especially important when there are
multiple allergies or when dairy is limited or eliminated, because it
is the best source of calcium in the diet.