Food allergies – don’t swallow everything you hear
When it comes to food allergies, rampant misinformation is far too easily digested. From food sensitivity testing to allergy prevention in babies, incorrect information is actually contributing to an increase in food allergies.
For Food Allergy Awareness Month in May, allergist Dr. Samira Jeimy with the Allergy and Immunology Program of St. Joseph’s Health Care London is debunking some of the most common food allergy myths.
More than 2.6 million Canadians, including nearly 500,000 children, are living with food allergies that need to be managed daily. In the last five years, research into the growing prevalence and incidence of food allergies is revolutionizing the approach to prevention, diagnosis and treatment. For example, says Dr. Jeimy, where the advice was to avoid feeding a child peanuts until age three or four, the thinking now is to expose children at low risk of the allergy (those without a family history, eczema or egg allergy) to peanuts by age six months to prevent the allergy from developing.
Food allergy myth-busting
According to Dr. Jeimy, the following myths are most in need of busting to reduce the incidence of allergies as well as spare individuals from unnecessarily, and sometimes dangerously, restricting their diet.
- MYTH: Food sensitivity testing can diagnose allergies
FACT: Food adverse reactions can have many forms. There are allergies, which present as hives/swelling along with breathing problems, lightheadedness, passing out and gut problems, which require an EpiPen to treat. Other reactions are non allergic – like food poisoning, symptoms of celiac disease, or gut upset only (in the absence of skin or breathing problems). In this case, an allergy test will not pick up the true diagnosis.
A commonly advertised – and expensive – test called immunoglobulin G (IgG), tests for up to 400 foods but there is no evidence to support its use to diagnose food allergies or predict future adverse reactions. Research shows that the presence of specific IgG antibodies to food is actually a marker of exposure and tolerance to food. In other words, positive test results for food-specific IgG are expected in normal, healthy adults and children who are regularly exposed to that food.
The inappropriate use of this test, which can cost as much as $400 and is not covered by the Ontario Health Insurance Plan, only increases the likelihood of false diagnoses being made, resulting in unnecessary dietary restrictions and decreased quality of life.
As well, there is a growing body of evidence that avoidance of a food can actually create an allergy.
Food related reactions can be complex. If you have concerns, see your physician, who may recommend evaluation by a gastroenterologist, allergist or other specialist, depending on the symptoms.
- MYTH: Infants are at high risk of severe food allergy reactions.
FACT: Teenagers and individuals with asthma are actually at highest risk of allergy reactions. Infants typically have mild reactions on first exposure to a food.
- MYTH: Allergenic foods should be avoided in baby's diet until they are 3 years old.
FACT: There is high-quality evidence that introduction of peanut and egg as early as four to six months of age is actually protective against food allergies. As well, early introduction was shown NOT to interfere with breastfeeding.
- MYTH: Allergists can't test infants for food allergy.
FACT: Allergists see patients of all ages, starting with newborns, especially if there is eczema or a concern for food allergy based on family history.
- MYTH: A woman’s diet in pregnancy can trigger allergies in her baby.
FACT: Current guidelines do not recommend pregnant women avoid any foods. It’s also important to know that a maternal diet rich in fruits, vegetables, fish, foods containing vitamin D, whole grains, legumes and healthy fats is associated with lower rates of children developing allergic diseases such as asthma and eczema and rhinitis (nasal congestion, runny nose, sneezing, red eyes, itchy nose or eyes).
- MYTH: The size of your skin test reaction or allergy blood test level determines severity of food allergy.
FACT: Every medical test has a false positive and false negative rate. In the case of food allergies, there is a risk of being falsely labelled with a food allergy, which can directly impact your quality of life. Your clinical history is the most important factor, not the magnitude of the test results. As well, the severity of a future reaction can’t be predicted based on extent of positive test results for a food allergy.
An excellent source of information on food allergy testing can be found on the Kids with Food Allergies website.
About St. Joseph’s Food Allergy Clinic
At St. Joseph’s Food Allergy Clinic children and adults with any kind of food allergy (referral required) can be definitively diagnosed using the latest, evidence-based approaches, including food challenges where the person is exposed to the food and monitored. For certain food allergies, such as peanut, the clinic offers oral immunotherapy under very strict and careful supervision of allergy specialists.
- Learn more about St. Joseph’s Allergy and Immunology Program
- Referral information to the Food Allergy Clinic (family physicians must complete the form)
- London Free Press: London doctor serves up straight goods on food allergies online