Food Sensitivity Tests: The Pitfalls of Home Testing Kits
Jul 19, 2018
If you’ve watched commercials, been online, or received mail in the past few months then you’ve likely see advertisements for food sensitivity testing that you can perform from the comfort of your own home. Several companies aggressively market these ‘one of a kind’ tests and even include celebrity endorsements. Before you spend your hard earned money (most tests start around $200), it’s important to understand exactly what these tests can and can’t do.
Food allergies are caused by an allergy antibody known as IgE. If someone has a food allergy, they will have immediate onset and reproducible symptoms every time they eat that food, regardless of what form. For instance, if someone has a milk allergy, they cannot eat cheese, ice cream, or yogurt. Food allergy symptoms can include itching, rash, hives, swelling, difficulty breathing or swallowing, vomiting and, in rare cases, death. Skin prick or blood IgE tests can help with diagnosis.
A food sensitivity, or intolerance, on the other hand, does not involve an immunologic or allergic response. These cause difficulty with digestion and symptoms such as bloating, cramping, and diarrhea. A common example is lactose intolerance. Lactose is a sugar found in dairy products. People with lactose intolerance lack the enzyme to digest the sugar, which passes into the gastrointestinal tract undigested and essentially draws water into the bowels, causing symptoms. People can either avoid lactose or take an enzyme replacement before eating dairy.
There are no validated tests to diagnose food sensitivity. Diagnosis relies on a detailed dietary history, eliminating suspected foods for several weeks to see if symptoms improve, then reintroduction of the food to see if symptoms return. Several studies have shown that people who suspect food sensitivity often identify the wrong food or have another reason for their symptoms.
Enter a unique opportunity to market a handy at-home ‘test’ to help people finally figure out their food sensitivities! These tests measure levels of IgG (not IgE) antibody towards hundreds of foods, then supply a report with IgG levels and their own interpretation of what the levels mean. Here are a few things to consider:
These tests lack proven benefit, evidence supporting their use, or validation. The leading allergy professional organizations specifically recommend againstusing these tests for any purpose.
IgG is a memory antibody that denotes tolerance or exposure. Immunizations cause increased IgG antibody production towards viruses and bacteria, which can mount a rapid response if encountered in real life.
Food specific IgG is a normal response to ingestion. Higher levels likely mean that food is eaten more regularly. Studies looking at children who outgrow their food allergies show IgE levels decrease and IgG levels increase as they develop tolerance.
Did you know that (according to these companies) food sensitivities can cause migraines, poor sleep, memory problems, skin rashes, fatigue, thirst, etc.? (For the record – they cannot). A common tactic lists any possible symptom to capture more people who can identify with the potential need to buy their product.
So what should you do if you suspect food sensitivity? Always talk to your personal doctor first, who can take a detailed history and work with you to determine what may be going on. ALWAYS exercise caution if the medical information you are reading is provided by the same company or product trying to sell you their service; this is a conflict of interest and will be biased. Lastly, if something sounds too good to be true, then it probably is. Save your money and time – talk to your doctor instead.
For more information about Nationwide Children's Hospital's Allergy and Immunology services, click here.
David Stukus, MD, is an associate professor of pediatrics in the Section of Allergy and Immunology at Nationwide Children’s Hospital. Dr. Dave, as his patients call him, is passionate about increasing awareness for allergies and asthma.
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