Over 32 million Americans battle food allergies, affecting one in three children and one in 10 adults. And recent research confirms millions more are troubled with food intolerances. The difficulty lies in deciphering what food is causing symptoms and whether it may be life-threatening or not. If food allergy has been ruled out, there are steps you can take to help you identify your triggers and reduce adverse food reactions.
What is a food allergy?
A food allergy is a serious immune response to a food antigen – a protein within a specific food – and may involve IgE antibodies or other parts of the immune system such as eosinophils or T cells.
Symptoms such as anaphylaxis, swelling, difficulty breathing, dizziness and digestive disturbances may occur. A type of “mixed allergy” involving both IgE antibodies and non-IgE immunity such as is the case with eosinophilic gastrointestinal diseases may cause immediate and delayed reactions. Those with asthma are at higher risk of severe adverse reactions to food allergens.
A food allergy of previously safe foods may spontaneously develop due to environmental allergies such as birch or ragweed pollen, presence of other food allergies, compromised intestinal permeability or leaky gut, and/or asthma.
A food intolerance or sensitivity is a less well-understood reaction but is more delayed, taking hours up to days to develop, and results in digestive symptoms first.
A food sensitivity or intolerance does not involve IgE antibodies like a food allergy and is therefore not immediately life-threatening.
Symptoms range from mild to severe abdominal pain, bloating, nausea, diarrhea, constipation, gas, headaches or inflammation, but not anaphylaxis. Tiny amounts or cross-contamination of trigger foods don’t typically cause major symptoms unlike a food allergy.
Some of the most common food triggers for sensitivity or intolerance include:
- Dairy (lactose): Lactose is the milk sugar found in mammals such as cows and goats. The majority of the world’s population is lactose intolerant due to a genetic decrease in internal lactase production, the enzyme required to digest lactose.
- Wheat (gluten): Gluten is the protein found in wheat, rye and barley. Though a true food allergy to wheat does occur, intolerance to gluten is more common.
- Histamine: This is a chemical naturally present in some foods like cheese.
- Sulfites: Chemicals found in red wine, fermented foods and dried fruits.
- FODMAPs: These are types of carbohydrates that are fermented by gut bacteria and may lead to gas, bloating, constipation, diarrhea and other digestive discomfort in susceptible individuals.
How to determine food triggers
An elimination diet is the current gold standard for identifying food intolerances because IgG antibody food sensitivity testing may be unreliable. A step-by-step plan is recommended.
Step 1: Plan
Meet with your doctor and/or dietitian to identify potential problem foods/substances to avoid. Complete lab work, meal plan, and gather resources.
Step 2: Avoid
Eliminate allergens/intolerances (all or targeted) by four to six weeks. Journal symptoms. Do not proceed to challenge step if symptoms don’t improve within six weeks.
Step 3: Challenge – three days on – three days off
Add one food/substance back in starting with a small portion on day one. If you experience few or no symptoms, double the portion for day two, then double again on day three. Stop the specific food challenge, then wait three more days in case of delayed reactions. Journal symptoms daily to identify patterns. Symptom-free foods become “okay” or “safe” foods, but do not eat this food again until all food challenges are over. Symptom-inducing foods remain on the avoid list until rechallenged at a later date. Follow the same three days on / three days off procedure for any other foods you need to challenge.
Tips to navigate store-bought and restaurant-prepared food
FARE reports that most food allergy reactions occur outside of the home, not to mention accidental ingestion of trigger or intolerance foods, so caution and planning is paramount to avoid reactions and minimize food-induced symptoms.
Due to the risk of cross-contamination during manufacturing or restaurant preparation, use these tips to more confidently enjoy your food:
- Inspect labels carefully. Ingredients change frequently – without warning – so practice caution by checking labels regularly, even those you consider “safe.” The top eight allergens – milk, soy, wheat, peanuts, tree nuts, fish, shellfish, and egg – must be listed but cross-contamination labels such as “may contain” or “manufactured in a facility that also processes” are voluntary.
- Speak with the manufacturer. Manufacturers may be able to provide more information about cross-contamination risk and processing practices than the label does.
- Carry a food allergy or intolerance card. Present this card to servers at restaurants so the chef can be notified of foods you need to avoid and minimize your risk of symptoms.
- Choose short and simple ingredient lists. Shorter ingredient lists mean you’ll be able to more easily pinpoint the source of any symptoms. In addition, simpler packaged foods mean less processed ingredients and often more whole, nutritious foods.
Allergies are more easily diagnosed because they involve IgE antibodies. Food intolerances and sensitivities are not immediately life-threatening but may cause significant symptoms. For a food intolerance, an elimination diet may help you determine your individual trigger foods. With awareness, planning and caution, you can reduce your chances of consuming allergens or trigger foods so you can feel your best and minimize symptoms.
- A food allergy is a life-threatening immune reaction involving IgE antibodies. Great care must be taken to avoid the allergenic foods for those with diagnosed food allergies.
- A food intolerance/sensitivity may still involve the immune system, but not IgE antibodies, and therefore is not immediately life-threatening. It may however still cause troubling symptoms and lower quality of life.
- An elimination diet can be a helpful tool in identifying your individual food sensitivities or intolerances.
- To ensure safety for those with food allergies, it’s best to avoid products with listed and cross-contamination allergens. Read labels carefully every time you eat whether you have an allergy or intolerance.
Food Allergy Research & Education. Facts & Statistics.
Cambridge Press. High prevalence of food intolerances among US internet users.
Alimentary Pharmacology and Therapeutics. Review article: The diagnosis and management of food allergy and food intolerances.
Allergy UK. Allergy vs. Intolerance.
UW Integrative Health. The Elimination Diet.