A food sensitivity or food intolerance is a non-immune toxic reaction against a food or food additive. A food allergy, on the other hand, is an immune-mediated allergic reaction against a particular food. Unlike food allergies, the reaction from a food sensitivity usually occurs in a delayed fashion and typically occurs between 1 hour and 3 days after eating the food. Generally, the reaction from a food sensitivity carries a much lower risk and is not as serious as a true allergic reaction. A food sensitivity or intolerance can affect different individuals in different ways and any organ system may be affected. As it may take several days to develop symptoms, people with food sensitivities are often difficult to diagnose and thus may go undiagnosed for many years. A good method to determine if one has a food sensitivity is to perform a food elimination diet and then add one food back at a time for several days to see if the symptoms re-occur. If they do re-occur, then the individual should remove that food from their diet. Some examples of food sensitivities and their causes are as follows:
- Lactose Intolerance – Deficiency of the enzyme “lactase” which normally breaks down the lactose, the sugar found in milk and dairy products.
- Fructose Intolerance – Deficiency of the enzyme which normally breaks down fructose (i.e., fruit sugar) or its precursors (i.e., sugar, sorbitol, brown sugar).
- Gluten Sensitivity – Inability to digest gluten (wheat, barley, and/or rye) or more recent research suggests that it may be the inability to digest FODMAPs (Fermentable Oligo-, Di-, Mono-saccharides and Polyols) rather than gluten.
- Salicylate Intolerance – Many foods naturally contain salicylates, a chemical found in aspirin. The most common foods to contain salicylates are fruits, vegetables, herbs, and spices.
- Histamine Intolerance – Many foods naturally contain histamine, the chemical that is responsible for allergic reactions. Some common foods that contain high levels of histamine are canned goods, fermented foods, alcohol, anchovies, avocado, banana, cheese, chocolate, citrus fruits, cured meat, mustard, peanuts, shellfish, smoked fish, soy, spinach, and tomatoes.
- Alcohol Intolerance – Genetic deficiency of an enzyme which normally breaks down alcohol. Flushing is the predominant symptom, although headaches, nasal congestion, nausea, vomiting, and diarrhea are not uncommon. More common in East Asians.
- Favism [Glucose-6-phosphate dehydrogenase deficiency (G6PD) deficiency] – Genetic deficiency in the enzyme G6PD causes anemia, abdominal pain, headache, fatigue, fever, etc. when eating fava beans or take certain medications (e.g., aspirin, sulfonamides, nitrofurantoin, dapsone, isoniazid, certain anti-malarial drugs).
- Adverse Reactions to Preservatives and/or Food Dyes – Some examples include sulfites, monosodium glutamate (MSG), nitrates, nitrites, tartrazine, sodium benzoate, aspartame (e.g., NutraSweet, Equal), parabens, and butylated hydroxytoluene (BHT).
- Pharmacologic Effect of Food – Some examples of chemicals found in foods include caffeine, tyramine, and histamine (See #5 above). These chemicals may cause untoward symptoms in some individuals.
- Food Poisoning – May be caused by bacteria, viruses, parasites, prions, histadine (i.e., scombroid poisoning from spoiled fish), and toxins.
- Tick Bites – Bite from lone star tick causes a person to develop delayed onset hives, swelling, and/or anaphylaxis after consumption of mammalian meat. Mammalian meat allergy is caused by the presence of alpha-gal antibodies after the tick introduces alpha-gal (i.e., a carbohydrate normally found in other mammals) into a human.
The diagnosis of food sensitivities or food intolerances require a comprehensive history and physical examination. Food skin prick testing and/or blood testing may help rule in or rule out a classic food allergy. Blood tests to enzymes, chemical mediators, and antibodies may be necessary. In very rare circumstances, genetic testing may be performed. Food challenges can help diagnose the problem although extreme care should be taken when performing food challenges.
The treatment of food sensitivities mainly involves avoiding the offending food or food additive. The effects of some food intolerances can be avoided or diminished by taking certain supplements such as taking Lactaid pills or consuming Lactaid products in lactose intolerant individuals. Lactaid contains the enzyme lactase which is the enzyme that breaks down lactose, the sugar found in milk and dairy products. Avoidance (i.e., food, food additives, tick bite) and good hygiene in relationship to foods (i.e., washing foods thoroughly, avoiding street food in underdeveloped countries) however is the key to food sensitivity treatment.
The board certified allergists at Black & Kletz Allergy have been diagnosing and treating food sensitivities, food intolerances, and food allergies for more than 50 years in the Washington, DC, Northern Virginia, and Maryland metropolitan area. We treat both pediatric and adult patients and have 3 convenient locations in the Washington, DC metro area. We have offices in Washington, DC, McLean, VA (Tysons Corner, VA) and Manassas, VA, each with on-site parking. The Washington, DC and McLean, VA offices are Metro accessible. Our McLean office location offers a complementary shuttle that runs between our office and the Spring Hill metro station on the silver line. For an appointment, please call one of our offices directly or alternatively, you can click Request an Appointment and we will respond within 24 hours by the next business day. Black & Kletz Allergy is committed to providing excellent allergy, asthma, and immunology care to the greater Washington, DC and Northern Virginia community.