Since several diagnoses have symptoms that mimic food allergy reactions, we should never assume that discomfort after eating specific foods indicates food allergy.
Doctors have to consider several possibilities when assessing symptoms triggered by food ingestion. Although allergy is a possibility, the following conditions also account for allergy-like abnormal responses to food.
Food Additives and Toxins
Food Additives. People can have adverse reactions to compounds that color food, enhance its flavor, or control the growth of microorganisms. The primary culprits are:
- Yellow dye number 5: can cause hives, though it is rare.
- MSG, or monosodium glutamate: a flavor enhancer that may temporarily cause lightheadedness, flushing, feelings of warmth, headache, chest pain, facial pressure, or a sense of detachment when eaten in large amounts.
- Sulfites: they emit a lung-irritating gas that can make breathing difficult for those with asthma.
Sulfites are occasionally added to food for increased crispness or to retard the growth of mold. They occur naturally in some foods, and in wines.
Histamine Toxicity. As you may know, an allergic reaction occurs when the body’s mast cells release histamine into our bloodstream. Foods such as cheese, certain wines, and some fish - mackerel and tuna particularly - may contain high levels of histamine. If a person consumes food containing much histamine they may have an allergic-like reaction to it.
The histamine in fish is thought to come from bacterial contamination owed to inadequate refrigeration. This is responsible for more than a third of seafood-related food-borne illnesses.
Food Poisoning. Eating eggs, milk, salad, or meat that is contaminated with microorganisms (e.g., Salmonella, Listeria) can cause symptoms that mimic food allergy.
Gluten-sensitive Enteropathy, or celiac sprue, is an intolerance to the gluten found in barely, wheat, and rye grains. People with gluten-sensitive enteropathy experience mal-absorption and diarrhea owed to an abnormality in the small intestine’s lining. Though this condition is often called a gluten allergy, it involves an immune system response differing from that of food allergy.
Lactose Intolerance, or lactase deficiency, affects about one out of ten people. They do not have enough of the enzyme lactase in their small intestine to break down and digest the complex milk sugar called lactose. Bacteria in the intestine then utilizes the undigested lactose producing gas, and symptoms of bloating, abdominal pain, and diarrhea.
Other GI Disorders. Several other gastrointestinal disorders, some triggered by food, can also mimic a food allergy reaction with symptoms such as nausea, diarrhea, vomiting, and pain. These disorders include gallstones, peptic ulcer, Crohn’s disease, non-ulcer dyspepsia, certain cancers, and eosinophilic gastroenteritis.
Trauma Related. Though uncommon, a food may become associated with a traumatic or highly emotional event. If this happens, the food can trigger symptoms resembling a food reaction. For instance, if someone chokes on a fishbone, or witnesses someone choking on one, they might later develop hives or difficulty breathing when eating fish.
Anxiety. Symptoms of intense anxiety such as flushing, sense of warmth, problems breathing, or loss of consciousness can also be mistaken for a food reaction.