The Most Common Causes of Food Sensitivity

The term “food sensitivity” is a catchall phrase. It could denote food intolerance or a food allergy. Basically, “food sensitivity” is used to describe a variety of symptoms or adverse reactions to a food that has been eaten, whether it is a food allergy or food intolerance.

Food intolerance occurs when you have difficulty digesting a particular food, and it doesn’t involve the immune system. Food intolerance can lead to symptoms such as gas, abdominal pain or cramping, and diarrhea. The most common food intolerance is lactose intolerance.

A food allergy is when the immune system reacts to a food after ingestion, typically “attacking” the food allergen and causing a host of symptoms including nausea, vomiting, diarrhea, hives, swelling, difficulty breathing, or in severe cases, anaphylaxis. The most common food allergies are to milk, soy, egg, wheat, peanut, tree nuts, fish or shellfish.

When it isn’t clear as to whether the negative reaction is caused by the immune system or due to a biological or physiological problem, the generic term “food sensitivity” is used.

Aside from food allergies, which are covered extensively on this website, food intolerances and sensitivities may be classified into three main categories:

Enzyme dysfunction:  Such as in lactase deficiency (lactase is the enzyme responsible for aiding in the digestion of lactose, or milk sugar), which causes lactose intolerance.

Pharmacological response: Such as with a reaction to a pharmacologically active agent, such as histamine or tyramine in food.

Reactions with unclear mechanisms: Such as reactions to food additives like sulfites, benzoates, tartrazine and other food dyes, and monosodium glutamate (MSG).

Even though the above categories help us understand why food sensitivity occurs, these reasons can still be confusing. For example, a person can be deficient in the enzyme used to break down tyramine (monoamine oxidase)—an enzyme dysfunction-- but the reaction that is experienced is a pharmacological effect, such as a migraine headache.

Another aspect to consider is that individuals react differently in their experience of food sensitivity, and this, in part, depends on the dose. In other words, each person’s threshold for a food sensitivity and reaction is different.

Here are the most common culprits and symptoms of food sensitivities:


lactose intolerance
Carbohydrates in milk can cause intolerance. iStockphoto/fatihhoca

A variety of carbohydrates can cause food sensitivity. Lactose, which is found in milk and milk products; sucrose (sugar); maltose, found in malt-based products like beer; and fructose, found in fruit are the carbohydrate-based foods may cause symptoms of food intolerance. Carbohydrate intolerance symptoms occur primarily in the digestive tract and include excessive gas, abdominal bloating and pain, diarrhea or loose bowel movements, occasional nausea and vomiting.

Histamine and Tyramine

Some spices can cause sensitivity. (c)2010 Jeanette Bradley, licensed to

Both of these are called biogenic amines and may cause symptoms throughout the body, but are typically localized to one or two areas. Symptoms may include hives; swelling around the mouth and eyes; itching, swelling and reddening of the mucous membranes; headaches; and migraine headaches. For tyramine: hives; itching; and disturbances in the gastro-intestinal tract. Foods to avoid are fermented foods, alcoholic beverages, some vegetables and fruits; some spices; some artificial colors and preservatives; vinegars; yeast extract; and chicken liver.  


Fruit can be problematic for some people. lacaosa/Getty Images

Sensitivity to salicylates can cause symptoms throughout the body including hives, angioedema, and asthma in people with asthma. If individuals are sensitive to aspirin, they are at higher risk for developing symptoms of intolerance to salicylates. Salicylates occur naturally in a wide variety of foods such as many fruits and vegetables and some spices. 

Artificial Colors

3 hard candies in wrappers
Candy commonly contains artificial colors. Rosemary Calvert/Getty Images

There are many artificial colors in our food supply. Tartrazine and other nitrogen-containing dyes (azo dyes) such as sunset yellow (FD&C yellow #6), ponceau (FD&C red #4) and amaranth (FD&C red #5) have been teased out as problematic for some individuals. After ingestion of artificial colors, some individuals will experience an imbalance in their immune system and a release of histamine. Symptoms may include asthma in those with pre-existing asthma, hives, nausea, headaches, rashes, and hyperactivity in some children with ADHD. Artificial colors are included in a variety of different foods that are manufactured for human consumption. You can learn about artificial colors and children in this article


fruit, thanksgiving, cornucopia
Berries may contain benzoates. Jill Castle, MS, RDN

It is not clearly known where the effects of benzoate ingestion will occur in the body, however it is suggested that benzoates negatively impact the immune system and cause a release of histamine and an imbalance in the immune system response. In benzoate sensitive people, symptoms may include asthma (in those with asthma), hives, angioedema, nasal congestion, headache, contact dermatitis, and problems in the gastrointestinal tract. Benzoates naturally occur in berries, cinnamon, spices, tea and prunes.

Butylated Hydroxyanisole (BHA) and Butylated Hydroxytoluene (BHT)

BHA and BHT are most commonly known for their presence in food packaging materials, especially plastic bottles. It is unknown how BHA and BHT cause reactions in the body, but the most common symptoms are skin reactions, including hives. 


Red wine with cheese and olives
Wine may contain sulfites. undefined

Sulfites are used as an antimicrobial preservative in foods that are prone to molding, as a color preservative to prevent browning, as a bleaching agent, and as a texturizer, especially for frozen, uncooked cookie dough. They are also used in the fermentation of food, like wine and other alcoholic beverages. For people who are sensitive to sulfites, symptoms can range from skin reactions to anaphylaxis in people with asthma. 

Monosodium Glutamate (MSG)

MSG may be found in Asian food. John Borthwick/Getty Images

Intolerance to MSG can cause symptoms involving the whole body. Commonly, MSG may cause flushing, facial numbness, tingling and numbness in the hands and feet, tightening of the chest, dizziness, balance problems, blurring of vision, visual disturbances, and “psychological reactions.” In people with asthma, MSG can further aggravate it. MSG is found in foods manufactured with “added flavor,” commonly in Asian food, and naturally occurs in cheeses, mushrooms and tomatoes.

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