What is Food Sensitivity?
Food sensitivity is also known as non-IgE mediated food hypersensitivity, non-allergic food hypersensitivity, or food intolerance. Food sensitivity is a reaction (which is usually delayed) to a food, drink, or food compound that is poorly tolerated by the body. These reactions cause symptoms in one or more body parts but the symptoms are not always as severe as those seen in a food allergy. The body will often respond to these foods through improper metabolism, pharmacological responses, or through gastro-intestinal problems. Individuals with food sensitivities can still tolerate small amounts of these foods.
Food Allergies vs. Food Sensitivity
Although food allergies and food sensitivities present similar symptoms, they are not the same thing. In a food allergy, any exposure to the specified food or drink will cause an adverse reaction. Food allergies are the result of abnormal and over-reactive immune responses to a substance, where the body will identify a food substance as a foreign danger and will trigger a protective response. The immune system normally produces immunoglobulin E (IgE, an antibody that helps to indentify foreign antigens in the body) for each foreign substance that enters the body. This is so that the next time the body is exposed to this same substance, IgE antibodies can quickly recognize it and trigger an immune response. When someone has an allergy, IgE antibodies have been inappropriately made to recognize a specific food or food molecule, and will cause an immune response whenever they recognize that specific food molecule in the body.
In food sensitivity, the immune system is not involved in the body’s reaction. Instead, there are issues with metabolism, digestion and pharmacological responses. As well, individuals with food sensitivities are still able to tolerate small amounts of a particular food or food substance. Food sensitivities are more common than food allergies and the symptoms are not always as severe. Finally, the symptoms tend to appear much later after food exposure in food sensitivity in comparison to food allergies.
Common Food Sensitivities
Some of the most common food sensitivities are lactose intolerance, egg sensitivities and gluten sensitivities.
Lactose intolerance is the result of a lack of lactase. Lactase is a digestive enzyme that is required by the body in order to digest the lactose, a sugar that is present in all dairy products.
Egg sensitivities are also common. This sensitivity is caused by the proteins found within eggs, which they body improperly reacts to.
Gluten sensitivity is a mild form of celiac disease, an autoimmune disorder that causes damage to the villi lining of the small intestine when foods containing gluten are ingested. Those with a gluten sensitivity are still able to eat small amount of gluten-contain foods but will commonly experience irritable bowel syndrome (IBS).
Causes of Food Sensitivity
Food sensitivity can be the result of a number of causes:
1. Defects in enzymes
Enzymes are molecules which help to speed up naturally-occurring reactions in the body. They accelerate chemical reactions in order to help sustain a cell’s life. In the digestive system, enzymes can help to increase the rate at which food is broken down into smaller units and subsequently absorbed by the intestines. In food sensitivity, enzymes that are normally required for digestion are either missing or are in short supply, resulting in improper breakdown of food.
Some foods cause food sensitivities if they contain toxic substances (such as toxins, viruses, bacteria or parasites). Toxins like lectin can be found in uncooked beans or chickpeas, while mouldy food will contain aflatoxins that can cause food sensitivities.
3. Pharmacological causes
Naturally-occurring and additives in foods can cause food sensitivities. The common substances that are food sensitivity culprits include:
- Chemicals: Some foods contain chemicals that may result in food sensitivity in a small subset of people. Although these chemicals are naturally occurring in foods, they can still cause symptoms. These natural chemicals include caffeine (found in coffee and tea) and amines (found in some cheeses).
- Histamines: Histamines can be found in alcoholic drinks, mushrooms, and pickled or cured foods. They can be naturally-occurring or build up over time, but in either case, they are able to cause food sensitivity symptoms in some individuals.
- Salicylates: Salicylates are derivatives of salicylic acid, and they occur naturally in plants. While they serve as immune hormones and preservatives in plants, excessive consumption of salicylates can cause adverse reactions.
- Additives: Food additives are used to preserve flavour or enhance the taste and appearance of food. They can be natural or manmade and thousands of additives exist. These include vitamins and minerals, flavourings (like MSG and sweeteners), coloring (like annatto and tartrazine) and preservatives (like benzoates and sulfites).
Symptoms of Food Sensitivity
Unlike allergic reactions (which usually occur immediately after exposure, and induce vomiting, hives and anaphylaxis), food sensitivities will occur at a much later time after exposure and the symptoms may not be as severe; because of this, food sensitivities are oftentimes very hard to diagnose in comparison to a food allergy.
Food sensitivity reactions can occur anywhere from a half an hour to 48 hours after food exposure. Symptoms can involve the:
- skin; such as rashes, eczema, dermatitis, or hives
- respiratory-tract; such as nasal congestion, irritations in the pharynx, or asthma
- gastrointestinal (GI) tract; such as nausea, gas, diarrhea, constipation or irritable bowel syndrome
Food sensitivity has also been found to cause rhinitis, headaches, intolerance to non-steroidal anti-inflammatory drugs, and chronic infection of Hepatitis C.