Food Sensitivity refers to an abnormal response of a subject to certain foods. It is an immune system reaction, usually delayed and is less severe than allergy. Symptoms may include headache, inflammation, fatigue, skin problems and digestive issues like stomach ache. You might think that food sensitivity may cause intolerance but it also includes food allergy.
Food Intolerance - It begins in the digestive system, not in the immune system. Symptoms include stomach pain, bloating and an irritable bowel. It may also occur due to absence of some digestive enzymes. For example - some people with lactase enzyme deficiency are not able to digest milk and milk products because they contain lactose.
Food Allergy - It triggers an immune system reaction which can be quite severe, or even life-threatening. Symptoms include vomiting, diarrhea, rashes, runny nose, eczema (severe burning sensation on skin and redness) and difficulty in breathing.
Causes
Certain researchers suggest that food sensitivities develop from a mix of genetic and environmental factors. Family history is also known to play a key role and allergies tend to run in families. Some of the important causes include:
- Absence of an enzyme - Enzymes (lactase, prolyl endopeptidase-cysteine proteases and subtilisins) are needed for complete digestion of food (milk and wheat that contains gluten). In case of an enzyme deficiency, proper digestion of food will not occur. For example, people with the deficiency of Lactase enzyme which helps in breaking down the milk sugar, lactose, to aid in its absorption, are lactose intolerant.
- Chemicals present in food:
- Caffeine present in food and drinks can cause intolerance. People with caffeine intolerance metabolize caffeine slowly.
- Monosodium glutamate (MSG) is a synthetic form of glutamate used as a food additive to enhance taste. Its sensitivity can drive migraines.
- Salicylates are naturally found in and also manufactured for different uses. Both natural and synthetic forms can cause severe allergic reactions in some people.
- Food toxins - Undercooked beans have toxins that can cause digestive problems while fully cooked beans do not have such toxins. Natural occurrence of histamine in some foods like fish, when not stored properly can accumulate histamine as they rot.
Risk Factors
The most important unmodifiable risk factors are:
- Age - Young children are more likely to develop food allergies than older ones. This is due to low immunity in young age.
- Family History - Having a patient or sibling with food allergy increases your risk.
Common foods involved in food sensitivity
People can be allergic to any food. But the most common foods involved are milk, egg, peanut, tree nuts, soy, wheat, fish and shellfish.
What happens when these foods are ingested?
Animal Sources
- Milk - In cow's milk, casein and some proteins are known to be the major allergens. It causes allergic reactions that can lead to stomach pain and passage of bloody stools. People who are sensitive to milk may become lactose intolerant or develop milk allergy.
- Milk allergy - It can result in rashes, upset stomach, vomiting, bloody stools (especially in infants). It can also be a life threatening allergic reaction.
- Lactose intolerance - People who cannot digest milk sugar (lactose) are lactose intolerant. This is because they have a deficiency of lactose breaking enzymes.
- Egg - Egg white is the allergy causing factor for egg allergy. People who consume egg white daily might develop egg allergy.
- Fish - Symptoms due to fish allergy are usually confined to a particular species. Crab, lobster and shrimp are the most common ones that cause allergies.
- Meats - Meats of all kinds may give rise to allergic reactions in some individuals.
- Cheese - Aged cheddar are among the best known triggers.
Plant Sources
- Wheat - In some people, wheat flour is known to develop typical symptoms of gluten sensitivity. Allergic reaction is involved due to the presence of wheat gluten.
- Soy - People who work in glue factories use soy as one of the components. It can cause severe asthmatic reactions. As a result, these workers usually give strong positive skin test reactions. The allergen is reported to be heat stable.
- Peanuts - Peanut allergy can result in abdominal pain, skin eruptions and asthmatic problems.
- Tree-nut - These are hard-shelled nuts often linked with life-threatening allergic reactions.
- Consumption of edible mushrooms, certain vegetables and fruits found to produce allergic reactions. Citrus fruits and tomatoes can cause skin allergies.
Beverages - If you consume alcoholic beverages and caffeinated drinks daily, they may give rise to clinical symptoms of allergy.
Food Contaminants - The contaminants of food for example preservatives, additives, insect excreta may act as allergens. The food itself may be harmless. The common additives added are food color and preservatives.
Takeaway
If you are having symptoms of food allergy, the best way to prevent an allergic reaction is to recognize and avoid the foods that trigger it. If you are not able to identify the food, then consult with an allergy specialist and do the needful.