Food Sensitivity – An abnormal response to food

Now a days, it seems that everyone is facing some kind of reaction to food. It can either result in mild or severe symptoms like eczema. It can occur due to various reasons like absence of an enzyme or presence of harmful chemicals or toxins. But, it is important to identify whether it is food sensitivity, intolerance or an allergy. It can be identified either by simply eliminating the suspected foods from diet or by proper testing.


What is Food Sensitivity ?

Food Sensitivity refers to an abnormal response of subject to certain foods. It is an immune system reaction, usually delayed and is less severe than allergy. The reaction takes place in blood instead of body tissues. Symptoms may include headache, inflammation, fatigue, skin problems and digestive issues like stomach ache.

Also, food sensitivity includes both food intolerance and food allergy.

Food Intolerance – It occurs in the digestive system not in immune system. Intolerance symptoms include stomach pain, bloating and an irritable bowel. It may occur due to absence of some digestive enzymes also.

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.



Certain researches suggests that they develop from a mix of genetic and environmental factors. Family history is also known to play a key role. Some other reasons identified are –

Absence of an enzyme

Enzymes are needed for complete digestion of food. As a result, if some of these enzymes are missing, improper digestion of food occur. So, people who are lactose intolerant do not have enough enzyme. It helps in breaking down milk sugar (lactose) for absorption.

Chemicals present in foods

Certain chemicals like caffeine present in foods and drinks can cause intolerance. Some people are more prone to these chemicals then others.

Food toxins

Some foods have naturally occurring chemicals. They can have toxic effect on humans. One common example seen is – under cooked beans have toxin that can cause digestive problems while fully cooked beans do not have such toxin.

Natural occurrence of histamine in some foods

Some foods such as fish, when not stored properly can accumulate histamine as they rot.


Risk Factors

The most important risk factors are things you cannot change. These 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.
  1. Milk allergy – It can result in rashes, upset stomach, vomiting, bloody stools (especially in infants). It can also be a life threatening allergic reaction.
  2. Lactose intolerance – People who cannot digest milk sugar (lactose) are lactose intolerant. This is because they have deficiency of lactose breaking enzyme.
  • 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 is usually confined to a particular species. Crab, lobster and shrimp are the most common one that cause allergy.
  • Meats – Meats of all kinds may give rise to allergic reactions in some individual.
  • 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 presence of wheat gluten.
  • Soy – People who work in glue factories use soy as one of the component. It can cause severe asthmatic reactions.  As a result, these workers usually give strong positive skin test reaction. 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 reaction.
  • Consumption of edible mushrooms, certain vegetables and fruits found to produce allergic reactions. Citrus fruits and tomatoes can cause skin allergy.


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.



If you think food is to blame for allergic reactions, an elimination diet is a good place to start. In this method, you remove certain foods from your diet, for a specific time period (around 1 month).Then you add them back slowly over time. This helps you in determining which foods are causing reaction.

But if this method does not works, then there are several tests available. They help you in identifying precise foods (and chemicals) causing an immune reaction in your body.The most common tests are –

Skin Allergy test – It is also known as scratch test.This test involves exposure of food component or chemical to cells of skin. It determines the patient’s reaction to specific food. A small quantity of suspected food is placed on patient’s back or forearm. The skin is pricked with the needle, allowing some of the substance to penetrate below the skin surface. As a result, people who are allergic would react with a raised bump.

IgE Allergy Blood test – This measures IgE  immune response. Their presence may be a part of the normal human response and indicate tolerance instead of an adverse allergic reaction.

IgG blood test – The system is a finger prick test that identifies specific immune based system response. Furthermore, studies suggests that an IgG immune response may contribute to headache, joint pain, inflammation of skin and other chronic conditions.



If you have a food allergy, the best way to prevent an allergic reaction is to recognize and avoid the foods that will trigger it. If you are not able to identify the food than consult with an allergy specialist.


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