Madhavi Trivedi explains the triggers and treatment of food allergies

IMAGINE what it would be like if eating a handful of peanuts or drinking a glass of milk left you vomiting, gasping for breath or furiously itching. Food allergies and food intolerances affect nearly everyone at some point as people often have unpleasant reactions to something they eat.

Food Allergy
In a true food allergy, the body's immune system recognises a reaction-provoking substance - an allergen in the food; usually a protein - as foreign and produces antibodies to halt the 'invasion'. As the battle rages, symptoms appear throughout the body.

Allergic Reactions
Allergic reactions to food allergens typically begin within minutes to a few hours after the eating of the offending food. The frequency and severity of symptoms vary from one person to another. Mildly allergic individuals may only suffer a running nose with sneezing, while highly allergic persons may experience severe reactions, such as asthma or swelling of the tongue, lips or throat.
Common sites and symptoms of food allergy:

Mouth (tingling; swelling of the lips, tongue or throat; itching lips)
Digestive tract (nausea; abdominal cramps; vomiting; diarrhoea)
Skin (hives; rashes or eczema)
Airways (cough; wheezing; itchy, stuffy, runny nose and sneezing; asthma or breathing problems)
Anaphylaxis, a severe allergic reaction (drop in blood pressure and loss of consciousness) may be life threatening.

What Causes An Allergic Reaction?
The immune system produces increased amounts of immunoglobulin E antibody, or IgE, in some people. When these antibodies battle with food allergens, histamine and other chemicals are released as part of the body's reaction to these substances. These chemicals can cause blood vessels to widen, muscles to contract and some skin areas to become red, itchy and swollen.

Most Likely Suspects
In children: Eggs, milk, peanuts, soya and wheat. Children typically outgrow their allergies to milk, egg, soya and wheat, while allergies to peanuts, fish and shrimp are usually not outgrown.

In Adults: Shrimp, lobster, crab, and other shellfish; peanuts, walnuts and other nuts; fish; and eggs. Adults usually do not lose their allergies.

Keep in mind that if you are allergic to a particular food, you might be allergic to related foods. For example, a person allergic to shrimp may not tolerate crab and lobster. Likewise, a person allergic to peanuts may not tolerate one or two other members of the legume family such as soya, peas or certain beans.

What Makes One Prone To Allergies?
Heredity is one of the prime reasons. If both your parents have allergies, you have approximately a 75 per cent chance of being allergic. If one parent is allergic, or you have relatives on one side with allergies, you have a 30 to 40 per cent chance of developing some form of allergy. If neither parent has an apparent allergy, the chance is 10 to 15 per cent. Although food allergy occurs most often in infants and children, it can appear at any age and can be caused by foods that have been previously eaten without any problems.

Determining The Culprit
Some people can determine what foods cause allergic reactions in them. But, when the symptoms occur several hours after intake of food, it becomes difficult to verify the cause. An allergist/immunologist is the best-qualified professional to diagnose food allergy.

Treatment
Avoid the food. The best way to treat food allergy is to avoid the specific foods that trigger the allergy.

Ask about ingredients. If you are prone to allergies, always enquire about ingredients when eating at restaurants or others' homes.

Read food labels. And also get familiar with technical or scientific names for foods. For example, milk may be listed as casein (a milk protein), sodium caseinate or milk solids. Sometimes wheat is listed as gluten. Similarly, egg white is frequently listed as albumin.

Be prepared for emergencies. Those who have experienced an anaphylactic reaction to a food must carry and know how to use injectable epinephrine and antihistamines to treat reactions due to accidental ingestion. People who are commonly around the patient, should also know how to administer the injectable epinephrine. Those with food allergies should also wear an identification bracelet that describes the allergy. For proper diagnosis and treatment, make sure to get follow-up care from an allergist/immunologist.

Food Intolerance And Additive Reactions
Food intolerance reactions are usually caused by factors in the diet other than the proteins that make up food allergens. As mentioned, one of the most common is lactose intolerance. Symptoms can include nervousness after consuming caffeine in coffee or soft drinks, headaches triggered by chemicals in cheese and chocolate, or various adverse reactions to chemicals and preservatives added to food, called food additives.

These additives may cause adverse reactions in sensitive people. The most common food additives that may cause reactions include benzoates, BHA and BHT, FD&C dyes Yellow No 5 and Red No 3, monosodium glutamate (MSG), nitrates/ nitrites and sulfites. However, true allergic reactions to food additives are very rare.

The best way to handle food additive sensitivity is to know which foods contain certain additives, and to avoid the additives that cause problems for you.
Madhavi Trivedi is a Nutritionist and Healthcare Consultant