Allergies are something we acquire throughout life, and some people are more susceptible than others. In fact, food allergy is sometimes confused with food intolerance. Many people who believe they have food allergies suffer from food intolerance, which is an undesirable reaction to a food but does not involve the immune system as is the case in food allergy.
Food allergy is defined as the body’s reaction to some food that it mistakenly considers harmful. The immune system (which fights infection and diseases) is involved in this kind of reaction and it produces antibodies to fight the food allergen. Initially, there may not be any signs of an allergic reaction. But, when the same food is consumed the next time, these antibodies react with the food and the body produces chemicals such as histamine to “protect” itself. These chemicals then cause a series of reactions which affect various systems of the body and produce signs and symptoms of food allergy.
 Did You Know?
- Although about 25% of people believe they have a food allergy, only about 1% of adults and 3% of children have clinically proven allergic reactions to food.
- Peanut allergy is the food allergy most likely to result in anaphylactic reactions (severe, potentially fatal allergic reactions),
- In children, common allergy-provoking foods include cow's milk protein, egg white, wheat, soybean, codfish and peanuts. In adults, nuts including Brazil, almond, hazelnut, peanut and walnut are common allergens. Seafood such as fish, mussels, crab, prawn, shrimp and squid may also cause allergic reactions.
 Food Intolerance and Food Allergy
Food allergy is often mistaken for food intolerence. However, the two differ significantly.
- Food intolerance is more common than food allergy.
- It is a food-induced reaction that does not involve the immune system.
- Adverse food reactions are of slower onset and usually are not life threatening.
- The symptoms produced may be similar to food allergy, but while people with true food allergies must avoid certain offending foods altogether, people with food intolerance can often eat small amounts of the offending food without experiencing symptoms.
- Food intolerance can be caused when a person is unable to digest certain substances, such as lactose.
- Food intolerance may develop over a number of hours or days, while food allergy typically produces symptoms immediately or within the next few hours.
- Reactions to food intolerance are usually dose related, with small amounts of the food being tolerated but larger amounts leading to reactions such rashes, abdominal pain, vomiting, nausea and diarrhea.
Symptoms of food intolerance include diarrhea, indigestion, bloating, headache, flatulence and abdominal pain. The most common food intolerances are intolence to lactose (the sugar found in milk) and gluten (this is called celiac disease). Food additives, such as preservatives can also cause skin rashes and wheezing in some people.
 Causes of Food Allergy
Food allergies can be inherited from parents. It has been observed that in most cases, both or one of the parents might pass on the tendency to produce certain antibodies, that take part in an allergic reaction. A person with two allergic parents is more likely to develop food allergies than someone with one allergic parent.
There are eight foods that account for 90 per cent of all food-allergic reactions. These are:
Besides these, a person could be allergic to any food, like meats, fruits and vegetables. The allergy causing foods in children (milk protein, egg white) differ somewhat from those that cause food allergy in adults (nuts, seafood, some fruits and vegetables). Children sometimes outgrow their allergies but adults usually continue to experience them.
Itching and swelling in the mouth, tongue and throat is often the initial symptom of a food allergy. The other symptoms that are common in case of an allergic reaction are:
- Breathing problems like wheezing.
- Symptoms associated with the abdominal area – cramps, diarrhoea, vomiting, etc.
- Loss of consciousness.
- Runny nose.
- Sore eyes.
In some cases the allergic reaction can develop into an Anaphylactic Shock (also called “anaphylaxis”). This condition involves many systems of the body and become potentially life threatening.
The primary treatment of food allergies involves complete avoidance of the allergy causing food. An elimination diet is also practiced where the suspected allergy food is removed from the diet. The allergy food may be reintroduced back into the diet to confirm diagnosis. However, this is not safe if you've had severe allergy symptoms in the past, except under medical supervision at hospital.
Then there is symptomatic therapy. Medications like antihistamines and bronchodilators are available for treating other symptoms of food allergy. Epinephrine is used to treat anaphylactic shock.
- Controversial treatment: Treatments involving injecting small quantities of food extracts to which the patient is allergic and those placing a dilute solution of the allergenic food under the tongue of the patient are both controversial and hence, not warranted.
- Alternative treatment: Alternative treatments like herbs (for example, chamomile flowers, and peppermint leaf), ayurveda, yoga and homeopathy are also being tried out to treat food allergies.
The only safe way to prevent an allergic reaction is to altogether avoid the allergy causing food. Other precautions include:
- Reading the food labels for ingredients.
- Avoidance of foods whose ingredients are not confirmed.
- Working with a dietitian to plan safe diets where allergy causing foods need to be eliminated.
Do keep in mind that heredity seems to play an important role in food allergies.
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