Food Allergy denotes an adverse immunologic response to a specific substance with characteristic symptoms whenever food is ingested. It can also be defined as “altered reaction of the tissue of foreign protein or antigen”.
Allergy can be caused due to ingestion of food or drugs, contact with food, pesticides, drugs, adhesives, feather and fungi, inhalation of pollen, cosmetics and perfumes and injections of vaccines, serums antibodies and hormones.
People of any age can suffer from food allergy including infants and aged also. But it is customary for them to know the main cause of allergy so that appropriate precaution can be taken.
Food As Allergens – Some Common Food Allergens Are Mentioned Below
Animal Source Of Food Allergy
- In cow’s milk, casein and beta lactglobulin which are milk protein are known to be the major allergen; cow’s milk when consumed may cause allergic reactions like colic pain and passage of blood. Milk tolerant children have positive weal and erythema reactions to one or more milk proteins.
- Egg is a common allergising agent among animal foods. Egg white is the allergising factor present in egg. Yellow part of egg can be consumed. Cutaneous manifestations occur more frequently than other symptoms.
- Allergic symptoms due to consumption of fish are usually confined to a particular species. Any species of fish can, in principle, be responsible for allergic reactions. As a rule, the allergic reactions appear very promptly as utricaria (skin eruptions round smooth raised pinkish itchy weal) angioneuroitic edema, dermatitis, gastrointestinal disorders and even asthma.
- Meats of all kinds may give rise to allergic reactions in some individuals.
Allergy Caused By Plant Sources
- Wheat flour has been associated in precipitating symptoms of celiac disease in some subjects. A few individuals may be allergic to peanuts resulting in abdominal distress, skin eruptions and asthmatic paroxysm.
- Peas, beans and lentils produce allergic reactions in some individuals.
- Consumptions of edible mushrooms sometimes may cause allergic reactions.
- Fats and oils have been found to produce allergic symptoms in a small number of individuals.
- The vegetables which are found to produce allergic reactions in some individuals are carrot, spinach, cabbage, onion, garlic, sweet potato, cauliflower and pumpkin.
- Among the fruits, straw berries, bananas, oranges, grapes and apples are the principal offenders. Occasionally allergic reactions can occur due to consumption of pears, cherries, plums, raspberries, gooseberries. Citrus fruits and tomatoes can cause atopic allergy.
Beverages As Food Allergan
Alcoholic beverages may cause clinical manifestations of allergy, both specifically and non-specifically. The allergic reactions are due to traces of foreign substances derived from food materials employed in the preparations or clarifying the beverages, such as barley malt and yeast in beer, rye, corn, and wheat in whisky, egg white, or yeast in cheap white wine and champagne. Allergic reactions to coffee and tea can occur occasionally.
Allergy Caused By Food Contaminants
The contaminants of food for example preservatives, insecticides and insect excreta or fragments may act as allergens and the food by itself may be harmless. Such contaminants may enter the plant food in the field or enter the food during storage, processing and shipping.