Reactions to food
The true incidence of adverse reactions to foods is not known, but studies indicate that only a fraction of children whose parents think they have food allergies test positive to the alleged substances.
True food allergies involve the body’s immune system and can be diagnosed by skin prick or blood tests. Allergies usually begin in infants and young childhood, and most disappear by school age, although allergic reactions to nuts and seafood may persist throughout life.
A intolerance to various natrural or added food chemicals is also common ans can arise at any age. Food intolerances are no less important than allergies, but are more difficult to diagnose as they do not involve the body’s immune system and no reliable diagnostic test are available.Diagnosis involves removing all foods likely to cause a reaction, and if symptoms disappear, specific foods or capsules of food chemicals are added in a systematic fashion, preferably by a doctor or dietitian who specialises in this area. it is important for you to maintain a nutritionally adequate diet during the elimination and re-introduction phases of diagnosis.
Doctors do not completely understand why so many people have adverse reactions to foods,although heredity is an important consideration. If both parents have alllergies, their children will almost always have them as well, although the symptoms and allergens may be quite different. There is no doubt that breastfeeding and the delayed introduction of solid foods reduces a child’s chances of developing food allergies.
Allergies develop in stages. When the immune system first encounters an allergen (or antigen)-a substance that it mistakenly sees as a harmful foreign invader-it signals specialised cells to make antibodies, or immunoglobulins, against it.There is no allergic reaction in that first exposure; however, if the substance again. In some cases, the response will not produce symptoms; but the stage will have been set for a future antigen-antibody reaction and an allergic response.
Food intolerances may develop at any age are related to the quantity of the substance ingested. This makes diagnosis difficult as small quantities f natural or added chemical may build up and it is only when the total amount consumed goes over an individual’s limit that a reaction will be apparent.
COMMON SYMPTOMS
Common symptoms of food allergies include neausea, vomiting, diarrhoea, skin rashes or hives, itching, shortness of breath (including asthma attacks) and, in severe cases,widespread swelling of the skin and mucous membranes. swelling in the mouth or throat is rare, but potentially fatal because it can block the airways to the lungs. In the most severe cases, anaphylactic shock-a life threatening collapse of the respiratory and circulatory system- may develop.
Allergens usually provoke the same symptoms each time, but many factors affect intensity, includeing how much of the offending food was eaten, and how it was prepared. Some people can tolerate small amounts of an offending food; others are so hypersensitive that they react to even a minute trace.
Symptoms of food intolerance vary but may include hives and eczema, headache,mouth ulcer, nausea, stomach cramps,and sinus problems. Feeling generally unwell or becoming these are also symptoms of many other problems.
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