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8 most common food allergens

8 most common food allergens
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First Published: Tue, Jun 16 2009. 01 15 AM IST

Illustration: Jayachandran / Mint
Illustration: Jayachandran / Mint
Updated: Tue, Jun 16 2009. 03 28 PM IST
What’s the difference between an allergy and intolerance?
Typically, an allergy to a specific food is caused when the body’s immune system reacts negatively to the protein present in that food. This can cause nausea, headaches and rashes or potentially fatal conditions such as constricted breathing or a block in blood supply. “When the body is allergic to a specific protein, the antibody immunoglobulin E, or IgE, is released. High concentration of IgE triggers a range of symptoms, including potentially fatal ones such as angio-oedema, which results in swelling of skin and subcutaneous tissue, blocking blood supply,” says Nagendra Prasad, head, Bangalore Allergy Centre. Such allergic reactions can occur in proteins in foods such as eggs, peanuts or fish, all of which are on a list of eight foods that
Illustration: Jayachandran / Mint
allergy specialists now term as the most common allergenic foods, causing 90% of all allergic reactions. “A food allergy...is typically a more serious condition than food intolerance,” says Ashutosh Shukla, consultant, internal medicine, Artemis Health Institute, Gurgaon.
Intolerance towards a specific food differs from an allergy: It is usually caused by the lack of an enzyme to digest that food. “The most common example of food intolerance is lactose intolerance, where some people lack the enzyme lactase, which is needed to digest the milk sugar lactose,” says Sheela Krishnaswamy, director, wellness, ChiHealth, a Web-based health consulting firm. When a lactose-intolerant person drinks milk, common reactions include a bloated stomach, flatulence, cramps and diarrhoea.
Sulphite-induced asthma is another common problem, notes Ishi Khosla, a New Delhi-based clinical nutritionist. Sulphites or sulphate agents (such as sodium sulphite, sodium bisulphite, sodium metabisulphite, potassium bisulphite and potassium metabisulphite) are common preservatives in various foods and medications. Sulphites can also occur in naturally fermented beverages and wines. So foods to avoid would be wines and processed foods, such as bottled juices, sausages, meats, canned seafood, pickled onions and dried fruits.
Most common food allergens
Allergy to fish usually means an allergy to shellfish (different biological categories). While fish allergies are more common in children, shellfish allergies affect more adults. Allergic reactions (which occur within minutes or a few hours in other allergies) can be delayed by almost 24 hours in the case of shellfish.
The good news is that almost 80 out of 100 allergic children outgrow it by their fifth birthday. The allergenic proteins are mostly in the egg white (albumin), but some are also found in the yolk. Cooking tends to denature the proteins, so some people can eat well-cooked eggs but not raw or soft-cooked ones.
Soybeans, like peanuts, are legumes, so those allergic to them may also need to beware of other legumes, including green peas, chickpeas and all beans. Soy is used in a lot of processed foods, so read food labels carefully.
These are the true nuts: cashew, chestnut, walnut, almond, hazelnut, pistachio... While some peanut-allergic people can eat tree nuts and vice versa, doctors recommend that those with an allergy stay away from all nuts.
This allergy, unlike some others, is not often outgrown. In fact, symptoms become worse with repeated exposure. The protein is the problem, but sometimes even gelatin (made from fish bones and skin) can induce an allergy.
You can be allergic to proteins in wheat (especially gluten) or sensitive to wheat. Some nutritionists say overenthusiasm for wholewheat grains and dietary fibre in recent years has contributed to an increase in this allergy. An adverse reaction to gluten in grains such as wheat, rye, oats and barley is diagnosed as coeliac disease.
The most common allergy-inducing food. Children with a family history of allergies should not be given peanuts or peanut products until the age of 3. Unlike some other allergies, a peanut allergy can be life-threatening.
Besides lactose intolerance, cow’s milk can also trigger a food allergy to the protein in milk, casein. In cases of allergy, all milk products (cheese, yogurt, butter, whey) are taboo; the lactose-intolerant may be able to eat yogurt, though.
Carrying cellphone in your shirt pocket safe
Is it safe to carry a cellphone in a shirt pocket over your heart all the time? Peter Libby, chief of cardiovascular medicine at the Brigham and Women’s Hospital, Boston, says cellphones and portable media players do indeed produce measurable electrical and magnetic fields. But the strength of these fields will not affect ordinary heart rhythm or function, studies suggest. Various studies have also looked at whether cellphones and media players can present a danger to those with an implanted pacemaker, internal defibrillator or a similar device. The results, for the most part, have been reassuring.
Long-term therapy better
Prostate cancer patients need three years of treatment, known as chemical castration, to suppress the production of tumour-fuelling hormones and improve their chance of survival, according to researchers led by Michel Bolla from Grenoble University Hospital in France. The study found that patients treated for six months were more likely to die than those on the drugs for several years. The overall mortality was higher with short-term androgen suppression than with long-term suppression. The study tracked 970 patients with locally advanced prostate cancer who were treated with radiation and either six months or three years of treatment. After five years, a standard measurement for cancer survival, 19% of the men given six months of drug treatment died, compared with 15.2% getting long-term therapy.
Anti-nausea drug safe for pregnant women
An anti-nausea drug that is widely used but little tested for safety in pregnant women does no obvious harm to the foetus, according to a team led by Ilan Matok of Ben-Gurion University of the Negev in Israel. Investigators found no increase in death rates or malformations among the babies of women given metoclopramide during the first trimester of their pregnancy. The team found that the drug produced no change in the risk of giving birth to a low-weight baby or to a child with a low Apgar score, a widely used measure of the health of a child immediately after birth.
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First Published: Tue, Jun 16 2009. 01 15 AM IST