Posts Tagged ‘small minority’

Allergens in Food
Anyone with true food allergy or coeliac disease needs to be very careful about avoiding certain foods. The information given here is aimed mainly at such people, rather than those with food intolerance (see p. 74), who can usually tolerate small amounts of their offending foods. However, some of the basic information given here is relevant to those with food intolerance as well.
There are different levels of sensitivity even among those with true food allergy. The ‘exquisitely sensitive’ can react to unbelievably minute traces of the food, and for them life is especially difficult. The same is true of some coelicacs, who can be affected by the tiniest quantity of gluten.
These people are a small minority. The level of vigilance required of such people will not be necessary for most people reading this book, so don’t get things out of proportion. While it is vital to be sensible about avoiding your problem food, it is also important not to become over-anxious.
Buying basic ingredients
Cooking for yourself is the safest way to eat for those with true food allergy and coeliac disease. There are relatively few hazards, but do beware of well-meaning assistants in health-food shops who try to sell you some exotic package of grain or flour – spelt or kamut or triticale, for example – reassuring
you that it is ‘definitely not wheat’. Be well informed about the different forms of your problem food and the names under which it is sold (see pp. 172-5).
Oils made from foods such as corn or peanut sometimes cause concern. Ordinary refined oils have been so thoroughly processed that they actually contain no allergenic proteins, so you can safely use these. Bottles of gourmet walnut oil and almond oil are a different story however, and should be avoided if you have nut allergies. Sesame oil is not purified either and can provoke serious reactions. With any oil, if you are unsure how safe it might be, go by the smell. Oils that smell or taste like the food from which they are made could well contain allergens.
Those with allergy to tuna can usually eat tinned tuna because the processing makes it safe. The allergens in fresh fruit and vegetables are generally inactivated by cooking too, so jams and tinned fruits tend to be safe – but test very cautiously. Cooking does not have much effect on other food allergens, apart from eggs. In rare cases, cooking can create allergens (see box on p. 186).
If you share your kitchen with others, and are highly sensitive, check that all cooking utensils are truly clean before use. Coeliac should watch out for breadcrumbs in the butter dish, jam or toaster. Where small children are allergic to a food, it may be best to keep the culprit out of the house entirely.
Genetic engineering and food allergy
Many people with food allergies are very concerned about the possibility that genetic engineering could introduce allergens from one plant species into another. This concern seems to be shared by government officials and those in the food industry, who are being extremely vigilant and cautious at present. As long as this attitude continues, there should be little danger to food allergy sufferers.
Finding food in funny places
If you are suffering some inexplicable reactions to non-food items, it might, just possibly, be a food reaction. Some latex gloves contain the milk protein casein, for example, added as a manufacturing aid.
Buying packaged foods
There are several different issues here:
• the need to read labels carefully for allergenic ingredients described by unfamiliar names (see p. 172)
• errors in the packaging used (see pp. 174-5)
• contamination by minute traces of a food substance due to processing machinery not being cleaned adequately. Cartons of fruit drink have occasionally been contaminated with traces of milk because the same production lines were used for packaging milk drinks. Tofu desserts made in ice-cream factories can also become contaminated with milk. These tiny traces of a food will only affect the most highly sensitive individuals, but contamination by nuts can involve large pieces and affect anyone with nut allergy (see p. 174).
• foodstuffs which are used as part of the production process
and leave a tiny residue in the finished item (see p. 174).
Be very cautious indeed about ready-made food that is unlabelled, such as that from bakeries and home-made stalls. Egg is frequently used as a glaze on baked products, nuts may lurk within, and milk or wheat can turn up in the most unlikely places.
Restaurants, cafes and takeaways
The majority of fatal and near-fatal incidents involving people with true food allergy are due to restaurants, cafeterias and canteens. Takeaways can also be a problem except in the case of the large chains such as McDonald’s, where ingredients are standardised. It is alarming that highly allergenic foods (e.g. peanut) are sometimes used – yet far from obvious – in recipes and sandwich fillings where they would simply not be expected. Anyone with peanut or shellfish allergy should be ultra-cautious about Chinese, Thai or Malaysian cooking – but those with milk allergy should find a haven here, because milk is not part of these culinary traditions.
The simplest solution is to eat very plainly when you go out –steak and salad, for example. Steer clear of casseroles and thick soups, where you can’t see what’s in it (the occasional chef throws in peanut butter to thicken the mix…). Food wrapped in pastry is best avoided for the same reason. Desserts and cakes are risky for anyone with nut, egg or milk allergy.
You must insist on accurate information about the food before you taste it. If the counter staff, the waiter or the waitress
is unsure of the ingredients, ask them to check with the chef, or with the label on pre-packaged food. Be persistent and never eat anything unless you are sure. Make eye contact with the person concerned, and learn to be a good judge of character. Your life could depend on telling the difference between the waiter who knows the facts about the food and the waiter who is being blandly reassuring for the sake of a quiet life.
It is a great mistake to pick out the pieces of offending food – kiwi fruit from a fruit salad for example – and eat the rest. There is often enough allergen left behind to cause anaphylaxis in the highly allergic individual.
Those who are extremely sensitive to the offending food must also consider the problem of contamination in the kitchen. Grills and fryers in restaurants and canteens can become contaminated with fish allergens or nut allergens (e.g. from nut cutlets) and these can be transferred to fried potatoes or other foods, provoking anaphylaxis in the highly allergic individual. One person with fish allergy died in this way. Sesame seeds can also contaminate equipment, work-surfaces or bakery counters.
Parties and buffets
Milk, egg, shellfish or nut allergies can make it especially hazardous to eat buffet or party food. Regard everything with suspicion. Cocktail snacks with nuts or peanut paste hidden inside are a particular problem.
When fish allergy isn’t fish allergy
Anisakis is a parasitic worm that infests fish and can sometimes survive the
cooking process to infect humans. The worms are easily thrown off by the human immune system, but the body is primed to make IgE antibodies should
it ever encounter Anisakis again. Another meal of parasitised fish – even if the Anisakis worms are all dead this time, and only the allergens remain
will provoke a massive IgE-mediated reaction, leading to anaphylactic shock. This problem is usually misdiagnosed as allergy to fish itself.
Other inconsistent reactions to food can be due to contaminants such as antibiotics, preservatives, other food additives or (especially in the case of shellfish) naturally occuring toxins.

Antihistamines and Allergy

Antihistamines were first introduced in 1947, and are very widely used, so their safety — at least in the case of the older antihistamines — is beyond doubt. Most of the antihistamines have no major ill effects, and no one should feel concerned about taking them. At worst they produce some rather annoying minor side effects, such as drowsiness, which often wear off in time.

These drugs are particularly valuable for hayfever and other allergies in the nose (perennial allergic rhinitis). They are also used for chronic urticaria, sometimes in combination with anotherhistamine-blocking drug — see p. 53.

Antihistamines are not much used for asthma. They have relatively little effect, probably because so many other messenger chemicals are involved in an asthma attack. However, doctors in Japan do use antihistamines for asthma, and it is possible that people of Asiatic origin react differently to them.

Only one antihistamine, ketotifen, is widely used for asthma in the West, and this has other effects besides blocking histamine (see p. 159). A new role may soon develop for antihistamines in thetreatment of asthma, combined with anti-leukotriene drugs (see p. 159).

If you suffer from anaphylaxis you might be given antihistamines in a liquid or chewable form, for use in an emergency. These are not enough in themselves to treat this dangerous condition - you must have an adrenaline injector (see p. 150).

In the past, some doctors prescribed antihistamines for atopic eczema, mainly for their sedative effect(see p. 139) which was thought to help children to sleep better and scratch less at night. This treatment has largely gone out of favour, because its value is in doubt. But a recent study has revealed that the non-sedating antihistamine cetirizine may be useful for very young children with atopic eczema, not only in treating their skin, but also in reducing the chance of them developing asthma (see p. 249).

Most people take their antihistamines in tablet or capsule form. Syrups and sugar-free elixirs areavailable for children.

Antihistamines can also be applied directly, in the form of nasal sprays or eye drops. These are mainlyused to treat hayfever and the conjunctivitis (inflammation of the eye) which often accompanies it.Levocabastine (brand name Livostin) is particularly effective for the eyes.

Antihistamine creams are also sold, without prescription, for the treatment of insect bites - i.e. thenormal non-allergic reaction to such bites. These creams are not recommended for atopic eczema or otherallergic conditions affecting the skin. Not only are they unlikely to help, but they may make mattersworse because, with regular use, skin sensitisation to the antihistamine occurs very readily (see pp.54-5).
Some common brand names

Common brand names include: non-sedating antihistamines - Clarityn, Semprex, Zirtek; Mistamine, Mizollen, Telfast, Terfenadine. Thefirst three are available without prescription.

older (sedating) antihistamines — Atarax, Dimotane, Optimine, Periactin, Piriton, Tavegil, Vallergan eye drops — Emadine, Livostin, Optilast nasal sprays — Livostin, Rhinolast

How antihistamines work
Of the messenger chemicals released when an allergic reaction occurs, the most important is histamine.

This does its work by attaching to specialised receptors in certain parts of the body, and so

triggering various reactions (see box on p. 12). The action of antihistamines is very simple: they bind

to the same receptors as histamine, but they do not trigger any reaction. Histamine cannot bind to the

receptor because the antihistamine is already there.
Unfortunately, the reverse is also true: if the histamine is already there, the antihistamine cannot

elbow it off the receptor, which is why it is important to take the antihistamine well before the

allergen is encountered. Taking antihistamines at the first sign of a snuffle or itch can also work,

but the effects will not be nearly as good as taking them in anticipation of an exposure.
The best approach to treating hayfever, for example, is to start taking the antihistamines at least a

week before the pollen season begins, and preferably two to three weeks before. You should then take

them continuously until it is over. This will make a huge difference to the degree of symptom control

you achieve.
Side effects
The older types of antihistamine, such as chlorphenamine (brand name, Rriton) are relatively

non-specific in their effects – they bind to several different kinds of receptors, not just those for

histamine. As a result they can have some unwanted effects, such as causing drowsiness and poor

coordination. While these sedative effects are no cause for concern in themselves, they can, of course,

be hazardous if you work with dangerous machinery or drive. Avoid both until you are sure how you react

to the antihistamine. Note that the effects of alcohol may be increased.
Very occasionally antihistamines have the opposite effect, causing stimulation rather than sedation;

this is most likely to occur in children and old people. Lowering the dose may solve the problem.
The other possible side effects of the older antihistamines –all of which are minor ones – are

headache, dry mouth, blurred vision, difficulty in passing urine, nervousness, shaky hands, upset

stomach or diarrhoea. A few men suffer impotence while taking antihistamines, but this disappears when

the drug is stopped.
The minor side effects of antihistamines, including drowsiness, often wear off after a while, although

the benefits of the drug remain. So it is worthwhile persisting with an antihistamine, even if it

causes some problems at first. Many people experience side effects from certain antihistamines but not

from others, so try several different types to find one that suits you.
The problem of drowsiness has been reduced, in recent years, thanks to the development of new drugs

that are far more
specific for histamine receptors, the non-sedating antihistamines. A few people do get drowsy even with

these drugs. Again, the effects vary from one drug to another, so if the first one disagrees with you,

try a different one.
It is worth noting – since some people may still have the odd packet in their medicine cabinet – that

two of the non-sedating antihistamines that were available without prescription a few years ago proved

to be unsafe for a small minority of people. One was astemizole (brand names: Hismanal, Pollon-eze),

which has now been withdrawn from use altogether in Britain. The other was terfenadine (brand names:

Triludan, Seldane, Terfenadine) which is still available, but only on prescription.
There are several special precautions relating to terfenadine:
• Never exceed the correct dose.
• If you have ever had any kind of heart problem, talk to your doctor before taking terfenadine.
• Stop taking the drug if you have palpitations, or if you feel faint; see your doctor promptly.
• Do not take terfenadine if you are taking the antibiotic erythromycin, or anti-fungal drugs

such as ketoconazole (Nizoral) or fluconazole (Diflucan), used to treat vaginal thrush.
• Do not take terfenadine if you have liver disease.
• Do not drink grapefruit juice while taking terfenadine: something found naturally in grapefruit

interacts unpleasantly with this antihistamine.
In addition to these special precautions concerning terfenadine, any antihistamine should be treated

with caution by those suffering from epilepsy, Parkinson’s disease, glaucoma, prostate enlargement,

kidney problems, urinary retention, a gastric ulcer, a thyroid disorder, porphyria or liver disease.

Check with your doctor before taking antihistamines if you have any of these conditions.
It may be inadvisable to use antihistamines if you are taking sleeping tablets, anti-depressants or

anti-anxiety drugs – again, see your doctor.
Stop taking antihistamines if you suffer any unusual kind of rash, or if your skin becomes more

sensitive to sunlight.
If you are breast-feeding, note that, because they go through into the milk, the older antihistamines

may make the baby sleepy. However, they do no harm.
Rescue treatment
Most antihistamines perform very badly if you take them once the allergic reaction has set in, but

acrivastine (Semprex) can be good in these circumstances and is non-sedating. No prescription is

required for this drug.
possibly identify all major side effects. We vary in our response to drugs, because we are all so

different at the chemical and cellular level. A drug might have a serious side effect that only affects

one person in 10,000, and no safety trial can hope to identify such a rare response. Only when a drug

is released, and becomes widely used, do such side effects come to light. Other unanticipated side

effects can sometimes arise when people taking the new drug are much older than those in the safety

trials, or belong to a different ethnic group with different susceptibilities. Combining the drug with

certain other drugs can also be a potential source of trouble, although pharmaceutical experts can

often predict such problems from a detailed knowledge of the chemistry of drugs and how they are broken

down in the body. Side effects that take several years to develop - more than the timespan of most

safety trials - will also fail to show up until the drug has been released.
All this may sound very alarming, but in fact severe reactions to new drugs are not that common. And

there are various safety nets in place - doctors keep a close eye on patients taking new drugs, and a

special reporting system ensures that, if unexpected side effects do show up, the information is

quickly shared with others in the medical community.
In order to relate the information here to a particular medicine that you take, you need to know what

drug category it belongs to. Does your inhaler contain a beta-2 reliever, a steroid, a cromoglycatetype

drug or an anti-cholinergic, for example? If you are not sure, ask your pharmacist.
Those are the category names for drugs: they denote families of drugs which are similar chemically
and work in roughly the same way. Within each category, or family, there are a number of individual

drugs. The individual drugs should, ideally, have a standard internationally agreed name - this is

known as the generic name. Unfortunately, a few of the drugs used for allergies and asthma have more

than one generic name - salbutamol is known as albuterol in some parts of the world, and adrenaline is called epinephrine.

Finally there are the brand names, which are the ones most patients are familiar with. These are always

shown with a capital letter, unlike the generic names. Long-established drugs are usually made by

several different pharmaceutical companies, and therefore marketed under several different brand names.

A newer drug, which is still covered by the patent of the pharmaceutical company that developed it,

will be sold under only one brand name.

The issue of brand names is important, because a different brand name might make you think you are taking a different drug, when in fact it is exactly the same drug being marketed in a different guise.If you have suffered side effects from a particular drug in the past, and wish to avoid it in future, take note of its generic name, rather than its brand name. Sometimes the generic name is used as the brand name, in what are called generic drugs. These arerelatively inexpensive copies of popular drug brands -they are just the same chemically, but they costless because there is no advertising of the brand to doctors, and profit margins have been cut to aminimum. In order to reduce National Health Service costs, doctors are now asked to prescribe generic drugs whenever possible.