Posts Tagged ‘avoidance’

Diet to Protect against Asthma
There is growing evidence that several aspects of the modern Western diet make asthma more likely to develop. Parts of this evidence are very convincing, while other findings are less conclusive as yet. Some people might argue that, until all the facts about diet and asthma are firmly established, no dietary changes should be recommended. However, all the dietary changes that might protect against asthma are also very valuable for general health.
This diet is potentially useful for:
0Atopic families who wish to reduce the chance of their chil- dren developing asthma. Other preventive measures, such as allergen avoidance and exercise (see Chapter 8), are obviously important as well.
•    Anyone who already suffers from asthma – with this diet, their symptoms may diminish.
The main elements of the anti-asthma diet are:
•    A high intake of fresh fruit. Researchers in Britain and the Netherlands have shown that people who eat more fruit have better lung function, and are less likely to develop asthma or bronchitis. Apples have a particularly good effect on the airways, according to one recent study. Many other studies show a link between Vitamin C – the major vitamin in fruit – and asthma prevention. This makes sense because Vitamin C is an antioxidant which inactivates the pro-inflammatory substances (called oxidants) that are found in cigarette smoke and other polluted air. In addition to Vitamin C, many fruits contain beta-carotene (see below) – mangoes and apricots are the richest sources.
•    Regular helpings of carrots, which contain the orange pigment beta-carotene. This is another antioxidant that can help prevent inflammation in the airways. It should be obtained from food, not supplements (see p. 207).
•    A high intake of fresh green vegetables, especially broccoli, spring greens, dark green cabbage, peas, parsley and courgettes. One Australian study has shown that children who eat fewer vegetables are more likely to wheeze. The benefits of vegetables may be partly due to the fact that they contain beta-carotene and (if eaten raw or only lightly cooked) Vitamin C. Dark green vegetables are also a good source of magnesium, and researchers find that people with a higher magnesium intake have healthier airways. Magnesium is believed to protect against asthma by helping the muscles of the airways to relax.
•    Plenty of tomatoes and tomato products, such as tomato juice, tomato sauce, ketchup and paste. The special protective effect of tomatoes is not entirely explained by their Vitamin C or beta-carotene content – another antioxidant, called lycopene, may be the crucial ingredient here. Good news for fast-food fans – the benefits of tomato paste are even seen among pizza eaters who are significantly less vulnerable to asthma.
•    Daily intake of sunflower seeds, or sunflower oil and margarine. These are by far the best natural source of Vitamin E, another antioxidant (see left) which helps to reduce the risk of becoming asthmatic. Vitamin E taken in supplements seems to have much less beneficial effect than natural Vitamin E from food.
•    A good intake of the minerals zinc, manganese and selenium, as well as magnesium (see p. 206). Shortage of any of these minerals may be linked with asthma. It is important not to eat too much wheat bran or unyeasted wholemeal bread, especially with main meals, as these block the absorption of several minerals.
Good sources of zinc include meat, shrimps, clams and oysters, with smaller amounts in cheese and egg yolks. Nuts, lentils and beans are fairly good sources of zinc, while soya protein blocks its absorption.
As well as being found in dark green vegetables, magnesium is plentiful in sardines, peanuts, hazelnuts, walnuts and lentils. Other fish, lean meat, milk, cheese and bananas contain smaller amounts.
Manganese is found in eggs and milk, and though the amounts are small, these are good sources because the mineral in them can be absorbed easily. While green leafy vegetables, whole grains and tea apparently contain more manganese – and are frequently recommended as a source of this mineral – in fact very little can be absorbed from those foods. Lentils are a moderately good source of manganese.
Selenium is most plentiful in fish and meat. It may be scarce in home-grown plant foods in areas of the world (notably Finland and parts of New Zealand) where selenium is lacking in the soil.
•    A limited intake of meat, especially red meat, plus a com-
-    plete avoidance of kidney, liver and other offal meats. An entirely vegetarian diet incurs a risk of mineral deficiencies however (see above). On balance, it is probably best to eat meat once a week or less.
•    A low intake of salt. Researchers in Kenya found that children eating a high salt diet (which equals the average salt intake in Britain and other parts of the developed world) were at greater risk of becoming asthmatic. For existing asthmatics, increasing the amount of salt eaten can make asthma worse, while reducing salt can lessen symptoms. Male asthmatics seem to be more vulnerable than females. Salt probably affects the muscles of the airways, making them more likely to contract.
The role of supplements
You should try to get all the nutrients you need from food rather than supplements. However, there are times when a supplement can be useful. Any asthmatic who has to cope with the effects of high air pollution, especially ozone and sulphur dioxide (see pp. 130-31), may find a supplement of Vitamin C beneficial. However, you should avoid very high doses of Vitamin C (e.g. I g/day) as they can cause disturbed sleep. Use natural sources for Vitamin E (see p. 206) if you can, but taking a supplement is better than nothing.
Vegans should think about taking a multi-mineral supplement, given the difficulties of ensuring an adequate intake of zinc, manganese and selenium from vegetable food (see left). Vegetarians may also benefit from a mineral supplement.
Some supplements, in certain circumstances, can do more harm than good. Omega-3 oils (also called w-3 oils, concentrated fish oils, or EPA and DHA) may make asthma worse for some people (see box on p. 221). Beta-carotene (sold alone and as part of mixed antioxidant supplements) may, according to some studies, promote cancer at the high doses used in many supplements. It should only be obtained from food.
Foods and drinks that bring on asthma attacks
The anti-asthma diet tackles the inflammation of the airways and the underlying tendency of the airway muscles to go into spasm – in other words, it is concerned with the long-term treatment or prevention of asthma. In addition, you should obviously avoid any foods which aggravate asthma in the short term. Various foods and drinks can bring on an asthma attack:
•    Foods and drinks containing sulphur-based preservatives tend to give off the irritant gas sulphur dioxide while being chewed or swallowed. Some asthmatics are more sensitive to sulphur dioxide than others. The foods that most commonly cause problems are dried apricots and other dried fruit (except those labelled ‘unsulphured’), shellfish, french fries, ready-made salads and fruit salads. Sulphur-based preservatives are used widely in the catering industry. On packaged food, look for ’sulphite’ and’metabisulphil or E numbers 220-227. Soft drinks, wine, beer and cider almost always contain sulphur-based preservatives.
•    Foods that cause heartburn (GER – see p.38) can aggravate asthma for some people.
•    Alcoholic drinks may make the airways contract for some asthmatics (see box on p. 160).
•    Some asthmatics need to avoid foods containing histamine (see box on p. 67).
•    A few asthmatics respond badly to the smell of food cooking. The most severely affected can suffer an asthma attack from anyfood aroma. Cromog lycate -type drugs (see p. 148) or anti -choli nerg ics (see p. 156) may block this reaction.
Needless to say, if you have a sensitivity reaction to any food listed for the anti-asthma diet you should not eat this food.

If you or your child are allergic to your pet, you should really find it another home. But a survey in the United States showed that more than a third of people with cat allergy still keep their cat - so there is detailed advice below for those who want to keep the pet, as well as those who decide to part company.
Often people with severe allergies find that, although they miss their pet badly at first, the vast improvement in their symptoms makes that difficult decision seem like a good one in the long run. Finding a home for an adult pet is often difficult, as most people want kittens or puppies, but try advertising locally, and explaining in your ad exactly why the pet needs a new home. Family and friends may be happy to help by offering your pet a home. Ask around among your older neighbours too – they may value having a mature pet that is calmer and already house-trained.
Cats
You can’t see cat allergen – many people wrongly assume that it is cat fur that is allergenic, or flakes of skin. The main allergen is a protein found in the sweat and saliva of the cat, which wafts about in the air in microscopic specks. These lightweight allergen particles are carried throughout the house.
So small are these particles that they remain airborne for six hours or more, however still the air. If they do finally settle, they are easily made airborne again by the least little breeze. Simply walking around a room is enough to disturb them.
Parting with the cat
After your cat has gone, there will be allergens everywhere – on and in the armchairs, sofas and cushions, on shelves and lampshades, in the carpets and even stuck to the walls and curtains. They will also be inside the mattress if the cat once slept on the bed, and will shoot out every time you lie down.
Once the cat has gone, air the house very thoroughly to shift all the allergen that is just hanging in the air. Wait a couple of
weeks, and see how much your symptoms improve, before going further. If you still have troublesome symptoms that are worse at home, then you need to:
• Buy a high-suction vacuum cleaner that retains allergen particles (these are marketed for dust mites – make sure it is a good one) so that you can vacuum your furnishings without redistributing the allergen everywhere.
• Wash anything that can be washed: duvets, sheets, curtains, loose covers, cushions and their covers, duvet covers, pillow cases, bedspreads etc. Cat allergen is not affected by heat, so a cool wash is as good as a hot one – but you must wash all the allergen away, so run the rinse cycle twice. No one knows if dry-cleaning removes cat allergen.
• If the cat ever slept on your bed, then consider buying new pillows and duvet. Covers designed for dust-mite avoidance (see p. 115) are an alternative option. They will keep some of the cat allergen from escaping into the air, but not the very smallest particles.
• The seat cushions of sofas and armchairs can be sprayed with tannic acid or a polysaccharide (see box on p. 116) to deactivate the allergens. Vacuum clean very thoroughly first to remove as much allergen as possible, then spray repeatedly for a few weeks or months.
A clean getaway
The allergic individual should go out while this work is done, and stay out for at least six hours afterwards (see p. 109).
The size of the allergen particles
Cat allergen is the tiniest allergen - most of the particles are less than 2.5 microns, and the smallest may be only 0.05 microns. (A micron is a thousandth of a millimetre.) You would need a really good dust mask or HEPA air filter (see pp. 108-9) for these particles. It probably won’t remove the very smallest particles, but will certainly reduce the allergen load.
Even after the cat has gone, and you have cleaned up meticulously, you may still sometimes have symptoms. Unfortunately, cat allergen is carried about on the clothes of cat-owners and gets into schools, cinemas, buses, banks and even the padded seats in hospital waiting rooms. However, only the most highly sensitised people are affected by these low levels of allergen.
Keeping the cat
Bear in mind that keeping the pet will result in significant continued exposure however hard you try with the methods described.
• Improve the ventilation in your house as this will reduce the amount of allergen in the air. If your house is tightly sealed against draughts at the moment, this will actually make a huge difference. Air the house regularly. Always keep a window slightly open whenever the cat and/or the allergic person is indoors. You could use a HEPA filter to clean the air, instead. These work fairly well for cat allergens because these are very small lightweight particles which easily become airborne, so there is quite a lot of allergen in the air most of the time. Of course, an air filter cannot do anything to protect you from a cat sitting on your lap (though advertisements have sometimes implied that they can!).
• Put the cat outdoors when it begins washing itself, as this generates a lot of airborne allergen. Provide the cat with a shelter outside where it can sleep and wash, to reduce the amount of allergen in the house. Make it as warm and comfortable as possible, feed the cat there, and provide a little catnip to make it more attractive.
• If your cat is still allowed indoors, remove all soft furnishings and fitted carpets. Buy leather- or vinyl-covered armchairs which can be wiped clean of cat allergen.
• Keep the cat out of the bedroom entirely. If it has been in the habit of sleeping there, wash all the bedding and buy new pillows. The mattress and duvet should be replaced or covered with anti-mite covers (see p. 124).
• If you have an un-neutered tom, consider having him neutered: the amount of allergen produced declines when male cats are neutered.
The following measures are sometimes recommended, but in fact they don’t work:
• treating the cat with acepromazine, an animal tranquilliser
• using a spray called Allerpet-C, which, so it is claimed, reduces the amount of allergen released. Scientific trials by a research group in Detroit have shown that it does not work.
• giving the cat a shower - i.e. drenching it in water. After a cat has had such a shower, the washing water contains a lot of cat allergen, so everyone assumed that this meant less cat allergen in the air. New research shows that the amount of allergen in the air around a cat after showering is no less than before. However, actually immersing the cat for three minutes followed by rinsing in clean warm water does reduce the allergen level in the air considerably. Unfortunately, the cat probably renews its stocks of allergen very fast, as a washed dog does (see below), so you need to repeat the wash at least once a week to reduce the allergen level in the air.
Dogs
Most of the advice given above, for cats, applies to dogs too because their allergens are also small and lightweight. Dogs produce less allergen than cats, and it seems to be less potent. However, you would still need to clean up thoroughly after the dog has gone, assuming you decide to find it another home.
If you decide to keep your dog, HEPA filters can be very useful, although you need also to take other measures, such as excluding the dog from bedrooms and keeping it outside for more (or most) of the time. Washing dogs thoroughly in a bath, using dog shampoo, reduces the amount of allergen in the air, but it builds up again to its former level within three days. You would need to wash the dog twice a week to achieve a useful reduction in allergen levels.
Other pets and domestic animals
Horses produce very powerful allergens, and those with allergies to horses are often so sensitive that even clothing that has been worn while riding and then brought indoors can elicit symptoms. Old furniture or mattresses stuffed with horsehair can sometimes cause problems too.
In the case of small mammals, such as mice and guinea pigs, it is usually the urine that causes allergic reactions. Proteins in the urine become airborne, and are carried around the house. You may be able to keep the pet if it is in a well-ventilated utility room or caged outside.
With snakes, lizards and other reptiles the allergens are found in tiny skin particles that float in the air. The same is true of stick insects and other insect pets.

Chemical Intolerance
`To start with, I just used to get this irritation in my throat when I was reading a magazine. Over the years it got much worse, and there was a dreadful burning feeling, not

just in my throat now, but also in my eyes and nose. Sometimes I could scarcely breathe. My doctor said it couldn’t be magazines and diagnosed asthma. Twenty years on, I can’t

look at a magazine, even for a few minutes, and other things affect me now too. If I go in a room with a photocopier running I start to choke and can’t breathe. Whenever I

describe this problem to anyone — apart from the doctor, that is — they almost always say they know someone else who has a similar problem. But the doctors still say that what

happens to me can’t happen.’
Mary has chemical intolerance, which is also known as chemical sensitivity, environmental Illness or idiopathic environmental intolerances. It is a condition that arouses more

passionate controversy than any other described in this book. Many believe that it simply does not exist, or rather that people who claim to have chemical intolerance are

actually victims of psychological problems, which express themselves as physical symptoms. Careful studies show that, while some people with supposed chemical intolerance do

fall into this category, others do not – they have no psychiatric problems, but they do appear to have valid symptoms when exposed to certain synthetic chemicals.
`People with MCS are desperate. They will go to great lengths and do almost anything to find a doctor, anyone, who believes them.’ So speaks one sufferer from MCS (Multiple

Chemical Sensitivity), the most extreme form of chemical intolerance. It is often severely disabling, with symptoms such as exceptional fatigue, nausea, headaches, poor memory

and concentration, dizziness. muscle aches, joint pain, chest pain and digestive problems. Those with MCS react to a very wide range of chemicals, and very often to foods and

food additives as well.
These severely affected patients are a small minority, however, and many more people are like Mary, with sensitivity to just one or two types of chemical exposure. Surveys in

the United States suggest that about 30% of the population are affected in this way. The authors of one such survey note that ‘the widespread idea that chemical sensitivity is a

condition of educated, urban housewives was not supported by our study. The region surveyed was rural… and individuals who reported chemical sensitivity were found in all age,

gender, income, race and employment groups.’
The chemical exposures that are identified as triggering symptoms include:
• perfumes
• pesticides
• cigarette smoke
• paint fumes
• petrol
• exhaust fumes
• cleaning products
• newspaper ink
• plastics, especially those with a strong smell
• glossy paper (e.g. In magazines).
Typical symptoms, in those with sensitivity to just one or two chemical products, are:
• a blocked or runny nose
• sore throat
• irritation of the eyes
• sinus pain and congestion
• headache
• breathlessness and wheezing
• nausea
• skin rashes
• extreme fatigue
• dizziness.
How does chemical intolerance begin?
For some of those with MCS, the problems began with a sudden over-exposure to a toxic chemical, such as a chemical spill, or pesticides from a crop-spraying plane. Others are

first affected by regular doses of pesticide at lower levels, such as spray drift from nearby fields or from a neighbour’s garden. It seems as if, for these people, their inborn

ability to detoxify both natural and manmade toxins is overwhelmed by an unusually heavy exposure, and never fully recovers. Although there have been no systematic studies of

this – it is difficult to imagine how they could be done –the wealth of well-documented cases is convincing. And studies of those exposed to high levels of pesticides in

accidents at work support the idea that this can cause lifelong sensitivity to very small doses of some synthetic chemicals. Sensitivity to alcohol and caffeine usually

increases enormously too.
In some cases, classical allergies also feature in the range of symptoms for those with MCS. If they had an allergic tendency before the accidental exposure to pesticides, this

is especially likely: after the accident, along with chemical intolerance, they have far more pronounced allergic reactions to common allergens.
The loss of tolerance to everyday chemicals may be related to some kind of damage to the enzymes in the liver that carry out the important task of detoxifying toxins that enter

the bloodstream. This detoxification system evolved to deal with natural toxins, such as those in plant foods, and those produced by bacteria living naturally in the gut. These

enzymes can also detoxify the widely used synthetic chemicals, when these are encountered in relatively small amounts, but the enzymes are overwhelmed by large doses.
Chronic Fatigue Syndrome (CFS)
This is a disease that probably has multiple causes rather than a single cause. The main symptom is fatigue that is not relieved by rest. Many people with CFS also have a

slightly raised temperature, problems with concentration and memory, headaches, sore throat and swollen lymph nodes (’swollen glands’). The lymph nodes are part of the immune

system, so this symptom suggests some disturbance of immune function. Other findings, related to immune cells in the blood, also support this idea. However, there are often

minor abnormalities in the brain as well, with some loss of the insulating material around the nerves (myelin).
For many patients, the disease develops in the wake of a viral infection, but for others the origin may be unclear. Whatever the origin of the disease, avoiding synthetic

chemicals is very helpful in many cases. Some sufferers also find an elimination diet helpful (see pp. 194-7). Doctors working in this area say that there is no sharp

demarcation between patients with Chronic
Fatigue Syndrome (CFS) and those with MCS.
Autism
In the search for a cause of autism, many possibilities are being investigated. The consensus now is that there is a genetic predisposition which, when combined with certain

trigger factors, leads to autism.
What are those trigger factors? Some researchers suggest that autistic children have poorly performing detoxification enzymes and are therefore sensitive to synthetic chemicals,

both in food and the environment. The suspicion is that these chemicals affect the developing nervous system.
Other researchers pinpoint food as the culprit. They believe that children who develop autism are affected by exorphins (see p. 76) produced from the proteins in wheat and/or

milk, and that these damage the child’s developing nervous system. There are claims that a dairy-free and gluten-free diet can help, but that it must be ultra-strict to work,

and may need to continue for at least six months before any improvement occurs. You must have your doctor’s approval for this.
Before starting them on such a diet, some doctors also give a course of anti-fungal drugs to those autistic children who have been treated repeatedly with antibiotics. This

combined treatment is reported to have very good effects for some children.
Treatment
Assuming that you really do have chemical intolerance rather than some deep-rooted psychological problem – and you have to be honest with yourself here, because otherwise you

will never get better – then careful avoidance of the offending synthetic chemicals is the only effective treatment. If you have eliminated everything that obviously affects you

and are not much improved, then try tackling common indoor pollutants (see pp. 128-30) as well.
Such measures are of value to some with chemical intolerance but may not be adequate for those most severely affected. If you need to take more radical steps, you may benefit

from the bedding, paints and other household items manufactured for those with chemical sensitivity. Once you reduce the level of synthetic chemicals in your everyday

environment, you may find that you can tolerate occasional exposures much more.
Some doctors recommend taking supplements of vitamins and minerals to speed your recovery. These (especially antioxidants – see p. 206) may be helpful for some people, but be

sure to get nutritional advice from someone with good medical qualifications, rather than a self-styled ‘nutrition therapist’.
Neutralisation therapy (see p. 211) seems to be effective for some people with chemical intolerance, but you will still need to avoid the offending substances. Hyperventilation

(see p. 236) can make chemical intolerance much worse.

The days when doctors wanted their patients to obey orders and ask no questions are largely gone. Patients with allergies and other forms of sensitivity - or their parents -

have to play a key role in managing the disease. Most doctors now recognise this, and encourage their patients to learn about their illness, its diagnosis and treatment, and to

be partners in their own medical care.
Quite apart from this, there are aspects of allergy management where few doctors can afford the time to become experts. The nitty-gritty details of dust-mite avoidance or food

labelling practices are good examples. You can usefully supplement your doctor’s treatment here, by informing yourself.
But where should this process stop? That is a difficult question which doctors are increasingly forced to consider. One modern phenomenon, being discussed in many medical

journals at present, is the abundance of medical information on the Internet. Some doctors dread the arrival of patients who have logged on the night before their appointment

and are armed with a huge number of facts about their illness -some accurate, some utterly wrong and some highly debatable. But other doctors welcome the fact that patients are

actively interested in their health problems.
The reactions of doctors to ‘Internet patients’ highlight an issue that also runs right through this
book - that of medical orthodoxy. Who decides what is true and what is false in medicine, and how do they do it? Make no mistake - this is a deep and abiding problem which

afflicts not just scientific medicine, but science in general.
If a doctor, confronted with a web-page claiming that allergies are caused by space aliens intent on
destroying Western civilisation, snorts ‘Rubbish!’, he or she is not, strictly speaking, taking a scientific approach. In science, you should consider all the different

hypotheses.
In theory, science works by questioning everything and taking nothing on trust - but you can’t make much practical progress if you stick rigorously to that approach. Neither

scientists nor doctors start their careers by running experiments to establish the truth of everything they were ever taught. At some point in science, and in scientific

medicine, you have to assume that certain things are probably true, and proceed accordingly. If you make significant progress working on those assumptions, then the chances are

they were correct. But a good scientist always remembers that they are only assumptions.
Scientific medicine rests on a huge number of assumptions. Some of these are clearly accurate - for example, that eating wheat triggers coeliac disease -and it would be

time-wasting to argue about them. But this ‘fact’ about coeliac disease began as just a theory (see p. 70), and a highly debatable one. It has taken time for it to become

substantiated by more and more evidence.
Some medical assumptions become enshrined as facts rather too quickly. Fifty years ago, orthodox medicine accepted as a ‘fact’ that many asthmatic children had ‘intrinsic

asthma’, which was psychological in origin. Research since then has shown that there is almost always an allergy underlying childhood asthma. Many other examples could be given

of medical ‘facts’ that are overturned by subsequent research.
Doctors thirst for certainty, something that is quite understandable when they are faced with so much human need. A significant part of the healing power of medicine comes from

placebo effect (see p. 233), and that relies on patients having faith in the doctor. The traditional way for doctors to cultivate that faith was by assuming an air of absolute

certainty - about their diagnosis of the patient’s illness, about the treatment, and about medicine in general. This need for certainty has always hastened the transformation of

assumptions into facts.
The fatherly authoritarian attitude of old-fashioned doctors was, in large part, a reflection of how little they had in the way of useful treatments, and how much they relied on

placebo effect. Modern doctors have far more genuinely effective remedies to offer and can afford to take a different approach. Many now rely on a different kind of authority,

one based on intelligence, good information, flexibility, curiosity and openness. It’s a form of authority that allows a doctor to say ‘I could be wrong…’ or, ‘Let’s try this

and see what happens…’ without losing face.
Unfortunately, there is another powerful force at work in this complex situation, and that is quackery -the age-old business of selling phoney cures (see p. 209). Official

bodies within the medical community try to curb quackery by weighing the evidence about novel treatments and coming to decisions on their validity. This can be very useful. But

in deciding what is, and what is not, good scientific medicine, medical organizations always run the risk of mistaking their own unverified assumptions for facts.
Establishing criteria for good treatment is essential in medicine, but when this develops into dogmatism, that is decidedly unhealthy. Among the treatments that are being

dismissed as valueless today, there are
several that deserve a fairer hearing.
Some of these treatments have been shown to work by the most excellent of scientific methods. The use of elimination diets in Crohn’s disease is a good example - for some

patients, there is a huge and sustained improvement, suggesting that their disease was caused, at least in part, by food sensitivity. The tactic used by those who want to reject

this evidence is simply to ignore it. When scientific review papers (summaries of all the current knowledge and latest research) are written about Crohn’s disease, the research

on diet is usually not mentioned. Evidence that is routinely ignored in this way slips into oblivion because most doctors only have time to read the review papers, not the

original research reports.
Occasionally - and this is even more shameful -good scientific evidence that goes against the grain of current orthodoxy is actually misreported in review papers. This happened

with an impeccable scientific study showing the benefits of an elimination diet for some patients with rheumatoid arthritis. By missing out certain key facts, a review author

managed to give the impression that the results of this study supported the conventional view on the subject (that diet makes no difference to rheumatoid arthritis), whereas

they actually disputed the conventional view.
Unthinking rejection of new treatments often occurs with currently untreatable diseases such as autism and Chronic Fatigue Syndrome (CFS). Such medical problems always attract

experimental treatments, just as they always attract sheer quackery, and sorting out one from the other is not easy - it takes time, and a clear-headed approach, not knee-jerk

dismissal.

FOOD SENSITIVITY IN ASTHMA, ECZEMA AND OTHER ALLERGIC DISEASES
In 1995, medical researchers in North Carolina, USA, asked over a hundred dermatologists how they treated atopic eczema. All used standard treatments such as moisturisers and steroid creams, but only 14% mentioned the possible role of food to the parents of children with eczema.
Between them, the dermatologists in this study treated about 17,000 children with atopic eczema per year. Using the most widely accepted estimates for food sensitivity in atopic eczema –38% of eczematous children are sensitive to food – one can calculate that there were over 5000 children in this study area who might perhaps have benefited from avoiding a problem food, but whose parents were never told about this treatment option.
North Carolina is by no means unique. The situation is much the same in other parts of the world, which adds up to millions of children and parents not even being told about a treatment that is frequently effective.
Other allergic diseases (see right) can also be triggered by food, although the percentage of patients affected is much lower than for atopic eczema. Here too, many doctors are unaware of (or sceptical about) the possible role of food.
These reactions are best described as ‘food sensitivity’. They cannot be called food allergy (see p. 62) if there are no symptoms in the mouth or gut and if skin-prick tests are negative – as is often the case. Negative skin tests suggest that the reaction is not IgEmediated (see box on p. 12).
However, in some children with atopic eczema. the skin-prick tests to culprit foods are positive. When these foods are eaten after a period of avoidance, such children sometimes suffer an
immediate reaction, with symptoms typical of true food allergy. For these individuals, their atopic eczema seems to be a symptom of IgE-mediated food allergy.
How can an atopic eczema reaction in response to food be IgE-mediated in one individual and not in another? Research is finally beginning to answer this question (see pp. 18-19).
The allergic conditions that may sometimes be induced, or simply aggravated, by a non-immediate reaction to food are:
• atopic eczema (atopic dermatitis)
• asthma
• perennial allergic rhinitis (constantly blocked or runny nose)
• chronic sinusitis
• secretory otitis media (’glue ear’).
In all of these conditions, many other causes exist. Except in the case of eczema, the other causes are far more likely than sensitivity to food. This fact will weigh heavily with your doctor, whose instinct, quite sensibly, is to look for likely causes first.
Taking asthma as an example, food sensitivity is relatively unusual as a primary cause, whereas allergy to airborne items. such as pollen or house-dust mite, is very common. Food probably affects only 8-10% of asthmatics overall, but is much more important for those with brittle asthma (the most severe and unstable form), affecting as many as 60% in a recent study.
The pollen connection
People who suffer from both birch-pollen allergy and atopic eczema may have worsening eczema when they eat certain fruits and vegetables, e.g. apples and carrots. These same foods cause Oral Allergy Syndrome (see box on p. 63) in some with birch-pollen hayfever, but they can aggravate eczema without causing Oral Allergy Syndrome.
Diagnosis
Consider other likely allergens first. Look at p. 28 for the airborne allergens that could play a part in perennial allergic rhinitis, chronic sinusitis, secretory otitis media (’glue ear’), and asthma. Only in the case of children with atopic eczema is food a prime suspect (between 38% and 69% of children with atopic eczema are affected by food), but even here there are a lot of other factors to consider (see pp. 43-4).
If you do decide to investigate the role of food, don’t abandon basic treatments in the meantime. By neglecting these. you could make the whole problem a great deal worse.
There are various clues that food is at fault:
• If you have other symptoms that suggest food intolerance (see p. 76). These problems often seem to go together with food-induced asthma or rhinitis.
• If you have noticed that a particular food makes your symptoms worse. Where there is intolerance to one food, there could well be intolerance to another, which you have not noticed.
• If you have exercise-induced asthma (see p. 41) and sometimes respond severely to exercise but sometimes have little or no reaction. Sensitivity to a food or foods may be instrumental in changing the response to exercise.
• If you have brittle asthma – but you must get your doctor’s consent for an elimination diet. Foods must be tested under medical supervision as severe life- threatening asthmatic reactions can occur on testing.
• If there are also digestive problems such as diarrhoea, vomiting or belching. This is a strong clue in the case of children with atopic eczema. Symptoms such as diarrhoea frequently precede atopic eczema, and it seems likely that a reaction to food in the gut increases the leakiness of the gut wall, allowing more food molecules through to the blood.
• If there is pronounced eczema around the mouth in children (but this can also be due to constant licking),
• For adults with atopic eczema, if there is a persistent rash on the hands, or the lips. Where there is a blistering rash on the hands that erupts at regular intervals, food is often the problem – or it may be metal contaminants of food such as nickel (see pp. 55-6). In general, food sensitivity is rarer among adults with atopic eczema than it is among children.
Skin-prick tests (see p. 91) for commonly eaten foods are worth
trying in all the diseases – if they give a positive result, they should
be noted, but if they give a negative one, they should be disre-
garded. The many alternative tests being marketed (see p. 93) are
highly inaccurate and unlikely to help.
Research from Tampere University Hospital in Finland suggests that babies are much more likely to give false-negative skin-prick tests for food than older children and adults with atopic eczema. The Finnish researchers found that 52% of babies with atopic eczema give a negative skin-prick test despite having a genuine reaction when tested by food challenge. In an attempt to tackle this problem, they have devised a patch test, similar to those used for contact dermatitis. The patch test, in which food is applied to intact skin and left there for two days, gives false negatives in only 39% of babies.
The best way to detect food-sensitive eczema, according to Dr Erika Isolauri. who heads the Finnish research team, is to use both tests, and take note of a positive reaction to either. This detects 80-90% of eczema-causing food reactions in infants.
Few other doctors are currently using patch tests for atopic eczema; because so much controversy surrounds this topic, and no standardised method has yet been devised. You may be lucky and find a specialist who does these tests.
To confirm the role of particular foods in atopic eczema, a food challenge test is essential, having first avoided the food carefully for two weeks. Great care is needed in testing (see p. 198).
If you cannot get suitable tests done. a simple elimination diet will be needed (see p. 198).
Treatment
There is a choice here, between avoiding the offending food, or eating normally and controlling the symptoms with drugs.
The difficulty comes when parents have to make this decision on behalf of their children. Unfortunately, there is insufficient evidence as regards the consequences of this decision. Treating food sensitivity can reduce the eczema symptoms substantially in the short term, but it does not necessarily improve the long-term prospects for the child. Orthodox doctors tend to think that eating a normal diet is much better for a child nutritionally and socially, and they have a point.
Doctors with a special interest in food sensitivity generally believe that treating the problem at source, rather than just suppressing the symptoms with drugs, must take the pressure off the child’s immune system, and give the child a better chance of growing out of sensitivity reactions in the long run.
The decision is yours – but it is vital that the diet is not more of an encumbrance than the disease itself, and that the child’s interests come first (see pp. 170-71). Whatever you do, don’t allow a child to become malnourished (see p. 198).