Food Allergies & Intolerances by Unknown


For most of us, food is more than a daily necessity. We get personal pleasure from it. We nurture our children with it. And sharing it around the table is at the heart of our family and social life. For some people, though, foods can cause distressing, even dangerous, reactions, or chronic ill health, and that’s why we’ve written this book.

Foods can upset people for many reasons. This book will help you understand more about the different kinds of reaction that can occur - food intolerance, food allergy and coeliac disease - and the various foods and food substances that can trigger them. Based on more than 20 years of experience and research at the Allergy Unit at Royal Prince Alfred Hospital and the University of Sydney, we’ve developed a comprehensive dietary testing and management program now in use throughout Australia for people with food reactions.

Having a food problem may restrict your food choices somewhat, but it doesn’t mean you can’t enjoy eating and sharing with family and friends. In this book we’ve provided a range of recipes for all occasions, helpful hints for food preparation, and lifestyle advice to help people living with a food problem stay well and enjoy a full and rich life.

Even if you don’t have a food problem yourself, you probably have a friend or relative who does. We hope this book will provide an opportunity for everyone to learn more about ‘friendly’ food.

Understanding food intolerance

Understanding the difference between intolerance and other types of food reaction is an important starting point because the approach to dealing with them is quite different. Unlike allergies and coeliac disease, which are immune reactions to food proteins, intolerances don’t involve the immune system at all. They are triggered by food chemicals which cause reactions by irritating nerve endings in different parts of the body, rather in the way that certain drugs can cause side-effects in sensitive people.

The chemicals involved in food intolerances are found in many different foods, so the approach involves identifying them and reducing your intake of groups of foods, all of which contain the same offending substances. By contrast, protein allergens are unique to each food (for example, egg, milk and peanut), and dealing with a food allergy involves identifying and avoiding all traces of that particular food. Similarly, gluten, the protein involved in coeliac disease, is only found in certain grains (wheat, barley, rye) and their elimination is the basis of a gluten-free diet.

Natural food chemicals

Chemicals are found everywhere in nature, including in foods. Some are beneficial; for example, the vitamins we need for good health, and the flavour and aroma substances that make foods so enjoyable. On the other hand, many plants contain substances which are poisonous to humans, and of course we avoid cultivating these as foods. The staple foods we eat today have been selected by trial and error over thousands of years, both for their nutritional value and because most people can tolerate them without getting sick.

Some people are born with a sensitive constitution and react more readily to food chemicals than others. The tendency is probably inherited, but environmental triggers — a sudden change of diet, a bad food or drug reaction, a nasty viral infection (for example, gastroenteritis, glandular fever) — can bring on symptoms at any age by altering the way the body reacts to food chemicals. Women often become more sensitive in their child-bearing years, perhaps due to hormonal changes, which might be nature’s way of preventing pregnant and breast-feeding women from eating foods that could harm the developing baby.

Babies are more vulnerable to food chemicals because their metabolism, gastrointestinal and nervous systems are immature, which is why they often prefer bland foods. As children mature, their bodies become accustomed to handling small amounts of rich, spicy and highly flavoured foods, which usually only cause ill effects if eaten in excess.

It’s important to realize that the natural chemicals in many ‘healthy’ foods can be just as much of a problem for sensitive people as the ‘artificial’ ones used as food additives. Foods vary tremendously in chemical composition. The natural substances most likely to upset sensitive individuals — salicylates, amines and glutamate — are the ones common to many different foods, and therefore consumed in greatest quantity in the daily diet. As a rule, the tastier a food is, the richer it’s likely to be in natural chemicals. A comprehensive list of foods and their natural chemical content is shown in the charts on pages 16-21 (not shown in this website extract).

Food additives

People who are sensitive to natural food chemicals are usually also sensitive to one or more of the common food additives such as preservatives, artificial colours and flavourings. Reactions to these can be easier to recognise than reactions to natural chemicals because of the higher doses present in processed foods. As with the natural chemicals, individuals vary in their sensitivity to particular additives, and it’s often worthwhile testing this out systematically rather than avoiding all additives. The ones most likely to be a problem in people with food intolerance are listed on page 244 along with their code numbers (not shown in this website extract).

Food intolerance reactions

Symptoms triggered by food chemical intolerances vary from person to person. The commonest ones are recurrent hives and swellings, headaches, sinus trouble, mouth ulcers, nausea, stomach pains and bowel irritation. Some people feel vaguely unwell, with flu-like aches and pains, or get unusually tired, run-down or moody, often for no apparent reason. Children can become irritable and restless, and behavioural problems can be aggravated in those with nervous system disorders such as ADHD (attention deficit hyperactivity disorder). Even breast-fed babies can have food intolerance reactions due to chemicals from the mother’s diet getting into the breast milk, causing colicky irritable behaviour, loose stools, eczema and nappy (diaper) rashes.

Dealing with food intolerances

People vary in their degree of sensitivity to food chemicals, and whether or not they get symptoms depends on the dose ingested. If you’re not too sensitive (with a high dose threshold) you may only react after a particularly rich meal or after bingeing on highly preserved/flavoured/coloured foods. Avoiding these may be all you need to do to stay well.

However, if you’re at the other end of the spectrum (with a low dose threshold) you may develop symptoms over several days or weeks from the cumulative effects of small amounts of natural chemicals. Because these are present in many otherwise ‘healthy’ foods in a normal diet, you’ll have to be much more careful with what you eat on a daily basis.

The hints in this book may be enough to get you on the right track, but before making any major change to your diet, go and see your doctor. Food intolerances can be distressing, but they don’t cause permanent damage to the body. If you have persistent symptoms it’s a good idea to first make sure some serious disease hasn’t been overlooked.

If you’re having trouble working out which foods are upsetting you, professional help may be needed to investigate the problem more systematically. This first step is to follow a strict elimination diet for 3 or 4 weeks to see if symptoms disappear. You may get a withdrawal effect in the first week or so (with a temporary flare-up of symptoms for a few days) so don't give up too soon. Once your symptoms have settled and you're feeling better for at least 7 days in a row, your're ready to start doing challenges to find out which chemicals in your diet cause reactions.

Challenges can either be done double-blind (with purified food chemicals taken in capsules), or with carefully selected foods each containing only one problem substance. Once your problem substances have been identified, a dietitian with experience in the field can advise you how to manage your diet using the Friendly Food charts on pages 16-21 (not shown in this website extract). Don’t be discouraged — food intolerances needn’t be permanent. You may well be able to build up your tolerance level by gradually increasing the amount and variety of ‘low’ and ‘moderate’ foods over several weeks or months, and eventually return to a more normal diet. Even if this is not possible, you’ll learn ways of avoiding severe reactions by looking out for the foods that upset you most.

Understanding food allergies

Allergies occur when an overactive immune system produces proteins called IgE antibodies against substances in the environment that are otherwise harmless — pollens, house dust mites, moulds, animal hair (dander), and in some cases, specific food proteins. Food allergy is mainly a problem of infants, toddlers and young children. Over 90% of cases are associated with atopic eczema — an intensely itchy chronic skin rash affecting the face, arms, legs, and other parts of the body — and there is usually a family history of allergic disorders such as asthma, hay fever and eczema.

In adults, a single food such as peanut or shellfish is usually involved, but children are commonly allergic to two or three foods, sometimes more. The most common ones are peanut, egg, milk, other nuts, seafoods and/or sesame. Fortunately, most children grow out of their egg and milk allergies before they reach school age, or during the early school years, but allergies to nuts and seafoods can persist. Wheat and soy can cause allergies, but they tend to be mild and transient.

New food allergies can occasionally arise in adult life, usually with crustaceans and other more exotic foods that are not eaten in childhood. With rare exceptions, reactions to fruits, vegetables, herbs and spices are due to chemical intolerances rather than allergies. Skin prick tests or blood tests (radioallergosorbent test or RAST) can detect IgE antibodies in people with allergies, but are of no value for diagnosis of intolerances.

Food allergy reactions

Food allergy reactions vary in severity, depending on how sensitive the person is and how much of the food they’ve eaten. Mild reactions may only cause a little eczema or a few hives, and the cause may not be obvious. More severe reactions are usually obvious and occur consistently, every time the person has the food. Contact with the mouth and tongue can cause an immediate burning sensation, with hives and redness around the face and, if the food is swallowed, an immediate feeling of being unwell can be followed by vomiting, cramps and diarrhoea. The face, mouth and eyes can swell dramatically, and hives on the body can join into large, rapidly spreading welts.

The most severe type of reaction — anaphylaxis — can progress rapidly with breathing difficulty (from swelling of the throat or severe asthma), allergic shock and collapse, and can be life-threatening if not treated immediately with adrenaline (epinephrine) by injection. In the most sensitive people with a food allergy, tiny amounts of the food (pin-head sized) can be enough to provoke a severe reaction.

Coeliac disease

Coeliac disease is caused by an immune reaction to gluten, a protein found in wheat, barley and rye. The reaction causes inflammation and damage to the lining of the small bowel, which impairs its ability to absorb nutrients. Typical symptoms include mouth ulcers, fatigue, bloating, cramps and diarrhoea, but some people have no symptoms at all, and in others the only clue may be anaemia (due to iron or folic acid deficiency) or an unusual chronic skin rash (dermatitis herpetiformis). Coeliac disease should not be confused with wheat allergy, which rarely occurs beyond infancy, or the stomach and bowel irritation that gluten can sometimes cause in people with chemical intolerances.

Screening blood tests are available, but definite diagnosis requires a small bowel biopsy. These tests can become negative after a few weeks of gluten avoidance, so it’s best to get checked before you go on a gluten-free diet if you think there’s a possibility you might have coeliac disease.

Untreated coeliac disease carries a long-term risk of nutritional deficiency, osteoporosis and/or bowel malignancy. Currently, a life-long gluten-free diet is the only known treatment.

Good nutrition on a low chemical diet

If you are on a long-term restricted diet because of food intolerances, you’ll need to pay careful attention to maintaining good nutrition.

Protein, fat and carbohydrates come from staple foods. Proteins provide the building blocks for your tissues. Fats and carbohydrates supply the fuel for your body to generate and store energy. Even on a low-chemical diet you should be able to meet your protein and energy needs. If you begin losing weight, you’re probably not getting enough kilojoules (calories) and need to increase your intake of staple foods. Ask your dietitian for help if necessary.

Vitamins and minerals are necessary in small amounts for your metabolism to function normally. Remember that energy comes from major nutrients, not vitamins, so if you feel tired and run-down more vitamins are not likely to be the answer.


  • Protein — meats, fish, poultry, eggs, dairy foods
  • Fat — oils, margarine, meat, eggs, dairy foods
  • Carbohydrate — rice, potato, bread, pasta, cereals, white sugar
  • Fibre — wholegrain cereals, wholegrain bread, cabbage, Brussels sprouts, lentils, beans, pears
  • Essential fatty acids (omega-3 fats) — canola, sunflower and safflower oils and margarine; flaxseed oil; egg yolk
  • Natural antioxidants — foods containing vitamins A and C (see below) and vitamin E (canola, sunflower and safflower oils and margarine)
  • Vitamin A — dairy foods, eggs, margarine, fish, lettuce, Brussels sprouts, beans, cabbage
  • Vitamin B1 — breads (brown and white), brown rice, wholemeal pasta, fortified breakfast cereals
  • Vitamin B12 — meat, chicken, fish, eggs, milk
  • Other B vitamins — dairy products, meat, chicken, fish, lentils, wholegrain cereals
  • Vitamin C — potato, parsley, Brussels sprouts, cabbage, peas, swedes (rutabaga)
  • Folic acid — Brussels sprouts, lettuce, cabbage, lentils, pulses, wholegrain cereals, fortified breakfast cereals
  • Iron — meat, chicken, fish, eggs, lentils, wholegrain cereals
  • Calcium — dairy products, calcium fortified soy products

Salt intake is significantly reduced when processed foods are eliminated, so table salt can safely be used to add flavour to meals on a low chemical diet.

Cholesterol intake is reduced by cutting out processed foods. It can be further reduced by trimming the fat off meats, discarding chicken skin, and using low-fat milk. Use polyunsaturated oils and margarines where possible.

Vegetarians need to choose suitable alternatives to provide the necessary proteins. Suitable low-chemical legumes include lentils, chick peas, soya and kidney beans. Combining these with dairy foods, cereals and/or nuts and seeds will provide all the essential amino acids.

Pregnancy and breast-feeding will increase your requirements for calories, iron, folic acid and calcium. See your dietitian for detailed advice.

Common misconceptions

Popular diets come and go based on whatever alternative theories are currently in fashion; for example, hypoglycaemia, food family rotation, Candida, leaky gut and liver detoxification. These diets generally eliminate all additives and a wide range of foods that are rich in natural chemicals, so it’s not surprising that people with food intolerance who follow these diets often feel better, at least temporarily.

This is also true of so-called ‘yeast-free’, ‘wheat-free’ and ‘sugar-free’ diets. If your health improves on one of these diets, it’s easy to jump to the mistaken conclusion that yeast, wheat or sugar must have been the culprit. If you find that sweet foods, such as cakes, honey, jam and chocolate, upset you, it’s likely to be due to the natural chemicals and/or additives in them rather than the sugar. In fact, white (refined) sugar is perfectly safe for sensitive individuals, because any natural chemicals that might cause reactions have been removed in the refining process.

There is a common belief that dairy products are bad for people with ‘allergies’. In fact, this is not usually so. If you feel better avoiding dairy it may be because you’ve cut out the natural amines in tasty cheeses and chocolates, or the flavourings in yoghurt, ice-cream and milk shakes. Milk or wheat can sometimes irritate the stomach and bowels in people with food intolerance, but this will often settle down after the relevant food chemicals have been identified and eliminated for a few weeks.

Lactose intolerance is a common genetic difficulty in digesting lactose, and can cause bowel symptoms. However, it’s not usually necessary to exclude all dairy products, as most people with lactose intolerance can tolerate small quantities of milk and yoghurt. If you react to cheese (which contains no lactose) you’re likely to have intolerance to food chemicals other than lactose.


A balancing act

Food intolerance reactions can be unpleasant and inconvenient, but they are rarely serious and, as far as we know, they cause no long-term harm. Their severity depends on the amount of the offending foods you’ve eaten, your degree of sensitivity, and the nature of your symptoms. Once you’ve worked out what your problem foods are, you’ll be able to decide how to balance the benefits of being free from distressing symptoms against the inconvenience of restricting your dietary choices.

Eating out and social occasions

People with food intolerances often have problems when dining out, but you’ll be able to minimize the severity of any reaction by ordering wisely, eating small portions, and being extra careful with what you eat for a few days afterwards.

If you’re planning to go out for a meal, choose a restaurant that offers some plain, simple dishes. Even if the menu doesn’t have suitable choices, you can call beforehand to ask whether a special meal can be prepared for you from your tolerated ingredients or foods. This will also save you the embarrassment of having to ask detailed questions about various dishes on the menu in front of your friends and acquaintances.

If you often dine at the home of close friends or relatives who know you’ve got food intolerances, you can give them a copy of Friendly Food and let them know which recipes you prefer. Beware, though — well meaning hosts will sometimes be tempted to spice up a meal, mistakenly believing you’ll enjoy it more if it has some extra flavour.

At dinner parties, where you don’t wish to offend the host by asking about all the ingredients and refusing what’s being offered, you can simply eat the meat and plain vegetables but leave the gravies, sauces and rich desserts. Wherever you’re planning to go, it sometimes helps to take the edge off your appetite in advance by having a snack before you leave. Then you’ll be less tempted to eat rich, tasty foods and suffer the consequences.

For drinking when you’re out, mineral water or plain water are the safest options if you’re food sensitive. If you want alcohol, choose whisky, gin or vodka (straight, or with ice, water, soda or tonic). Less sensitive individuals can often tolerate half a glass of wine. High quality wines are less likely to cause reactions — a good excuse to choose a more expensive bottle.

Packing or buying your lunch

Stick to fresh rolls, unpreserved bread or plain crackers. For fillings, choose foods you know are safe, such as chicken, roast beef or lamb, egg, lettuce, celery, chives, bean sprouts, pear jam and golden syrup. If you’re not too sensitive, you may be able to tolerate a thin slice of fresh tomato, mild cheese, beetroot, grated carrot or asparagus.


Plan your trip carefully. When going by road, pack suitable foods in a portable cooler, book your overnight accommodation and order your meals in advance. For long flights, take your own snacks, and avoid eating airline meals unless specially prepared. Pack enough food to last you for the first day at your destination, giving you time to find your way around, and try to book accommodation that has facilities for cooking your own food.

Smells & fumes

Some people with food intolerances find that their sense of smell gets more acute on a restricted diet. Strong perfume, car exhaust, petrol fumes, fresh paint, cigarette smoke and other irritant smells and fumes may make you feel ill or give you a headache. Reactions like this can be unpleasant, but are not dangerous and usually resolve quickly after exposure ceases. Predictable exposures such as the the perfume section in department stores, supermarket aisles with cleaning products, petrol stations and underground car parks are easily avoided. If you’re unexpectedly exposed, don’t hang around — leave the area quickly and get some fresh air.

Toiletries, cosmetics and cleaning agents

Strong peppermint and menthol flavours and aromas are derived from natural salicylates, so clean your teeth with unflavoured toothpaste, salt, or bicarbonate of soda (baking soda), and avoid mouthwashes. If you react to preservatives, read the labels of products carefully — most liquid cosmetics and sunscreens are preserved. If you’re smell-sensitive, be careful with perfumes, deodorants, scented soaps, shampoos, conditioners, hair sprays, after-shave lotions and other toiletries. Vinegar and bicarbonate of soda (baking soda) are alternatives to strong-smelling detergents and bathroom cleaning agents.

Home environment

Indoor air can become quite polluted with volatile chemicals released from carpets and underlays, chipboard and other furnishing materials, cooking odours and cigarette smoke. Make sure your home is well ventilated with fresh air. Avoid using products with a strong aroma such as air fresheners, concentrated detergents, perfumed candles, incense, eucalyptus oil, and massage and aromatherapy oils. If you feel unwell in your home environment and you’re not sure why, check for hidden damp or mould, gas leaks and other sources of irritant smells or fumes.

If you’re planning to paint or renovate your home, and you’re smell-sensitive, choose your materials carefully. Watch out for oil-based paints, glues, floor varnishes, chipboard and treated timbers, all of which can emit volatile chemicals for quite some time when fresh or new. It’s best not to handle these materials yourself, and you may even consider staying somewhere else for a few days or weeks while the work is being done, and airing out your home before going back. If you’re not sure about a particular material or product, ask for a sample, take it home and see what happens after you’ve had it in your bedroom or living room for a few days.


People with food intolerances often react adversely to medicines. It’s best only to take essential medications prescribed by your doctor. If you’re salicylate sensitive, anti-inflammatory drugs and aspirin-containing pain killers should be avoided — paracetamol and codeine are suitable alternatives in most cases.

The colouring agents used in tablets and capsules can be a problem for people who are sensitive to food colourings. If there are no suitable white alternatives, surface colourings can be washed off tablets (by rubbing them gently under running tap water) and capsules can be opened, emptied onto a spoon and taken with some maple syrup or golden syrup.

Antibiotics are of no benefit against viruses and should only be taken for bacterial infections — if your doctor is uncertain, a swab can be taken and cultured before you start any treatment.

Dental anaesthetic injections usually contain preservatives and can sometimes cause unpleasant reactions. If this happens, ask your dentist to use plain lignocaine. For major surgical procedures, general anaesthetics are rarely a problem but the premedications and post-operative pain killers can cause distressing side effects. Discuss the choice of medications with your anaesthetist beforehand.

Many antacids and children’s syrups are coloured, flavoured and/or preserved. Check with your doctor to find suitable alternatives if necessary. Cough syrups, throat lozenges, menthol, oil of wintergreen, eucalyptus oil, liniments, massage oils, essential oils and most herbal remedies contain natural salicylates or closely related substances which frequently cause reactions in people with food intolerances, and should be avoided. If you’ve got a sore throat, gargle with warm salt water. If you need them, over-the-counter cold and flu preparations (with paracetamol, codeine and antihistamines) and nose sprays (with pseudoephedrine) are generally well tolerated if used as directed. Make sure you see your doctor if symptoms persist.

archive posted on 9 Feb 2011 in #healing & #teaching