This detailed article was contributed from the final print issue (December 2009) of Foods Matter Magazine (have no fear, Foods Matter is continuing online). It was written by Professor John Hunter and Agri-Food Scientist Karen Huntley of the Gastroenterology Research Unit, Addenbrooke’s Hospital, Cambridge.
Although unpleasant reactions to food are often referred to as ‘food allergy’, in many cases classical allergy mediated by IgE or IgG antibodies is not the true cause. Rather, the balance of normal healthy bacteria in the large intestine is disturbed. Undigested food residues passing down the gut are then broken down differently, leading to the production of chemicals which upset the gut, or, if absorbed, may cause symptoms (eg headache, skin rashes) affecting other parts of the body.
Thus the problem may arise after gut infections or antibiotic treatment, both of which are liable to damage the gut bacteria. Abnormal production of bacterial chemicals (eg hydrogen) can be demonstrated, and techniques such as skin-prick testing or treatment with antihistamines, which are very valuable in true allergy, are of little relevance. Treatment must be directed at controlling bacterial activity, and, if possible, at correcting the bacterial imbalance.
The symptoms of food intolerance are focused primarily on the gut but may also affect other organs of the body. Local manifestations of abnormal fermentation in the gut include rumblings, wind, bloating abdominal hypersensitivity and pain, as well as recurrent diarrhoea or constipation. Nausea is common, often at mealtimes.
Symptoms beyond the gut are often neurological with general malaise, headache, tiredness and inability to concentrate. Mood swings, sleep disturbances, and food cravings or aversions are common, and sufferers may become intensely sensitive to smells such as petrol, perfumes and paints. Aching joints, skin rashes and an irritable bladder are not unusual.
The principals of dietary management are simple but the practice is less straightforward. The patient follows a restricted diet for 2–3 weeks; the symptoms clear and the offending foods are detected by reintroducing them one by one and seeing which cause problems.
In practice the initial diet may be difficult to choose. Stricter diets (eg lamb rice and pears) are more likely to be successful but are very difficult to follow and nutritionally incomplete; less restrictive diets are easier to follow but are less likely be successful.
Ideally, during this crucial trial period no ordinary foodstuffs would be eaten at all, but the patient’s nutrition maintained. Artificial pre-digested liquid diets such as Elemental 028 Extra are ideal for this purpose, but are very expensive and strictly are only available on prescription in the NHS for patients with Crohn’s disease.
We have found that the Addenbrooke’s exclusion diet is a very valuable standard diet, which gives excellent results in most cases. Practical details of this diet and how to use it are given in the book Solve your Food Intolerance.
Food intolerances are not fixed and can sometimes dramatically vanish. Having avoided an offending food for several months, the patient may be able to tolerate it once again, sometimes in unrestricted quantities, sometimes in only small amounts.
Equally, new food intolerances may develop. Repeated eating of the same food may also lead to further food intolerances. One way of avoiding such a situation is to follow a rotation diet using safe foods. Ideally, such a diet should be based on a fourday plan so that the food eaten on Monday is not eaten again until Thursday.
It may also help to rotate foods according to their food families. However, in practice, a four-day rotation, especially by food family, is often not feasible in cases where multiple food intolerances are present and there are too few safe foods to provide an adequate diet. In such cases, a shorter rotation should be used without reference to food family.
It is important to choose foods from as wide a range as possible, taking advantage of the availability of unusual items such as quinoa and buckwheat, and meats such as ostrich or wild boar. Foods low in fibre are usually the easiest to digest. Likewise the digestion of foods (which reduce the residue available for fermentation) is increased by breaking them down as much as possible before swallowing. Blending of foods in a high-powered food processor is helpful. Cooking makes food more tender and releases nutrients from within fruit and vegetable cells. Some carbohydrates (eg rice and potatoes) are more easily digested when taken hot. However, patients who are starch intolerant may prefer to eat the foods raw. It is usually better to eat small frequent meals and to chew them carefully!
Complex dietary studies should only be undertaken with the help of a qualified health professional.
REDUCING BACTERIAL ACTIVITY
Antibiotics attack both good and bad bacteria in the bowel. Whilst they can certainly produce transient benefit, improving symptoms and food tolerance, the long-term effect is often further damage to the gut flora, resulting in increased problems, which manifest as soon as the antibiotic is stopped. Antibiotics must be used with care and discretion.
In women of childbearing age, food intolerances frequently get worse just before their periods. This is because gut bacteria are more active under the influence of the female sex-hormone progesterone, which is released during the second half of the menstrual cycle.
In severe cases of food intolerance, the symptoms developing at this stage of the cycle may be difficult to cope with. We have had considerable success in such cases by temporarily suspending the menstrual cycle for three months or so by implanting hormone inhibitors such as Zoladex under the skin. This is usually followed up by the insertion of an intrauterine device (a Mirena coil),which releases small amounts of progesterone locally and so protects the uterus itself without affecting the bowel bacteria. There are unfortunately snags with this treatment, which prevent it being used except in difficult cases. Prolonged use of Zoladex may lead to osteoporosis.
Women who are trying to conceive will not wish to have a coil, and in any case such treatment must always be supervised by a gynaecologist.
The term probiotic refers to living beneficial bacteria which contribute to the health and balance of the intestinal tract. There are many probiotic products available today but generally it is those containing significant numbers of friendly organisms which are most useful in helping to relieve symptoms.
The basic requirements for a suitable probiotic supplement are as follows:
- They contain a large number (over 10 billion) of viable friendly organisms. These bacteria are counted as colony forming units (CFUs)
- They must contain only bacterial species and strains for which there is scientific evidence of health benefit. Many strains of lactobacilli, for example, fulfil this criterion. These include L. rhamnosus GG, L plantarum, L salivarius, L reuteri, L acidophilus and L casei Shirota.
- Organisms should be able to withstand the stomach acid, digestive enzymes and bile salts and to colonise the gut at least temporarily.
Use a mixture of species and strains to improve the chance of at least one being effective. Some preparations contain inulin, which may be a disadvantage.
Probiotics which fulfil this most of these criteria:
- VSL#3 distributed by Ferring Pharmaceuticals (may be prescribed on the NHS)
- Custom Probiotics distributed by The Gut Doctor
- Metabolics Single Strain products
- Replete made by Biocare
A probiotic regime should be started gradually, beginning with small quantities daily, or perhaps every other day for severely affected patients. The dosage can be increased in small and steady increments.
Sensitive patients may experience a temporary exacerbation of symptoms when starting or when increasing the probiotic quantities ingested – probably from the death of bacteria in the bowel. Such symptoms should not be confused with intolerance as these reactions usually settle with the second dose, which can thereafter be taken without difficulty.
It is most unusual for probiotics permanently to colonise the bowel, and so their effects quickly wear off when they are stopped.
These are not absorbed by the small intestine, so pass along into the colon undigested, where they promote the growth of bacteria. Many prebiotics contain substances such as inulin or fructose oligosaccharide (FOS). Theoretically, these substances support only friendly bacteria. However, in practice, where the gut flora are unbalanced, they also appear to promote the growth of other bacteria as well, resulting in an exacerbation of symptoms, and a worsening of the overall situation. For this reason, we generally advise food intolerant patients to avoid prebiotics.
It is possible temporarily to reduce the number of bacteria in the bowel by washouts. From time immemorial people have visited clinics for colonic lavage, which they found helpful. However, colonic lavage, even as practised by experienced hospital nurses, is much less effective in emptying the bowel than is a vigorous purge such as Picolax or Citramag. That said, emptying the bowel this way is more energy depleting and time consuming than colonic irrigation. Approximately 12 hours are required for bowel cleansing drugs to take effect and empty the bowel.
Nonetheless, irrespective of which method is used, bowel clearouts may help patients with multiple food intolerances, although unfortunately their effect soon wears off.
Nevertheless, it is usually beneficial to keep the bowel contents moving through as smartly as possible, to reduce the time available for bacterial fermentation and the production of toxic chemicals. Laxatives are often helpful, even when a patient is not clearly constipated. We recommend bulking agents such as cracked linseed or sterculia (Normacol), as these have the advantage that they cannot be fermented by the bowel bacteria themselves (with the production of further symptoms).
Osmotic laxatives such as magnesium sulphate (Epsom salts) and Movicol may also be useful, as are glycerol suppositories.
Conversely, laxatives which increase colonic fermentation, such as lactulose and ispaghula husk (Fybogel), may cause problems.
DISORDERED BREATHING PATTERNS AND STRESS
Many food intolerant patients notice their symptoms worsen under stress. This is often because of a disordered breathing pattern, sometimes referred to as over-breathing or chronic hyperventilation. They breathe rapidly and shallowly, using the upper chest to draw air into the lungs, rather than the diaphragm.
include yawning or sighing deeply, breathlessness, palpitations, dizziness and fatigue as well as digestive problems including stomach and chest pain, belching and gas. Such breathing styles are often the result of anxiety caused by long-term stress, although they may also follow nasal obstruction, asthma or painful abdominal surgery.
Physiotherapy to retrain breathing and psychotherapy to reduce and manage the patient’s response to stressful stimuli are the cornerstones of treatment.
Reactive hypoglycaemia, where eating too much refined sugar leads to excess insulin release and a fall in the level of glucose in the blood, is an important factor in hyperventilation. Protein snacks between meals will help maintain a normal blood glucose.
Physiotherapy sessions for breathing retraining focus on teaching slow, diaphragmatic breathing as well as correcting musculo-skeletal problems arising from chronic hyperventilation.
Restoring a normal breathing pattern requires considerable effort and persistence on the part of the patient, who will need to practise several times daily. In time, however, this discomfort dissipates.
Once diaphragmatic breathing has been restored the patient can focus on the rate of breathing and timing. An excellent tool for teaching this is the Breathing Pacer, a software programme produced by York Biofeedback. This helps the user develop a good breathing pattern by use of a tone, which rises (inhalation) and falls (exhalation) in pitch.
Psychotherapy to overcome stress-related hyperventilation includes:
- Acceptance and Commitment Therapy (ACT)
- Cognitive Behavioural Therapy (CBT)
- Tapping (Emotional Freedom Technique EFT) is particularly useful for acute stress.
Additionally, patients are advised to undertake relaxation training, such as yoga, tai chi, meditation (mindfulness, visualisation and transcendental meditation) and progressive muscle relaxation.
MALABSORPTION – PANCREATIC ENZYMES
As food intolerance is caused by undigested food residues being wrongly metabolised by gut bacteria, it makes sense to see if such residues can be reduced. The activity in the saliva of amylase, the enzyme that breaks down starch, varied widely in a study of dental students at Birmingham University. Amylase from the pancreas is more important in human digestion than in the saliva, but is very difficult to obtain for measurement. It may be that its activity is as variable as the amylase in saliva.
Furthermore, there has recently been interest in the role in gut diseases of complex compounds derived from fructose and glucose called fructans, which cannot be digested at all in the human gut. Supplements of enzymes to digest fructans (fructanases) might therefore also be useful, but are not yet commercially available.
Nevertheless, taking supplements of amylase with other pancreatic enzymes might be helpful in some individuals, and is certainly worth trying.
The use of vitamin and mineral supplements is clouded by controversy. Persons who avoid milk and dairy products often need a calcium and vitamin D supplement, and if the diet is very limited a daily supplement providing the recommended amount of other micronutrients (eg Centrum, one tablet daily) may be very useful. No definite evidence exists to recommend other specific supplements.
Chronic fatigue in persons with these problems is very common and difficult to relieve. A paper published in The Lancet a few years ago suggested that extra magnesium might help. As this is poorly absorbed from the gut (indeed it is a laxative) this has to be given by injection. Unfortunately, others could not confirm the value of magnesium injections and as they are painful they are probably best avoided.
Fatigue is one of the earliest symptoms of vitamin B12 deficiency, and people receiving regular B12 injections because of other problems frequently report that they become intensely tired before their next injection is due. Furthermore, the measurement of the level of B12 in the blood may be inaccurate, although other tests such as methyl malonic acid or homocysteine may be more sensitive indicators of early B12 deficiency. Unfortunately these tests are not yet routinely available, but B12 levels should be measured whenever chronic fatigue is a problem, and if the levels are in the lower reaches of the normal range, there should be a trial of a course of B12 injections.
It is also important to exclude anaemia, thyroid dysfunction and low iron (ferritin) levels which can all cause fatigue and yet are easily corrected.
Food intolerance remains a controversial issue. In our opinion, the only current reliable diagnostic method is to follow a greatly restricted diet for two weeks to show that symptoms resolve and that they return when specific food items are reintroduced. Only such a technique can be relied upon to detect all forms of food intolerance.
A diagnosis of food intolerance must never be based on skin or blood tests alone. Such a diet requires careful medical supervision and in the most severe cases diet alone will not be sufficient. Many aspects are still poorly understood and new understandings and treatments will emerge in the future. Nevertheless, our knowledge of the role of the intestinal bacteria has provided a basis for further understanding and research.
CURRENT TREATMENTS FOR FOOD INTOLERANCE
Reducing bacterial activity (a. antibiotics; b. hormonal manipulation; c. temporary reduction in bowel bacteria – bowel washouts, laxatives)
Changing the bacterial flora (a. probiotics; b. prebiotics)
Breathing retraining and psychotherapy
Dietary intervention by means of elimination diets, fibre reduction, use of rotation diets and unusual foods
Laxatives, nonfermentable bulking agents
Psychotherapy and meditation
NOT COST-EFFECTIVE TREATMENTS
Nambudripad Allergy and Elimination Technique (NAET)
Unnecessary supplementation (vitamins, minerals, colon cleansers, amino acids)
Blood tests for allergy diagnosis (RAST, IgG, white cell testing)
Natural antibacterial agents such as oregano oil, goldenseal etc
Anti-candida diets and related treatments
Live blood analysis
Bradley, D, Hyperventilation Syndrome Kyle Cathie 2006
Fehmi, L, The Open Focus Brain Trumpeter Books, Boston 2007
Forsyth, JP, Eifert, GH, The Mindfulness & Acceptance Workbook for Anxiety New Harbinger 2007
Greenberger, D & Padesky C, Mind over Mood: Change How you Feel by Changing the Way you Think The Guilford Press, New York 1995
Hayes SC, Get Out of Your Mind and into Your Life New Harbinger Publications, Oakland 2005
Hunter JO, Workman E, Woolner J, Solve your Food Intolerance, 5th Edition, Vermilion, London, 2005
Hunter J O, Irritable Bowel Solutions, Vermilion, London, 2007
Kabat-Zin, J, Full Catastrophe Living Piatkus, London, 2006
Knaus, W J, The Cognitive Behavioral Workbook for Anxiety New Harbinger Publications 2008
USEFUL INTERNET SITES (U.K.)
http://www.physiohypervent.org/ ~ Physiotherapy for Hyperventilation
http://www.york-biofeedback.co.uk/ ~ York Biofeedback Clinic
http://www.babcp.com/ ~ British Association for Behavioural and Cognitive Psychotherapies
http://www.gutdoctor.co.uk/ ~ UK distributor for Custom Probiotics
http://www.vsl3.co.uk/ ~ VSl#3 probiotics
http://www.metabolics.com/ ~ Manufacturer of single strain probiotics
http://tinyurl.com/yj7csop ~ Granovita – Linusit Gold
http://www.laverstokepark.co.uk/ ~ Suppliers of rare meats
http://www.graigfarm.co.uk/ ~ Suppliers of rare meats
http://www.energiseyourlife.com/ ~ Supplier of juicers, alternative milk (nut, seed, soya) makers, high-speed blenders
http://www.freshwaterfilter.com/ ~ Supplier of water filters
http://www.stores.vitality4life.co.uk/ ~ Supplier of juicers, alternative milk makers (ie nut, seeds, soya)
http://www.breathworksmindfulness.org.uk/ ~ Mindfulness courses and mediation CDS
http://www.emofree.com/ ~ Emotional Freedom technique – tapping