4.2 Food Chemicals

Pages 159-223 from The Food Intolerance Handbook
Copyright (c) Sharla Race. All rights reserved.

4.2 FOOD CHEMICALS

Lectins

MSG

MSG, monosodium glutamate, is the sodium salt of a naturally occurring amino acid—glutamic acid. Glutamate is essential to life and is found in cells throughout our body. It occurs in two forms, naturally in food and as an added flavour enhancer. Most of the glutamate our bodies receive is in a “bound” form and is gradually released as enzymes digest the protein food that it is part of. MSG, on the other hand, is a form of “free” glutamate that is instantly available to us and it is too much of this type that can lead to problems.

The degree of sensitivity experienced depends on the individual. Some people can tolerate vast amounts, others find themselves shaking and in an anxiety state after very little. The “toxic” reactions experienced by some people are generally because of an overload of MSG in its form as a flavour enhancer.

MSG intensifies some flavours and lessens others. It is an ideal additive for food manufacturers to “adjust” the taste of highly processed food and you can, without realising it, be ingesting quite large amounts of MSG. Generally made from the fermentation of corn, sugar beets, or sugar cane, MSG is a potential problem for anyone with an intolerance of these foods.

MSG has been linked with a number of conditions. It has been found to bring on asthma in some individuals, with the asthma developing anywhere from one to two hours to as long as twelve hours after ingestion.[i],[ii] More general concerns have been expressed about damage being caused to the nervous system and brain cells which can contribute to the onset of serious illnesses, like Parkinson’s disease and dementia, in later life.[iii]
[i] Allen DH, Baker GJ. Chinese restaurant asthma. N Eng J Med 1981;278:796.
[ii] Allen DH, Delohery J, Baker G. Monosodium L-glutamate-induced asthma. J Allergy Clin Immunol 1987;80(4):530-7.
[iii] Blaylock RL. Excitotoxins: The Taste that Kills. Health Press, 1997.

Squire reported on a case of a fifty-year old man whose recurrent angioedema of the face, hands and feet was related to MSG intake. The angioedema occurred sixteen to twenty four hours after ingestion of MSG.[Squire EN. Angioedema and MSG. Lancet 1987;24:167-72.] Botey et al reported on four children whose urticaria was caused by MSG. Symptoms developed between one and twelve hours after the MSG challenge was given.[Botey J, Cozzo M, Marin A, Eseverri JL. Monosodium glutamate and skin pathology in pediatric allergology. Allergol Immunopathol (Madr). 1988 Nov-Dec;16(6):425-8.]

A condition that became known as “Chinese Restaurant Syndrome” was identified in the late 1960s and linked MSG with a collection of symptoms including headaches, stomach pains, breathing problems, nausea and thirst.[Blaylock RL. Excitotoxins: The Taste that Kills. Health Press, 1997.]

In summary, the various symptoms and conditions that have been linked with MSG sensitivity are listed below. These have been combined from a number of sources including the review in Joneja’s book [Joneja JV. Dietary Management of Food Allergies and Intolerances: A Comprehensive Guide. Second edition. J.A. Hall Publications, 1998].

Anxiety, Asthma, Balance problems, Behavioural problems, Bloating, Blood pressure changes, Blurred vision, Breathing difficulties, Burning sensation in the back of the neck and forearms, Changes in heart rate, Chest pain, Depression, Diarrhoea, Difficulty focusing, Disorientation, Dizziness, Extreme dryness of the mouth, Facial tightness, Flu-like achiness, Flushing, Headache, Hyperactivity, Insomnia, Irritable bowel, Joint pain, Lethargy, Light-headedness, Loss of balance, Mental confusion, Migraine, Mood Swings, Nausea, Numbness or paralysis, Panic attacks, Paranoia, Rapid heartbeat, Runny nose, Sciatica, Seizures, Shortness of breath, Skin rashes, Sleepiness, Slurred speech, Stiffness, Stomach cramps, Urinary and prostate problems, Wheezing.

Fatigue has been noted as a side effect of too much MSG. As this often occurs up to twelve hours after ingesting MSG it is sometimes difficult to link the symptoms to the cause (a food diary will help). If you frequently eat food containing large amounts of MSG, such as some forms Chinese takeout, then you may have a hidden MSG problem.

MSG does seem to set away an addictive response and hence cause food cravings. One of the difficulties with diagnosing if you have an MSG sensitivity is that it is often an ingredient that is hidden. You will need to follow the avoidance process very carefully.

To test for MSG sensitivity avoid all foods containing added MSG for at least five days. Avoid the additives:

E621 Monosodium glutamate
E622 Monopotassium glutamate
E623 Calcium diglutamate
E624 Monoammonium glutamate
E625 Magnesium diglutamate

Unfortunately this is not a straightforward process. These additives creep into many foods and it is probably best if during these five days you avoid eating any restaurant or take-out food and preferably only eat what you cook yourself. The foods to check carefully include:

All ready meals.
Snack foods such as cheese and spicy flavoured crisps, chips, tacos.
Soya products, mainly soy sauce, miso, tamari, tempeh.
Most sauces, gravy mixes, and stock cubes.
Meat and yeast extracts, pastes and pâtés made from fish and meat.

Be aware of hidden MSG. It is possible that any of the following may contain MSG:

Autolyzed yeasts, bouillon, barley malt, broth, calcium caseinate, flavourings (including those listed as natural), HVP (hydrolysed vegetable protein), HPP (hydrolysed plant protein), kombu extract, malt extract, seasonings, sodium caseinate, textured protein.

At the end of the five days, eat a meal that you would previously have eaten containing MSG and wait—an “immediate” reaction can take up to twelve hours to present itself.

Some people react immediately on eating any MSG whilst for others it is dose related—whereas one meal containing MSG may cause no problems, a second meal followed by a snack food with high levels can produce the symptoms. It is a cumulative process—you may be able to eat it once a week but not over a number of days in succession. If a large, for you, amount of MSG is ingested it is possible that the initial reaction will be severe but of short duration. You should not be fooled into thinking this is the only reaction you will get.

Monitor yourself carefully over the next few days and notice any additional changes such as bloating, rashes, mental confusion, false energy and headaches. If reactions have taken place you will be able to keep your MSG levels very low simply by avoiding it in its additive form. Some people’s sensitivity is great enough to warrant that they also avoid foods that are very high in naturally occurring free glutamates.

Emsley and Fell list some of the foods with the highest amounts of naturally occurring MSG as follows (highest first):

Kelp, parmesan cheese, peas, tomatoes, corn, potatoes, spinach, chicken, carrots, beef, mackerel, pork, eggs.

Swain et al[Swain AR, Soutter VL, Loblay RH. Friendly Food: The essential guide to avoiding allergies, additives and problem chemicals. Murdoch Books, 2004.] list the following foods as being high in natural glutamate:

Vegetables: broccoli, mushroom, silver beet, English spinach, tomato, vegetable juice.
Fruit: grape, plum, prune, raisin, sultana.
Animal protein: processed meats.
Dairy: strong tasting cheese.
Condiments: miso, soy sauce, tempeh.

Don’t forget that if you are attempting to lower your overall levels of MSG that you need to ensure that you are not taking in any of it in additive form (check the lists in the earlier part of this section).

If you had no reaction to added MSG but reacted to some of the foods in which it occurs naturally then you may have a problem with another food chemical such as salicylate rather than MSG.

Oxalic acid

Oxalic acid and oxalates are naturally occurring toxins in many foods. They are generally dealt with in the gastrointestinal tract and removed from the body in the faeces as calcium oxalate. In some people oxalates have been detected in the urine indicating that absorption from the gastrointestinal tract has taken place. It appears that this absorption takes place when calcium in food is tied up with other dietary components.

A build up oxalic acid can lead to kidney and bladder stones. Other symptoms that have been linked with high oxalic acid levels include abdominal pain, diarrhoea and sore throats. Plant leaves, especially rhubarb, beet tops and spinach, have the highest concentrations: the concentration is so high in rhubarb leaves that they have been classed as poisonous.

It is not possible to provide a full list of foods containing oxalic acid but the ones listed below have all been found to contain it.

Beer, beetroot, blackberries, broad beans, celery, cocoa powder, gooseberries, green peppers, leeks, parsley, peanuts, pears, potatoes, red currants, runner beans, sorrel, spinach, strawberries, tea.

An average serving of each of these provides about 15mg of oxalate. Rhubarb has the highest amount, followed by spinach, beetroot, and cocoa powder. Star fruit[Fang,H.-C., Lee,P.-T., Lu,P.-J., Chen,C.-L., Chang,T.-Y., Hsu,C.Y., et al. Mechanisms of star fruit-indused acute renal failure. Food and Chemical Toxicology. 2008; 46: 1744-52.] and high doses of ascorbic acid[Barness, L.A. Safety considerations with high ascorbic acid dosage. Annals of the New York academy of science. 1975; 258: 523-8.] have also been linked with oxalic acid problems. No oxalates have been identified in cereals, cheese, eggs, and most other fruit and vegetables.[Emsley J, Fell P. Was it something you ate? Food Intolerance: what causes it and how to avoid it. O.U.P. 1999.]

If you suspect an oxalic acid problem the general advice is to avoid the foods high in oxalate, limit your fat intake and increase your calcium intake. Do discuss these changes with your doctor first.

Phenylethylamine

Purines

The production of uric acid is a normal bodily function. It is a waste product of digestion and is excreted via the kidneys as urine. In some individuals the removal of uric acid is impaired and it accumulates in the body eventually leading to unwanted symptoms.

Foods that contain the compound purine can raise the uric acid levels in the body leading, if you are susceptible, to conditions such as gouty arthritis or joint pain. These conditions are generally recognisable by their accompanying sudden and severe attacks of pain, redness and swelling of joints. The condition has been found to be helped by eating a low purine diet.

Gout generally comes on very suddenly with pain, swelling, warmth and redness usually in one joint. It has been commonly been associated with the big toe but can in fact afflict any joint. Some types of kidney stones can also be caused by uric acid build up and autism in some children has also been linked with an inability to correctly metabolise purines.[http://purineresearchsociety.org/]

Other problems have also been linked with purines. Moss reported on a study of the relationship between the consumption of alcohol, purines and boron, and the incidence of irritable bowel syndrome or frequent diarrhoea. The findings showed that individuals on diets high in alcohol, purines and boron had a higher prevalence of irritable bowel syndrome or frequent diarrhoea. The relationship was found to be significant.[Moss M. Purines, Alcohol and Boron in the Diets of People with Chronic Digestive Problems. J Nutrit Env Med 11(1):23-32.]

You will find it useful to test for purine sensitivity if:

you have recurring gout like symptoms,
only recently had a gout like episode but are also overweight and drink alcohol, or
have irritable bowel syndrome that has not fully responded to other forms of dietary intervention.

It should be noted that not everyone with gout will have a purine sensitivity. As gout has become more prevalent there is now more awareness of the condition and many treatment protocols include some degree of dietary changes. If you have been given a diet to follow because of gout please do not stray from it without checking with your doctor first.

To test for a purine sensitivity, reduce the number of high purine foods in your diet for at least two weeks. Increase your intake of fruit and vegetables (choosing from those not on the lists) that you can eat as these increase the alkalinity of the blood and can help in the removal of excess uric acid. Avoid alcohol. High purine foods include: [ [i]Jordan KM, Cameron JS, Snaith M, Zhang W, Doherty M, et al. (SGAWG). British Society for Rheumatology and British Health Professionals in Rheumatology guideline for the management of gout. Rheumatology (Oxford). 2007 Aug;46(8):1372-4.]

Meat especially red meat and offal, such as liver and kidneys, heart and sweetbreads.
Game, including pheasant, rabbit, and venison.
Seafood especially mussels, crab, shrimps and other shellfish, anchovies, herring, mackerel, sardines, sprats, whitebait trout, fish roe, caviar.
Yeast containing foods and beverages such as Marmite and beer.
Mushrooms and fungal proteins such as mycoprotein (Quorn), asparagus, cauliflower, spinach, lentils and soya beans.

For some the relief will be quite sudden but for others it can take time for the body to deal with removing the excess uric acid. If after a fortnight you are noticing some improvement you should maintain the diet. To actually test for a purine sensitivity is difficult as it is affected by the build up of uric acid to a level that is a problem for the individual—in some the response can be sudden, in others it can take weeks.

Persevere and monitor your success. As always with food testing, keep a food diary. It might be worth noting that strawberries, oranges, tomatoes and nuts, even though they are not high in purines, have triggered gout in some people.[ [i] UK Gout Society. All about gout and diet. http://www.ukgoutsociety.org/docs/2009FinalDietsheet.pdf]

The other food that has increasingly been linked with gout is fructose.[Zychowicz ME. Gout: no longer the disease of kings. Orthop Nurs. 2011 Sep-Oct;30(5):322-30; quiz 331-2.] Fructose rich drinks such as sugar sweetened soda and orange juice can increase serum uric acid levels and, hence, the risk of gout.[Choi HK, Willett W, Curhan G. Fructose-rich beverages and risk of gout in women. JAMA. 2010 Nov 24;304(20):2270-8. ] It is therefore probably best to also exclude these types of drinks. There will be a temptation to switch to sugar-free varieties but until you are sure that you need to eliminate the sugar drinks it would be best to stick to drinking water. Artificial sweeteners are often very complex products and adding them into your diet at this stage may lead to confusion with results of food testing.

Salicylates

The word “salicylate” is derived from the botanical name for the willow family “salicaceae” In 1838 salicylic acid was isolated from willow bark and, by 1899, acetylsalicylic acid was synthesised and marketed as aspirin. We come into contact with salicylate in two forms: In man-made substances such as medicines, solvents and perfume fixatives, and in its natural form in vegetables, fruit, spices, herbs and plants.

In nature, salicylates appear to exist as a natural preservative or insecticide protecting the plant and elongating its life span. The work of Anne Swain and others in Australia in the mid 1980s demonstrated the extent to which salicylate is present in food.[Swain A , Dutten SP, Truswell AS. Salicylates in Food. J Am Dietetic Assoc 1985;85(8).] Virtually every meal we ever eat contains some salicylate and for most people this causes no problem but for an individual who is salicylate sensitive the consequences for their long-term health can be disastrous. The brain is often seriously affected as an overdose of salicylate first stimulates and then depresses the central nervous system leading to emotional and behavioural problems.

It has been particularly linked with hyperactivity as a result of the work of Dr Feingold in the 1970s. The results of research carried out by Williams et al support the theory that some food additives and industrial chemicals induce intolerance because of their aspirin-like properties.[i] A study of aspirin allergy by Speer et al found that 90% of those with aspirin sensitivity were also sensitive to inhalants, food or other drugs.[ii] Others, including Thune and Granholt[iii] have also found a cross-reactivity with aspirin. So, if you have an aspirin sensitivity consider testing salicylates more generally.
[i] Williams WR et al. Aspirin-like effects of selected food additives and industrial sensitising agents. Clin Exp Allergy 1989;19(5):533-37.
[ii] Speer F et al. Aspirin allergy. Ann Allergy 1981 46(3):123-6.
[iii] Thune P, Granholt A. Provocation tests with antiphologistica and food additives in recurrent urticaria. Dermatogica 1975;151:360-64.

Many of the symptoms that arise as a result of salicylate intolerance mimic those of allergy but a reaction to salicylate is not an allergy. There is no simple method of testing to establish salicylate sensitivity—the most usual is the administration of an elimination diet followed by some form of challenge testing.

Salicylate is cumulative in the body and symptoms will only arise when the tolerance level of the individual has been exceeded. A large number of symptoms and conditions have been linked with salicylate and these are outlined below.

Mainly physical: Abdominal pain, Aching legs, Asthma, Bed wetting, Bladder Problems, Dermatitis, Dizziness, Ear Infections, Eye muscle disorders, Fatigue, Headaches, Hives, Hypoglycaemia, Nasal polyps, Persistent cough, Physical sluggishness, Poor physical co-ordination, Psoriasis, Rhinitis, Sinusitis, Sleep disorders, Skin problems, Speech difficulties, Stomach irritation, Swelling of face, hands, feet, Tics, Tinnitus, Urticaria.

Emotions, Behaviour and Feelings: Accident proneness, Anxiety and agitation (no reason), Bouts of excessive energy followed by fatigue, Confused thinking, Depression, Distraction, Dyslexia, Excessive or constant talking, Hyperactivity, Impatience, Lack or loss of concentration, Memory problems, Mental sluggishness, Mood swings, Needing to be left alone, Nervousness, Poor self-image, Sudden bouts of paranoia, Sudden highs, Suicidal thoughts, Temper flare ups, Unpredictability, Workaholism

How do you know if you are salicylate sensitive?

Check the symptom list. How many of the symptoms do you currently have or have frequently had before? The greater the number the more likely you are to be sensitive. Have you had periods of times when you have experienced clusters of the symptoms? Salicylate sensitivity is generally a life-long condition and a pattern of symptoms and behaviour will be noticeable. Do spices, herbs or vegetables make you feel ill or do you have an aversion to them? This is not necessarily an indicator as we have often been conditioned about our responses but think back to childhood and how you responded to these at that time.

The only way to determine if you are salicylate sensitive is to reduce the level of salicylate in your system and the only way of doing this is to eat food containing no salicylate or very low levels. Once the body has eliminated the stored salicylate it is then possible to reintroduce foods containing a higher level and to assess the extent of any reaction.

If you suspect that salicylates may be a problem for you and you are taking any medication containing aspirin or another form of salicylate DO NOT undertake this test. Check ALL your medicines first and if in doubt ask your doctor. Ideally, all medications should also be additive (especially colour) free. If you are taking a salicylate medication then consult your doctor before even considering this test.

Please do take the above advice seriously. Aspirin, and other salicylate based drugs, contain a very concentrated form of salicylate. If you stop taking them, reduce the overall salicylate level in your system, and then take one you could be putting your life at risk. Death can result from anaphylactic shock.

As salicylate is cumulative in the body you need to lower your level over a period of at least two weeks. During this time you must be absolutely certain that you do not expose yourself to any high levels. Choose your fortnight with care as meals away from home will be very difficult to deal with. You can eat any amount of the foods listed as safe. If you are currently a vegetarian do not suddenly start eating meat, if you know that lettuce or one of the other foods makes you ill or you have an aversion to it then don't eat it—stick to foods you are used to eating, you can (if you want to) try the other ones later.

To make it easier for you the foods have been allocated a number so that you can keep score of how much salicylate you are eating—the score relates to an average portion. Your maximum allowance during this fortnight is FIVE a day and it is essential that you do not exceed this amount on any day. Keep a food diary and write down the total score for each day. Your food diary is going to become an incredibly important ally in unravelling your food sensitivities. Use it fully.

None of us are perfect and if you slip up don't beat yourself up about it. Correct it. If you find that on one day you unwittingly had a score of ten then make sure the next day's score is zero. Do not do the reverse—this means that if, for example, on the Friday, you scored three you must not increase Saturday's score to seven. KEEP TO FIVE. If you have slipped up on more than two consecutive days you will probably need to start your fortnight again.

At the end of the fortnight you will need to decide on the next stage. The degree of your sensitivity, your age, your overall health and the speed at which your body can detoxify will all have influenced what took place. You will probably find yourself in one of the following categories:

There was no noticeable change.
There was a gradual improvement in symptoms.
There was no change at first then you had two or three days of feeling wonderful followed by days of being generally unwell and very tired—not too dissimilar to flu symptoms. Unless you have contracted a virus this is probably detoxification and nothing to be unduly concerned about.
There was a substantial improvement in symptoms.

If you had no improvement in your symptoms then it is unlikely that you are salicylate sensitive. You can test this by eating as many foods from the high lists as you like. If after a fortnight these cause you no problem you can safely assume that you do not have a problem with salicylates. If there was a gradual improvement then you are probably salicylate sensitive. You can try to increase your salicylate level gradually. Increase your score allowance to ten a day over a two week period. If your symptoms begin to get worse again drop your level to five for a few days and then increase slowly until you find the level you can tolerate.

If you can tolerate a score of ten a day then increase to fifteen a day, once again for two weeks, and keep on doing this until you reach the level at which your symptoms reappear. The easiest way of dealing with a return of symptoms is drop your level to five for a few days and then take it back up when you feel better.

If you had a few days of feeling great and then feeling generally ill and tired it is likely that you have some degree of salicylate sensitivity. To give your body a chance to detoxify it is safest if you stay at this level for at least a further two weeks.

Testing for salicylate content in food has been slow in taking place. The lists that follow are based mainly on the research carried out by Swain et al.[i] Other studies have taken place but none has tested the same number of foods.[ii],[iii] The findings from the other studies are explored in more detail in the Salicylate Handbook.[iv]
[i] Swain A , Dutten SP, Truswell AS. Salicylates in Food. J Am Dietetic Assoc 1985;85(8).
[ii] Wood A, Baxter G, Thies F, Kyle J, Duthie G. A systematic review of salicylates in foods: estimated daily intake of a Scottish population. Mol Nutr Food Res. 2011 May;55 Suppl 1:S7-S14.
[iii] Scotter MJ, Roberts DPT., Wilson LA, Howard FAC, Davis J, Mansell N. Free salicylic acid and acetyl salicylic acid content of foods using gas chromatography–mass spectrometry. Food Chemistry, Vol 105, 1, 2007, 273-279 .
[iv] Race, S. The Salicylate Handbook. Tigmor Books, 2012.

The other issues about salicylate levels is that the amount may vary from different crops and harvests, not all foods have been examined, results have not been retested and, in the future, newer methods of analysis may be discovered. Having said that, the lists are more than adequate for establishing if you have a salicylate sensitivity and, if you do, will also enable you to establish your level of tolerance.

You are welcome to try foods not on the lists but so as not to confuse the results it would be advisable to treat them as suspect and only introduce them at a later stage when you can clearly determine what is happening. The categories of food are safe, very low, low, moderate, high, very high and extremely high

If you get a reaction, be gentle with yourself. If salicylates affect your mind you may find it useful, when well, to write yourself a note you can read when a reaction takes hold—it should explain what is happening and reassure you that it will pass. If you have someone who understands what is happening talk to them—sometimes this helps minimise the effects of the anxiety.

Increase the number of safe fruit and vegetables you can eat as this increases the alkalinity of your blood. Taking extra Vitamin C can also help. If your blood sugar has been affected, don't worry. Eat lots of small meals for as long as you need—include “safe” treats. If you need to rest then take the time do so. It will pass. The length and severity of reactions will vary from individual to individual but, as it takes time for the body to eliminate salicylate, you can expect to experience symptoms for at least a few days.

Safe Salicylate Foods, Score = 0
Fruit: Banana, pear (peeled).
Vegetables: Bamboo shoot, cabbage (green/white), celery, dried green split peas, lentils, lettuce (iceberg), swede. Potatoes are fine but they must be of the old white variety and you must peel them.
Beans—dried (not borlotti). You may use canned beans but avoid any that have added ingredients such as sugar and salt.
Grains: Barley, buckwheat, millet, oats, rice, rye, wheat. To avoid additives and hidden preservatives, all bread, biscuits, cakes etc... should be home-made.
Seeds and nuts: Poppy seeds.
Sweeteners: Maple syrup, white sugar.
Meat, fish, poultry: Meat, fish, poultry and eggs are generally salicylate free but avoid liver and prawns and do not eat any processed meat.
Herbs, spices and condiments: Malt vinegar, saffron, sea salt, soy sauce.
Oils and fats: Cold pressed oils such as soy or sunflower. Butter. Margarine and processed rapeseed (canola), safflower, soya bean, sunflower oils although probably low in salicylate are likely to contain preservatives that may mimic salicylate reactions and are best avoided.
Dairy: Butter, cheese (not blue vein), milk, yoghurt—natural only but you can add your own fruit.
Misc: Carob powder, cocoa, tofu.
Beverages: Decaffeinated coffee, milk, ovaltine, home-made pear juice, soya milk, rice milk, water. Water should be the drink of your choice.

Very Low Salicylate Foods, Score = 1
Fruit: Golden delicious apple without the peel (green variety only), paw paw, pomegranate, tamarillo.
Vegetables: Brussels sprouts, borlotti beans, chives, choko, garlic, green peas, leek, mung bean sprouts, red cabbage, shallot, yellow split peas.
Nuts and seeds: Cashew nuts.
Herbs, spices and condiments: Fennel—dried, fresh parsley.
Sweeteners: Golden syrup.
Meat and fish: Liver, prawns.

Low Salicylate Foods, Score = 2
Fruit: Fresh figs, lemon, mango, passion fruit, persimmon, red delicious apple (peeled), rhubarb.
Vegetables: Fresh asparagus, beetroot, cauliflower, green beans, onion, marrow, potato—with peel, pumpkin, tomato, turnip. Frozen spinach.
Seeds and nuts: Hazelnuts, pecan, sunflower seeds.
Herbs, spices and condiments: Fresh coriander leaves.
Oils and fat: Ghee.
Beverages: Dandelion coffee, shop bought pear juice.

Moderate Salicylate Foods, Score = 3
Fruit: Custard apple, kiwi fruit, loquat, lychee, pear with peel.
Vegetables: Aubergine—peeled, carrot, lettuces other than iceberg, tomato juice, mushrooms. Tinned asparagus, beetroot, black olives, sweetcorn.
Seeds and nuts: Desiccated coconut, peanut butter, walnuts.
Sweeteners: Molasses.
Beverages: Coco-cola, rose hip tea.

High Salicylate Foods, Score = 4
Fruit: Avocado, most other varieties of apples, cantaloupe melon, cherries, grapefruit, mandarin, mulberry, nectarine, peach, tangelo, watermelon.
Vegetables: Alfalfa sprouts, aubergine with peel, broad bean, broccoli, cucumber, tinned okra, parsnips, fresh spinach, sweet potato, tinned tomatoes and tomato puree, watercress.
Grains: Maize.
Seeds and nuts: Brazil nuts, macadamia nuts, pine nuts, pistachio, sesame seeds.
Herbs, spices and condiments: Yeast extracts.
Oils and fats: Almond oil, corn oil, peanut oil, sesame oil, walnut oil.
Beverages: Coffee.

Very High Salicylate Foods, Score = 5
Fruit: Fresh apricots, blackberry, blackcurrant, blueberry, boysenberry, cranberry, fresh dates, grapes, guava, orange, pineapple, plum, strawberry, sultana.
Vegetables: Chicory, chilli peppers, courgette, endive, tinned green olives, peppers, radish, water chestnut.
Seeds and nuts: Almonds, peanuts with skins on.
Sweeteners: Honey.
Herbs, spices and condiments: Basil, bay leaf, caraway, chilli powder, nutmeg, vanilla essence, white pepper.
Oils and fats: Coconut oil, olive oil.
Beverages: Peppermint tea.

Extremely High Salicylate Foods, Score = 6
Fruit: Dried apricots and dates. Currant, loganberry, prunes, raisin, raspberry, red currant.
Vegetables: Gherkins.
Herbs, spices and condiments: Allspice, aniseed, black pepper, cardamom, cayenne, celery powder, cinnamon, cloves, cumin, curry powder, dill, fenugreek, garam masala, ginger, liquorice, mace, mint, mustard, oregano, paprika, rosemary, sage, tarragon, turmeric, thyme, wine and cider vinegars.
Beverages: Cordials and fruit flavoured drinks, fruit and vegetable juices, tea.

Alcohol varies in amount. Given the difficulty in fully ascertaining the ingredients of alcoholic beverages, it is best to avoid drinking alcohol during the first two weeks. The following list can be only be treated as a very basic guide to levels. The safest course of action would be to introduce your favourite drink as a test.

Gin, whisky and vodka are probably safe.
Beer, brandy, cider, and sherry have a high salicylate content.
Liqueurs, port, rum, and wine are extremely high in salicylate.

Living with salicylate sensitivity is not easy. To maintain a level of salicylate that you can tolerate in your diet, you really are going to have to take responsibility for your diet—you can never allow anyone else to make a meal for you without first ensuring that they have a full list of the foods you can eat (it is easier to give a list of foods you can eat than those that need to be avoided).

Some food additives can also be a problem not necessarily because they contain any salicylate but because some of them mimic salicylate in the body. For example, adverse reactions to tartrazine are common in people who also react badly to salicylate,[i] probably because both are similar in structure and are detoxified in the same way. Similar problems have been found with the antioxidants BHA and BHT.[ii]
[i] Settipane GA, Pudupakkam RK. Aspirin intolerance III: sub-types, familial occurrence and cross reactivity with tartrazine. J Allergy Clin Immunol 1975;56:215-21.
[ii] Fisherman EW, Cohen GN. Aspirin and other crossreacting small chemicals in known aspirin intolerant patients. Ann Allergy 1973;31:476-84.

Establishing a salicylate tolerance level is not an easy process and it can lead to a restrictive diet which is why many doctors advice against following one. Depending on your age and other factors unique to you, you may find that over a period of time you will be able to tolerate more salicylate. I suspect that at first, for some of us, our bodies are so relieved to have a reduction in the toxin that they rebel at the input of any but when the body has had time to recover it is more able to deal with eliminating salicylate and then accepts more.

Sadly, salicylates are found in a whole range of everyday products and, depending on your sensitivity, you will have to watch out for them. Perry et al have estimated that 12-20% of the salicylate in skin preparations is absorbed into the bloodstream via the skin.[Perry CA et al. Health effects of salicylates in foods and drugs. Nutrition reviews 1996;54(8):225-240.] As some ointments can contain high proportions of salicylate the risk for a sensitive person is serious. Ensure that none of the high and very high foods, especially herbs and spices, are present. Make sure you avoid anything with the word salicylate or salicylic within it. Some of the substances you need to watch out for include:

Acetylsalicylic acid, Almond oil, Aspirin, Benzoic acid, Benzoate—any form, Beta hydroxy, Birch, Bisabolol, Bismuth subsalicylate, Camphor, Castor oil, Homosalate, Hydroxybenzoate, Hydroxybenzoic, Menthol, Methyl salicylate, Methylene disalicylic acid, Oil of wintergreen, Ortho-hydroxybenzoic acid, Oxylsalicylate, Salicylaldehyde, Salicylanilide, Salicylic acid, Salicylic alcohol, Sodium salicylate, Stroncylate, Willow.

Carefully check medications, vitamins and other supplements, herbal remedies, cosmetics, creams and ointments, deodorants, toothpaste, teething gels, soap, shampoo, household cleaning products, air fresheners, insecticides, washing powders. Beware of perfumes as salicylate is often used as a fixative. It is best to avoid using perfume and scented products. Fragrance and colour free products are increasingly available.

I suspect that some people who tried a low salicylate diet for themselves or their children have run into this problem—an improvement followed later by seemingly salicylate unrelated problems. The symptoms are the same as before but you know the tolerance level has not been exceeded. If this happens check your environment—at work, home, school, wherever you spend time.

Crinon in an article on the health effects of airborne solvent exposure tell us that chemicals known as solvents are part of a broad class of chemicals called volatile organic compounds. These compounds are frequently used in a variety of settings and off-gas readily into the atmosphere. As a result of their overuse, they can be found in detectable levels in virtually all samples of both indoor and outdoor air. Once in the body they can lead to a variety of neurological, immunological, endocrinological, genitourinary, and hematopoietic problems.[Crinnion W J. Environmental Medicine, Part 2 - Health Effects of and Protection from Ubiquitous Airborne Solvent Exposure. Altern Med Rev 2000;5(2):133-143.] Some individuals also have metabolic defects that diminish the liver's clearing capacity for these compounds.

Perfumes and solvents can give you these reactions and with these it is very difficult to know if they contain salicylate or not. The only way of knowing is to trust your nose which at first can lead to many unwanted reactions. If it all sounds difficult then you're reading the situation correctly. The positive side, and it is a massive one, is the better health that follows. Salicylate causes so many problems within the nervous system that all aspects of your life are affected by it—reducing the level substantially can, for someone with a salicylate sensitivity, lead to many positive changes.

Saponins

Saponins are a type of glycoside found in some plants. They are often particularly known for the soap-like foaming they produce when shaken in water.

Saponins occur in a wide variety of plant foods including soy and kidney beans and quinoa. Whilst some saponins are thought to have positive health benefits, they are also linked with adverse reactions in particular gastrointestinal reactions.

A large proportion of saponins can usually be removed by carefully washing the food in running water but some will inevitably remain in the food. There are many anecdotal reports of severe stomach cramping, vomiting and diarrhoea after eating foods like quinoa. We currently don’t know if these problems have been caused by incorrect preparation/cooking or as a result of a sensitivity to either the food or the saponins.

A study by Fenwick and Oakenfull found the food plants, of the ones tested, that were highest in saponins to be: Chickpeas, soya beans, lucerne (alfalfa) sprouts, navy beans, haricot beans, and kidney beans.

Tests showed that saponins were not destroyed by processing or cooking but that fermentation appears to make a difference—the saponin content of tempeh, a fermented soya bean product, was only half that of whole soya beans.[Fenwick DE, Oakenfull D. Saponin content of food plants and some prepared foods. J Sci Food Agric. 1983 Feb;34(2):186-91.]

If you suspect a problem with saponins then eliminate pulses and quinoa from your diet for seven days and monitor your progress when reinstating them into your diet—at this stage only add in ones that you ate before the test and please ensure that you follow preparation and cooking guidelines.

Serotonin

Solanine

Solanine is a toxic alkaloid found in certain vegetables most notably potatoes. It probably acts as a preservative in the plants that works by making itself poisonous to fungi and bacteria and so preserving the life of the plant. It has been implicated in serious cases of food poisoning and has even resulted in death. A toxic dose will usually result in severe digestive upset and, possibly, trembling, weakness, breathing difficulties and paralysis.

McMillan et al reported on seventy eight schoolboys who became ill after eating potato at lunch, seventeen of them required admission to hospital. It was eventually found that the potatoes eaten by the boys who became ill were from an old batch and were found to be high in solanine. The symptoms were gastrointestinal, circulatory, neurological and dermatological with some boys being far more ill than others.[McMillan M, Thompson JC. An outbreak of suspected solanine poisoning in schoolboys: Examinations of criteria of solanine poisoning. Q J Med 1979;48(190):227-43.]

Vegetables containing solanine are all members of the deadly nightshade family. Everybody should know that eating potatoes that are green is dangerous and should be avoided. Always ensure that your potatoes are thoroughly peeled with all the sprouting parts removed and if the potato is green—throw it away. Solanine is not destroyed by heating.

Aside from the rather serious toxic aspect of solanine there is a lesser problem of sensitivity that affects certain individuals. Ordinarily the liver will break down solanine and help us dispose of it but in some individuals this is not the case and an excess of solanine leads to inflammation.

If you have any condition involving painful joints you might like to try a solanine free diet for a while—improvements can be dramatic. Identified symptoms include:

Arthritis, Confusion, Drowsiness, Gastrointestinal problems, Hallucination, Migraine, Painful joints, Skin problems, Stomach irritation, Trembling.

Testing for a solanine problem is relatively straightforward as so few foods are involved. Simply eliminate them all from your diet for two weeks. If there is an improvement you will then have to decide on whether you wish to test or not. If there has been no change then solanine is not a problem for you.

Be cautious if you are still eating any processed food as potato starch creeps into products as diverse as soup, cakes and ice cream. The foods which contain solanine are:

Aubergine
Cayenne
Chilli
Green and red peppers
Paprika
Potato
Tomato

If you have experienced an improvement but feel you cannot live without some of these foods then gradually reintroduce them and increase the amount you eat. If you keep a careful note in your food diary you should be able to find the amount you can get away with before your problems return or the discomfort becomes unacceptable to you.

One way of reducing the solanine level is by removing the outer layer by peeling—this method can certainly be used with potatoes and, to a lesser extent, with tomatoes.

Sulphites

“Sulphur” occurs naturally in a number of foods. “Sulphites” are sulphur based preservatives that are used to prevent or reduce discoloration of fruit and vegetables, prevent black spots on shrimp and lobster, inhibit the growth of micro-organisms in fermented foods such as wine, condition bread dough, and maintain the stability and potency of certain medications. Sulphites have been used since Roman times as preservatives in wine, sulphur dioxide was also used to sanitise wine and cider containers. Sulphites continue to be used in the wine making business in addition to their many other uses including the wet milling of corn to soften the kernel and facilitate the removal of corn starch.

A person can develop sulphite sensitivity at any point in life and no one knows, for definite, what triggers the sensitivity. Sulphites are broken down in the body by the same detoxification system that deals with other sources of sulphur in the diet such as amino acids like methionine and cysteine. In some individuals this detoxification system may not be working well and could give rise to a sulphite problem. Some countries have now prohibited the use of sulphites on fresh fruit and vegetables and insist on clear product labelling.

Sulphites have been most frequently linked with asthma. They are not generally seen as a cause of asthma but as a substance that can seriously exacerbate the condition. It has been estimated that between 5 and 10% of asthmatics are affected in this way. The Federation of American Societies for Experimental Biology (FASEB) in 1985 estimated that more than one million asthmatics are sensitive to or allergic to the substance.

Kochen in 1973 was among the first to suggest that the eating of sulphated food could cause bronchial problems. At the time he described the case of a child with mild asthma who repeatedly experienced shortness of breath, wheezing and coughing when exposed to dehydrated fruit that had been treated with sulphur dioxide.[Kochen J. Sulfur dioxide, a respiratory tract irritant, even if ingested. Letter. Pediatrics 1973;52:145-6.]

It became more accepted after work published by Baker et al,[Baker GJ, Collet P, Allen DH. Bronchospasm induced by metabisulfite-containing foods and drugs. Med J Aust 1981;2:614-16.] and Stevenson and Simon,[Stevenson DD, Simon RA. Sensitivity to ingested metabisulfites in asthmatic subjects. J Allergy Clin Immunol 1981;68:26-32.] both in 1981. Stevenson and Simon showed that challenges with potassium metabisulphite could produce significant changes in pulmonary function for some asthmatics. Other reported symptoms include flushing, tingling and faintness.

Problems with sulphites can result from ingestion, inhalation and topical application. Werth describes the case of an asthma sufferer who developed flushing, wheezing, and diaphoresis after inhaling vapours from a bag of dried apricots. In this case the person did not react to ingested sulphite when tested with a capsule of metabisulphite.[Werth GR. Inhaled metabisulfite sensitivity. Letter. J Allergy Clin Immunol 1982;70:143.]

Schwartz and Sher reported on a case in which breathing problems arose after an application of potassium metabisulphite solution to the eye during treatment for glaucoma.[Schwartz H, Sher TH. Bisulfite intolerance manifest as bronchospasm following topical dipirefrin hydrochloride therapy for glaucoma. Letter. Arch opthalmol 1985;103:14-15.] Howland and Simon demonstrated that sulphated lettuce can trigger asthmatic reactions in asthmatics with a confirmed sulphite sensitivity.[Howland WA, Simon RA. Restaurant-provoked asthma: sulfite sensitivity? J Allergy Clin Immunol 1985;75:145.]Less serious reactions can include:

Abdominal pain and cramps, Chest tightness, Eczema, Headache, Hives, Itching, Localised angioedema, Minor breathing problems, Nausea and vomiting, Stomach ache, Throat irritation, Urticaria.

Changes in body temperature and heart rate have also been noted.[Tollefson L. Quarterly report on consumer complaints on sulfiting agents. US Dept H&H Services, memo, April 2 1986:1-7.] A typical low-grade reaction would be as follows: after a meal you would suddenly find yourself a little tight chested and feeling as if you are starting with a cold. The sensation would probably disappear within a few hours and, most likely, you would forget about it. The symptoms need not all be physical.

Randolph cites cases in which individuals experienced mental symptoms including tension, nervousness, and depression. He says that "Sulfur can bring on acute mental and physical symptoms".[Randolph TG, Moss R W. An Alternative Approach to Allergies: The new field of clinical ecology unravels the environmental causes of mental and physical ills (revised edition). Perennial Library, Harper & Row 1990.] A sulphite sensitivity could also be a hidden problem for some individuals with irritable bowel syndrome as sulphites can interfere with the process of bacterial fermentation.

If you suspect a sulphite sensitivity and have breathing problems do NOT under any circumstances take this test without medical consent and supervision. Anaphylactic shock has been recorded as a result of sulphite reactions.

Foods high in naturally occurring sulphur have given rise to a number of symptoms including:

Abdominal pain, Bloating, Constipation, Diarrhoea, Dizziness, Generally feeling unwell, Headaches, Lack of co-ordination, Nausea and vomiting, Respiratory problems, Sneezing, Tight sensation in the chest. Tremors, Visual disturbances.

It is possible to be sensitive to naturally occurring sulphur and not to added sulphites and vice versa. It has also been found that sulphites destroy vitamin B1 which can be a problem for anyone on a poor diet. In some countries it is now banned from foods high in B1 such as meat. Eberlein-Konig et al also found that sulphites can contribute to UVB sensitivity.[Eberlein-Konig B, Bergner T, Diemer S, Przybilla B. Evaluation of phototoxic properties of some food additives: sulfites exhibit prominent phototoxicity. Acta Derm Venereol 1993;73(5):362-4.]

As sulphite is a product that is added to foods it is impossible to provide a full list of foods containing sulphite. The following list, based in part on the re-examination of the GRAS status of sulfiting agents, is intended to serve only as a guideline—you must check labels of all foods for sulphite containing ingredients.[LSRO (Life science research office). The re-examination of the GRAS status of sulfiting agents. Fed Am Socs for Exp Biology, Jan 1985.]

Foods that are often very high in sulphites include: Dried fruit, grape juice, lemon juice, lettuce, lime juice, molasses, sauerkraut juice, and wine.
Those that are often high in sulphites include: Dried potato, fruit toppings, gravies, sauces, maraschino cherries, and wine vinegar.
Foods often with moderate amounts of sulphites include: Corn starch, corn syrup, frozen potatoes, jams and jellies, maple syrup, mushrooms, pickles and relishes, sauerkraut, and shrimp.
Those often with low amounts of sulphites include: Beer, coconut, dried cod, dry soup mixes, frozen pastries, gelatin, instant tea, malt vinegar, soft drinks, sugar, tinned potatoes.

Check all processed products including biscuits, crackers, enriched milk, meat and fish pies, pastes and ready meals, pies and pizza crusts, tortillas, any baked goods, any containing dried or processed fruit or vegetables, and all tinned foods. During the testing period avoid eating away from home especially in restaurants as in some countries sulphites are added to help keep food fresh.

These are the additives you need to watch out for:
E220 Sulphur dioxide
E221 Sodium sulphite
E222 Sodium hydrogen sulphite
E223 Sodium metabisulphite
E224 Potassium metabisulphite
E226 Calcium sulphite
E227 Calcium hydrogen sulphite
E228 Potassium hydrogen sulphite
E150(b) Caustic Sulphite Caramel
E150 Sulphite Ammonia Caramel

Unless you are extremely sensitive you will find that you can tolerate some sulphites. Your challenge will now to be find out just what you can get away with. Whilst establishing a safe level you would be advised to avoid take out, fast food and restaurant meals. Remember that exposure to sulphites can result from ingestion, inhalation and topical application.

If you have had any serious reactions in the past and you don’t know what has caused them DO NOT undertake this test at home—discuss the way forward with your doctor. Whilst rare, anaphylaxis has been linked with sulphites so testing is safest under medical supervision.

Check all medicines, supplements, creams, toiletries, cosmetics and ointments as some of these can also contain sulphites. If any of these have been prescribed for you by a doctor you must not take this test—explain your concerns with your doctor and ask for their advice on how to establish if you have a sulphite problem whilst still being able to take the medication that you need.

At this point do not be too concerned about the foods that contain sulphur naturally—a complete elimination will probably be unnecessary and would cause you problems with eating sufficient protein.

Eliminate sulphites for at least ten days before testing. Follow the testing protocol given to you by your doctor or, if he was given you the go ahead to carry out the test at home, eat one of the foods you would have previously eaten that contained sulphites. If you have no reaction, gradually increase the number of foods with sulphites. If you experience any form of reaction—immediately stop the test and eliminate them from your diet once again.

If you found that you do have a sulphite sensitivity and have made some improvement but are still experiencing problems you may also need to reduce the amount of naturally occurring sulphur in your diet as well. Foods that contain natural sulphur include:

Bran, broccoli, Brussels sprouts, cabbage, cauliflower, cheese, dried beans, egg yolk, fish, garlic, lentils, meat, molasses, nuts, onions, pasta, wheat germ.

You need to take great care with this type of dietary restriction as you need to ensure that you are eating sufficient protein. If after two weeks you continue to experience problems then it is likely that you have a problem other than sulphur. Before embarking on further tests double and triple check the foods that you are eating, writing to manufacturers if need be, as residual sulphite concentrations can be found in many foods. Also ensure that you are avoiding corn products in case of sulphite contamination during rehydration processes.

Tannins

Tannins are naturally occurring chemicals found in a wide range of foods. It could be that, in a similar way to salicylates, they act as a form of natural protection for plants. They are also found in processed foods, medications and supplements where they are used as binders, coatings and preservatives.

The main symptom that has so far been linked with a tannin sensitivity is migraine.[Mather M. Migraines and tannins-any relationship? Headache 1997;37(8):529.] So, if you suffer from migraines and no other test has worked, consider checking your tannin tolerance level.

As with most food chemicals, there is no definitive list of tannin levels in foods but the information in the lists below should help establish if tannins are a problem. The easiest way of testing for a tannin sensitivity is to remove all tannin foods, listed below, for two weeks and then gradually reintroduce them. You will need to keep a food diary to be able to closely monitor how you react and you should bear in mind that reactions may be delayed and may also be the result of a cumulative effect.

Legumes: The redder ones appear to have more than whiter beans but, for the test period, remove them all. It is worth noting that tannins tend to be more concentrated in the outer layers.[i]
Fruit: Berries such as blackberry, blueberry, cranberry, raspberry, strawberry.[ii],[iii],[iv]
Nuts: Black walnut, cashew, English walnut, pecan, pistachio.[v]
Herbs and spices: It would appear that many herbs and spices contain tannins including cinnamon, cloves, cumin, tarragon, thyme, vanilla. As it is not currently possible to identify which are high and which are not, avoid all herbs and spices for the testing period.
Additives: You will need to avoid all added colours and flavourings as tannins can be used in the production of colours, flavour modifiers, and flavours such as butter, caramel, fruit, brandy, maple and nut.[vi]
Cocoa: Cocoa powder and chocolate in all its forms.[vii]
Misc: Any smoked foods.
Cheese: Avoid any cheese that has an added colour.
Beverages: Apple cider, beer, coffee, fruit juices, guarana, mate, tea, wine (especially red).[viii]
[i] Gupta YP. Anti-nutritional and toxic factors in food legumes: a review. Plant Foods Hum Nutr. 1987;37(3):201-28.
[ii] Vattem DA, Ghaedian R, Shetty K (2005). "Enhancing health benefits of berries through phenolic antioxidant enrichment: focus on cranberry". Asia Pac J Clin Nutr 14 (2): 120–30.
[iii] Puupponen-Pimiä R, Nohynek L, Meier C, et al. (April 2001). "Antimicrobial properties of phenolic compounds from berries". J. Appl. Microbiol. 90 (4): 494–507
[iv] http://clients.teksavvy.com/~mmather/foods.html
[v] http://www.widomaker.com/~jnavia/tannins/tannlist.htm
[vi] http://www.allallergy.net/fapaidfind.cfm?cdeoc=1977
[vii] Natsume M., Osakabe N., Yamagishi M., Takizawa T., Nakamura T., et al. Analyses of polyphenols in cacao liquor, cocoa, and chocolate by normal-phase and reversed-phase HPLC. Bioscience, Biotechnology and Biochemistry 64:2581-2587.
[viii] http://clients.teksavvy.com/~mmather/foods.html

If you have found yourself to be very tannin sensitive, you need to know that there are non-food products which may also give you a problem. Tannins are a sub-group of phenolics which are found in fragrances, paints, solvents, cleaning materials and the like.

Do not let this concern you at this stage. Continue with a low tannin diet and if you later get a re-occurrence of migraines then consider checking on the products commonly used, by yourself and others, in your home, work and social environment. This type of delayed reaction is not uncommon (often referred to as unmasking). Do not panic or necessarily suspect other foods. Keep a diary of all products used and how you feel in different places and you should soon be able to identify the primary culprits.

Tyramine

Other chemicals

This section contains a brief outline of some of the other chemicals found in food that can cause some people problems.

Aflatoxin: Aflatoxin is a mycotoxin produced by certain moulds. It can be found in foods as varied as nuts, peanuts, corn, milk, and dried fruit. Strict regulations govern the amount of permissible aflatoxin in foods, and poisoning in “developed” countries is rare.

Carvone: Carvone is a member of a family of chemicals called terpenoids. It is found naturally in many essential oils especially oil from seeds of caraway and dill. It is used in the production of flavours especially those that resemble spearmint, caraway, dill, mint and rye. It is also added to toiletries such as shampoos and hair conditioners.One woman’s head dermatitis was found to be caused by carvone.[i] Carvone has been responsible for cases of inflammation of the lips when it has been present in toothpaste.[ii]
[i] Quertermous J, Fowler JF Jr. Allergic contact dermatitis from carvone in hair conditioners. Dermatitis. 2010 Apr;21(2):116-7.
[ii] Corazza M, Levratti A, Virgili A. Allergic contact cheilitis due to carvone in toothpastes. Contact Dermatitis. 2002 Jun;46(6):366-7.

Glycyrrihizic Acid: Russo et al describe two cases of hypertension encephalopathy which resulted in pseudo hyperaldosteranism syndrome as a result of daily intake of low doses of liquorice. They propose that some people could be susceptible to low doses of glycyrrhizic acid because of a deficiency in a certain enzyme.[Russo S, Mastropasqua M, Mosetti MA, Persegani C, Paggi A. Low doses of liquorice can induce hypertension encephalopathy. Am J Nephrol 2000, 20(2):145-8.]

Goitrogens: Goitre, thyroid enlargement, has been linked with over consumption of naturally occurring goitrogens in vegetables. The vegetables include Brussels sprouts, broccoli, cabbage, cauliflower, kale, mustard, radish, rapeseed, soya beans, and turnip. It appears that cooking reduces the goitre effect of these vegetables.

Hymenoptera insects: Red wine is often implicated in adverse reactions. The suspects have included sulphites, salicylates and histamine. Armentia introduced us to a new problem for some people by identifying allergic reactions, in some individuals, to Hymenoptera insects that fall into the wine when grapes are collected and pressed.[Armentia A. Adverse reactions to wine: think outside the bottle. Curr Opin Allergy Clin Immunol. 2008 Jun;8(3):266-9.]

Linamarin: Linamarin is found in cassava (manioc), an important vegetable in some parts of the world yet also inherently toxic. Linamarin can be converted to hydrocyanic acid and lead to toxic cyanide effects. Neurological disorders and thyroid enlargement have been found in people who eat large amounts of cassava that has not been adequately processed. To reduce toxic cyanide effects, cassava must be correctly processed by soaking, boiling, drying, and fermentation.

Moulds

Sometimes it is very difficult to identify the food culprit that is causing health problems. An example of this difficulty is when moulds are present in food either as a result of the way the food is processed or because of contamination.

Flavour-enhancing moulds are added to traditional foods such as dry sausage, salami, Spanish ham, and French cheese in Central and Southern Europe.[López-Díaz TM, Santos JA, García- López ML, Otero A. Surface mycoflora of a Spanish fermented meat sausage and toxigenity of Penicillium isolates. Int J Food Microbiol. 2001;68:69-74.]

In Northern Europe, the addition of moulds to meat products is not permitted but there are studies that have found contamination by Penicillium, Cladosporium, and Eurotium moulds in equipment and raw materials used during the manufacture of meat products. For example: In order to determine the mycobiota in processing areas of fermented sausage and liver pâté, filamentous fungi were isolated from air, equipment and raw materials in the processing areas of two fermented sausage processing plants and two liver pâté processing plants.

A total of three hundred and thirty six samples were examined. The diversity of filamentous fungi in the processing areas was high; at least seventeen different genera were identified. The main isolated genera were identified as Aspergillus, Botrytis, Cladosporium, Epicoccum, Eurotium, Penicillium, Phaeoacremonium and Phoma.

Of these, Penicillium and Eurotium were the most important for contamination of fermented sausage, whereas Penicillium and Cladosporium were most important for liver pâté. In total, sixteen Penicillium species were identified. Sorensen et al concluded that Penicillium species are the most important contaminants of the meat products because of their high prevalence in the production environment, their presence on meat products and their toxinogenic properties.[Sorensen LM, Jacobsen T, Nielsen PV, Koch AG. Mycobiota in the processing areas of two different meat products. Int J Food Microbiol. 2008;124:58-64.]

Occupational respiratory diseases due to prolonged or repeated exposure to organic dust containing moulds (rhino conjunctivitis, asthma, hypersensitivity pneumonitis, and organic dust toxic syndrome) among food industry workers is well documented but food allergy to mould proteins is rare, with very few reports in the literature—two examples are given below.

Morriset et al presented two cases of recurrent angioedema after eating dry fermented sausages. These type of sausages are coated with various Penicillium strains and testing showed positive reactions in both cases to Penicillium.[Morisset M, Parisot L, Kanny G, Moneret-Vautrin DA. Food allergy to moulds: two cases observed after dry fermented sausage ingestion. Allergy. 2003;58:1203-4.]

Bobolea et al presented the case of a twenty-four year old man diagnosed with rhino conjunctivitis and asthma due to allergy to pollens, mites, and moulds at the age of nine years. In the past year he had experienced two episodes of facial angioedema immediately upon eating a few slices of dry sausage, which he had previously tolerated. The symptoms subsided in less than six hours. He had avoided the sausage since then and tolerated all other types of meat products.

A range of tests were carried out. Skin prick tests were positive for grass pollen, house dust mites, and moulds (Alternaria alternata, Penicillium notatum, Mucor racemosus, and Pullularia, Stemphylium, Helminthosporum, and Fusarium spp.), and negative for all the food allergens tested. The prick-by-prick test was positive for the outer sausage skin and negative for the sausage meat.

The microbiologists isolated Penicillium and Mucor spp. in the sausage skin. A further test led to angioedema of the lips, tongue, and soft palate within five minutes. The diagnosis was facial angioedema after dry sausage ingestion due to IgE-mediated allergy to Penicillium and Mucor spp. The man was advised to avoid all products commonly contaminated with moulds such as dry fermented sausages, Spanish ham, foie gras, and French cheeses such as Roquefort and Camembert.[I Bobolea, P Barranco, J Jurado-Palomo, M Pedrosa, S Quirce. Allergy to Dry Fermented Sausage. J Investig Allergol Clin Immunol 2009; Vol. 19(4): 324-335.]

If you eat fermented cheese or sausages and have problems you have been unable to link with a specific food it may be worth arranging for allergy tests to moulds.

Myristicin: Myristicin is found in nutmeg and carrots and can cause blurred vision, chest pressure, dry mouth, flushing, hallucinations, nausea, palpitations and a sense of impending doom. It is unlikely that you will be able to consume enough carrots to cause a problem but nutmeg poisoning has been reported.

Nickel

Flyvholm et al reviewed the nickel content of food as it is now thought that flare of hand eczema can occur after oral nickel exposure. The incidence of nickel allergy in the Danish population is thought to be 10% for women and 2% for men. Intake of nickel from the diet is estimated to be on average 150 micrograms per person per day.[i] Anderson et al found that nickel in tap water can also influence flare of hand eczema.[ii] Nielsen et al found quite clear links between diet and flare of hand eczema due to nickel content.[iii]
[i] Flyvholm MA, Nielsen GD, Andersen A. Nickel content of food and estimation of dietary intake Z Lebensm Unters Forsch 1984;179:427-31.
[ii] Anderson KE, Nielsen GD, Flyvholm MA, Fregert S, Gruvberg B. Nickel in tap water. Contact dermatitis. 1983;9(2):140-3.
[iii] Nielsen GD, Jepsen LV, Jorgensen PJ, Grandjean P, Bradnrup Y. Nickel-sensitive patients with vesicular hand eczema: oral challenge with a diet naturally high in nickel. Br J Dermatol 1990;122(3) 299-308.

Vegetables and grains supply the average diet with nickel. Cocoa and chocolate, soya beans, oatmeal, nuts and legumes also have a very high nickel content. Consumption of these foods in large amounts can increase the nickel intake to 900 micrograms per person per day or more. It is possible for flare of hand eczema to take place within the range of 600-5,000 micrograms. It would be necessary to establish the individual threshold.

Nickel content does vary. Joneja’s review of nickel levels in common foods has the highest as being buckwheat, oats, dark chocolate, peanuts, walnuts, flaxseed, cocoa powder, tea, and legumes.[Joneja JV. Dietary Management of Food Allergies and Intolerances: A Comprehensive Guide. Second edition. J.A. Hall Publications, 1998.]

Avoiding canned and processed foods would seem to be helpful as Smart and Sherlock found high concentrations in canned vegetables, sugars and preserves (also in bread and cereals) and suggest that nickel content can increase as a result of food processing.[Smart GA, Sherlock JC. Nickel in foods and the diet. Food Addit Contam 1987;4(1):61-71.]

Nitrates

Nitrates and nitrites have been used for centuries to preserve meat. The problem with them occurs when nitrate combines with certain other compounds in the digestive system it forms nitrosamines which are thought to be powerful cancer causing chemicals. There have been studies that have linked the regular ingestion of nitrates with some forms of cancers especially in the intestines.[Ferrucci LM, Sinha R, Huang WY, Berndt SI, Katki HA, Schoen RE, Hayes RB, Cross AJ. Meat consumption and the risk of incident distal colon and rectal adenoma. Br J Cancer. 2011 Dec 13.]

Nitrates have also been linked with less serious forms of sensitivity. For example, a case of severe itching was found to be caused by nitrates—a forty-year old woman experienced severe itching on the arms and back. Testing after an elimination diet established that nitrates were the cause; within three hours of ingesting sodium nitrate the itching emerged and remained for four days, nitrate intolerance was diagnosed.[Asero R. Nitrate intolerance. Allergy 2000;55:678–679.]

Many processed and cured meats contains added nitrates. The additives to avoid are:
E249 Potassium nitrite
E250 Sodium nitrite
E251 Sodium nitrate
E252 Potassium nitrate

Phenols

Phenolic compounds are found in a wide range of foods. These are natural substances that colour and flavour foods. The fact that they are toxic could be nature's way of protecting itself against micro-organisms and aiding the dispersal, and germination, of the seeds. Generally our body eliminates these toxins with no difficulty but for some people they cause problems. The discovery of phenolic compounds led Dr Robert Garner to devise a neutralisation technique using dilutions of these substances to stop his own allergic reactions. Some examples of phenols are:

Eugenol found in almond, beef, carrot, celery, cheese, milk, orange, pea, soya bean, tomato.
Piperine found in beef, beet sugar, cheese, chicken, cow's milk, grape, lamb, onion, pea, potato, soya bean, tomato, yeast.
Cinnamic acid is one of the better known ones, its precursor in most plants is phenylalanine. Cinnamic acid gets its name from oil of cinnamon where it was first discovered. Its presence may reach as much as 13 mg/100g in such foods as apples or 14 mg/100g in sweet cherries and 14.5 mg/100g in grapes (68).[Charambous I, ed. The Quality of Foods And Beverages, Vol. 1. Academic Press, 1981.]

The amount and concentration of phenols varies greatly from plant to plant. How they affect health is complex as it is influenced by their interaction with each other and with other chemical compounds. As yet it is not clearly known which phenols are beneficial, which are harmful and which may lead to sensitivities.

Propionates: The food additive “calcium propionate” has been linked with some migraine headaches and skin rashes.A report in 2002 also linked it with behaviour problems (irritability, restlessness, inattention, and sleep disturbance) in children.[Dengate S, Ruben A. Controlled trial of cumulative behavioural effects of a common bread preservative. J Paediatr Child Health 2002;38(4):373-6.] The propionates, listed below, are quite frequently found in bread and other products made with flour: E281 Sodium Propionate, E282 Calcium Propionate, and E282 Potassium Propionate.

Tin: Tin plate is commonly used in the construction of metal cans for foods. If the tins are not adequately lined when used for acidic foods such as tomato juice and fruit cocktail then tin intoxication can take place. Tin is poorly absorbed and hence the early symptoms are bloating, nausea, abdominal cramps, vomiting, diarrhoea and headache within thirty minutes to two hours.[Barker WH Jr, Runte V. Tomato juice associated gastroenteritis, Washington and Oregon, 1969. Am J Epidemiol 1972;96:219-26.]

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