An Introduction to Food Chemical Intolerance

Human beings do not have an infinite capacity to consume and safely neutralise the artificial chemicals found in processed foods, or the natural toxins found in plant and animal wholefoods without experiencing side effects. When our capacity to neutralise toxins is exceeded we start to suffer from health problems. Just as consuming alcohol can produce a hangover the following day, so a variety of artificial and natural flavour and colour chemicals found in foods can cause negative symptoms too.

Because food chemicals are so widespread in our diet and their effects can build up very slowly in the body, most people with food chemical intolerance never realise that the cause of their chronic health problems is related to food. If they are lucky enough to spot a connection to food, they may not be able to figure out which foods bother them because they appear to react to so many. They may feel that they are "allergic" to everything.

Imagine having a constant hangover because you drink all of the time. You might suffer from headaches, back ache, aching joints and muscles, hypoglycaemia, allergies, brain fog, and be easily irritated. Imagine that some people experience the same symptoms - and many more diverse health problems - from consuming more food chemicals every day than their bodies can neutralise. These individuals often crave the foods that are causing them problems. Cravings for chocolate, cheese, fruit, dairy, wheat, and junk foods (i.e. foods that contain additives) are very common.

Everyone has a different capacity to be affected by food chemicals. Some people only experience feeling a bit "off" after they eat too much strong cheese or chocolate, drink too much red wine, or eat too many artificially coloured sweets. Some never notice a thing. Other people may find they suffer chronically even when eating an apparently pure and healthy diet of natural wholefoods. In fact, when these people perform a food chemical elimination diet they often find they cannot eat apparently harmless foods like broccoli or oranges without experiencing symptoms of ill health. If you are one of these people, because you eat fruit, vegetables, cheese, vacuum-packed or hung meat, or drink tea or coffee every day, you may never realise that your problem is associated with food.

How can it be that some people are so sensitive to the natural chemicals in food? At first, an assertion like this sounds ludicrous and seems to go against our common-sense idea of what our evolutionary diet was. But there are numerous historical examples of such reactions, and also a great deal of evidence that food chemicals have risen massively in our diet in recent years due to current agricultural and food storage and processing practices.

There is also ample medical evidence dating right back to the 1950's and 60's - that this condition exists, that it is quite common (around 1-5% of people), and that it is treatable with a bland, low-chemical diet. In the 1950's it was discovered that a group of people who seemed to be chronically ill with asthma, eczema, urticaria and GI symptoms were actually experiencing the side effects or symptoms of aspirin overdose, yet these individuals were not consuming aspirin. It was realised that natural plant foods like vegetables and fruits contain small amounts of aspirin (salicylate), and that these individuals were actually reacting to these small amounts. Due to their particular genetic makeup, these individuals were unable to neutralise some of aspirin's effects on the body and as a result experienced an amplification of the unpleasant side-effects associated with aspirin ingestion.

Food chemical intolerances exist because of the natural variation in our population to deal with chemicals. To extend the metaphor, whilst one person may only be able to drink one glass of wine without feeling hung over the next day, another can get away with three or four glasses, whilst someone else can drink only a few sips without getting a headache and feeling ill. The same effect is true of some of the natural chemicals found in food like salicylates, free glutamate (MSG) and biogenic amines (such as histamine, serotonin, dopamine, phenylethylamine, tyramine), and some artificial additives (a selection of colours, flavours, flavour enhancers, preservatives and antioxidants). This is because we all have different genetic variations that govern how we make different enzymes in our bodies.

Enzymes are required to break down toxins or attach elements to them that help to draw them from the body. They also regulate and manufacture hormones, peptides, amino acids, prostaglandins, endorphins, neurotransmitters and numerous other endogenous chemicals in the body. The production of various key enzymes has a natural variation of something like 10-15 fold in the population.

For example, tyramine is a stimulant pseudo-neurotransmitter found in some fermented and aged foods, like cheese or pickled fish. Tyramine is notorious for causing heart palpitations, insomnia, brain "noise", sweating, and is the reason that cheese and chocolate have a reputation for causing nightmares. If you give a group of people some tyramine, 90% of them will react to a dose greater than 125mg, but many will react to much smaller doses. Depending on the capacity of an enzyme known as monoamine oxidase (MAO), some people will react to as little as 6mg of tyramine. Quantities of tyramine vary in different cheeses from zero up to 100-200mg per 100 grams, depending on how the cheese has been made. Most people have probably had a tyramine reaction at some point in their life, without ever realising what it was. Because it is common to eat strong foods like this at restaurants along with alcohol, many people may have blamed a reaction like this on the alcohol they were drinking, or even on caffeine or MSG.

Food chemicals like salicylates, amines and glutamates produce many more diverse symptoms than drinking alcohol or caffeine. The different symptoms that individuals suffer vary widely depending on apparently inherited tendencies. For example, a study found that 66% of asthmatic children reacted (experienced asthma attacks) to the preservative metabisulphite, and 21% reacted to acetylsalicylic acid (aspirin). What's more, individuals who suffer from chronic asthma have found that just by avoiding the chemicals they react to, they no longer suffer from asthma. This is a table of the different amounts of food chemicals that are required to produce bronchial constriction in patients that arrived at an asthma clinic. As you can see there is a great deal of variation⁽¹⁾:

Rather than being a majority of people who have high tolerance and a small distinct group of people with a low tolerance, the Gaussian distribution for graphs of this kind is a fairly smooth bell curve, indicating the variation is fairly normal and caused by a selection of genes, not as a result of one deterministic gene.

As you can see, reactions to food chemicals are pharmacological and dose dependent rather than immune-system related like allergies. However, the symptoms of food chemical intolerances are often mistaken for allergies, and they can cause autoimmune-like conditions such as eczema, asthma, arthritis and chronic back pain, and have been implicated in a number of other autoimmune disorders including coeliac (celiac) disease, fibromyalgia, and can produce multiple sclerosis-like symptoms. They may even contribute to heart disease.

If you are interested in learning more about the symptoms of food chemical intolerances and how to do a food chemical elimination diet, please click the links on the left.

References

1. Corder EH, Buckley CE 3rd. Aspirin, salicylate, sulfite and tartrazine induced bronchoconstriction. Safe doses and case definition in epidemiological studies. J Clin Epidemiol. 1995 Oct;48(10):1269-75. [PubMed]

Copyright © 28 November 2006

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