In the UK sulphites are now one of the twelve potential allergens (along with the likes of peanuts, fish, crustaceans, gluten and milk) that have to be labelled on a food or drink product - where they appear at a certain concentration or above. Warnings are now common on products such as wine or cider - yet in practice there is still a huge amount of ignorance and misinformation about their use and the health problems they can cause.
What are sulphites?
Sulphites consist of a group of sulphur-based chemicals, including sulphur dioxide (SO2). They are essentially food preservatives (E220-228) that are used to prevent the browning or discoloration of foods. SO2 now has to be labelled at levels above 10 mg/kg or 10 mg per litre.
E numbers and names of sulphite food preservatives in use in UK
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
E numbers in use in the UK that contain sulphites
E150b Caustic sulphite caramel
E150d Sulphite ammonia caramel
Late in 2003 I experienced a really bad reaction to sulphite food preservatives, which severely affected my breathing. Staff at the Royal Brompton Hospital in London had diagnosed my sulphite sensitivity about six years earlier, after several years of investigation into what seemed to be unexplained anaphylactic shock.
One evening in 2003, I recklessly ate a take-away Thai curry - as I couldn’t face cooking having just been made redundant. Up to this point after being diagnosed, I had been very careful with my diet, and had not taken any risks - but on this evening, slightly upset and shocked, I hoped I would be OK. Soon after eating, my mouth throat and ears started itching and then I started to cough. My throat felt very tight and I was struggling for breath. I had to take adrenaline, anti-histamines and an ongoing course of steroids to recover and it took over a month.
Afterwards, I was struggling for breath, feeling dizzy when walking or speaking and rarely getting my peak flow (a measure of breathing) above a third of what it should have been. Concerned that my recovery was taking longer than normal, my GP referred me to the allergy clinic for asthma and chest patients at St Mary’s Hospital in London for more tests.
There I tried to tell the doctor that I was sulphite sensitive - he seemed angry that the tests undertaken were negative and basically said there was ‘no such thing as sulphite sensitivity’.
This astounded me. How could a doctor working in a chest and allergy clinic be unaware of sulphite sensitivity? I knew sulphite sensitivity was not exactly commonplace - but after my diagnosis I had spent years researching sulphites and the problems they can cause. I had even started studying nutrition and was in the middle of writing a dissertation on the subject. So I informed the doctor that I was surprised he had no knowledge, given that many people (especially asthmatics) get a reaction from consuming sulphites.
Sadly, this level of ignorance seems all too typical amongst many health professionals and I wonder about the true consequences of this ignorance.
There is now a well-documented and academically researched link between asthma and sulphites. Indeed, there was a huge body of research available in the public domain at the time I visited St Mary’s.
I believe that any chest and allergy doctor working at the time should have had an awareness of this - in fact, I believe that every doctor or asthma nurse should have some knowledge of the link.
The asthma-sulphite link
The Office of Health Economics estimated that the cost of asthma to the NHS in 2001 totalled £889 million. This is a huge cost - perhaps some of this money could be saved with a greater awareness of the problems sulphites can cause? Given that asthma is also one of the commonest causes of acute medical admission to hospital in children and that many working days are lost to asthma each year; it would seem more than sensible for there to be some attempt to publicise the link between asthma and sulphites.
Increased awareness might also help improve the lives of the 5.2 million people that Asthma UK currently estimates suffer from asthma. The first case of sulphite sensitivity was reported in 1976 and the USA then led the way in reporting adverse reactions. Twelve fatal cases in the USA had been documented by 1986. By 1988 complaints about sulphites in the USA had totalled 887 – this led to a warning being carried on sulphited items in the USA from 1991. It took the UK nearly 15 years to catch-up.
So, what problems are associated with sulphites?
The most common symptom appears to be bronchoconstriction – causing wheezing and difficulty breathing.
A scientific paper published in 1987 (Gunnison et al) cites other signs and symptoms of sulphite sensitivity as wheezing, shortness of breath, nausea, stomach cramps, diarrhoea, itching, swelling, hives, laryngeal oedema, tingling sensations, flushing, low blood pressure, cyanosis, shock and loss of consciousness.
Many of the symptoms mirror those of anaphylaxis - the life-threatening systemic allergic reaction. It is important to remember that some people react even though they are not asthmatics. If you suspect that sulphites are affecting you, you need to avoid food containing higher levels and the new labelling system should help you identify which foods might be problematic.
Foods and drinks containing sulphites?
Foods and drinks that commonly contain sulphites include wine, cider, beer, soft drinks, frozen seafood such as prawns and shrimp, sausages, dried fruits, fruit yoghurts, bottled lemon juice, fruit juices and jams. Also breads and food items containing vinegar such as mayonnaise, pickles or sauces. And processed potatoes, potato starches, anything containing stock cubes or dried onions, dried mushrooms or dried garlic. It’s important to remember that sulphites can also occur naturally in foods and drinks eg a yeast called saccharomyces cerevisiae generates between 1-30 parts per million (ppm) SO2 in wine fermentation and some strains produce in excess of 100 ppm.
Recognition of sulphite sensitivity
It is now acknowledged by most authorities, including the UK Government and the World Health Organisation, that sulphites are problematic for some people. This is as a result of the numerous studies that have demonstrated that sulphite preservatives can cause asthma, anaphylaxis and contact allergy; they are also acknowledged to have caused a number of deaths in the USA and Canada.
The true prevalence of sulphite sensitivity in the general population is not known and the real causes are very complex.
There are several reported mechanisms for sulphite sensitivity; the most common appears to be SO2 inhalation and irritation of the airways (as this affects asthmatics).
However, immune system involvement (involving IgE antibodies) has been demonstrated in some subjects in clinical trials - this alone seems to confound conventional medical opinion.
Theoretically, the immune system can only produce antibodies in response to proteins in foods - so doctors are not readily willing to accept that anaphylaxis can result as from consumption of a chemical food additive.
To conclude, I hope for greater awareness of the problems sulphites can cause and more medical research in this area and I very much hope that asthmatics will advised to be careful with highly sulphited foods.
See the next page for practical suggestions as to how to deal with sulphite sensitivity.
Justine Bold is a nutritional therapist who runs practices in Gloucestershire, Herefordshire and London as well as being a tutor and lecturer for the U.K. College of Nutrition and Health.
She also works on community healthy eating initiatives for a London council and delivers corporate training for the Food Doctor and seminars for Lamberts.
You can contact her at www.healingnutrition.co.uk. 01594 862676
First published in 2008
Back to top