Sensitivity to sulphites in foods is sometimes reported to cause an increase in hyperactive behavior or other central nervous system reactions. Food regulations on sulphites differ from country to country.
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 labeled on a food or drink product when 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 sulfur-based chemicals, including sulfur dioxide (SO2). They are essentially food preservatives that are used to prevent the browning or discoloration of foods. SO2 now has to be labeled at levels above 10 mg/kg or 10 mg per litre.
Late in 2003 I experienced a serious 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 that same year, I recklessly ate a take-away Thai curry as I had [just lost my job.] 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. For treatment I had to take adrenaline, antihistamines and an ongoing course of steroids to recover, and it took over a month. During this time, 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 is all too typical among 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 pulmonary and allergy specialist 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 National Health Service in 2001 totaled £889 million. Given that asthma is also one of the most common causes of acute medical admission to hospital in children, and that many working days are lost to asthma each year, it would seem sensible to publicize the link between asthma and sulphites. Increased awareness might also help improve the lives of the 5.2 million people that are estimated to suffer from asthma in the UK. 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 totaled 887. This led to a warning being carried on sulphited items in the USA from 1991 on. It took the UK nearly 15 years to catch-up.
What Problems Are Associated with Sulphites?
The most common symptom appears to be broncho-constriction, 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, diarrhea, 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 labeling 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 yogurts, bottled lemon juice, fruit juices and jams. Also, breads, pizza crust, 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 e.g., 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.
Practical Tips for Managing Sulphite Sensitivity
A sulphite-free diet is fairly hard to implement and requires lifestyle changes, as more time has to be spent cooking foods and shopping — but it is worth it for a sensitive individual!
- Prepared and packaged foods, sauces, vinegars and condiments, many snacks and soft drinks, most wine, all ciders and most beers have to be avoided.
- Choose organically produced baked products or invest in a breadmaker.
- All food has to be freshly prepared from ingredients, ideally organic, that are known to be sulphite-free.
- Frozen seafood, dried fruit, dried vegetables and frozen potato products should be avoided at all costs, unless from organic sources.
- Even when buying organic, check the label as sometimes non-organic ingredients can creep in (e.g., onion/garlic powder or potato starch).
- Keep a well stocked larder/pantry, to avoid the need for takeaways and convenience foods.
- If you work, you may need to get into the habit of taking foods to work with you.
- If eating out, call in advance to make the chef aware of your needs, and try to get to know the mangers/chefs in favorite restaurants (this makes eating out much easier).
- Avoid fast food outlets and restaurants where food is not prepared on the premises.
- Teach your family and best friends about sulphites and how to cook for you so you can still socialize easily.
- Choose self-catering holidays and take your own food on planes and long journeys.
- Always read the label and if in doubt don’t eat it!
What Foods Contain Sulphites in the UK?
Read labels and become familiar with food that typically have sulphites. In the UK, readers can check labels for “E” numbers on foods. E numbers in use are E150b Caustic sulphite caramel; E150d Sulphite ammonia caramel.
- Sausages (usually contain metabisulphite – an organic butcher may sell without MBS)
- Chips (unless they are homemade or you are sure they are made from freshly peeled potatoes)
- Sliced breads, crumpets and many baked goods (may contain vinegar or flours treated with sulphite)
- Readymade pizzas (dough may have been treated with a sulphite)
- Prawns/shrimp (usually frozen; fresh ones are also sulphited)
- Frozen seafood like prawns, mussels etc
- Bottled lemon juice (nearly always sulphited)
- Pickles, ketchup, vinegar, mayonnaise, horseradish sauce (unless homemade as it usually contains vinegar or bottled lemon juice)
- Dried fruits and candied peel or glace cherries (e.g., apricots, raisins, desiccated coconut, bananas)
- Coconut milk (may be sulphited so check the label)
- Dried mushrooms, onion, garlic
- Potato/corn starches (in most ready meals and low fat/diet products)
- Powdered ginger
- Stock/boullion cubes (unless all ingredients are organic)
- Gelatin (in cakes, sweets, desserts etc)
- Glucose and other syrups, molasses (in desserts, ice creams etc)
- Fruit nectar drinks and yogurts or puddings containing pectin or fruits (usually sulphited)
- Fruit squashes (drinks), soft drinks such as colas, lemonade or tonics containing a hint of lemon
- Beer/lager, cider and wine (SO2 is added to organic cider and most wines. White wine has a higher SO2 content than red.) NB Beer/lager commonly has sulphites added as a preservative and some may be formed naturally during fermentation. Biodynamic wines use fewer chemicals in production and sulphites are avoided during the production process. I suggest that you contact the producer to check the content and opt for reds rather than whites.
- Vinegars with fresh lemon juice
- Bought dressings with cold pressed seed/nut oils or olive oil and fresh lemon juice
- Apricots/sultanas etc with non-sulphited organic ones
- Stock cubes, gravies with homemade or organic brands
- Frozen and dried foods with fresh
- Bought juices with freshly made juices or organic juices
Recognition of Sulphite Sensitivity
It is now acknowledged by most authorities, including the UK Government and the World Health Organization, 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 some 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 sulphite problems and more medical research in this area, and I very much hope that asthmatics will be advised to be careful with highly sulphited foods.
Reprinted with permission from Foods Matter.