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The lowdown on: sulphites

The lowdown on: sulphites

by FoodMaestro | 24 May 2016

Hannah Hunter (Specialist Allergy Dietitian, Guys Hospital) provides the lowdown on ‘sulphites’.

Due to their useful properties in helping to preserve foods, sulphites are common ingredients in many pre-prepared products. Adverse reactions to these preservatives can sometimes be due to an IgE mediated allergy, but this is extremely rare. Most reactions involving sulphites are not due to an allergy but a sensitivity, and this is more common in people with asthma.

What is sulphite sensitivity?

Sulphites refers to a group of preservatives:

  •        E220: sulphur dioxide
  •        E221: sodium sulphite
  •        E222: sodium hydrogen sulphate
  •        E223: sodium metabisulphite                        
  •        E224: potassium metabisulphate
  •        E226: calcium sulphite
  •        E227: calcium hydrogen sulphite
  •        E228: potassium hydrogen sulphite

They help to preserve foods by preventing browning and spoiling of foods through the release of sulphur dioxide. When foods containing sulphites are ingested, this gas is also released in the acid environment of the stomach. It is thought that this causes symptoms in susceptible people (such as asthmatics) by traveling up and irritating the airways. This causes symptoms such as wheezing, coughing and tight-chestedness.

What should be avoided?

Many people with sulphite sensitivity have a certain tolerance level to sulphites. A trial period of excluding all sulphites followed by reintroduction is the only way to diagnose a sensitivity. This also helps to identify the tolerance level. This is ideally done under the guidance of an experienced dietitian. 

Sulphites are commonly added to:

  •        Processed meats
  •        Wine, beer, cider
  •        Dried fruit and vegetables
  •        Bottled lemon juice
  •        Prepared potato products

As well as being present naturally in:

  •        Parmesan
  •        Mushrooms
  •        Fermented foods

Under EU food labelling laws sulphites need to be clearly labelled if they are added as an ingredient over 10mg per kg. They must be emphasised (usually in bold or underlined) on product labels, although foods that naturally contain sulphites will not be labelled in this way.

You can use the FoodMaestro app to show you how to avoid added sulphites by setting up your personal food profile to exclude either all forms of sulphites including those that may contain sulphites or simply exclude foods with sulphites as an ingredient:

Where can I get more information?

If you suspect that you have a sensitivity to sulphites, then speak to your GP, Dietitian or hospital Consultant for individual advice.

Other useful websites:

See more in our Lowdown series: