Sulphur dioxide

Studies in people

• Concern

  Gut and oral bacteria²

  Eating sulphur dioxide has been linked to upset gut and mouth bacteria, plus allergic reactions in some people.

• Open question

  Children's intake risk³

  In some Chinese children, eating sulphur dioxide in food added up to more than the safe daily amount.

• Concern

  Asthma attacks from food⁶

  Some asthmatics react to sulphur dioxide in food with breathing attacks, though tests often give false alarms.

• Concern

  Asthma in sensitive people⁸

  Some people with asthma say sulphur dioxide in soft drinks makes their asthma worse.

• Concern

  Asthma flare-ups from drinks⁹

  Some people with asthma reacted to sulphur dioxide in orange drinks, with breathing getting worse after drinking them.

• Open question

  Daily intake limits¹⁰

  Adults who always pick preservative-containing foods may take in more sulphites than the recommended daily limit, mostly from wine.

Animal and lab studies only

• Concern

  Male fertility¹¹

  In animal studies, sulphur dioxide in drinks made from dried apricot leather raised sperm problems and lowered testosterone.

• Concern

  Long-term health effects¹²

  In animal studies, low levels of sulphur dioxide seemed relatively harmless, but the authors say those studies may mislead.

Found in some samples or products

These come from where it was grown, how it was processed or cooked, or what it was made into. They are not about the ingredient itself, so the signal does not count them.

• Sensitivity to food additives⁵

  Some people react badly to sulphites left in food, so scientists measure them to check levels.

Allergies and intolerances

These are about people with an allergy, an intolerance or coeliac disease. The signal is about the ingredient itself, and these are about the person eating it, so the signal does not count them.

• Asthma flare-ups⁷

  Sulfur dioxide and sulfites used in foods may set off sudden asthma attacks in some people.

How it’s made and used

• Children's health risk⁴

  In some dried fruits and vegetables, sulphur dioxide levels were high enough that children could take in too much.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least one finding in people. When most findings in people point one way, the page leans that way (“Mostly”), and every finding is still shown. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.

Expert panels that weigh all the research. Shown for context: the signal at the top does not count them. IARC rates whether something can cause cancer at all, not how likely it is at the amounts in food.

• UN and WHO food additive experts (JECFA), 1998

  Acceptable daily intake: up to 0.7 mg per kg of body weight.

• WHO cancer agency (IARC), 1991

  Not enough evidence to say whether it causes cancer in people (Group 3).