E421 — Mannitol
E421 (Mannitol), a sweetener, is rated "watch": fine in moderation. A sugar alcohol with a strong cooling, sweet taste. Used in mints and sugar-free candies. Causes diarrhea and bloating at higher intake.
What is Mannitol?
A sugar alcohol with a cooling sweet taste, naturally found in seaweed and mushrooms. Used as a powder coating on chewing gum, in sugar-free mints and candies, and as a bulking agent.
What does it do to the body?
Like sorbitol, your gut absorbs only part of it, so larger amounts cause gas, bloating, and diarrhea. Most people tolerate up to about 10 g per day without symptoms.
What regulators say
EFSA and the FDA both approve it. EU labels above a threshold must carry the "excessive consumption may produce laxative effects" warning.
Risk rating: Watch
Mixed evidence or a specific concern (gut, allergy, or contested safety data). Not alarming, but worth keeping an eye on rather than eating without limit.