E249 — Potassium nitrite
E249 (Potassium nitrite), a preservative, is rated "avoid": worth avoiding. A preservative used in cured meats. During cooking it can form nitrosamines, compounds linked to colorectal cancer. IARC classifies processed meat as a known carcinogen.
What is Potassium nitrite?
A curing salt used in bacon, ham, salami, and other cured meats to keep them pink, prevent botulism, and extend shelf life.
What does it do to the body?
During high-heat cooking and digestion it can form nitrosamines, which are tied to colon cancer in long-term studies. Daily processed-meat eaters have measurably higher cancer risk; occasional weekend bacon is not the worry.
What regulators say
IARC (the WHO's cancer research arm) classifies processed meats containing nitrites or nitrates as Group 1 (known carcinogen). The EU lowered the maximum allowed levels in cured meats in 2023.
Risk rating: Avoid
Known or suspected to cause harm: a substance EFSA or another regulator has flagged, or one restricted in some jurisdictions. Best kept out of a regular diet.
Source: WHO Q&A — processed meat (Group 1) ↗