Published: 02:00 BST, 21 August 2026 | Updated: 02:00 BST, 21 August 2026
Eating certain types of leafy green vegetables could put you at higher risk of developing bowel cancer, a study has suggested.
Scientists have discovered that consuming high quantities of a compound found in greens such as rocket and swiss chard could raise the risk of the deadly disease by up to 50 per cent.
It's long been known that the compounds, called nitrites, contribute to the development of bowel cancer.
The World Health Organisation lists nitrites as a Group 1 carcinogen, meaning they're deemed as dangerous as tobacco and asbestos.
Concerns have largely focused on nitrites added to processed meats – which are used to extend shelf-life and keep meat pink.
It's thought that the additives react with protein in meat to form nitrosamines, which can turn healthy bowel cells cancerous.
But now scientists say the source of dietary nitrites may not matter as much as previously thought.
Cases of bowel cancer have soared in recent years – with more than 48,000 people diagnosed in the UK every year. It's now the leading cause of death in under 50s.
Experts warn that failure to ban nitrites from bacon and ham has cost thousands of lives
The new study – published in the Journal of the National Cancer Institute – analysed the diet of 82,009 middle-aged Swedish adults, who completed food questionnaires in 1997, 2009 and 2019.
Anyone with a previous cancer diagnosis – with the exception of non-melanoma skin cancer – was excluded.
The researchers used data held by the Swedish Food Agency, alongside their own measurements of nitrites in hundreds of foods to estimate participants' average daily intake.
Results showed that meat products accounted for just over half of men's nitrite intake, with processed meats contributing around a quarter.
Around 20 per cent came from vegetables, cheese and other dairy products.
