Preservative butylhydroxytoluene could make people hungrier and more likely to gain weight.

A common preservative added to breakfast cereals increases appetite and promotes obesity, a study in human stem cells has found.

The preservative butylhydroxytoluene (BHT) is included in processed foods such as breakfast cereals to stop fats in the food from turning rancid. But it is also a suspected endocrine disruptor – a class of chemicals that interferes with human hormones.

Finding out the effects of endocrine disruptors in humans is ethically difficult, as conducting a systematic test of these substances on people could well do them harm. Scientists at the Cedars-Sinai Medical Centre in Los Angeles invented a method using gut tissues grown from human stem cells to measure exposure to several likely endocrine disruptors.

As well as BHT, the researchers tested perfluorooctanoic acid (PFOA), which is used in non-stick pots and pans, and tributyltin (TBT) ,which is found in paints that often leak into waterways and accumulates in seafood. The scientists added these chemicals to the gut tissues to see what effect they had.

All three of them were found to interfere with the hormone production of the stem-cell-derived tissues. The disruption is thought to affect the nerve signals that the gut sends to the brain to signal when to stop eating.