Eating tinned soup may be associated with increased levels of a chemical that is linked to heart disease, obesity and diabetes, a study suggests.
Bisphenol A (BPA) is added to the lining of food and drinks cans to stop rusting and keep food fresh. It is also found in plastic bottles, pizza boxes and dental sealants.
The chemical mimics the effects of oestrogen and some studies suggest it hinders neurological and reproductive development. It is already banned from baby bottles in Europe.
The study by the Harvard School of Public Health divided 75 volunteers into two groups. One group ate a 12oz serving of vegetarian canned soup every day for five days and the other group ate the same amount of fresh vegetarian soup daily for five days. The groups then switched the type of soup they ate for another five days.
Those eating the canned soup had 1,221 per cent higher levels of BPA in their urine compared with those eating the fresh soup, according to the research published in the Journal of the American Medical Association.
Jenny Carwile, who led the study, said: "We've known for a while that drinking beverages that have been stored in certain hard plastics can increase the amount of BPA in your body. This study suggests canned foods may be an even greater concern."
The study authors said the increase may be temporary and more research was needed. But a senior author, Karin Michels, said: "It may be advisable for manufacturers to consider eliminating BPA from can linings."
The UK Food Standards Agency said it would study the findings.