Canned products such as soup and baked beans could contain 1,000 times more of a “gender bending” chemical than fresh goods, a study has found.

The chemical, Bisphenol-A (BPA), is used in the lining of cans to prevent rusting and keep food fresh, and has also been linked to male infertility, heart disease, stroke and diabetes.

Researchers at Harvard University divided 75 volunteers into two groups; one was asked to eat a tin of soup every day for five days, while the other was told to eat soup made only with fresh ingredients. After a weekend of rest, the groups’ diets were switched.

The results, published in the Journal of the American Medical Association, revealed that drinking one can per day for a five-day period increases the amount of BPA in the urine by 1,221%.

Lead researcher, Jenny Carwile, 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 that canned foods may be an even greater concern, especially given their wide use."

The study did not investigate what the health implications of this might be but it did raise concerns.

Fellow researcher Karin Michels said: "The magnitude of the rise in urinary BPA we observed after just one serving of soup was unexpected and may be of concern among individuals who regularly consume foods from cans or drink several canned beverages daily.

"It may be advisable for manufacturers to consider eliminating BPA from can linings."

The UK's Food Standards Agency said: "Our current advice is that BPA from food contact materials does not represent a risk to consumers but the agency will be looking at this study, as it would at any new piece of work, to see if it has any implications for our advice to consumers."

In the EU the chemical is already banned from baby bottles.