Only about one in 10 hospital trusts know where the food they serve in canteens comes from – but Shropshire's two main hospitals are bucking the trend by buying British.
The Countryside Alliance Foundation said buying food produced in this country improved its quality, reduced transport pollution and helped British farmers. NHS trusts are not required to put British produce first when it comes to buying food.
According to the charity's findings, only 37 out of 262 hospital trusts knew where the food they bought came from, and only 62 per cent of that food was British.
The Shrewsbury and Telford Hospital NHS Trust spent £959,000 last year on buying goods including milk, bottled water, eggs and yoghurt from British producers – around 87 per cent of its £1.1 million food budget.
Shelley Gooding, the trust's Food Safety Advisor, said: "We aim to provide our patients, visitors and staff with a high quality catering service that uses locally-sourced produce wherever possible.
"In the past two years we have managed to buy between 85 and 90 per cent of the food we serve in our hospitals either locally or from within the UK."
The Countryside Alliance Foundation said British food was produced to some of the highest standards, but that meant it cost more to produce.
Chief executive Alice Barnard said: "Although the current economic conditions are making life difficult for hospitals, the importance of buying high-quality British food should not be overlooked."
Oliver Cartwright, NFU spokesman, said: "The NFU is keen to see more British produce bought and used by Shropshire hospitals, schools, local authorities and others so this latest news is very encouraging.
"There has been a drop in home-grown food bought by the public sector in recent years and we believe this is where the example should be set.
There should be no need for the public sector to rely on cheaper, foreign imports when there is an abundance of great ingredients available locally that are produced to world class standards."