The retailer says that cranberry sales have jumped 67 per cent year-on-year, while pomegranates - thought to have heart health benefits - have grown 79 per cent in the same period.

Sainsbury's believes the sucess is partly due to the backing of a study into alternative therapies by the Prince of Wales, a known supporter of the use of alternative medicine.

The report, by economist Christopher Smallwood and published in October last year, concluded that complementary therapies should be given a greater role in the public health service.

A spokeswoman from Clarence House said at the time that the Prince hoped to "encourage an informed debate about how an evidence-based, integrated approach to health, which draws on the best of both orthodox and complementary medicines, might offer wider benefits".

Sainsbury's Marcus Hoggarth said: "We believe the Prince's study may have persuaded many people to try these natural remedies for themselves. The biggest impact has been upon fresh cranberries and pomegranates, which have sold in record volumes since the Prince's report was launched."

Sales of ginger, believed to help nausea and improve blood flow, have risen by 15 per cent at the supermarket, a similar growth to lemons, which are commonly used to treat colds and flus.