In what is to date the largest epidemiological study of oesophageal cancer - cancer of the gullet - in South Africa, Dr Vikash Sewram has identified some very unlikely culprits.

To pinpoint risk factors for the cancer, Sewram turned to the Eastern Cape, the province with the highest incidence of OC in the country. Specifically, he conducted a study of 670 cases of squamous cell carcinoma of the oesophagus at three major hospitals in the province.

Yes, the usual suspects - tobacco and alcohol - were there, but Sewram also found that there was a strong link between the consumption of an edible plant known as imifino (a wild spinach) and oesophageal cancer in both men and women. Diets centred on maize, imifino and beans were associated with increased risk, Sewram says.

Even more worrying is that of the 48 indigenous plants Sewram looked at in his study, six used as diary supplements and four used as medicinal plants could be linked to oesophageal cancer.

Good news, though, is that diets of sorghum, green leafy vegetables, legumes, fruits, meat and wheat-based products offered some protection against the disease.

An important finding was that, contrary to previous reports of a link between the consumption of mouldy maize and OC, Sewram's better designed and more powerful study - in the words of his supervisor - showed no such association.

Sewram's doctoral work was supervised by Professor Jonny Myers of UCT's Department of Public Health.