The chemicals that give many of the world's favourite cuisines their peppery "zing" may be carcinogenic, new research has suggested.
An epidemiological study found elevated levels of stomach and liver cancer in areas where people consumed larger quantities of pepper-based food.
Victor Archer, a researcher at the Rocky Mountain Center for Occupational and Environmental Medicine at the University of Utah, in the US, published his results in Medical Hypotheses , a journal that often deals with radical new ideas.
He focused on four ethnic cuisines in the US that use large amounts of pepper. Mexican-American and Cajun are dominated by red, cayenne, chilli and jalapeno peppers, usually in the form of salsa and sauces. They have relatively high levels of the natural chemical capsaicin.
Black and white Creole cuisines in New Orleans both have a greater proportion of black and white pepper and high levels of safrole, another natural chemical.
Dr Archer used data from the US census of 1990 to identify counties with large concentrations of people who considered themselves to belong to the four ethnic groups.
He then identified suitable control counties to compare the health of residents.
Age-adjusted mortality data for the period 1970-79 revealed levels of various cancer deaths county by county. Allowing for the limitations of the study, the analysis revealed striking matches.
Deaths caused by liver and stomach cancer in counties where more than 50 per cent of the population was Mexican-American were almost twice as prevalent as in control counties.
Cajun populations suffered elevated levels of stomach, liver, oesophagus and pancreas cancers. Creole groups had lower levels, though the black population showed a heightened vulnerability to stomach and rectal cancer.
Dr Archer said the study strengthened previous research that suggested capsaicin was probably a human carcinogen.
"Prudent persons will minimise its consumption," he concluded.