Blind belief bad for health

Consumers should be more critical of studies on the causes of cancer, obesity and the like, and of reports that trumpet the value of vitamins.

Professor Alex Broadbent - who teaches philosophy at the University of Johannesburg - warned that researchers could make mistakes or succumb to confirmation bias .

"Technical [research] methods are not enough," said Broadbent.

"It is always necessary to consider ways in which you might be wrong. Then you need to explain why you are probably not wrong."

Broadbent said several studies have been found to be wrong on further examination.

A recent case in point was a study that claimed VitaminC supplements are beneficial but studies by epidemiologists showed that they have no value.

"They might be useful for someone with a vitamin deficiency but the number of people who have enough to eat [but] have vitamin deficiencies is very small," he said.

"The whole [vitamin] industry is basically a con."

Broadbent said it was widely accepted that in-house studies by multinational pharmaceuticals companies were more likely to "prove" the efficacy of their products than independent studies by impartial scientists.

Broadbent, who has a doctorate in philosophy, believes that there are insufficient checks and balances in countries such as South Africa to verify the research of big pharmaceutical companies, whose research and development budgets often rival a nation's gross domestic product.

"It is established that, if the drug companies do the research, they are much more likely to find a [positive] result for their product and controlling bodies [such as the SA Medicines Control Council] approve the drugs based on the companies' research," he said.

"There are a number of horror stories, including relatively recent ones, of drugs making it onto the market when their safety has not been established, or when they are not particularly effective," Broadbent said.