Popular soft drink ingredient poses cancer risk

Drinking caramel-coloured soft drinks, such as cola, regularly could put you at higher risk of cancer, a new study has warned.

Public health researchers have analysed soda consumption data in order to characterise people's exposure to a potentially carcinogenic byproduct of some types of caramel colour.
Caramel colour is a common ingredient in colas and other dark soft drinks.

The results show that between 44 and 58 per cent of people over the age of six typically have at least one can of soda per day, possibly more, potentially exposing them to 4-methylimidazole (4-MEI), a possible human carcinogen formed during the manufacture of some kinds of caramel colour.

Building on an analysis of 4-MEI concentrations in 11 different soft drinks first published by Consumer Reports in 2014, researchers led by a team at the Johns Hopkins Centre for a Livable Future (CLF) estimated exposure to 4-MEI from caramel-coloured soft drinks and modelled the potential cancer burden related to routine soft drink consumption levels in the US.

"Soft drink consumers are being exposed to an avoidable and unnecessary cancer risk from an ingredient that is being added to these beverages simply for aesthetic purposes," said Keeve Nachman, senior author of the study and director of the Food Production and Public Health Programme at the CLF.

"This unnecessary exposure poses a threat to public health and raises questions about the continued use of caramel colouring in soda," said Nachman, also an assistant professor at the Johns Hopkins Bloomberg School of Public Health.

In 2013 and early 2014, Consumer Reports partnered with the CLF to analyse 4-MEI concentrations of 110 soft drink samples purchased from retail stores in California and the New York metropolitan area.

This study pairs those results with population beverage consumption data from the National Health and Nutrition Examination Survey (NHANES) in order to estimate the population risks and cancer burden associated with 4-MEI exposures through soda.

While the 2014 study of the 110 samples of soda brands was not large enough to recommend one brand over another or draw conclusions about specific brands, results indicated that levels of 4-MEI could vary substantially across samples, even for the same type of beverage.

"For example, for diet colas, certain samples had higher or more variable levels of the compound, while other samples had very low concentrations," said Tyler Smith, lead author of the study and a programme officer with the CLF.