A dangerous combination of two preservatives in soft drinks and fruit juices could be increasing consumers' risk for cancer.
That's according to a report in BeverageDaily.com, which states that tests on 230 soft drinks sold in the United Kingdom have benzene levels above the safety limit for water.
But while some researchers have been aware of this risk for a while now, the dangerous interaction doesn't seem to be general knowledge.
The UK study
The latest study was carried out on a range of soft drinks containing sodium benzoate and ascorbic acid (vitamin C) – two preservatives that seem to produce benzene in the presence of heat and ultra-violet light.
Tests showed that the average benzene levels in the soft drinks were above the UK limit of one part per billion, but still below the World Health Organisation limit of 10 parts per billion.
Following the reports, a spokesperson for the British Soft Drinks Association assurred consumers that the levels in the drinks were still too low to be a real health risk.
Highly toxic substance
However, the Environmental Working Group, which published a similar report on drinks produced in the United States, advised consumers to make a point of avoiding soft drinks and juices that contain both ascorbic acid and sodium benzoate because of the possible danger of ingesting benzene.
In higher quantities, benzene is a highly toxic, hazardous substance and a known human carcinogen.
The question is now whether lifetime, chronic exposure to small quantities of benzene could increase a person's risk for cancer.
An underreported issue?
Surprisingly enough, the issue isn't new – it only seems to be underreported.
Some US scientists have known for 15 years that the two preservatives could react to form benzene in drinks, according to reports. And several products were altered due to his interaction in the early 1990s.
In 1998 and 1999, there were massive recalls of both Coca-Cola and Pepsi products due to benzene contamination.
However, the issue has been so low-key that a database of food additives – used by researchers at the University of Stellenbosch in South Africa – doesn't even list the potential dangerous interaction of the two preservatives, according to Dr Gunnar Sigge of the Department of Food Science, University of Stellenbosch.
Sigge says that, while both these preservatives are also commonly used in South African beverages, the interaction is definitely not common knowledge.
"Both sodium benzoate and ascorbic acid are listed as 'safe', according to World Health Organisation guidelines," Sigge says.
But, Sigge notes, the combination is generally not used in Coca-Cola. Rather, he suspects that fruit juices are more likely to be affected due to the high ascorbic acid content.
Ascorbic acid is a natural component of fruit juices and is also added to beverages to preserve colour, while sodium benzoate has strong anti-microbial qualities.
– (Carine van Rooyen, Health24)
For more info on avoiding benzene exposure, see Beware benzene