KEY POINTS:
New Zealand food safety officials will re-examine the use of a preservative found in everything from fizzy drinks to salad dressings after a British study found it causes cell damage on a scale similar to binge drinking.
But people are advised to continue consuming sodium benzoate until the
evidence is incontrovertible.
The University of Sheffield study on sodium benzoate, or E211, has raised new questions around the use of food additives.
It comes just weeks after a leaked independent study commissioned by the UK's Food Standards Agency found a link between commonly used colourings and preservatives - which included sodium benzoate - and behavioural problems such as hyperactivity in young children.
Its use in soft drinks was already the subject of a full-scale investigation in the US and UK after tests revealed the preservative interacts with ascorbic acid (Vitamin C) and citric acid inside the can to form small amounts of benzene, a carcinogen.
The Sheffield University research, reported by the Independent, suggested that sodium benzoate has the ability to switch off vital parts of the DNA.
The problem - more usually associated with ageing and alcohol abuse - can eventually lead to cirrhosis of the liver and degenerative diseases such as Parkinson's.
Laboratory tests on living yeast cells conducted by Professor Peter Piper, an expert in ageing, found benzoate damaged an important area of DNA in the mitochondria, the cell's power station.
"These chemicals have the ability to cause severe damage to DNA in the mitochondria to the point that they totally inactivate it: they knock it out altogether," he told the Independent on Sunday.
"The mitochondria consumes the oxygen to give you energy and if you damage it - as happens in a number of diseased states - then the cell starts to malfunction very seriously. And there is a whole array of diseases that are now being tied to damage to this DNA - Parkinson's and quite a lot of neuro-degenerative diseases, but above all the whole process of ageing."
Professor Piper stressed, however, that he was not saying that sodium benzoate was unsafe, but that the food industry could not state with certainty that it was safe.
"We are feeding vast amounts of them to children inadvertently. Is this a completely safe process? This is what we have to worry about."
Food Standards Australia NZ spokeswoman Lydia Buchtmann said the preservative had been used safely for a long time. It notes on its website that there is no clinical evidence to suggest that a high dietary intake of benzoates can cause adverse effects.
"We're always interested in new studies that come out and certainly we'd be happy to have a look at it.
"If there is any need, we certainly will review our risk assessment of sodium benzoate but, at this stage, it is at very low levels a commonly used preservative, and people should just continue to use it while we have a look."
But food safety campaigner Sue Kedgley said that ignored the "cocktail effect" from consuming various additives over the years.
A study in her book, Eating Safely in a Toxic World, found that the average child could consume up to 158 doses of different additives in a day.
"That's the point that everyone ignores - that it might be present in only a tiny amount in one piece of food, but if it's widely present in food, it's very easy, particularly for children, to consume very large quantities of it," said Ms Kedgley, a Green MP.
A recent Australian Total Diet Study found most Australians were well below the acceptable daily intake for benzoates - except in boys between 2 and 5 years old, who exceeded the limit by 140 per cent.
But young children were always more likely to exceed the limit than adults because of their smaller body mass.
Proponents also argue that foods benefit from the preservative as it inhibits the growth of harmful microorganisms and preserves nutrients.
