A new health scare erupted over soft drinks last night amid evidence they may cause serious cell damage. Research from a British university suggests a common preservative found in drinks such as Fanta and Pepsi Max has the ability to switch off vital parts of 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.

The findings could have serious consequences for the hundreds of millions of people worldwide who consume fizzy drinks. They will also intensify the controversy about food additives, which have been linked to hyperactivity in children.

Concerns centre on the safety of E211, known as sodium benzoate, a preservative used for decades by the £74bn global carbonated drinks industry. Sodium benzoate derives from benzoic acid. It occurs naturally in berries, but is used in large quantities to prevent mould in soft drinks such as Sprite, Oasis and Dr Pepper. It is also added to pickles and sauces.

Sodium benzoate has already been the subject of concern about cancer because when mixed with the additive vitamin C in soft drinks, it causes benzene, a carcinogenic substance. A Food Standards Agency survey of benzene in drinks last year found high levels in four brands which were removed from sale.

Now, an expert in ageing at Sheffield University, who has been working on sodium benzoate since publishing a research paper in 1999, has decided to speak out about another danger. Professor Peter Piper, a professor of molecular biology and biotechnology, tested the impact of sodium benzoate on living yeast cells in his laboratory. What he found alarmed him: the benzoate was damaging an important area of DNA in the "power station" of cells known as the mitochondria.

He told The Independent on Sunday: "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.

"The mitochondria consumes the oxygen to give you energy and if you damage it - as happens in a number if 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."

The Food Standards Agency (FSA) backs the use of sodium benzoate in the UK and it has been approved by the European Union but last night, MPs called for it to investigate urgently.

Norman Baker, the Liberal Democrat chair of Parliament's all-party environment group said: "Many additives are relatively new and their long-term impact cannot be certain. This preservative clearly needs to be investigated further by the FSA."

A review of sodium benzoate by the World Health Organisation in 2000 concluded that it was safe, but it noted that the available science supporting its safety was "limited".

Professor Piper, whose work has been funded by a government research council, said tests conducted by the US Food and Drug Administration were out of date.

"The food industry will say these compounds have been tested and they are complete safe," he said. "By the criteria of modern safety testing, the safety tests were inadequate. Like all things, safety testing moves forward and you can conduct a much more rigorous safety test than you could 50 years ago."

He advised parents to think carefully about buying drinks with preservatives until the quantities in products were proved safe by new tests. "My concern is for children who are drinking large amounts," he said.

Coca-Cola and Britvic's Pepsi Max and Diet Pepsi all contain sodium benzoate. Their makers and the British Soft Drinks Association said they entrusted the safety of additives to the Government.

CONCLUSION ON STUDY ON THE MUTAGENICITY OF SODIUM BENZOATE AND POTASSIUM SORBATE

COM/08/S2 - May 2008

1. Sodium benzoate (E211) and potassium sorbate (E202) are two examples of organic acid food preservatives based on benzoic and sorbic acids. Benzoic acid and its sodium, potassium and calcium salts and sorbic acid and its potassium and calcium salts are permitted for use in a wide range of foods in the EU. These preservatives have been subject to a risk assessment by the Joint FAO/WHO Expert Committee on Food Additives (JECFA).^1,2

2. In 1999, a study was published in Free Radical Biology and Medicine by Professor Peter Piper, then from University College London, which raised the possibility that these preservatives may be mutagenic to the yeast mitochondrial genome. ³

3. This study used genetically modified yeast cells in an in vitro system to demonstrate the effects of potassium sorbate and sodium benzoate on the respiratory capabilities of the cells. Yeast superoxide dismutase (SOD) mutant S. cerevisiae cells were incubated with the two preservatives and the effects observed using a halo assay. The author concluded that the test substances produced an increased number of respiratory-deficient yeast cells under aerobic conditions which indicates that damage was occurring to the mitochondrial DNA in the yeast cells.

4. Using a postal consultation, COM members were asked by the Food Standards Agency to comment on the paper by Professor Piper whilst taking into account the large package of other toxicological data available on these preservatives.

5. Members were interested in the hypothesis presented by Professor Piper but were of the opinion that direct extrapolation of these results from SOD mutant yeast cells to mammalian cells in vivo was not possible. Members considered that mammalian mitochondria in vivo have sufficient anti-oxidant and DNA repair mechanisms to deal with any oxidative stress that may be attributed to the action of these preservatives in addition to that normally seen through the normal respiratory activities of the cell. The SOD mutant cells used in the study by Professor Piper have a significantly attenuated anti-oxidant and DNA repair response and therefore had a greater susceptibility to oxidative DNA damage.

6. In conclusion, COM members noted the evaluation of sorbates and benzoates by JECFA and were aware of the large package of toxicology data, including rodent carcinogenicity studies. COM members concluded that the study by Professor Piper did not suggest a need for a full re-evaluation of the mutagenicity data on benzoates and sorbates. On the basis of this conclusion, no further in vivo mutagenicity testing of these two preservatives was considered necessary at this time.

May 2008
COM/08/S2