Potential safety issues surrounding the use of benzoate preservatives

Sodium benzoate (E211) and potassium sorbate (E202) have long been used for large-scale beverage preservation, yet it is potassium sorbate that is now the preferred option for most soft drink manufacturers. Partly this is a reaction to the discovery that benzoate can cause drinks to contain traces of the carcinogen benzene. This benzene is thought to have its origins in a free-radical catalysed reaction of the benzoate with ascorbic acid. However, there may be additional benefits to using potassium sorbate rather than the benzoate preservatives in beverages. In children, a high dietary intake of sodium benzoate may be associated with asthma, allergy, or attention deficit–hyperactivity disorder. Benzoate is now known to influence cognitive functioning. By acting as a competitive inhibitor of the enzyme D-amino acid oxidase (DAAO), thereby reducing the DAAO-catalysed degradation of D-serine, it can upregulate the activity of the N-methyl-d-aspartate receptors in the brain. A high benzoate intake might also generate glycine deficiency, lack of glycine generally exerting a negative impact on brain neurochemistry. There are therefore strong grounds for suspecting that dietary benzoate can have neuromodulatory (mood, learning, and personality) effects and influence child hyperactivity disorders.