UK pharmaceutical manufacturer GlaxoSmithKline (GSK) has announced that it will be removing zinc from its denture adhesive products, after fears were raised that the trace mineral could cause side effects such as numbness or balance problems if used long term.

The Daily Mail reports that the move by GSK follows dozens of US lawsuits that allege products such as Poligrip caused nerve damage, as well as blood problems such as anaemia, after prolonged and excessive use.

Although zinc is not absorbed in the mouth and should cause no problems if the amount directed on products is complied with, consumers who use more than the recommended amount of denture adhesive because of poor fitting dentures might be exposing themselves to additional risks of side effects. Zinc only enters the body if swallowed, which become more likely if the products are used excessively.

Many patients in the US are claiming they developed neuropathy, which is also linked to diabetes – all the patients involved were using around two tubes of denture adhesive per week. A 40g tube of a product such as Polygrip should last around six weeks if used in accordance with manufacturer’s recommendations.

Chief medical officer of GSK Consumer Healthcare, Dr Howard Marsh, said:

'It is important for consumers to know that Poligrip Ultra and Poligrip Total Care remain safe to use as directed on the product label.

'We are taking this voluntary action because we have become aware of potential health problems associated with the long-term excessive use of our zinc-containing denture adhesive products.'

Dr Marsh added that reports of consumers developing side effects were ‘very rare, given that several million people worldwide are users of the products’. He added:

'If anyone is concerned that they may have been using the product in excess they should stop using it, talk to their doctor and switch to a zinc-free alternative.'

A study involving four patients who wore dentures and who used two tubes of a zinc-containing denture adhesive each week found they were suffering from neurological symptoms. The findings of the study are published in the journal ‘Nature’.

GSK said that it had received ‘an increased number of adverse event reports’ in the last year, in which people reported side effects associated with denture fixatives:

'Together with published literature, these suggest that excessive use of these products – typically for several years – may lead to the development of high levels of zinc in the body, which are associated with neurological symptoms such as numbness, tingling or weakness in the arms and legs, difficulties with walking – and balance and blood problems such as anaemia.'

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