London’s Muslims are being warned to avoid a holy water from Mecca in a government cancer warning.

The holy month of Ramadan starts on August 10 and there are fears Zam Zam could seriously damage people’s health. Tests by the Food Standards Agency showed the drink contained levels of arsenic that were three times the legal limit and high levels of nitrates.

The water from a sacred well in Mecca is banned from export by the Saudi government but there is a strong commercial demand from Muslims overseas, especially in London.

The FSA said Muslims need to be aware of the risks and that there was “no completely safe level of arsenic in water – and the more arsenic consumed the greater the risk (of cancer)”.

Officers are working with The Muslim Organisations Working Group (comprising representatives from Muslim community groups and companies involved with the production of halal food) which advises the Agency on foods appropriate for Muslim faith groups.

Infants are also sensitive to the level of nitrate present and so we do not recommend that they are given the water to drink.

If consumers find any water on sale that is labelled as Zam Zam, they are asked to contact their local authority enforcement office at their council.