Why is it some people in Hong Kong leap onto their high horse when they discover monosodium glutamate (MSG) has been added to their lunch noodles but don't cause a ripple when they learn their domestic water supply is treated with a toxic chemical?

Since 1961, domestic water in Hong Kong has been fluoridated to prevent tooth decay. But studies have since linked fluoride in water to all sorts of things, from lower IQ in children to infertility.

Most developed nations don't fluoridate their water (in Western Europe only 3 per cent of the population consumes fluoride with their H2O) and the World Health Organisation says there is no discernible difference in the levels of tooth decay between developed countries that do and those that do not. The decline in tooth decay the United States has experienced over the past 60 years, which is often attributed to fluoridated water, has been matched in all developed countries.

So how can the Hong Kong government continue to add fluoride if there is doubt over its safety?

Local health adviser Anita Cheung Shuk-kwan thinks water fluoridation is an archaic practice: "There is compelling evidence that exposure to fluoride during the early stage of life can damage children's brains. One needs to ask: why force infants who have no teeth to take fluoride? … If someone wants fluoride they can get it from their dentist, or from fluoridated oral-care products. There is no need to put a drug in the public drinking water without public consent … Low-income families can't afford equipment to remove fluoride [most home water-treatment systems can't completely remove it anyway]."

So to those officials in control of the city's taps, instead of mass medicating Hong Kong people via the water supply, why not improve dental care by encouraging proper brushing and flossing or, even better, by removing sugary drinks and snacks from school canteens?