The Council for Scientific and Industrial Research warned yesterday about plans to add fluoride to South Africa’s drinking water, saying it posed a possible health risk to people with HIV and Aids, as well as those suffering from malnutrition.

Briefing Parliament’s water affairs portfolio committee, Bettina Genthe, a water analysis expert with Environmentek, a business unit of the CSIR, said recently enacted legislation prescribed the addition of fluoride to water to stop tooth decay.

However, while she recognised this was beneficial when it came to preventing dental caries, it was “not necessarily a good idea”.

She said: “We’ve got a number of factors which affect the health impact of fluoride in this country – one of these is that malnutrition makes fluoride more toxic than it is to people who are well nourished.

“So this is a factor we would have to consider before going ahead and adding fluoride to the water supply.”

There was also the potential danger of fluoride compromising people’s immune systems.

In an obvious reference to the Aids pandemic, Genthe said “a large percentage of the population in South Africa already have a compromised immune system; this (fluoridation) just adds more fuel”.

“Maybe we shouldn’t be going at it in this particular way. There is no doubt that fluoride is good for teeth, and it protects against decay … but water fluoridation might not be the best way of achieving this protection,” she told MPs.

Speaking after the briefing, Genthe said fluoridation was “potentially a problem” for people with HIV.

“It’s potentially a problem; we’re not 100% sure. Not on humans specifically, but in the test tube … it appears to be that fluoride can be toxic at very low concentrations to immune system cells.”

However, it was very difficult to prove a link, because other factors had first to be eliminated.

“The animal studies and the cell studies are showing that there’s a potential problem, and we haven’t proven it yet.”

However, she would rather “err on the side of safety”.

“If we think something is potentially harmful or toxic, especially with malnourished people. I think we need to hold off.

“The benefits of protecting people’s teeth compared to potentially affecting their whole body … I don’t think it’s the right way to go, until we know more. There’s too many gaps in the scientific data,” she said.

Asked if the CSIR was planning to issue a warning to municipalities, advising them to hold off on plans to fluoridate their water, Genthe said the council’s views were contained in a report by the Water Research Commission, which had been available since the beginning of the year.

As far as she knew, none of South Africa’s municipalities had started adding fluoride to their drinking water systems.