A medication for high cholesterol can drastically cut "forever chemicals" (PFAS) -- associated with an increased risk of cancer and banned in Europe -- in the blood, researchers said Thursday.

But the drug was not suitable for widespread and prolonged use because of its side effects and more research was needed to explore its possible impact on certain chronic health conditions.

A clinical trial with cholestyramine led to a reduction 20 times greater than the normal result without intervention, Morten Lindhardt, a doctor involved in a clinical trial, told AFP.

"The effect of treatment was actually a decrease in the plasma of 63 percent," said Lindhardt, who is based at Holbaek hospital.

Researchers say the results are promising for treating people who have been exposed to high doses of the "forever chemicals", so called because they tend to accumulate and stay in the body.

But Lindhart added of the new treatment: "I don't think you should take this medication permanently because there are side effects."

It could nevertheless alleviate the "feeling of being poisoned" that people with high levels of pollutants could feel, he added.

PFAS (Per- and polyfluoroalkyl substances), refer to a family of some 4,000 chemical compounds.

They can reduce the immune response from vaccination, hit cholesterol levels, and have also been linked to cancers or obesity.

- Side effects risk -

Some residents of the town of Korsor in central Denmark, were exposed to high levels of one of them; perfluoroctane sulfonic acid (PFOS).

It was present in a foam used to extinguish fires at a local firefighting training facility.

This community, where the measured PFOS levels are well above normal levels, was chosen for the clinical trial on 45 residents.

Despite the small sample size, Lindhardt argued that the effect of the treatment was beyond dispute.

Nevertheless, widespread treatment for everyone with elevated PFAS levels was out of the question, he added.

"The risk of side effects is way too big," he explained. "If you went on to treat everybody, it will be a disaster."

But one potential use could be for women of child bearing age, to limit the transmission of the chemicals to their children.

"It could break the chain of delivering these chemicals to the next generation," Lindhart said.

Lindhart argued for caution, even though the effects of the drug were documented in terms of their effect on PFAS levels in the blood.

The impact on the kidney or on immune deficiencies was not studied, he said.