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Wednesday, 19 September, 2001, 12:27 GMT 13:27 UK
Antioxidants fight smog damage
Ozone is found in smog
Ozone is found in smog
Taking antioxidant supplements could help reduce the effects of ozone pollution on lung health, say researchers.

The supplements may help the body prevent damage from toxins and pollutants.

US researchers gave supplements to half of a group of people whose diets were altered so they were not eating foods rich in antioxidants.

When exposed to ozone, those who had taken the supplements had better lung function, and were had much higher levels of vitamins than those who had not.

Participants in the study had their lungs tested
Participants in the study had their lungs tested
The scientists believe that this shows people whose lungs have been damaged by ozone could be given supplements to improve their condition.

The research is published in the American Journal of Respiratory and Critical Care Medicine - the journal of the American Thoracic Society.

Ozone damage

Ozone gas is the produced in photochemical smog - a noxious smog produced by chemical reaction under ultraviolet (UV) light from the sun.

Other studies have shown that the gas does damage the lung, and causes decreased lung function.

This latest research was carried out by scientists from the University of North Carolina, the National Institutes of Health, Bethesda, Maryland.

Thirty-two healthy, non-smoking adults aged 18 to 35 were put on an antioxidant-restricted diet for three weeks.

Antioxidants include vitamin E, found in vegetable oils, vitamin C from fruit. and betacarotene in yellow, orange and dark green vegetables like pumpkin, carrots and spinach.

After a week in which they had been exposed to air that had been filtered and purified, they underwent several tests on how their lungs functioned.

For the next two weeks, half the group in the study were given antioxidant supplements, and the other half a placebo.

All were exposed to 0.4 parts per million of ozone gas for two hours, while intermittently taking moderate exercise.

Researchers then gave them a lung "wash out", or brochoalveolar lavage.

This showed that those who had been given supplements had 85% higher levels of vitamin C, 28% more vitamin E and 27% more vitamin A, compared to the group which received the placebo.

They also showed a 24% improvement in one lung test and a 30% increase in another, compared to the group who did not take the supplements.

But there was no difference in how members of the two groups in a test for inflammatory response.

Dr John Harvey, from the British Thoracic Society, said that this was "good quality" research.

"It adds weight to the findings of other studies that fruit and vegetables may improve lung function," he said.

Pollution reduction

Tony Bosworth, pollution campaigner for Friends of the Earth, told BBC News Online said ozone was a confusing gas - "good" when it was in the sky, protecting the earth from the sun's UV light - and "bad" when it was at ground level, when it is highly damaging to people's health.

He said government experts had estimated air pollution had played a part in 12,000 deaths in Britain in 1998, and said pollution aggravated asthma and bronchial, heart and lung problems.

He added: "If we want to tackle ozone pollution, then the way to do it is to tackle pollution as a whole, and reduce the number of vehicles on the road, and the use of cars and lorries."

See also:

11 Jun 01 | Health
Air pollution heart attack link
03 Dec 00 | Sci/Tech
Ozone hole 'set to shrink'
30 Nov 00 | Sci/Tech
Clouds speed ozone loss
26 Oct 00 | Sci/Tech
Arctic ozone damage 'likely by 2020'

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