Vitamin C ‘mitigates’ passive smoking risks
Vitamin C may ‘significantly reduce’ the cell damage that causes a variety of chronic diseases – such as heart disease and cancer – in those forced to inhale second hand smoke, US researchers have found.
It has been long accepted that passive smoking ups the risk of lung cancer and heart disease, but many of those subjected to other people’s smoke cannot avoid the problem as they have to operate in a smoky environment at home or work.
So a team of nutrition experts from University of California, Berkeley looked at how much protection to these unwilling smokers could be afforded by taking vitamin C supplements.
Cigarette smoke is damaging because it contains large amounts of reactive free radicals, which are chemicals that cause oxidative damage to cells, triggering heart disease, cancer, atherosclerosis (hardening of the arteries), and other chronic diseases.
“It has been well established in test tube studies that vitamin C quenches reactive free radicals from cigarette smoke,” said Marion Dietrich, lead author of the study.
“However, there are few studies that have looked at the effects of vitamin C on oxidative stress in second hand smokers the way we have.”
Using a reliable and sensitive biomarker, researchers monitored the level of oxidative stress in 67 non-smokers who were dosed with either vitamin C; a mixture of vitamin C, vitamin E and an antioxidant; or a placebo.
Participants were chosen who were exposed to the smoke of at least one cigarette per day, five days a week, in an indoor setting..
After two months of treatment, the blood level of the oxidative stress biomarker had dropped by 11.4% and 12.7% in those taking vitamin C and the mixture respectively, compared to those given the placebo.
Vitamin C was judged to be the key anti-oxidant as the difference between the two treated groups was insignificant, and vitamin C was the common factor.
“These results are very encouraging,” said Dr Dietrich. “They show that vitamin C may help protect non-smokers from the oxidative damage caused by second hand tobacco smoke. “
The team cautions that they have not proven that vitamin C prevents heart disease or other health problems associated with passive smoking, but simply that vitamin C reduces the cellular damage thought to cause these problems.
Principle investigator Gladys Block adds that it does not follow from the team’s findings that taking vitamin C makes smoking or exposing others to smoke acceptable.
“But, if you are in a situation where you cannot escape frequent exposure to second hand smoke, it may be worthwhile to take vitamin C supplements as a precautionary measure”, she explains.
The study is published in the journal Nutrition and Cancer.
