Vitamin C may help prevent the damage caused by passive smoking, suggests a new study.
Exposure to smoke in close environment is thought to increase non-smokers' risk of lung cancer and cardiovascular diseases.
The small study found that non-smokers who took a daily vitamin C supplement significantly reduced their levels of oxidative stress, thought to indicate the damage done by inhaling smoke and one of the risk factors for smoking-related diseases.
However vitamin E and alpha-lipoic acid seemed to have little effect on outcome, reported the researchers in this week's issue of Nutrition and Cancer.
The researchers from the University of California in Berkeley, US investigated the effect of antioxidants on a biomarker for lipid peroxidation, F2-isoprostane, in blood samples of 67 passive smokers.
The subjects (47 women, 20 men), aged 45 years old on average, received either 500mg of vitamin C, a mix of vitamin C, vitamin E, and alpha-lipoic acid, or a placebo daily over a period of two months.
The scientists controlled for baseline levels of antioxidants, excluding people with a high intake of fruit and vegetables, believed to combat oxidative stress through their high antioxidant content. Cholesterol profiles, transferrin saturation, and C-reactive protein were also taken into account.
In the vitamin C and mixture groups, oxidative stress decreased significantly by 11.4 per cent and 12.7 per cent respectively compared with the placebo group.
While the results do not confirm a reduced risk for lung cancer or heart disease, they suggest that a daily vitamin C supplement could protect passive smokers from some of the risk factors leading to these diseases, suggest the researchers.