Vitamin C Benefits Infants’ Lungs Damaged By Smoking During Pregnancy

Vitamin C may reduce the harm done to lungs in infants born to mothers who smoke during their pregnancy. These are the results of a new study published in the American Thoracic Society’s ‘American Journal of Respiratory and Critical Care Medicine’. 

To this end, a co-author of the study, Cindy T. McEvoy said that a relatively low dosage of vitamin C may be a safe intervention to help lung health of millions of infants worldwide, though, helping mothers quit smoking should remain the primary goal for health professionals and public health officials. 

According to the researchers, the study results support the hypothesis that oxidative stress caused by cigarette smoking reduces the amount of ascorbic acid, a component of vitamin C, available to the body. McEvoy and her co-authors reported that at three months of age, the infants whose mothers took 500 mg of vitamin C in addition to their prenatal vitamin had significantly better forced expiratory flows (FEFs).

FEFs measure how fast air can be exhaled from the lung and are an important measure of lung function because they can detect airway obstruction. Similarly, they discovered an association between the infant FEFs and a genetic variant some of the mothers possessed that appeared to amplify the negative impact of nicotine on the babies before they were born. 

McEvoy said finding a way to help infants exposed to smoking and nicotine in utero recognises the unique dangers posed by a highly advertised, addictive product and the lifetime effects on offspring who did not choose to be exposed.

Previous studies show that the primary effects of maternal smoking on offspring lung function and health are decreases in forced expiratory flows, decreased passive respiratory compliance, increased hospitalisation for respiratory infections, and an increased prevalence of childhood wheeze and asthma.

Nicotine appears to be the responsible component of tobacco smoke that affects lung development, and some of the effects of maternal smoking on lung development can be prevented by supplemental vitamin C. In the current study, 251 pregnant women who smoked were randomly assigned at 13 to 23 weeks of gestation to either receive vitamin C (125 women) or a placebo (126 women). 

Smoking was defined as having had one or more cigarettes in the last week. All participants received smoking cessation counselling throughout the study, and about 10 per cent of the women quit smoking during the study. At the time they enrolled in the study, the women had lower levels of ascorbic acid that have been reported among women who do not smoke. However, those levels rose in study participants who received vitamin C to become comparable to women who do not smoke.