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.