Past research has shown that smoking lowers vitamin C levels in smokers themselves. However, scientists wanted to know if children exposed to second-hand smoke would also show lower vitamin C levels.

Researchers from the University of Puerto Rico gathered a study group which included 512 children aged 2 to 12 years old. Half of the children were exposed to environmental tobacco smoke (ETS) in the home because their parents smoked, while the others were not. All of the children’s’ dietary intake of vitamin C were assessed and blood levels were also measured. The amount of smoke exposure was also assessed by measuring for a biomarker in the urine called cotinine. Age, sex, and body mass index were also factored in.

The researchers found that blood levels of vitamin C were significantly lower in children exposed to tobacco smoke than in those children who were not exposed. They added that the reduction in vitamin C levels occurred even with very low exposure to smoke. They conclude that second-hand tobacco smoke can indeed “reduce concentrations of vitamin C (ascorbate), an important blood antioxidant, even when the amount of smoke exposure is minimal.” They suggest that “children exposed to smoke should be encouraged to consume increased amounts of foods rich in vitamin C, or should be given the equivalent amount of this vitamin as a supplement.” No doubt, parents should also be encouraged to quit – for the children’s sake!

American Journal of Clinical Nutrition, Vol. 77, No. 1, 167-172