Vitamin C is an important antioxidant thought to play a role in preventing cancer and helping fighting off infections.
Previous studies show smoking lowers vitamin C levels in adults.
This study involved an analysis of data collected for a large national study that evaluated a range of health and nutrition issues. The investigators compared the levels of vitamin C, or ascorbic acid, in the blood of children who were exposed to secondhand smoke to their blood levels of cotinine, a component of cigarette smoke that shows up in the blood. Even after adjusting for other factors, such as whether or not the children took vitamin C or multivitamin supplements, results showed that children with higher levels of cotinine in their blood had lower levels of ascorbic acid. The study, which involved nearly 3,000 children, estimates that 43 percent of all children in the United States live in a home with at least one smoker. Researchers believe their results may help explain why children of smokers are more susceptible to respiratory ailments, including asthma.