Exposure to cigarette smoke may rob people of folate (also known as folic acid), an important vitamin that helps protect against a variety of diseases, including a number of birth defects, a large nationwide study concludes. Both active smokers and those exposed to high levels of secondhand smoke had lower levels of folate in their blood than nonsmokers, according to researchers.

“Overall, we found that red blood cell folate levels in current smokers were 20% lower than those in our entire group of nonsmokers,” said David M. Mannino, MD, of the Centers for Disease Control and Prevention. Nonsmokers exposed to heavy amounts of secondhand smoke also had decreased folate levels, but their loss was only 60% of the amount leeched from active smokers.

Previous studies have linked low folate levels to several different diseases. Mannino and colleagues suggest that the association between folate and smoke exposure might help explain the increased risk of these diseases among active smokers.

“The finding provides biological support for recent studies linking tobacco smoke exposure to heart disease and breast cancer and provides biological plausibility to examine the role of tobacco smoke exposure in other folate-related diseases such as neural tube defects and colon cancer,” they say.

Center for the Advancement of Health, June 25, 2003