Dietary Contributions to Nicotine Body Burden. L. B. Gratt, IWG Corp., 2241 Kettner Blvd., Suite 220, San Diego, CA 92101; and W. R. Chappell, University of Colorado at Denver, P.O. Box 173364, Denver, CO 80217
Recent USDA food intake surveys are used to perform a probabilistic analysis of dietary intake of nicotine. Using limited data on nicotine content of foodstuffs (tea, tomato, potato, green pepper, and eggplant) and the 198991 Continuing Survey of Food Intakes by Individuals (CSDII), the absorbed dose of nicotine is shown to be significant compared to present day environmental tobacco smoke (ETS) nicotine exposures. CSDII contains 3day dietary intake data for 11,912 individuals and weighting factors for extrapolation to the entire US population. Using tea as an example, the tea consumption cumulative distribution function for adults (>18 years) shows an average tea consumption of 142 g/d, noting that 62.7% of the US population has no tea intake. The average for those who drink tea is about 1.6 cup/day (using 250 g/cup). Using the available data for nicotine in 10 brands of brewed tea (2 instant and 8 leaves) tea nicotine concentration is modeled as a lognormal distribution (with a mean of 68.9 ng of nicotine per gram of brewed tea and a standard deviation of 75 ng/g). Oral nicotine bioavailability is modeled as a triangular distribution. Using a study of the oral nicotine bioavailability for a group of 10 male subjects, the most likely absorption factor was 44% with a range of 24% to 59%. The dietary tea dose was calculated using the daily tea intake, the concentration of nicotine in tea, and the absorption factor. Using @RISK simulation for 25,000 trials the average absorbed nicotine dose for those who drink tea is 12.5 mg/d. The median is about 5 mg/d. The 95th percentile for the entire US population aged 18 years and older is 22 mg/d. The dietary contributions of absorbed nicotine dose are significant when compared to present ETS exposures. A recent study of workplace ETS exposure results in mean and median absorbed nicotine doses of 11 and 3 mg/d, respectively. Thus, ETS exposure analysis based on total nicotine absorption needs to consider dietary intake. This includes the use of cotinine (a major metabolite of nicotine) which has been a widely used biomarker.