An Analysis of the Proportion of the U.S. Population that Ingests Soil or Other Non-Food Substances

Reliable quantitative data are lacking that document the prevalence of ingestion of soil and other “non-food” substances among U.S. children and adults. This article explores the proportion of the U.S. population that ingests substances such as soil, clay, starch, paint, or plaster. We compiled data from the National Health and Nutrition Examination Survey (NHANES) collected from years 1971–1975 (NHANES I) and 1976–1980 (NHANES II) because these particular surveys asked participants specific questions about non-food ingestion practices. We examined the prevalence of the behavior across multiple demographic variables, such as age, gender, education, and income level. Approximately 1% (NHANES II) to 2.5% (NHANES I) of the U.S. population ingests some type of non-food substance. The most notable variation across the demographic subgroups studied was the difference in estimated prevalence among young children (1 to <3 years) compared to older children and adults. Estimated prevalence was also higher among blacks compared to whites and within lower compared to higher socioeconomic groups. This analysis helps fill data gaps on the relative pattern of non-food ingestion practices on a national scale. This information provides perspective for risk assessors when evaluating exposure variables and for risk managers when weighing risk management alternatives.