Beverage displacement between elementary and middle school, 2004-2007.

BACKGROUND: Sweetened beverages of low nutritional quality might be displacing more nutritious beverages, such as 100% fruit juice and milk, from children's diets. However, previous research has not examined changes in beverage intake over time using nationally representative longitudinal data.

OBJECTIVE: Our objective was to examine changes in sweetened beverage, milk, and juice consumption between 5th and 8th grade.

DESIGN: We used a longitudinal analysis of self-reported beverage consumption.

PARTICIPANTS/SETTING: Data were from the Early Childhood Longitudinal Survey-Kindergarten Cohort 1998-1999 (ECLS-K), a nationally representative study of children followed from kindergarten through 8th grade. This analysis used data from Spring 2004 and 2007, when most children were in 5th and 8th grade, respectively (n=7,445).

MAIN OUTCOME MEASURES: Main outcome measures were changes in consumption of sweetened beverages, milk, and 100% fruit juice last week.

STATISTICAL ANALYSES PERFORMED: Survey-adjusted linear regression was used to estimate longitudinal relationships between servings of milk, sweetened beverages, and 100% fruit juice, controlling for child and family characteristics and food consumption.

RESULTS: Children's milk consumption decreased between 5th and 8th grade, and these decreases were larger among children who drank sweetened beverages daily. However, after controlling for demographic characteristics, changes in children's milk consumption were not significantly related to changes in their consumption of sweetened beverages over time (β=.005; P=0.81), while changes in milk consumption were positively related to changes in juice consumption (β=.087; P<0.01).

CONCLUSIONS: Observed decreases in average milk consumption from 5th to 8th grade were not related to changes in sweetened-beverage consumption. They were positively related to changes in fruit juice consumption, so not indicating displacement. Caloric beverages generally tended to increase or decrease in tandem, so focus must be placed on their role in children's entire diet and on balancing them with food and total beverage intake.