Trends in children's consumption of beverages: 1987 to 1998

Family Economics and Nutrition Review,  Spring, 2002  by Yi Kyung Park,  Emily R. Meier,  Peri Bianchi,  Won O. Song

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Children consume fewer meals at the dining table and more meals and snacks away from home. Only 36 percent of respondents to a recent study on eating habits reported that they ate together as a family five or more nights a week (Anonymous, 2000). For teenagers, 5 percent of out-of-home eating occasions consisted of a trip to a convenience store--most often for a beverage purchased from a vending machine (Anonymous, 1999b). Throughout the day, children consume a variety of beverages, which often include milk, juice, fruit drinks, carbonated soft drinks, powdered soft drinks, and water.

To implement strategies to improve the health of children, the nutrition community needs to understand the effect of beverage consumption on nutrition, in terms of the frequency and quantity of each beverage consumed, as well as the relationship of beverages to food consumption and health. However, it is somewhat difficult to determine the contribution of each beverage to the overall diet, especially children's diets.

Efforts to promote milk consumption have increased, and their effects on health and nutrition have yet to be understood fully. Calcium intake is low for adolescent girls, a particular concern because calcium absorption is at its highest during adolescence (Amschler, 1999). When calcium intake is inadequate early in life, the risk of osteoporosis increases (National Institutes of Health [NIH], 1994). Some studies have reported that consumption of carbonated soft drinks has increased; this may have a significant effect on nutrition (Borrud, Enns, & Mickel, 1997).

Research suggests that caffeine, which is more frequently found in cola beverages than in other soft drinks, may reduce calcium retention (Weaver, Proulx, & Heaney, 1999). Also, the phosphoric acid in carbonated beverages (cola and others) interferes with the metabolism of calcium (Calvo, 1994; Wyshak, 2000; Wyshak & Frisch, 1994). Other researchers, however, disagreed with these findings (The Pediatric Forum, 2001). Heaney and Rafferty (2001) concluded that the net effect of caffeine on calcium economy was negligible.

Finally, no conclusive evidence has indicated that carbonated soft drinks are the "cause" of low intakes of other beverages or that they are displacing other beverages in the diet, although some studies indicate a very suggestive relationship between higher quantities of carbonated soft drinks and lower quantities of milk consumption (Bowman, 1999; Harnack, Stang, & Story, 1999).

The debate over the consumption of fruit juice remains, having been argued to have effects on children's health that are both favorable (Doucette & Dwyer, 2000; Skinner & Carruth, 2001) and unfavorable (Dennison, Rockwell, & Baker, 1997; Tanasescu, Ferris, Himmelgreen, Rodriquez, & Perez-Escamilla, 2000). Regardless, 100-percent fruit juice is an excellent source of many essential vitamins and minerals and is consumed by a significant number of U.S. children (Ballew, Kuester, & Gillespie, 2000).

In recent years, fruit drinks--often made with only 5 to 10 percent fruit juice--have emerged as a growing component of the American diet. In 1997, sales of fruit drinks surpassed sales of 100-percent fruit juices (Sfiligoj, 1998). Fruit drinks, despite their higher sugar content, compared with fruit juices, provide about 17 percent of vitamin C for children age 2 to 5 and are the second greatest source of vitamin C for children of all ages (Subar, Krebs-Smith, Cook, & Kahle, 1998). Although fruit drinks could contribute to improved vitamin intakes, their effect on nutrition is not understood fully.

Beverages are a significant portion of the American diet, contributing to the intake of various nutrients as well as added sugars. The Dietary Guidelines for Americans recommend that Americans "Choose beverages and foods to moderate their intake of sugars" (U.S. Department of Agriculture [USDA] and Department of Health and Human Services [DHHS], 2000). However, a recent study found that among children age 2 to 17, 38 to 56 percent of the added sugars they consumed came from beverages (Guthrie & Morton, 2000). Because childhood obesity is rising, more information is needed to investigate the changes in children's diets over time. The purpose of this study was to investigate trends in children's beverage consumption (both prevalence and quantity) over a 1 O-year period.

Methods

Survey Design

Data were obtained from the National Family Opinion Research/Beverage Unit's Share of Intake Panel (SIP) (National Family Opinion World Group [NFO], 1999; National Soft Drink Association [NSDA], 1999), a syndicated marketing research program at the national level. Since 1980, SIP has used mail surveys, which are primarily purchased by industry members, to monitor beverage consumption. The survey instrument is a 2-week diary that collects all beverage intakes (excluding tap water) for all members of the selected household. Participants are told to exclude tap water, but to include bottled water. Tap water is difficult for consumers to quantify, even though its contribution to beverage consumption may be significant. In this study, milk intake reflects only beverages; milk consumed with cereal was not included, nor was milk in other forms of dairy products (e.g., cheese).