The main findings of this study were that during early childhood there were distinct differences between high- and low-risk children in their beverage consumption patterns over time. Specifically, at a young age children born at high risk for obesity showed beverage consumption patterns that favored increased intakes of sugar-sweetened beverages such as fruit juice and soft drinks whereas intake of milk was comparatively low. The consumption of milk progressively increased among high-risk children over time; however, this increase did not displace calories consumed from sugar-sweetened beverages and fruit juice.
Increased consumption of fruit juice, soda, and soft drinks have been associated with increased energy intake (36
), excessive weight gain in children (3
), and child overweight (8
). In this study, we observed a significant linear risk group by time interaction for the amount of fruit juice, soda, and soft drinks including fruit juice that children consumed. Specifically, while fruit juice consumption was relatively stable over time for low-risk children, high-risk children’s intake was significantly higher at ages 3–4, but then declined over time. Similarly, the increase in soda intake over time was more pronounced for high-risk children than for low-risk children. Finally, high-risk children consumed significantly greater amounts of soft drinks (including fruit juice) at ages 3–5 years compared to low-risk children. These results are intriguing in that they point to different beverage consumption patterns between children with a different predisposition to obesity. It is possible that children who were born at high risk for obesity may exhibit a greater preference for these types of beverages by ways of their genetic predisposition (39
). It is also possible that families with a history of obesity may create a food home environment, which provides more easy access to sugar-sweetened beverages to their children than do families with no prior history of obesity. Studies using genetically sensitive designs are necessary to address these issues.
While high-risk children consumed more fruit juice and soft drinks at an early age, they also consumed relatively smaller amounts of milk compared to low-risk children (trend for a significant difference at age 3). Over time, however, high-risk children progressively increased their intake of milk to the level of low-risk children. Interestingly, while a greater increase in milk consumption over a 3-year period was inversely correlated with a 3-year change in calories consumed from soft drinks and fruit juice in low-risk children, there was no association among high-risk children. Thus, for low-risk children only, increased milk consumption may have displaced the consumption of soft drinks and fruit juice. For high-risk children, the results suggest that rather than having displaced calories that were consumed from soft drinks and fruit juice, milk intake instead may have added onto the calories consumed from these beverages. Previous studies among children and adolescents suggested that decreases in milk consumption may be due to an increased consumption of soft drinks and juice drinks over time (36
). While these results may speak to a possible displacement of calories consumed from certain beverages, only an experiment which systematically adjusts intake from beverage categories could generate more conclusive answers. Finally, a decrease in milk consumption over a 3-year period predicted an increase in children’s waist circumference from ages 5 to 6 years in the full sample. These results are in line with findings from previous studies that showed that increased milk/dairy intake may have a protective effect on child overweight (18
A curious finding from the longitudinal analysis was that change both in the relative (percent) and absolute calorie intake of beverages over time was inversely related to change in child waist circumference. In light of the previous finding of an inverse relationship between milk consumption and change in waist circumference, we attribute this inverse relationship to the inclusion of milk and milk-based beverages in this overall category. When examining the percentage of calories consumed from beverages as milk during ages 3–6 years, the data showed that children, on average, consumed ~47% beverage calories from milk (data not shown). Thus, having milk included in the all beverages category may explain the inverse relationship between changes in calories consumed from all beverages and changes in waist circumference. It is interesting to note that in the longitudinal analysis there were significant findings only for changes in waist circumference and not for changes in BMI z
-score. It is not clear as to why changes in beverage consumption patterns may differentially affect abdominally accumulated fat (i.e., central adiposity) but not the sum of fat-free mass and fat mass. It has been shown that the central distribution of body fat has a major genetic component (46
It is noteworthy that fruit juice intake of high-risk children exceeded recommendations put forward by the American Academy of Pediatrics and the US Department of Agriculture 2005 Dietary Guidelines which recommend limiting fruit juice consumption to 4–6 oz per day for children ages 1–6 years. When examining the mean intakes of fruit juice in this study, it becomes clear that the children born at high risk for obesity exceeded this recommended intake during ages 3–5 years. The current recommendation for milk intake for children 2–8 years per the US Department of Agriculture Dietary Guidelines and the American Dietetic Association amounts to two servings (approximately two cups) per day. Children in both risk groups thus consumed less than the recommended amount of milk during all 4 years. Children in our study (groups combined and intakes averaged across 4 years) also consumed overall smaller amounts of milk (9.2 oz vs. 12.32 oz) and more fruit juice (6.8 oz vs. 4.7 oz) per day compared to intakes of children in a nationally representative sample (37
The strengths of this study include (i) the unique sample of children born at high risk and low risk of obesity who were studied prospectively and (ii) the use of weighed food records as opposed to visual estimates. There are several ways in which this study should be extended. First, the results from this study are limited to the relatively narrowly defined study sample, namely healthy, full-term, white children, and may therefore not be generalizable to children as a whole. It thus would be desirable to examine beverages consumption patterns in a larger cohort of children who are ethnically diverse and show greater variability in their weight status. The relatively small sample size in this study may have also prevented us from finding more significant between-group differences in beverage consumption patterns as well as a greater number of significant associations with longitudinal anthropometric measures. Second, it would be desirable to obtain intake data over a longer period of time to determine children’s habitual diet and to complement the self-reported intake data by laboratory measures. Third, it is possible that parents’ education level and children’s physical activity habits may have affected children’s beverage consumption patterns. These data were not readily available for the years under study but should be examined in future investigations. Finally, the present designs, unlike a classic twin design or other genetically sensitive designs, could not formally test the respective influence of genetic and environmental influences on beverage intake patterns.
In conclusion, this study showed that children who were born at high risk for obesity showed increased intakes of fruit juice and soft drinks and lower intakes of milk and milk-based beverages during early childhood compared to low-risk children. For the group as whole, greater increases in soda consumption from ages 3 to 5 years was associated with greater increases in child waist circumference during the subsequent year whereas a decrease in milk consumption was associated with greater increases in child waist circumference during the subsequent year. Among low-risk children only, increases in milk consumption from ages 3 to 5 years were negatively associated with calories consumed from soft drinks and fruit juice. Future research should examine whether an increase in intake in one beverage category displaces intake from another beverage category or whether these increases are additive.