More Salt in Kids' Diets May Mean More Obesity
By Rita Rubin
WebMD Health News
Reviewed By Louise Chang, MD
Dec. 10, 2012 -- Limiting children's salt intake could be one way to reduce childhood obesity, new research suggests.
The study of more than 4,200 Australian children 2 to 16 years old found that those who ate more salt also drank more fluids, particularly sugar-sweetened beverages -- namely soda, fruit drinks, flavored mineral waters, and sports and energy drinks.
Previous research has implicated sugar-sweetened beverages in the rise in childhood obesity, which has more than tripled in the past 30 years in the United States, according to the CDC.
Boys 12 to 19 drink an average of 22 ounces of sugar-sweetened soda a day -- nearly two cans -- compared to only about 10 ounces of milk, the CDC says. Girls drink a little less of both: about 14 ounces of sugar-sweetened soda and 6 ounces of milk each day.
In the new study, children who drank at least one serving of a sugar-sweetened drink a day were 26% more likely to be overweight and obese.
On average, children who reported drinking sugar-sweetened beverages ate 6.5 grams of salt per day, compared to 5.8 grams of salt per day for the children who did not drink them. “This is a significant difference,” says researcher Carley Grimes, a PhD candidate at Deakin University.
What About That Salt Shaker?
The scientists did not count salt added at the table or used in cooking when calculating how much the children ate. “It is likely that the amount of salt reported in this paper is an underestimation of the true intake of salt,” Grimes says.
“It is difficult to speculate” how the additional salt would have influenced the link with sugar-sweetened beverages, she says.
Whether eating salty foods causes children to drink more sugary beverages can't be determined from her study, Grimes says. “It is possible that the association may in part be due to a clustering of unhealthy dietary behaviors.” People who prefer salty snacks over more nutritious options might also be more likely to prefer soda to water. After all, people commonly order fries with their Coke, and vice versa.
But, Grimes says, the notion that eating more salt increases children's thirst for sugary drinks “is clearly plausible,” based on studies in adults and animals.
“One of the reasons bars provide free salted nuts, snacks, and popcorn is that they know that eating these foods makes people thirsty, and they will buy more drinks,” she says.
In Grimes' study, 62% of participants reported drinking sugar-sweetened beverages, considerably lower than the 80% found in studies of U.S. children.
Barry Popkin, PhD, a nutrition professor at the University of North Carolina, Chapel Hill, says Australian children may not drink as much soda or sports drinks, but they make up for it by drinking fruit juice and are just as likely to be overweight or obese as their U.S. peers.
One weakness in Grimes' study was that fruit juice, which has the same impact as drinks with added sugar, wasn't included when tallying up children's drinking of sugary beverages, Popkin says.
The study was published online today in Pediatrics.
Carley Grimes, PhD candidate, Deakin University, Burwood, Victoria, Australia.
Barry Popkin, PhD, nutrition professor, University of North Carolina, Chapel Hill.
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