FRIDAY, Feb. 24, 2006 (HealthDay News) -- As teenage girls get older, they drink less milk and more soda, which translates into lower intakes of calcium and higher body-mass indexes, a new study finds.
Soda consumption among teens has been a concern of nutrition experts for years, with excess soft drink intake linked to increased risk for dental decay and weight gain, among other health problems.
Now, in a study published in the February issue of The Journal of Pediatrics, researchers followed 2,371 girls who kept food diaries from age 9 or 10 through age 19. The findings mirror those of other studies, but what's new is the length of time the girls were tracked.
"We have 10 years of details," said study co-author Douglas Thompson, a senior statistician at the Maryland Medical Research Institute, in Baltimore.
As participants in the National Heart, Lung and Blood Institute Growth Health Study, the girls turned in food diaries during annual visits. Over the years, the researchers looked at three-day food records and evaluated them. Participants noted, among other information, their intake of milk, regular soda, diet soda, fruit juice, fruit-flavored drinks and coffee/tea.
Milk consumption decreased by more than 25 percent during the course of the study, while soda intake nearly tripled, becoming the No. 1 beverage consumed by the older girls. Because beverage habits have been associated with characteristics such as age and race, the researchers looked separately at white and black teens.
The consumption of regular soda among white girls rose from about 4.7 ounces a day at age 9 to 13.2 ounces daily by age 18. Among black girls, regular soda consumption was 4 ounces daily at age 9, and rose to 11.8 ounces by age 18. Milk consumption among white girls was 12.3 ounces daily at age 9 but only 8.4 ounces at age 18. Black girls averaged 8.5 ounces of milk a day at age 9, but just 5 ounces by age 18.
The more soda girls drank, the lower their calcium intake and the higher their body-mass index (BMI), the researchers found.
"The nutrient impacts are a great concern," Thompson said, referring to the calcium intake finding. "A girl who drank 200 grams [about 8 ounces] a day decreased calcium intake by 7 milligrams, compared to one who drank only 100 grams [4 ounces]."
Advice for parents? Give your daughter more milk, and fewer other beverages. "The beverages associated with poor nutrient profiles were regular sodas, fruit-flavored drinks, coffee and teas," Thompson said.
"Girls who drank more of those -- regular soda, fruit-flavored drinks [not fruit juice], coffee and teas -- take in more calories generally, have more sugars and less calcium in their diets," he added.
Moderation of soda is key, said Lona Sandon, a spokeswomen for the American Dietetic Association and an assistant professor at the University of Texas Southwestern in Dallas. "Whether drinking sugary sodas or fruit juices causes weight gain or not, the bigger issue is overall diet quality," she said. "According to the American Dietetic Association's position statement on [the] use of nutritive and nonnutritive sweeteners, diet quality suffers when intake of these beverages reaches 25 percent of total calories or above."
"It is pretty clear that as intake of sugary beverages increases, the intake of beverages with higher nutritional quality decreases," Sandon said. "Replacing milk with sodas or fruit drinks means less protein needed for growth and healthy immune systems, less calcium for strong bones for the future, less potassium, less vitamin D and other nutrients needed for optimal health."
"Sweetened beverages providing calories without nutrition should be consumed with caution," she added. "An adolescent eating a diet that meets the dietary guidelines for Americans and nutrients needed for growth and development can safely enjoy a sugary drink occasionally."
By occasionally, Sandon said she meant no more than three to four times a week.
To learn more about nutrition, visit the American Dietetic Association.