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.
