Frequent consumption of sugary drinks—including soda, fruit mixes, and sweetened iced tea—has been linked with an early start to menstruation in girls, according to new research.
The study followed 5,583 girls and found that those who drank more than 1.5 servings of sugary drinks a day had their first period at 12.8 years old, 2.7 months earlier than girls who drank two or fewer per week and started menstruating at 13 years old.
This could be bad news when it comes to breast cancer risk, according to the study authors. They point out that “A one-year decrease in age at menarche is estimated to increase the risk of breast cancer by 5 percent”—and although the girls in this study who drank sugary beverages only started menstruation 2.7 months earlier, the authors are quick to note that “The amount of sugar-sweetened beverages consumed by girls in our highest category of consumption, more than 1.5 servings per day, however, is likely low compared with consumption in certain other populations, in which we would expect an even more dramatic decrease in age at menarche.” In fact, kids are drinking more soda then ever—from 1989 to 2008, calories consumed in the form of sugary beverages jumped by 60 percent in children ages 6 to 11. Sugary drinks are also the top calorie source in teens’ diets, at 226 calories a day.
This effect was independent of other factors that could contribute to an earlier period, like body mass index, physical activity, and height. Diet soda and fruit juice didn’t have the same effect—the researchers explain that drinks with added sugar have a higher glycemic index than naturally sweetened drinks and result in a rapid increase in insulin concentrations in the body. Higher insulin concentrations can result in higher concentrations of sex hormones, which has been linked to earlier menstruation.
And the negative effects of sugary drinks don’t stop at an increased risk of breast cancer—women who consumed a can of sugary drink per day were found to have a 75 percent higher risk of gout than women who rarely had sugary drinks, while men who drank one can a day had a 20 percent higher risk of having or dying from a heart attack. In children, not only is soda consumption linked to a higher body mass index and higher risk of obesity, but it’s also been shown to contribute to aggressive behaviors like attacking others and destroying other people’s belongings.