When researchers at the Harvard School of Public Health in Boston followed 5583 prepubertal girls aged 9 to 14 years from 1996 to 2001, they found that girls who drank more than 1.5 servings of sugar-sweetened beverages a day entered menarche 2.7 months earlier than girls who drank 2 or fewer servings per week (a serving was defined as 1 glass, can, or bottle). Girls who drank the most such beverages got their first menstrual period at an average age of 12.8 years, whereas girls who drank the fewest began their periods at age 13 years on average.
Sugar-sweetened beverages included sodas, noncarbonated fruit drinks, and iced teas sweetened with sucrose, glucose, or corn syrup. Diet soda and naturally sweetened fruit juices weren’t associated with earlier menarche. The findings were independent of body mass index, food consumption, and exercise.
The researchers note that their results show an association, not a cause-and-effect relationship, between sugar-sweetened drinks and earlier menarche. The mechanisms behind the association are unclear, they say, but may have to do with the higher glycemic index of sugar-sweetened drinks compared with lower-glycemic beverages such as fruit juices. Foods with a high glycemic index raise insulin levels rapidly, which in turn increases sex hormone concentrations. Previous research has suggested a connection between higher hormonal concentrations and earlier menarche.
“Our findings provide further support for public health efforts to reduce [sugar-sweetened beverage] consumption,” the researchers conclude.