Here's yet another strike against sugary drinks. A new study has found a link between their consumption and the early onset of menstruation in young girls.

Sugary beverages — like sodas and iced teas — have been in the hot seat for several years due to a link between consumption and obesity, particularly childhood obesity. But with the new association between sugary drinks and early puberty, health experts are re-sounding the alarms, because early puberty is also associated with a greater risk for breast and endometrial cancer later in life.

For the study, which was published in the journal Human Reproduction, researchers used data on 5,583 girls ages 9 to 14. At the beginning of the study, none of the girls had yet started their periods (menarche). The girls were followed and evaluated yearly from 1996 to 1998, with questionnaires that tracked eating habits, weight and puberty status. By 2001, 159 had not yet had their first period. Researchers found that the girls who drank an average of 1 1/2 twelve-ounce cans of sugary beverages each day had their first period 2.7 months earlier than those who drank two or fewer 12-ounce servings per week. This link held, even after researchers controlled for factors such as birth weight, height, total food intake, maternal age at puberty, and activity level. 

The findings are important for two reasons. First, they make a connection between diet and the age of puberty — an age that has been dropping rapidly over the last several years. And they are also significant because they could show a link between the consumption of sugary drinks in childhood and the development of breast or other cancers later in life.

The study's authors, including researchers from Harvard Medical School, noted, "the public health significance of SSB [sugar-sweetened beverage] consumption at age of menarche, and possibly breast cancer, should not be over-looked, since, unlike most other predictors of menarche, SSB consumption can be modified." 

The researchers did not find a link between age of menarche and drinking diet sodas or fruit juices. This could be because sweetened sodas and iced teas have added sugar which gives them a higher glycemic index than naturally sweetened fruit juices or drinks that use artificial sweeteners. Higher glycemic foods increase insulin rapidly in the body and this increased insulin could result in higher concentrations of sex hormones. 

Karin Michaels, an associate professor at Harvard commented, "Our findings provide further support for public health efforts to reduce the consumption of sugary drinks."

Related on MNN: