Besides causing unsightly cavities and making children fat, there's a new reason why kids, young girls in particular, should avoid having those sugary drinks.

Findings of a new study reveal that sugary drinks may also be causing girls to start menstruating earlier with girls who frequently drink sugary beverages such as sodas being found to more likely start their periods earlier compared with their counterparts who do not overindulge in these drinks.

For the new research published in the journal Human Reproduction on Jan. 27, Karin Michels, from the Harvard Medical School, and colleagues involved nearly 6,000 adolescent girls to look at the link between sugary drinks and the age when girls have their menarche, or their first menstrual cycle.

The researchers used questionnaires to gather information on the girls' diet and what they drank. By the end of the five year study period, only three percent of the participants had not started their menstrual period. The researchers, however, observed that the girls who consumed more sugary drinks had their first period at 12.8 years old on average while those who drink the least sugary drinks start to have their period at 13 years old.

Michels and her team found that the girls who consume more than 1.5 servings of sugary beverages daily had their first menstrual period 2.7 months earlier on average than the girls who only drink two or less of such drinks per week. The researchers likewise found that the effects are regardless of the girls' body mass index (BMI), height, and other lifestyle factors.

Although the few months' difference may not seem to matter much, the researchers said that this is significant because an earlier onset of menstrual periods is known as one of the factors that contribute to increased risks for breast cancer later in life.

"More frequent SSB consumption may predict earlier menarche through mechanisms other than increased BMI. Our findings provide further support for public health efforts to reduce SSB consumption," the researchers wrote.

How does drinking too much sugary drinks influence the onset of puberty in girls? The researchers said that sugary drinks have higher glycemic index compared with naturally sweetened drinks and this can result in a rapid increase in the body's insulin concentration, which in turn can cause increased concentration of sex hormones. Big changes in the concentration of these hormones that circulate in the body have been associated with earlier onset of menstrual periods.