Sugary drinks linked to earlier onset of menstrual periods

http://www.eurekalert.org/pub_releases/2015-01/esoh-sdl012615.php

Public Release: 27-Jan-2015
European Society of Human Reproduction and Embryology

Girls who frequently consume sugary drinks tend to start their menstrual periods earlier than girls who do not, according to new research published online today (Wednesday) in Human Reproduction [1], one of the world's leading reproductive medicine journals.

In the first study to look at the relation between sugar-sweetened drinks and the age at which girls have their first period, researchers followed 5583 girls, aged 9-14 years between 1996 and 2001 and found that those who drank more than 1.5 servings of sugary drinks a day had their first period 2.7 months earlier than those who consumed two or fewer such drinks a week. This effect was independent of the girls' body mass index (BMI), height, total food intake and other lifestyle factors such as physical activity.

The findings are important not only because of the growing problem of childhood obesity in a number of developed countries, but also because starting periods earlier is linked to an increased risk of breast cancer later in life.

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Diet sodas and fruit juices were not associated with any difference in the age at which girls started their periods. However, at any age between nine and 18.5 years, girls who reported consuming more than 1.5 servings of sugar-sweetened drinks a day were, on average, 24% more likely to start their first period in the next month relative to girls consuming two or fewer servings a week, taking into account factors that could affect the age of first menstruation, such as birth weight, physical activity, race or ethnicity, height, frequency of eating dinner together as a family, and family composition (whether or not a father or step-father lived at home). The average age of the first period among girls consuming the most sugary drinks was 12.8 years, compared to 13 years for those drinking the least.

When the researchers adjusted their results to take account of BMI, the effect of sugary drink consumption on the age of onset of menstruation was still significant: girls consuming the most were 22% more likely to start their first period in the next month compared to girls consuming the least.

The researchers say that drinks with added sugar have a higher glycemic index than naturally sweetened drinks such as fruit juices, and high glycemic foods result in a rapid increase in insulin concentrations in the body. Higher insulin concentrations can result in higher concentrations of sex hormones, and large alterations in the concentrations of these hormones circulating in the body has been linked to periods starting earlier. Greater caffeine intake has also been associated with earlier periods. However, the researchers found that total sugar or caffeine intake did not explain their results, and that it was the added sugar in drinks such as sodas that was the culprit. Greater BMI only partially explained the results and was not the main mediator.

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