Soft drinks with high sugar content linked to breast cancer

Girls who frequently consume soft drinks containing large quantities of sugar reach puberty more quickly and are more at risk of getting breast cancer later in life, according to a major study.

The US study found that girls who drank more than 1.5 servings of sugared drinks per day had their first period nearly three months earlier than those who consumed just two drinks or fewer each week.

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, according to the report.

The 6,000 girls examined for the research, published in the journal Human Reproduction, are part of a 17,000-strong group living throughout the US's 50 states, who are studied periodically as they age.

Each girl filled in questionnaires detailing their consumption of carbonated drinks, non-carbonated drinks or sweetened ice teas, which each contain sucrose, glucose or corn syrup, while many contain caffeine.

The accelerated arrival by one year of a girl’s first period raises the risk of breast cancer by 5 per cent – though the consumption of high-sugar drinks among some at-risk groups, particularly those from poorer backgrounds, is far higher now than it was during the period examined.

The health dangers posed should “not be under-estimated”, because unlike other factors that affect the arrival of a girl’s first period, the consumption of high-sugar drinks “can be modified”, said the report’s authors.

Drinks containing added sugar lead to rapid increases in the concentration of insulin found in the body, which can trigger higher concentrations of sex hormones and their earlier circulation around the body.

Higher caffeine consumption has been associated, too, with triggering earlier periods, but the researchers found that it was the amount of sugar added to a drink, rather than the amount it naturally contained, that “was the culprit”, according to the research.

Saying that the findings are “statistically significant”, Dr Ken Ong said it has long been known that high-sugar drinks prompt weight-gain and that extra weight accelerates the arrival of puberty.

“The surprise here is the claim that the association is independent of childhood size – ie, that there is a more direct effect of SSB on puberty. This is unexpected,” said the University of Cambridge academic.