A woman drinking at least one sugar-sweetened soda every day is 25 per cent less fertile, and it has an even bigger effect on the man, whose fertility levels drop by an average of 33 per cent.
Researchers from Boston University School of Medicine fear that energy drinks could be having an even bigger effect, although they say the study group size was too small to definitively draw that conclusion.
They surveyed 3,828 women, aged from 21 to 45, and 1,045 of their male partners, and they analysed lifestyle factors, including the number of sugar-sweetened sodas they drank.
Even after allowing for other factors that could affect fertility—such as obesity, caffeine intake, alcohol, smoking and diet—the researchers found that soda drinks were directly linked to fecundity, defined as an ability to conceive in any 30-day cycle.
Around 15 per cent of couples in the US have difficulty conceiving, and the researchers suggest that one simple remedy could be to stop drinking soda drinks. It could be an inexpensive remedy compared to the $5 bn that is spend every year on fertility treatments.
Sodas and colas reduce semen quality and start early menstruation, according to other studies, and they've also been linked to weight gain and type 2 diabetes.