A new study by researchers at Boston University has shown that sugary drinks - including fizzy drinks, energy drinks and sports drinks - can have a detrimental impact on fertility. The study of over 3000 women and 1000 of their male partners, who were trying to get pregnant naturally, was published in the journal, Epidemiology, in January 2018.
The research was carried out as part of PRESTO, the Pregnancy Study Online, an ongoing web based prospective study of couples in North America and Canada. Participants completed a comprehensive baseline survey on medical history, lifestyle factors, and diet, including their intake of sugar-sweetened beverages. Female participants then completed a follow-up questionnaire every two months for up to 12 months or until pregnancy occurred.
Intake of sugary drinks was associated with reduced fertility for both men and women in the study and this effect was consistent after controlling for other factors including obesity, alcohol, smoking, caffeine and diet.
Researchers were looking at ‘fecundability’, which is the average monthly probability of conception. Intake of one or more sugary drinks a day by women was associated with a 25% reduction in fecundability; the same level of intake by men was associated with a reduction of 33%. The effect was worsened in people who drank more than one sugary drink a day and energy drinks had an even more pronounced effect, though the study sample size for those was smaller.
Sugar affects fertility through its negative impact on your hormones. When you consume something sugary - and drinks have a very fast impact - the amount of sugar in your bloodstream skyrockets. This causes your body to release insulin to get your blood sugar levels back under control. Too many peaks and troughs in your blood sugar cause your body to release the stress hormones, adrenaline and cortisol, which have a detrimental effect on the balance of your reproductive hormones, progesterone, oestrogen and testosterone. Sugary drinks are also full of empty calories which cause weight gain, which has been shown to impact fertility in both men and women.
This study did not show a correlation between consumption of diet fizzy drinks and fertility. However, at our clinic, we recommend that you try to cut the fizzy drinks out altogether rather than switch to diet versions. The artificial sweeteners in diet drinks still raise your blood sugar and have a detrimental impact on your gut bacteria, leading to greater sugar intolerance and inflammation. These things all impact your reproductive hormones. I once met a couple who each took a pint of Diet Coke to bed with them every night to put on their nightstand and sip through the night! They had no idea of the impact that was having on their bodies. Within 3 months of stopping that habit they had both lost loads of weight and were pregnant shortly afterwards.
If you can’t bear the thought of life without a sweet drink try making your own at home with some sparkling water, a little fruit juice and some stevia or xylitol, which are sweeteners that have a much lower impact on your blood sugar. Or check out the recipe using raw honey in this funny short video that explains what diet drinks do to your body in 1 hour.