I’ve been known to take a great scientific interest in the effects of caffeine consumption on human health.
And why wouldn’t I?
Something like 80% of the global population ingests caffeine on a daily basis, the overwhelming majority of which comes from coffee.
Coffee is, in fact, the top source of dietary antioxidants for the average American and its moderate consumption is associated with numerous health long-term benefits.
The question we ask today, however, is does caffeine uniquely affect women’s hormones and menstrual cycle?
I have to thank my colleague Ayman Subhani (@livingwellwithaymen) for encouraging me to explore this intriguing topic.
With that said, let’s get right into the good stuff.
Caffeine & Women’s Health – Is There A Unique Connection?
I want to preface today’s content with a reminder that the Public Health Agency Of Canada recommends caffeine intake during pregnancy to be no greater than 300mg daily whereas the American College Of Obstetricians and Gynecologists recommends an even lower target of 200mg .
These caffeine limits for pregnant woman are also supported by the WHO and European Food Safety Authority.
The average cup of coffee contains close to 100mg of caffeine, depending on source.
If you are or trying to become pregnant, I’d recommend speaking to your healthcare team about your caffeine intake if you have any lingering uncertainties.
With that said, let’s look towards the best available scientific evidence regarding caffeine intake and women’s health, particularly around fertility & menstruation.
Caffeine & Fertility
We’ll start back in 1999, when the American Journal Of Epidemiology surveyed 400 women about their caffeine intake and menstrual cycle characteristics.
They found that a women’s caffeine intake was not strongly related to the risk of anovulation (when an egg does not release from the ovary during menses, a leading contributor to infertility.).
In 2009, the Epidemiology journal followed 18,000+ married women as they attempted to become pregnant over an 8 year period and found that total caffeine intake was not related to the risk of ovulatory disorder infertility (among the most common cause of infertility in women).
They did note, however, that the intake specifically of soft drinks (all types) was positively related to this type of infertility and women with highest consumption of these products had a higher infertility risk.
These findings align with a 2010 study out of the American Journal Of Epidemiology looking at sperm health in males which found soda intake >7 litres weekly was associated with reductions in sperm count and quality.
Finally, A 2017 systematic review and meta-analysis also out of the Epidemiology journal found no association between coffee or caffeine intake and the likelihood of getting pregnant whether naturally or via fertility treatments.
Caffeine, Hormones & Menstruation
In 2016 the American Journal Of Clinical Nutrition explored whether caffeine intake was correlated with hormone levels and anovulation risk in 250+ premenopausal women.
They found that, when compared to the lowest caffeine consumers, women who consumed the most caffeine in this population group tended to have lower testosterone levels and were least likely to experience anovulation, providing some suggestion that caffeine intake may contribute positively to menstrual function in premenopausal women.
As it relates to premenstrual syndrome (PMS), the picture is slightly less clear.
Recommendations by reputable organizations generally recommend avoiding caffeine entirely for those who hope to minimize PMS symptoms.
However, a 2016 prospective study out of the American Journal Of Clinical Nutrition looking at the caffeine habits of nearly 2500 women found that caffeine intake patterns were not associated with the presence, symptoms or severity of PMS.
While neither study presented here is conclusive by any stretch, there is at least an indication towards the notion that caffeine intake is not, by default, explicitly detrimental to a women’s menstrual cycle.
This is an extremely complicated subject matter where conventionally shared knowledge and the latest scientific evidence are somewhat at odds.
I don’t pretend by any stretch to have offered definitive answers in today’s post, but certainly there are details within that help shape our understanding of the interaction between caffeine in its various forms and subject matter that are uniquely relevant to women’s health.
There were many studies and layers of evidence out there that fell just beyond the scope of this content, and I encourage you to explore it further if your scientific interest takes you in that direction.
Until next time,
Andy De Santis RD MPH
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