A prospective study of caffeine and coffee intake and premenstrual syndrome among more than 3,600 women by epidemiologists at the University of Massachusetts Amherst School of Public Health and Health Sciences found that caffeine intake is not associated with PMS, and current recommendations for women to reduce caffeine intake may not help prevent the development of PMS. Details appear in the current early online edition of the American Journal of Clinical Nutrition.
Lead author and PhD student Ms. Alexandra Purdue-Smithe, her advisor Dr. Elizabeth Bertone-Johnson, and colleagues point out, “The prospective design of our study and 14-year follow-up allowed us to assess whether caffeine and coffee intake could impact the initial development of PMS; to our knowledge, no other studies have addressed this question.”
[Photo: Ms. Alexandra Purdue Smith (Left), Dr. Elizabeth Bertone-Johnson (Right)]
The researchers explain that clinically significant premenstrual syndrome may include irritability, mood swings, anxiety, depression, bloating, food cravings, breast tenderness and difficulty concentrating. It affects 15-20 percent of premenopausal women and can substantially reduce quality of life. “Women with PMS often are counseled to minimize caffeine intake, although only limited evidence supports this recommendation,” they write.
In this study, they evaluated total caffeine intake and frequency of coffee and tea consumption with PMS in a subset of participants of the Nurses’ Health Study II (NHS2), taking into account a variety of potential confounders. “Because current medical recommendations are targeted particularly at women experiencing breast tenderness, we also evaluated whether total caffeine intake and coffee consumption were associated with three specific symptoms of PMS: breast tenderness, fatigue and irritability,” they add.
The team found that when adjusting only for age, higher caffeine intake was modestly but not significantly associated with PMS. But after adjusting for such variables as smoking, body mass index and other factors, they observed no increased odds of PMS or specific PMS symptoms such as breast tenderness, irritability or fatigue, “even among women reporting an intake of four or more cups of caffeinated coffee per day.”
Ms. Purdue-Smithe and colleagues note that their results are consistent with three earlier studies, but they conflict with four other small, retrospective studies upon which current medical recommendations are based. The authors propose that the differences in findings are due to previous studies not controlling for important confounders such as smoking, and from previous studies evaluating women who already developed PMS and may have altered their caffeine intake because of their symptoms.
They also point out that although a number of biologic mechanisms have been proposed to support an adverse impact of caffeine and coffee intake on PMS, including effects on vasoconstriction, a neurotransmitter and concentrations of estradiol and progesterone, epidemiologic evidence suggests that “caffeine and coffee intake is not associated with increased risk of adverse reproductive outcomes.” Further, “ample evidence indicates that moderate daily coffee intake is associated with lower risks of Type 2 diabetes, heart disease and all-cause mortality.”
“Overall, we did not find that women with high caffeine intake or who frequently drank coffee or tea were more likely to develop PMS, including PMS with symptoms such as breast tenderness,” says Ms. Purdue-Smithe. “Our results, in conjunction with those of other studies, suggest that current recommendations to reduce or eliminate caffeine to prevent PMS may be unnecessary.”
This work was supported by research grants from the National Institutes of Health.