A recent study published in the journal Nutrients investigates the association between coffee consumption and polycystic ovarian syndrome (PCOS) in women.

Study: Association between Coffee Consumption and Polycystic Ovary Syndrome: An Exploratory Case–Control Study. Image Credit: Daria Aleshina / Shutterstock.com

PCOS: Symptoms, Prevalence and Treatment

Women with PCOS often suffer from dysfunctional gonadotropin hormonal synthesis that leads to ovulatory problems. PCOS also triggers psychological and metabolic disorders, such as cardiovascular disease, type 2 diabetes, obesity, insulin resistance, gut microbiota dysbiosis, eating disorders, anxiety, and depression.

Recently, a United Kingdom-based study reported that 26% of PCOS patients develop diabetes, which significantly increases costs to the National Health System (NHS). Healthcare-related costs have similarly increased within the U.S. to $15 billion USD each year due to PCOS.

Due to differential diagnostic criteria, the global prevalence of PCOS is difficult to estimate. For example, the PCOS incidence rate in Spain is between 5% and 10%, whereas the global prevalence of this condition has been estimated to affect up to 15% of women of reproductive age. An increasing PCOS incidence trend has been recorded in Western countries.

The etiopathogenesis of PCOS is multifactorial and includes genetic, environmental, and epigenetic factors. One previous study indicated that women diagnosed with PCOS generally consume a low-quality diet, with lower magnesium and zinc intake than recommended levels, and are engaged in a sedentary lifestyle.

Lifestyle-based interventions, such as diet and exercise, have been shown to effectively improve PCOS symptoms. More specifically, a low-carbohydrate diet intervention can reduce glucose and insulin-like growth factor-binding protein 1 (IGFBP1) levels and improve hyperandrogenism-related symptoms.

Previous studies have indicated that coffee consumption improves PCOS symptoms through several pathways. Coffee contains high phenol levels that improve insulin sensitivity and alleviate hypersecretion. Reduced expression of the phosphatidylinositol 3-kinase (PI3K) pathway also decreases insulin sensitivity and improves β-cell function.

About the study

The current case-control study was conducted between September 2014 and May 2016 at the Department of Obstetrics and Gynaecology of the University Clinical Hospital in Spain. Both clinical and biochemical tests were considered for PCOS diagnosis, including total testosterone levels of 2.6 nmol/L or more indicative of hyperandrogenism (HA), ultrasound images to confirm the presence of polycystic ovarian morphology (PCOM) and oligo-anovulation/amenorrhea or anovulation (OD) tests.

Each PCOS patient represented one of the four phenotypes. Phenotype A consists of patients with HA, OD, and PCOM, whereas phenotype B comprises patients with HA and OD. Moreover, Phenotype C comprises patients with HA and PCOM, whereas phenotype D includes patients with OD and PCOM.

Phenotypes A and B are more likely to be associated with type 2 diabetes (T2DM), hyperinsulinemia, obesity, insulin resistance, dyslipidemia, or metabolic syndrome. Phenotypes A, B, and D were reclassified as anovulatory phenotypes, phenotype C as an ovulatory phenotype, and phenotypes A, B, and C as hyperandrogenic phenotypes.

Daily caffeine and alcohol intake was assessed through a semi-quantitative food frequency questionnaire (FFQ). The dietary quality was estimated using the Alternate Healthy Eating Index 2010 (AHEI2010) and Dietary Approaches to Stop Hypertension (DASH). The level of physical activity in patients was estimated using the International Physical Activity Questionnaire (IPAQ-SF).

Study findings

The current study cohort included 126 patients diagnosed with PCOS and 159 controls. The control group consisted of women who visited the clinic for routine gynecological check-ups and had no gynecological symptoms.

The study cohort’s mean age and body mass index (BMI) were 29 years and 24.33, respectively. The mean caffeine intake of the study cohort was 52.46 mg/day.

Women with PCOS were relatively young, obese, and engaged in less vigorous physical exercise than those in the control group. Moreover, women in the control group consumed more caffeine and alcohol.

Consistent with previous findings, the current study revealed that consuming at least one cup of coffee daily reduces the risk of PCOS. Furthermore, study participants who consumed approximately two cups of coffee every day were at a 70% lower risk of developing PCOS symptoms than those who never drank coffee. Mechanistically, this protective role of coffee has been attributed to its effects on the metabolism of sex hormones like testosterone in the plasma.

Conclusions

The study findings indicate that coffee consumption reduces the risk of developing PCOS symptoms in a dose-dependent manner. Coffee contains an abundance of numerous bioactive compounds with anti-inflammatory activities, which may efficiently regulate plasma hormone levels and improve insulin sensitivity.

However, excessive caffeine consumption is also associated with the development of estrogen-dependent cancers. Therefore, additional studies are needed to confirm these observations and ensure the formulation of a safe and effective coffee-based intervention for PCOS.