Effects of alcohol consumption on plasma and urinary hormone concentrations in premenopausal women.
Level 2 - randomized trial
Randomized controlled crossover trial
PubMed 8478958 · doi:10.1093/jnci/85.9.722
What was done
In a controlled-diet crossover study lasting six consecutive menstrual cycles, 34 premenopausal women aged 21–40 years with regular menstrual cycles were randomized to consume 30 g of ethanol daily (approximately two drinks) for three cycles and no alcohol for three cycles, in crossover fashion. All food and alcohol were provided to maintain stable baseline body weight. Hormones were measured in pooled plasma or 24-hour urine samples collected during the follicular (days 5–7), peri-ovulatory (days 12–15), and mid-luteal (days 21–23) phases of the third cycle in each diet condition.
What was found
Alcohol intake was associated with significant hormonal increases compared to the alcohol-free period. In the follicular phase, plasma dehydroepiandrosterone sulfate rose 7.0% (P = .05). In the peri-ovulatory phase, plasma estrone increased 21.2% (P = .01), plasma estradiol increased 27.5% (P = .01), and urinary estradiol increased 31.9% (P = .009). In the luteal phase, urinary estrone increased 15.2% (P = .05), urinary estradiol increased 21.6% (P = .02), and urinary estriol increased 29.1% (P = .03). The percentage of bioavailable estradiol did not change, but absolute bioavailable estradiol was elevated due to higher total estradiol.
Why it matters
This controlled trial experimentally demonstrates that moderate alcohol intake increases circulating and urinary estrogens in premenopausal women, providing a plausible biological mechanism for the link between alcohol intake and breast cancer risk.
Limits
The study was limited to 34 healthy premenopausal women and tested only a single daily ethanol dose (30 g) under strictly controlled feeding conditions. The abstract does not evaluate breast tissue changes, long-term disease outcomes, or washout dynamics between phases.
Cited by
- supports Daily consumption of 30 grams of alcohol elevates DHEAS in the follicular phase, estrone and estradiol in the periovulatory phase, and estrone, estradiol, and estriol in the luteal phase in women.