Regulation of energy expenditure by estradiol in premenopausal women.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 26338457 · doi:10.1152/japplphysiol.00473.2015
What was done
Premenopausal women underwent five months of ovarian hormone suppression using a gonadotropin-releasing hormone agonist (leuprolide acetate, 3.75 mg/month) and were randomized to transdermal estradiol (0.075 mg/day, n = 24, mean age 37 years, mean BMI 27.3 kg/m²) or transdermal placebo (n = 21, mean age 34 years, mean BMI 26.8 kg/m²). Resting energy expenditure was measured by metabolic cart. Whole-room indirect calorimetry was used to measure total energy expenditure, sleep energy expenditure, exercise energy expenditure during bench stepping, non-exercise energy expenditure, and the thermic effect of feeding.
What was found
Resting energy expenditure decreased in the placebo group [mean (95% CI), -54 (-98, -15) kcal/d] but not in the estradiol group [+6 (-33, +45) kcal/d], with a statistically significant difference in between-group changes (P < 0.05). Total energy expenditure decreased in both placebo [-128 (-214, -41) kcal/d] and estradiol [-96 (-159, -32) kcal/d] groups, with no significant difference between groups (P = 0.55). Sleep energy expenditure decreased identically in both groups [-0.07 kcal/min]. Exercise energy expenditure decreased in the placebo group [-0.46 (-0.79, -0.13) kcal/min], but not significantly in the estradiol group [-0.30 (-0.65, +0.06) kcal/min]. There were no changes in the thermic effect of feeding or non-exercise energy expenditure in either group.
Why it matters
This study demonstrates that estradiol specifically maintains resting metabolic rate in women, helping explain the reduction in resting energy expenditure that accompanies sex hormone deficiency.
Limits
The sample size is small (45 participants total). The pharmacologic suppression model (GnRH agonist) induces rapid and severe hormone withdrawal, which may not fully reflect the gradual transition of natural menopause. The abstract does not report blinding status, adherence, or body composition changes.
Cited by
- supports Replacing low estrogen can increase energy expenditure by approximately 100 calories per day.