Glucose ingestion acutely lowers pulsatile LH and basal testosterone secretion in men.
Level 2 - randomized trial
Randomized crossover trial in humans
PubMed 22252939 · doi:10.1152/ajpendo.00520.2011
What was done
A randomized crossover trial in 57 healthy men aged 19–78 years (BMI 20–39 kg/m²) evaluated luteinizing hormone (LH) and testosterone (T) secretion kinetics after oral glucose ingestion versus water ingestion. Blood was drawn every 10 minutes for deconvolution and LH-T dose-response modeling, with responses regressed against metabolic markers, age, BMI, and CT-estimated abdominal visceral fat.
What was found
During the first 120 minutes post-glucose ingestion, each unit decrease in LH concentration was associated with a decrease in T concentration of 86 (95% CI: 27–144) ng/dl (r = 0.853, P < 0.001). Based on deconvolution analysis, glucose compared to water ingestion reduced basal (nonpulsatile; P < 0.001) and total (P < 0.001) T secretion without altering pulsatile T output, and reduced pulsatile (P = 0.043) but not basal LH secretion. Pulsatile LH secretion positively predicted basal T secretion after glucose (r = 0.374, P = 0.0042). The fall in pulsatile LH was exacerbated by higher fasting insulin (P = 0.054) and attenuated by higher adiponectin (P = 0.0037). LH-T dose-response curves showed no detectable change (P > 0.30).
Why it matters
This study demonstrates that acute carbohydrate intake transiently suppresses the male gonadal axis at both the pituitary and testicular levels, clarifying that acute postprandial drops in testosterone reflect decreased pulsatile LH and basal secretion rather than altered Leydig cell responsiveness.
Limits
The study tested only pure glucose rather than mixed meals, evaluated acute effects over a short postprandial window, and included only healthy men without clinical hypogonadism or diabetes.
Cited by
- supports Consuming a high dose of sugar causes an acute drop in testosterone levels of 25%.