Effects of glucoraphanin-rich broccoli sprout extracts on sleep quality in healthy adults: An exploratory study

[Display omitted] •Sulforaphane may potentially improve quality of sleep.•Sulforaphane increases melatonin production, which may enhance quality of sleep.•Sulforaphane decreases prostaglandin D2 levels, which causes inflammation.•Sulforaphane may improve sleep by increasing melatonin and anti-inflammation. Increased oxidative stress and inflammation cause abnormal sleep regulation. Sulforaphane, which is derived from glucoraphanin, has antioxidant and anti-inflammatory effects; however, its effects on sleep are unknown. Therefore, a randomized, double-blind, parallel-group, placebo-controlled study was conducted to explore the effects of sulforaphane on sleep quality. Eighteen healthy adults who reported poor sleep quality consumed broccoli sprout capsules (30 mg glucoraphanin) or placebo capsules for 4 weeks. The visual analogue scale questionnaire on sleep quality (4.8 ± 1.6 vs. 6.4 ± 1.9) and area under the curve of melatonin concentration (109.7 ± 80.0 pg/mL・h vs. 143.5 ± 79.9 pg/mL・h) were significantly increased and prostaglandin D2 levels at 21:00 (44.2 ± 24.6 pg/mL vs. 20.2 ± 15.5 pg/mL) were significantly decreased in the sulforaphane group, although there were no significant differences between the groups. These suggest that sulforaphane may improve sleep quality by increasing melatonin and anti-inflammatory activity.