Figure 1.

Dietary zinc improves sleep quality in humans and increases NREM sleep in mice. (A) Two groups of 30 volunteers absorbed daily 15 mg of zinc (in 40 g of Pacific oysters) or placebo (40 g of scallops). After 12 weeks of supplementation, sleep efficiency and sleep onset latency improved in the group treated with zinc compared to the control group. (B) Oral administration of zinc-containing yeast extract (80 mg/kg) in mice at the onset of dark time increased the amount of NREM sleep for 6 h compared to mice receiving vehicle. * p < 0.05, ** p < 0.01, *** p < 0.001 compared with vehicle treatment.