How does zinc-rich food promotes sleep: a role for Gut-Brain Axis?

2022 Fiscal Year Research-status Report

• Project/Area Number: 22K05506
• Research Institution: University of Tsukuba
• Principal Investigator: シェラス ヨアン 筑波大学, 医学医療系, 研究員 (60544319)
• Project Period (FY): 2022-04-01 – 2025-03-31
• Keywords: sleep / zinc / gut-brain axis

Outline of Annual Research Achievements

A lack of sleep is associated with long-term health consequences (diabetes, high blood pressure, heart disease) and these conditions may lead to a shortened life expectancy. We recently identified Zinc as a powerful modulator of sleep. Zinc-containing food dose dependently increased the total amount of non-rapid eye movement (NREM) sleep in mice and in humans. This is the first evidence ever published that zinc can actually modulate sleep (Cherasse et al., Mol. Nutr. Food Res., 2015). In addition, we also found that Japanese people with low serum zinc concentration sleeps poorly. In a randomized controlled trial, we produced evidence that chronically absorbing a proper amount of zinc has beneficial effects on Japanese citizen’s sleep (Saito, Cherasse et al., Mol. Nutr. Food. Res., 2017).

Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

Sleep is so essential to every animal on Earth (including humans) that a complete sleep deprivation is leading to a quick death. The elementary mechanism regulating sleep (which remains unknown) must be very simple and present in every organism, therefore we hypothesize that zinc may be that sleep “master regulator”. We designed a zinc-deficient diet which allows us to manipulate zinc concentration in the blood of mice without affecting the body weight or global health of the animal. By using this diet, we evaluated the effects of a zinc deprivation on sleep and general health in mammals. We successfully depleted zinc concentration in the blood serum of our sample mice and observed the effects on sleep and locomotion.

Strategy for Future Research Activity

With a daily absorption of 8.3mg/day of zinc, the Japanese population barely meets with the zinc intake international recommendations (8mg/day for women, 11mg/day for men). We plan to develop an optimized formula for food supplement that would drastically improve zinc bioavailability. We will first measure the kinetic of mouse serum zinc concentration and sleep after supplementation of a fixed amount of zinc (40mg/kg body weight) from different inorganic sources and select the most potent source. Then, we will combine a fixed dose of the most potent inorganic zinc with several cofactors and determine which molecules improve zinc-induced sleep.