The Effects of 12-Week Hydrogen-Rich Water Intake on Body Composition, Short-Chain Fatty Acids Turnover, and Brain Metabolism in Overweight Adults: A Randomized Controlled Trial

The aim of this randomized controlled trial was to analyze the effects of medium-term supplementation with hydrogen-rich water on brain metabolism, appetite-regulating hormones, body composition, and safety biomarkers in overweight adults. Twenty (n = 20, 10 females) apparently healthy adults with a body mass index >24.9 kg/m2 were assigned to receive 0.5 L per day of hydrogen-rich water (7.5 mg of hydrogen) or hydrogen-free water (tap water) for 12 weeks. Two-way analysis of variance with repeated measures revealed a significant difference between the two interventions in several body composition indices (P ≤ 0.05), with hydrogen-rich water superior to placebo to reduce waist circumference and mid-upper arm circumference by 1.31 cm (95% confidence interval, from –0.23 to 2.85) and 0.65 cm (95% confidence interval, from –0.10 to 1.40), respectively. Hydrogen-rich water outcompeted placebo to raise serum ghrelin levels, as the mean difference from the placebo group was 17.28 pmol/L (95% confidence interval, from 1.81 to 32.75) (P = 0.02). A non-significant strong positive trend (P = 0.10) was reported toward hydrogen-rich water being superior to placebo in augmenting total serum short-chain fatty acid levels, with a mean difference from the control group of 195.6 μmol/L (95% confidence interval, from –64.55 to 275.85). The mean fecal calprotectin levels were significantly reduced after hydrogen-rich water intervention for 19.7 μg/mg (95% confidence interval, from 0.31 to 39.09) (P = 0.03). Our findings advance hydrogen-rich water as a promising metabolic intervention in overweight adults, but further validation via multicentric longitudinal randomized controlled trials in metabolic and nutritional disorders is required.