Breath hydrogen produced by ingestion of commercial hydrogen water and milk

Novel Role of Molecular Hydrogen: The End of Ophthalmic Diseases?

Molecular hydrogen (H2) is a colorless, odorless, and tasteless gas which displays non-toxic features at high concentrations. H2 can alleviate oxidative damage, reduce inflammatory reactions and inhibit apoptosis cascades, thereby inducing protective and repairing effects on cells. H2 can be transported into the body in the form of H2 gas, hydrogen-rich water (HRW), hydrogen-rich saline (HRS) or H2 produced by intestinal bacteria. Accumulating evidence suggest that H2 is protective against multiple ophthalmic diseases, including cataracts, dry eye disease, diabetic retinopathy (DR) and other fields. In particular, H2 has been tested in the treatment of dry eye disease and corneal endothelial injury in clinical practice. This medical gas has brought hope to patients suffering from blindness. Although H2 has demonstrated promising therapeutic potentials and broad application prospects, further large-scale studies involving more patients are still needed to determine its optimal application mode and dosage. In this paper, we have reviewed the basic characteristics of H2, and its therapeutic effects in ophthalmic diseases. We also focus on the latest progress in the administration approaches and mechanisms underlying these benefits.

Effects of Intestinal Bacterial Hydrogen Gas Production on Muscle Recovery following Intense Exercise in Adult Men: A Pilot Study

This study aimed to examine the effects of hydrogen gas (H₂) produced by intestinal microbiota on participant conditioning to prevent intense exercise-induced damage. In this double-blind, randomized, crossover study, participants ingested H₂-producing milk that induced intestinal bacterial H₂ production or a placebo on the trial day, 4 h before performing an intense exercise at 75% maximal oxygen uptake for 60 min. Blood marker levels and respiratory variables were measured before, during, and after exercise. Visual analog scale scores of general and lower limb muscle soreness evaluated were 3.8- and 2.3-fold higher, respectively, on the morning after treatment than that before treatment during the placebo trial, but not during the test beverage consumption. Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) concentrations and production rates significantly increased with placebo consumption; no changes were observed with test beverage consumption. After exercise, relative blood lactate levels with H₂-producing milk consumption were lower than those with placebo consumption. A negative correlation was observed between the variation of 8-OHdG and the area under the curve (AUC) of breath H₂ concentrations. Lipid oxidation AUC was 1.3-fold higher significantly with H₂-producing milk than with placebo consumption. Conclusively, activating intestinal bacterial H₂ production by consuming a specific beverage may be a new strategy for promoting recovery and conditioning in athletes frequently performing intense exercises.

Molecular Hydrogen Mitigates Performance Decrement during Repeated Sprints in Professional Soccer Players

Hydrogen-rich water (HRW) supplementation has been shown to have an antifatigue effect across different modes of exercise. However, its effect on repeated sprint performance is unknown. The aim of this study was to assess the effect of pre-exercise HRW consumption on repeated sprint performance, lactate, and perceptual responses using a repeated sprint protocol. This randomized, double blinded, placebo controlled, crossover study included 16 professional, male soccer players aged 18.8 ± 1.2 years. Athletes performed two indoor tests, particularly 15 × 30 m track sprints interspersed by 20 s of recovery, separated by a 1-week washout period. Sprint time was measured at 15 m and 30 m. Ratings of perceived exertion were assessed immediately after each sprint, and post-exercise blood lactate concentration was measured after the last sprint. There were significantly faster sprint times after HRW consumption compared with placebo at 15 m for the 14th and 15th sprints, representing improvements in time of 3.4% and 2.7%, respectively. Sprint time at 30 m also significantly improved by 1.9% in the HRW group in the last sprint. However, neither lactate concentrations nor ratings of perceived exertion were significantly different between HRW and placebo. Pre-exercise HRW supplementation is associated with an increased ability to reduce fatigue, especially during the later stages of repeated sprint exercise.

Combating Oxidative Stress and Inflammation in COVID-19 by Molecular Hydrogen Therapy: Mechanisms and Perspectives

COVID-19 is a widespread global pandemic with nearly 185 million confirmed cases and about four million deaths. It is caused by an infection with the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), which primarily affects the alveolar type II pneumocytes. The infection induces pathological responses including increased inflammation, oxidative stress, and apoptosis. This situation results in impaired gas exchange, hypoxia, and other sequelae that lead to multisystem organ failure and death. As summarized in this article, many interventions and therapeutics have been proposed and investigated to combat the viral infection-induced inflammation and oxidative stress that contributes to the etiology and pathogenesis of COVID-19. However, these methods have not significantly improved treatment outcomes. This may partly be attributable to their inability at restoring redox and inflammatory homeostasis, for which molecular hydrogen (H2), an emerging novel medical gas, may complement. Herein, we systematically review the antioxidative, anti-inflammatory, and antiapoptotic mechanisms of H2. Its small molecular size and nonpolarity allow H2 to rapidly diffuse through cell membranes and penetrate cellular organelles. H2 has been demonstrated to suppress NF-κB inflammatory signaling and induce the Nrf2/Keap1 antioxidant pathway, as well as to improve mitochondrial function and enhance cellular bioenergetics. Many preclinical and clinical studies have demonstrated the beneficial effects of H2 in varying diseases, including COVID-19. However, the exact mechanisms, primary modes of action, and its true clinical effects remain to be delineated and verified. Accordingly, additional mechanistic and clinical research into this novel medical gas to combat COVID-19 complications is warranted.

Randomized, crossover clinical efficacy trial in humans and mice on tear secretion promotion and lacrimal gland protection by molecular hydrogen

The incidence of dry eye disease is increasing worldwide because of the aging population and increasing use of information technology. Dry eye disease manifests as tear-layer instability and inflammation caused by osmotic hypersensitization in tear fluids; however, to our knowledge, no agent that treats both pathologies simultaneously is available. Molecular hydrogen (H₂) is known to be effective against various diseases; therefore, we aimed to elucidate the effects of H₂ on tear dynamics and the treatment of dry eye disease. We revealed that administering a persistent H₂-generating supplement increased the human exhaled H₂ concentration (p < 0.01) and improved tear stability (p < 0.01) and dry eye symptoms (p < 0.05) significantly. Furthermore, H₂ significantly increased tear secretion in healthy mice (p < 0.05) and significantly suppressed tear reduction in a murine dry eye model (p = 0.007). H₂ significantly and safely improved tear stability and dry eye symptoms in a small exploratory group of 10 human subjects, a subset of whom reported dry eye symptoms prior to treatment. Furthermore, it increased tear secretion rapidly in normal mice. Therefore, H₂ may be a safe and effective new treatment for dry eye disease and thus larger trials are warranted.

Hydrogen-Generating Silica Material Prevents UVA-ray-Induced Cellular Oxidative Stress, Cell Death, Collagen Loss and Melanogenesis in Human Cells and 3D Skin Equivalents

Ultraviolet-A (UVA) irradiation induces harmful effects on skin cells and accelerates skin aging through oxidative stress. In this study, the effects of a hydrogen-generating silica material named ULH-002 against UVA injuries in human cells and 3D skin equivalents were investigated. The oxygen radical absorption capacity (ORAC) assay showed that both freshly prepared ULH-002 solutions and 7-day-old solutions exhibited equal peroxyl radical (ROO·) scavenging activities concentration-dependently. CellROX^® green/orange staining showed that ULH-002 could reduce UVA-induced oxidative stress in human keratinocytes HaCaT and human gingival fibroblasts (HGFs). ULH-002 significantly prevented UVA-induced apoptotic/necrotic cell death and cell-viability decline in HGFs and keratinocytes, as shown by Annexin V/PI apoptosis assay and PrestoBlue assay, respectively. Immunostaining showed that ULH-002 prevented the UVA-induced deterioration of expression of both type IV and I collagens in the 3D skin equivalents, and similarly in monolayer HGFs. UVA-enhanced melanogenesis was observed in human melanocytes HMV-II and HMV-II cell-containing 3D skin equivalents, but markedly prevented by ULH-002 as demonstrated by Fontana–Masson’s staining. In conclusion, our data suggested that ULH-002 could protect human keratinocytes and fibroblasts from UVA-induced injuries, prevent the loss of type IV and I collagens, as well as reduce melanogenesis. ULH-002 might be developed as a skin care reagent in the cosmetic industry.

Acute ingestion of hydrogen-rich water does not improve incremental treadmill running performance in endurance-trained athletes

There is emerging evidence that hydrogen-rich water (H2-water) has beneficial effects on the physiological responses to exercise. However, few studies investigate its ergogenic potential. This randomized controlled trial examined the effects of H2-water ingestion on physiological responses and exercise performance during incremental treadmill running. In a double-blind crossover design, 14 endurance-trained male runners (age, 34 ± 4 years; body mass, 63.1 ± 7.2 kg; height, 1.72 ± 0.05 m) were randomly assigned to ingest 2 doses of 290-mL H2-water or placebo on each occasion. The first bolus was given before six 4-min submaximal running bouts, and the second bolus was consumed before the maximal incremental running test. Expired gas, heart rate (HR), and ratings of perceived exertion (RPE) were recorded; blood samples were collected at the end of each submaximal stage and post maximal running test. Cardiorespiratory responses, RPE, and blood gas indices were not significantly different at each submaximal running intensity (range: 34%–91% maximal oxygen uptake) between H2-water and placebo trials. No statistical difference was observed in running time to exhaustion (618 ± 126 vs. 619 ± 113 s), maximal oxygen uptake (56.9 ± 4.4 vs. 57.1 ± 4.7 mL·kg−1·min−1), maximal HR (184 ± 7 vs. 184 ± 7 beat·min−1), and RPE (19 ± 1 vs. 19 ± 1) in the runners between the trials. The results suggest that the ingestion of 290 mL of H2-water before submaximal treadmill running and an additional dose before the subsequent incremental running to exhaustion were not sufficiently ergogenic in endurance-trained athletes.

Novelty Acute ingestion of H2-water does not seem to be ergogenic for endurance performance. A small dose of H2-water does not modulate buffering capacity during intense endurance exercise in athletes.

Hydrogen-producing milk to prevent reduction in tear stability in persons using visual display terminals

PURPOSE

To examine the effect of hydrogen (H₂)-producing milk, which induces H₂ production by intestinal microbiota, on the prevention of dry eye disease.

METHODS

A randomized, double-blind, placebo-controlled, parallel-group comparative study was conducted in humans. Of 118 candidates aged 20-60 years who were using visual display terminals daily, 54 subjects (mean age, 42.4 years) with mild-to-moderate dry eye symptoms, who were not dry eye patients based on the 2006 Japanese Diagnostic Criteria for Dry Eye, were included in the study. Subjects were assigned to the H₂-producing milk group or the placebo group. They were instructed to ingest the assigned test beverage once per day for three consecutive weeks. Breath H₂ concentration, fluorescein tear film breakup time (fTBUT), Schirmer's test, 8-OHdG concentration in tears, reported ocular symptoms using the dry eye-related QOL score questionnaire, and the visual analogue scale were assessed at weeks 0 and 3.

RESULTS

Change in fTBUT in the H₂-producing milk group was significantly greater than that in the placebo group. A significant decline in fTBUT was observed in the placebo group (p = 0.04), but not the H₂-producing group (p = 0.26). This phenomenon was strongly observed in females. We found a positive correlation between the change in fTBUT and net H₂ production, and a negative correlation between the change in 8-OHdG concentration and net H₂ production in young females.

CONCLUSIONS

H₂-producing milk appeared to retard the decline in tear stability and may prevent short fTBUT-type dry eye by decreasing oxidative stress in the lacrimal functional unit.

Mixed-Potential Gas Sensors Using an Electrolyte Consisting of Zinc Phosphate Glass and Benzimidazole

Mixed-potential gas sensors with a proton conductor consisting of zinc metaphosphate glass and benzimidazole were fabricated for the detection of hydrogen produced by intestinal bacteria in dry and humid air. The gas sensor consisting of an alumina substrate with platinum and gold electrodes showed good response to different hydrogen concentrations from 250 parts per million (ppm) to 25,000 ppm in dry and humid air at 100-130 °C. The sensor response varied linearly with the hydrogen and carbon monoxide concentrations due to mass transport limitations. The sensor responses to hydrogen gas (e.g., -0.613 mV to 1000 ppm H₂) was higher than those to carbon monoxide gas (e.g., -0.128 mV to 1000 ppm CO) at 120 °C under atmosphere with the same level of humidity as expired air.

Hydrogen resuscitation, a new cytoprotective approach

1. Hydrogen is a colourless, odourless, tasteless and flammable gas. Hydrogen is considered a physiologically inert gas and is often used in deep sea diving medicine. In mammals, endogenous hydrogen is produced as a result of the fermentation of non-digestible carbohydrates by intestinal bacteria and it is absorbed into the systemic circulation. 2. Recent evidence indicates that hydrogen is a potent anti-oxidative, anti-apoptotic and anti-inflammatory agent and so may have potential medical application. The present review evaluates the concept of 'hydrogen resuscitation', based on knowledge that hydrogen treatment effectively protects cells, tissues and organs against oxidative injury and helps them recover from dysfunction. 3. Hydrogen therapy can be delivered by inhalation, the administration of hydrogen-enriched fluid or by approaches that affect endogenous hydrogen production. 4. Studies have shown that hydrogen resuscitation has cytoprotective effects in different cell types and disease models, including ischaemia-reperfusion injury, inflammation, toxicity, trauma and metabolic disease. The underlying mechanism may be the selective elimination of hydroxyl radicals, although other mechanisms may also be involved (e.g. hydrogen functioning as a gaseous signalling molecule). 5. Hydrogen resuscitation may have several potential advantages over current pharmacological therapies for oxidative injuries. However, more work is needed to identify the precise mechanism underlying the actions of hydrogen and to validate its therapeutic potential in the clinical setting.

Medical applications of breath hydrogen measurements

In this article, technical developments in breath analysis and its applications in the field of clinical diagnosis and the monitoring of various symptoms, particularly molecular hydrogen in breath, are introduced. First, a brief overview of the current uses of the hydrogen breath test is provided. The principles of the test and how hydrogen can be used as a biomarker for various symptoms, and monitoring microbial metabolism, are introduced. Ten case-study applications of breath hydrogen measurements for which hydrogen exhibits beneficial effects for diagnosis, including the contexts of oxidative stress, gastrointestinal disease, and metabolic disorders, are discussed. The technologies and problems involved in breath hydrogen testing, sampling, pretreatment, and detection in exhaled breath are discussed, and research including current analytical systems and new sensors is focused on in the context of hydrogen detection.

Pilot study: Effects of drinking hydrogen-rich water on muscle fatigue caused by acute exercise in elite athletes

Background

Muscle contraction during short intervals of intense exercise causes oxidative stress, which can play a role in the development of overtraining symptoms, including increased fatigue, resulting in muscle microinjury or inflammation. Recently it has been said that hydrogen can function as antioxidant, so we investigated the effect of hydrogen-rich water (HW) on oxidative stress and muscle fatigue in response to acute exercise.

Methods

Ten male soccer players aged 20.9 ± 1.3 years old were subjected to exercise tests and blood sampling. Each subject was examined twice in a crossover double-blind manner; they were given either HW or placebo water (PW) for one week intervals. Subjects were requested to use a cycle ergometer at a 75 % maximal oxygen uptake (VO₂) for 30 min, followed by measurement of peak torque and muscle activity throughout 100 repetitions of maximal isokinetic knee extension. Oxidative stress markers and creatine kinase in the peripheral blood were sequentially measured.

Results

Although acute exercise resulted in an increase in blood lactate levels in the subjects given PW, oral intake of HW prevented an elevation of blood lactate during heavy exercise. Peak torque of PW significantly decreased during maximal isokinetic knee extension, suggesting muscle fatigue, but peak torque of HW didn’t decrease at early phase. There was no significant change in blood oxidative injury markers (d-ROMs and BAP) or creatine kinease after exercise.

Conclusion

Adequate hydration with hydrogen-rich water pre-exercise reduced blood lactate levels and improved exercise-induced decline of muscle function. Although further studies to elucidate the exact mechanisms and the benefits are needed to be confirmed in larger series of studies, these preliminary results may suggest that HW may be suitable hydration for athletes.

Drinking hydrogen water and intermittent hydrogen gas exposure, but not lactulose or continuous hydrogen gas exposure, prevent 6-hydorxydopamine-induced Parkinson's disease in rats

Background

Lactulose is a synthetic disaccharide that can be catalyzed only by intestinal bacteria in humans and rodents, and a large amount of hydrogen is produced by bacterial catalysis of lactulose. We previously reported marked effects of ad libitum administration of hydrogen water on prevention of a rat model of Parkinson’s disease (PD).

Methods

End-alveolar breath hydrogen concentrations were measured in 28 healthy subjects and 37 PD patients, as well as in 9 rats after taking hydrogen water or lactulose. Six-hydroxydopamine (6-OHDA)-induced hemi-PD model was stereotactically generated in rats. We compared effects of hydrogen water and lactulose on prevention of PD. We also analyzed effects of continuous and intermittent administration of 2% hydrogen gas.

Results

Hydrogen water increased breath hydrogen concentrations from 8.6 ± 2.1 to 32.6 ± 3.3 ppm (mean and SEM, n = 8) in 10 min in healthy subjects. Lactulose increased breath hydrogen concentrations in 86% of healthy subjects and 59% of PD patients. Compared to monophasic hydrogen increases in 71% of healthy subjects, 32% and 41% of PD patients showed biphasic and no increases, respectively. Lactulose also increased breath hydrogen levels monophasically in 9 rats. Lactulose, however, marginally ameliorated 6-OHDA-induced PD in rats. Continuous administration of 2% hydrogen gas similarly had marginal effects. On the other hand, intermittent administration of 2% hydrogen gas prevented PD in 4 of 6 rats.

Conclusions

Lack of dose responses of hydrogen and the presence of favorable effects with hydrogen water and intermittent hydrogen gas suggest that signal modulating activities of hydrogen are likely to be instrumental in exerting a protective effect against PD.

Hydrogen-rich electrolyzed warm water represses wrinkle formation against UVA ray together with type-I collagen production and oxidative-stress diminishment in fibroblasts and cell-injury prevention in keratinocytes

Hydrogen-rich electrolyzed warm water (HW) was prepared at 41°C and exhibited dissolved hydrogen (DH) of 1.13 ppm and an oxidation-reduction potential (ORP) of -741 mV in contrast to below 0.01 ppm and+184 mV for regular warm water (RW). Fibroblasts OUMS-36 and keratinocytes HaCaT were used to examine effects of HW against UVA-ray irradiation. Type-I collagen was synthesized 1.85- to 2.03-fold more abundantly by HW application for 3-5 days than RW in OUMS-36 fibroblasts, and localized preferentially around the nuclei as shown by immunostain. HW application significantly prevented cell death and DNA damages such as nuclear condensation and fragmentation in UVA-irradiated HaCaT keratinocytes as estimated by WST-1 and Hoechst 33342 assays. HW significantly suppressed UVA-induced generation of intracellular superoxide anion radicals in both the cell lines according to NBT assay. Wrinkle repression was clinically assessed using a HW-bathing. Six Japanese subjects were enrolled in a trial of HW-bathing (DH, 0.2-0.4 ppm) every day for 3 months. HW-bathing significantly improved wrinkle in four subjects on the back of neck on 90th day as compared to 0 day. Thus, HW may serve as daily skin care to repress UVA-induced skin damages by ROS-scavenging and promotion of type-I collagen synthesis in dermis.