Combination of tea catechins and ornithine effectively activates the urea cycle: an in vitro and human pilot study.

PURPOSE: Accumulation of ammonia causes central and peripheral fatigue. This study aimed to investigate the synergistic effect of tea catechins and low-dose ornithine in activating the urea cycle to reduce blood ammonia levels during exercise. METHODS: We used hepatocyte-like cells derived from human-induced pluripotent stem (iPS) cells to assess the effect of tea catechins combined with ornithine on urea cycle activity. The urea production and expression of key genes involved in the metabolism of urea were investigated. We then examined the synergistic improvement in ammonia metabolism by tea catechins in combination with ornithine in a human pilot study. RESULTS: Tea catechins combined with ornithine increased urea cycle activity in hepatocyte-like cells derived from human iPS cells. Intake of 538.6 mg of tea catechins with 1592 mg of ornithine for 2 consecutive days during exercise loading suppressed the exercise-induced increase in the blood ammonia concentration as well as stabilized blood glucose levels. CONCLUSION: Controlling the levels of ammonia, a toxic waste produced in the body, is important in a variety of situations, including exercise. The present study suggests that a heterogeneous combination of polyphenols and amino acids efficiently suppresses elevated ammonia during exercise in humans by a mechanism that includes urea cycle activation. TRIAL REGISTRATION: This study was registered in the University Hospital Medical Information Network Clinical Trial Registry (No. UMIN000035484, dated January 8, 2019).

Investigation of the Oral Retention of Tea Catechins in Humans: An Exploratory Interventional Study.

Green tea catechin ingestion or gargling exhibit anti-viral activity against upper respiratory infection. We hypothesized that retention in the oral cavity could improve the anti-viral effects of catechins. The present study investigated the oral retention of catechins in humans and the effect of catechin beverage viscosity on oral retention. Two intervention studies with different test beverages, beverage-C (40 mL, containing 73.4 mg of catechins) and beverage-XT (40 mL, beverage-C containing 100 mg xanthan gum) were conducted in 20 healthy volunteers (mean age 38.7 years). Catechin concentrations were measured in buccal mucosa samples collected at 10 min, 40 min, and 60 min after ingesting test beverages, and the catechin variability of the tissue after intake was compared between test beverages. As a result, the mean (SEM) concentrations of EGCG were 99.9 (27.2), 58.2 (16.6), and 22.3 (5.7) ng/mg-mucosa at 10, 40, and 60 min, respectively, after ingestion of beverage-XT. Similarly, the catechin concentrations were 86.1 (20.3), 32.2 (5.3), and 27.8 (5.9) ng/mg-mucosa after ingestion of beverage-C. The total retention volume over 60 min tended to be slightly higher after ingestion of beverage-XT, though the difference was not statistically significant. Additional studies are needed to confirm the effect of xanthan gum on improving oral retention of catechins.

The Impact of Milk Fat Globule Membrane with Exercise on Age-Related Degeneration of Neuromuscular Junctions.

Morphological changes in neuromuscular junctions (NMJs), which are synapses formed between α-motor neurons and skeletal muscle fibers, are considered to be important in age-related motor dysfunction. We have previously shown that the intake of dietary milk fat globule membrane (MFGM) combined with exercise attenuates age-related NMJ alterations in the early phase of aging. However, it is unclear whether the effect of MFGM with exercise on age-related NMJ alterations persists into old age, and whether intervention from old age is still effective when age-related changes in NMJs have already occurred. In this study, 6- or 18-month-old mice were treated with a 1% MFGM diet and daily running wheel exercise until 23 or 24 months of age, respectively. MFGM treatment with exercise was effective in suppressing the progression of age-related NMJ alterations in old age, and even after age-related changes in NMJs had already occurred. Moreover, the effect of MFGM intake with exercise was not restricted to NMJs but extended to the structure and function of peripheral nerves. This study demonstrates that MFGM intake with exercise may be a novel approach for improving motor function in the elderly by suppressing age-related NMJ alterations.

Involvement of ammonia metabolism in the improvement of endurance performance by tea catechins in mice.

Blood ammonia increases during exercise, and it has been suggested that this increase is both a central and peripheral fatigue factor. Although green tea catechins (GTCs) are known to improve exercise endurance by enhancing lipid metabolism in skeletal muscle, little is known about the relationship between ammonia metabolism and the endurance-improving effect of GTCs. Here, we examined how ammonia affects endurance capacity and how GTCs affect ammonia metabolism in vivo in mice and how GTCs affect mouse skeletal muscle and liver in vitro. In mice, blood ammonia concentration was significantly negatively correlated with exercise endurance capacity, and hyperammonaemia was found to decrease whole-body fat expenditure and fatty acid oxidation-related gene expression in skeletal muscle. Repeated ingestion of GTCs combined with regular exercise training improved endurance capacity and the expression of urea cycle-related genes in liver. In C2C12 myotubes, hyperammonaemia suppressed mitochondrial respiration; however, pre-incubation with GTCs rescued this suppression. Together, our results demonstrate that hyperammonaemia decreases both mitochondrial respiration in myotubes and whole-body aerobic metabolism. Thus, GTC-mediated increases in ammonia metabolism in liver and resistance to ammonia-induced suppression of mitochondrial respiration in skeletal muscle may underlie the endurance-improving effect of GTCs.

5-Caffeoylquinic Acid Ameliorates Cognitive Decline and Reduces Aß Deposition by Modulating Aß Clearance Pathways in APP/PS2 Transgenic Mice.

The accumulation of amyloid ß (Aß) in the brain is a major pathological feature of Alzheimer's disease (AD). In our previous study, we demonstrated that coffee polyphenols (CPP) prevent cognitive dysfunction and Aß deposition in the brain of an APP/PS2 transgenic mouse AD model. The underlying mechanisms, however, remain to be elucidated. Here, we investigated the effects of the chronic administration of 5-caffeoylquinic acid (5-CQA), the most abundant component of CPP, on cognitive dysfunction in APP/PS2 mice to identify the role of CPP in Aß elimination. Relative to the untreated controls, the mice fed a 5-CQA-supplemented diet showed significant improvements in their cognitive function assessed by Y-maze and novel object recognition tests. Histochemical analysis revealed that 5-CQA substantially reduced Aß plaque formation and neuronal loss in the hippocampi. Moreover, 5-CQA upregulated the gene encoding low-density lipoprotein receptor-related protein 1, an Aß efflux receptor, and normalized the perivascular localization of aquaporin 4, which facilitates Aß clearance along the paravascular pathway. These results suggest that 5-CQA reduces Aß deposition in the brain by modulating the Aß clearance pathways and ameliorating cognitive decline and neuronal loss in APP/PS2 mice. Thus, 5-CQA may be effective in preventing cognitive dysfunction in AD.

Coffee polyphenols prevent cognitive dysfunction and suppress amyloid ß plaques in APP/PS2 transgenic mouse.

Epidemiological studies have found that habitual coffee consumption may reduce the risk of Alzheimer's disease. Coffee contains numerous phenolic compounds (coffee polyphenols) such as chlorogenic acids. However, evidence demonstrating the contribution of chlorogenic acids to the prevention of cognitive dysfunction induced by Alzheimer's disease is limited. The present study investigated the effect of chlorogenic acids on the prevention of cognitive dysfunction in APP/PS2 transgenic mouse model of Alzheimer's disease. Five-week-old APP/PS2 mice were administered a diet supplemented with coffee polyphenols daily for 5 months. The memory and cognitive function of mice was determined using the novel object recognition test, Morris water maze test, and the step-through passive avoidance test. Immunohistochemical analysis revealed that chronic treatment with coffee polyphenols prevented cognitive dysfunction and significantly reduced the amount of amyloid ß (Aß) plaques in the hippocampus. Furthermore, we determined that 5-caffeoylquinic acid, one of the primary coffee polyphenols, did not inhibit Aß fibrillation; however, degraded Aß fibrils. In conclusion, our results demonstrate that coffee polyphenols prevent cognitive deficits and reduce Aß plaque deposition via disaggregation of Aß in the APP/PS2 mouse.

Continuous Supplementation of Milk Fat Globule Membrane with Habitual Exercise from a Young Age Improves Motor Coordination and Skeletal Muscle Function in Aged Mice.

Since the decline of physical performance gradually progresses with aging, continuous exercise with nutritional supplementation from a young age is a feasible and effective way to maintain a comfortable life until late old age. We examined the effects of continuous milk fat globule membrane (MFGM) supplementation combined with voluntary running exercise (VR) for prevention of aging-associated declines in physical performance in naturally aging mice. The MFGM with VR group showed a significantly attenuated age-related decline in motor coordination and suppression of the loss of muscle mass and strength. Compared with the control group, the MFGM with VR group showed significantly higher mRNA and protein expression for docking protein 7, which maintains neuromuscular junction (NMJ) integrity, in the quadriceps muscles. These results suggest that dietary MFGM and VR attenuate natural aging-related decline in motor coordination and muscle function by regulating NMJ integrity.

Combined Supplementation of Pre-Exercise Carbohydrate, Alanine, and Proline and Continuous Intake of Green Tea Catechins Effectively Boost Endurance Performance in Mice.

Continuous intake of green tea catechins (GTC) increases fatty acid utilization as an energy source and improves endurance capacity. Conversely, the single pre-exercise intake of maltodextrin (MD) as a carbohydrate source and the gluconeogenic amino acids alanine (Ala) and proline (Pro) effectively maintain blood glucose levels and increase endurance performance. In this study, we investigated the synergistic combinational effect of these interventions on endurance performance in mice. Male BALB/c mice were fed a 0.5% GTC diet or Control diet for 8 weeks. Maximum running time was measured every 2 weeks. MD (2 g/kg body weight (B.W.)), MD (1 g/kg B.W.) + AlaPro (9:1, 1 g/kg B.W.), and vehicle were orally administrated 60 mins before measurements in each diet group. The GTC + MD + AlaPro group showed significantly higher endurance performance than the Control-Vehicle group at all measurements. Indirect calorimetry analysis during running exercise at 4 weeks in the Control and GTC groups supplemented with pre-exercise MD + AlaPro administration revealed significantly higher fat oxidation in the GTC groups compared to the Control group. The combined increase in fatty acid utilization through continuous GTC intake and pre-exercise MD + AlaPro carbohydrate energy supplementation synergistically improves endurance capacity.

Effects of Psidium guajava Linn. leaf extract in Japanese subjects with knee pain: a randomized, double-blind, placebo-controlled, parallel pilot study.

The extract of Psidium guajava Linn. (guava) leaf was recently revealed to suppress the advance of osteoarthritis (OA) in rat anterior cruciate ligament-transection models. To investigate the efficacy of guava leaf extract in improving knee pain, which is a common symptom of OA, we conducted a double-blind parallel pilot clinical study in Japanese subjects with knee pain. The subjects, who had no medical history of knee treatment, were randomly assigned to two groups with similar total Japanese Knee Osteoarthritis Measure (JKOM) scores. During the 12-week intake period, the subjects in each group ingested 1 g of guava leaf extract (the guava group) or placebo (the placebo group) daily. At week 12, pain and stiffness in knees (one subcategory of JKOM score) in the guava group was significantly lower than that in the placebo group. Using the visual analogue scale (VAS) for knee pain, a significant association between treatment effect and test period was shown, and the guava group had a lower VAS score at week 12 than the placebo group. In conclusion, continuous intake of guava leaf extract might relieve knee pain, suggesting a potential preventive effect against OA symptoms.

Milk fat globule membrane supplementation with voluntary running exercise attenuates age-related motor dysfunction by suppressing neuromuscular junction abnormalities in mice.

Age-related loss of skeletal muscle mass and function attenuates physical performance, and maintaining fine muscle innervation is known to play an important role in its prevention. We had previously shown that consumption of milk fat globule membrane (MFGM) with habitual exercise improves the muscle mass and motor function in humans and mice. Improvement of neuromuscular junction (NMJ) was suggested as one of the mechanisms underlying these effects. In this study, we evaluated the effect of MFGM intake combined with voluntary running (MFGM-VR) on morphological changes of NMJ and motor function in aging mice. Seven months following the intervention, the MFGM-VR group showed a significantly improved motor coordination in the rotarod test and muscle force in the grip strength test compared with the control group at 13 and 14months of age, respectively. In 14-month old control mice, the extensor digitorum longus muscle showed increased abnormal NMJs, such as fragmentation and denervation, compared with 6-month old young mice. However, such age-related deteriorations of NMJs were significantly suppressed in the MFGM-VR group. Increase in the expression of NMJ formation-related genes, such as agrin and LDL Receptor Related Protein 4 (LRP4), might contribute to this beneficial effect. Rotarod performance and grip strength showed significant negative correlation with the status of denervation and fragmentation of NMJs. These results suggest that MFGM intake with voluntary running exercise effectively suppresses age-related morphological deterioration of NMJ, thus contributing to improvement of motor function.

Reduction in hydroxyhydroquinone from coffee increases postprandial fat utilization in healthy humans: a randomized double-blind, cross-over trial.

The present study aimed to clarify the effect of reduction in hydroxyhydroquinone (HHQ) from roasted coffee on energy utilization in humans. Indirect calorimetry showed that one-week ingestion of HHQ-reduced coffee led to significantly higher postprandial fat utilization than that of HHQ-containing coffee. This finding indicates that reduction in HHQ from coffee increases postprandial fat utilization.

Daily consumption of tea catechins improves aerobic capacity in healthy male adults: a randomized double-blind, placebo-controlled, crossover trial.

Our previous studies demonstrated that dietary supplementation with tea catechins combined with exercise improved endurance capacity in mice. This study aimed to demonstrate the effect of daily tea catechin consumption on aerobic capacity in humans. Sixteen Japanese non-athlete male subjects (aged 25-47 years) took 500 mL of a test beverage with or without tea catechins (570 mg) daily for 8 weeks and attended a training program twice a week. Aerobic capacity was evaluated by indirect calorimetry and near-infrared spectroscopy during graded cycle exercise. Catechin beverage consumption was associated with a significantly higher ventilation threshold during exercise and a higher recovery rate of oxygenated hemoglobin and myoglobin levels after graded cycle exercise when compared to subjects receiving the placebo beverage. These results indicate that daily consumption of tea catechins increases aerobic capacity when combined with semiweekly light exercise, which may be due to increased skeletal muscle aerobic capacity.

Effects of Nutritional Supplementation with Milk Fat Globule Membrane on Physical and Muscle Function in Healthy Adults Aged 60 and Over with Semiweekly Light Exercise: A Randomized Double-Blind, Placebo-Controlled Pilot Trial.

This study aimed to demonstrate the beneficial effects of nutritional supplementation with dietary milk fat globule membrane (MFGM) on physical performance and skeletal muscle function in healthy adults aged 60 and over with semiweekly light exercise. The study was designed as a randomized double-blind controlled trial. Twenty-two Japanese participants (10 men, 12 women) aged 60-73 y were assigned to one of two groups (11 [5 men, 6 women] in each). One group received MFGM tablets (1 g MFGM/d), and the other received placebo tablets daily for 10 wk. Both groups participated in a twice-weekly light exercise program. Physical function tests and surface electromyography (EMG) were conducted at the baseline and after 5 and 10 wk. Chair stand time significantly shortened in both groups after 10 wk compared with that at the baseline. The average time shortened more considerably in the MFGM group than in the placebo group, although the change was not statistically significant. Both knee extension strength and the cross-sectional area of the quadriceps muscles significantly increased from baseline in the MFGM group but not in the placebo group. Surface EMG showed that muscle fiber conduction velocity increased significantly after 10 wk from the baseline only in the MFGM group. The increase from the baseline was significantly greater in the MFGM group than in the placebo group. Daily supplementation with MFGM increased motor unit action potential conduction and improved muscle strength and physical performance in healthy Japanese adults aged 60 y and over paired with semiweekly light exercise.

Dietary milk fat globule membrane supplementation combined with regular exercise improves skeletal muscle strength in healthy adults: a randomized double-blind, placebo-controlled, crossover trial.

BACKGROUND: Our previous studies demonstrated that dietary supplementation with milk fat globule membrane (MFGM) combined with habitual exercise improved muscle strength by stimulating neuromuscular development in mice. This study aimed to demonstrate the beneficial effects of dietary MFGM supplementation plus regular exercise on muscle strength and neuromuscular function in healthy humans. METHODS: The study was designed as a randomized, double-blind, placebo-controlled, crossover trial. Fourteen Japanese adults aged 31-48 years took daily MFGM (1 g) or placebo tablets during the 4-week study period and attended a training program twice a week. Physical function tests and surface electromyography (EMG) were conducted at baseline and at the end of the study period. RESULTS: The MFGM group had significantly greater leg extension strength than the placebo group after the 4-week study period. Surface EMG showed that the MFGM group had a significantly higher root mean square amplitude than the placebo group, which indicated that the MFGM group had higher motor unit activity. CONCLUSIONS: Dietary MFGM supplementation combined with regular exercise improves skeletal muscle strength, which may be due to increased motor unit recruitment in healthy Japanese middle-aged adults.

Effects of exercise and milk fat globule membrane (MFGM) supplementation on body composition, physical function, and hematological parameters in community-dwelling frail Japanese women: a randomized double blind, placebo-controlled, follow-up trial.

OBJECTIVE: To investigate the combined and separate effects of exercise and milk fat globule membrane (MFGM) supplementation on frailty, physical function, physical activity level, and hematological parameters in community-dwelling elderly Japanese women. METHODS: A total of 131 frail, elderly women over 75 years were randomly assigned to one of four groups: exercise and MFGM supplementation (Ex+MFGM), exercise and placebo (Ex+Plac), MFGM supplementation, or the placebo group. The exercise group attended a 60-minute training program twice a week for three months, and the MFGM group ingested 1g of the MFGM supplement in pill form, daily for 3 months. The primary outcome measure was change in frailty status based on Fried's frailty phenotype. Secondary outcome measures included body composition, physical function and hematological parameters, and interview survey components assessing lifestyle factors. Participants were followed for 4 months post-intervention. RESULTS: Significant group × time interactions were observed for usual walking speed (P = 0.005), timed up & go (P<0.001), and insulin-like growth factor-binding protein 3/insulin-like growth factor 1 ratio (P = 0.013). The frailty components revealed that weight loss, exhaustion, low physical activity, and slow walking speed were reversed, but low muscle strength did not significantly changed. Frailty reversal rate was significantly higher in the Ex+MFGM (57.6%) than in the MFGM (28.1%) or placebo (30.3%) groups at post-intervention (χ2 = 8.827, P = 0.032), and at the follow-up was also significantly greater in the Ex+MFGM (45.5%) and Ex+Plac (39.4%) groups compared with the placebo (15.2%) group (χ2 = 8.607, P = 0.035). The exercise+MFGM group had the highest odds ratio (OR) for frailty reversal at post-intervention and follow-up (OR = 3.12, 95% confidence interval (CI) = 1.13-8.60; and OR = 4.67, 95% CI = 1.45-15.08, respectively). CONCLUSION: This study suggests that interventions including exercise and nutrition can improve frailty status. Statistically significant additive effects of MFGM with exercise could not be confirmed in this population, and further investigation in larger samples is necessary. TRIAL REGISTRATION: The Japan Medical Association Clinical Trial Registry (JMACCT)JMA-IIA00069.

Dietary milk fat globule membrane improves endurance capacity in mice.

Milk fat globule membrane (MFGM) comprises carbohydrates, membrane-specific proteins, glycoproteins, phospholipids, and sphingolipids. We evaluated the effects of MFGM consumption over a 12-wk period on endurance capacity and energy metabolism in BALB/c mice. Long-term MFGM intake combined with regular exercise improved endurance capacity, as evidenced by swimming time until fatigue, in a dose-dependent manner. The effect of dietary MFGM plus exercise was accompanied by higher oxygen consumption and lower respiratory quotient, as determined by indirect calorimetry. MFGM intake combined with exercise increased plasma levels of free fatty acids after swimming. After chronic intake of MFGM combined with exercise, the triglyceride content in the gastrocnemius muscle increased significantly. Mice given MFGM combined with exercise had higher mRNA levels of peroxisome proliferator-activated receptor-γ coactivator 1α (Pgc1α) and CPT-1b in the soleus muscle at rest, suggesting that increased lipid metabolism in skeletal muscle contributes, in part, to improved endurance capacity. MFGM treatment with cyclic equibiaxial stretch consisting of 10% elongation at 0.5 Hz with 1 h on and 5 h off increased the Pgc1α mRNA expression of differentiating C2C12 myoblasts in a dose-dependent manner. Supplementation with sphingomyelin increased endurance capacity in mice and Pgc1α mRNA expression in the soleus muscle in vivo and in differentiating myoblasts in vitro. These results indicate that dietary MFGM combined with exercise improves endurance performance via increased lipid metabolism and that sphingomyelin may be one of the components responsible for the beneficial effects of dietary MFGM.

Stimulation of postprandial fat utilization in healthy humans by daily consumption of chlorogenic acids.

Long-term ingestion of coffee polyphenols (chlorogenic acids, CGAs) reduces body fat in humans and rodents. While CGA supplementation has been shown to increase fat utilization in rodents, evidence in humans is still limited. The present study clarifies the effect of daily CGA consumption on energy metabolism in humans. Eighteen healthy male subjects (36.1 ± 7.4 y of age) participated in a placebo-controlled, double-blind, crossover, intervention study with two different test beverages. The subjects consumed 185 mL of a test beverage with or without CGAs (329 mg) daily for 4 wk. The energy metabolism was evaluated by using indirect calorimetry before and after the test period during fasting and up to 180 min postprandially. Indirect calorimetry showed that a 4-wk ingestion of the CGA beverage led to a significantly higher postprandial energy expenditure than that of the control beverage. The subjects ingesting the CGA beverage exhibited higher postprandial fat utilization than those consuming the control beverage. The daily CGA consumption therefore increased postprandial fat utilization in healthy humans.

Tea catechins prevent contractile dysfunction in unloaded murine soleus muscle: a pilot study.

OBJECTIVE: Extended periods of muscle disuse, physical inactivity, immobilization, and bedrest result in a loss of muscle mass and a decrease in muscle force, which are accompanied by an increase in oxidative stress. We investigated the effects of the intake of green tea catechins on unloading-induced muscle dysfunction in tail-suspended mice. METHODS: Ten-week-old male BALB/c mice were fed a purified control diet or a diet containing 0.5% tea catechins for 14 d. Thereafter, the mice were subjected to continuous tail suspension for 10 d. On the final day, muscle mass, contractile force production, antioxidant potential, and carbonylated protein levels were evaluated. RESULTS: Hind limb unloading caused a loss of soleus muscle weight and muscle force. Intake of tea catechins significantly inhibited the unloading-induced decrease in force in isolated soleus muscle by 19% compared with the control group, although tea catechins did not affect muscle weight. In addition, intake of tea catechins suppressed the decrease in antioxidant potential and the increase in carbonyl myofibrillar protein. CONCLUSION: Ingestion of tea catechins minimized contractile dysfunction in skeletal muscle and muscle atrophy in unloaded muscle. This effect might be partly due to the lower oxidative modification of myofibrillar protein through the antioxidant activity of tea catechins.

Tea catechin ingestion combined with habitual exercise suppresses the aging-associated decline in physical performance in senescence-accelerated mice.

Catechins, which are abundant in green tea, possess a variety of biologic actions, and their clinical application has been extensively investigated. In this study, we examined the effects of tea catechins and regular exercise on the aging-associated decline in physical performance in senescence-accelerated prone mice (SAMP1) and age-matched senescence-accelerated resistant mice (SAMR1). The endurance capacity of SAMR1 mice, measured as the running time to exhaustion, tended to increase over the 8-wk experimental period, whereas that of SAMP1 mice decreased by 17%. On the other hand, the endurance capacity of SAMP1 mice fed 0.35% (wt/wt) catechins remained at the initial level and was significantly higher than that of SAMP1 mice not fed catechins. In SAMP1 mice fed catechins and given exercise, oxygen consumption was significantly increased, and there was an increase in skeletal muscle fatty acid beta-oxidation. The mRNA levels of mitochondria-related molecules, such as peroxisome proliferator-activated receptor-gamma coactivator-1, cytochrome c oxidase-II, III, and IV in skeletal muscle were also higher in SAMP1 mice given both catechins and exercise. Moreover, oxidative stress measured as thiobarbituric reactive substances was lower in SAMP1 groups fed catechins than in the SAMP1 control group. These results suggest that long-term intake of catechins, together with habitual exercise, is beneficial for suppressing the aging-related decline in physical performance and energy metabolism and that these effects are due, at least in part, to improved mitochondrial function in skeletal muscle.