Satoko Soga

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.

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.

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.

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. Graphical abstract Tea catechins improved the recovery rate of oxygenated hemoglobin and myoglobin levels after graded cycle exercise.

Light rhythmic exercise with dietary milk fat globule membrane improves physical fitness in an elderly Japanese population: a double-blind randomized placebo-controlled trial

Abstract This study aimed to investigate the efficacy of home-based, light gymnastic exercise plus dietary milk fat globule membrane (MFGM) intake on physical fitness of an elderly Japanese sample in a pilot, double-blind, randomized, placebo-controlled trial. Seventy-one subjects (male, n = 13; female, n = 58) were randomly assigned into two groups: placebo (n = 35 [male, n = 6; female, n = 29]) and MFGM group (n = 36 [male, n = 7; female, n = 29]). The intervention was eight weeks. Subjects ingested either MFGM (1 g/day) or placebo tablets daily and engaged in an exercise program daily. Physical function tests were performed at baseline and after four and eight weeks. Foot tapping and open–close stepping scores significantly increased from baseline to eight weeks in the MFGM group. Study results suggest daily MFGM ingestion might further enhance the effects of light-intensity exercise in healthy elderly people. Combination of MFGM intake and light rhythmic gymnastic exercise improved agility in the healthy elderly people. *A significant difference was noted between the two groups in the results of the unpaired t-test (P < 0.05).