Effects of L-serine ingestion on human sleep.

To investigate the effects of L-serine intake on human sleep, we conducted two randomized double-blinded crossover studies. In Study 1, healthy subjects who were dissatisfied with their sleep were given L-serine or a placebo 30 min before going to bed. After waking the next morning, subjective sleep quality was rated using the Ogri-Shirakawa-Azumi subjective sleep rating scale. In Study 2, subjective sleep quality was rated using the St. Mary's Hospital sleep questionnaire, and objective parameters, including sleep initiation time, number of nighttime awakenings, and hours of sleep, were evaluated using actigraphy. In Study 1, factors related to "sleep initiation" and "sleep maintenance" during the L-serine intake period were significantly improved compared to the placebo intake period (p = 0.02 and p = 0.008, respectively). In Study 2, scores for "How well did you sleep last night?" and "How satisfied were you with last night's sleep?" were significantly better during L-serine intake compared to placebo (p = 0.04 and p = 0.03, respectively). Subjective evaluation of sleep quality on waking was thus improved. In addition, objective evaluation using actigraphy showed that the "number of nighttime awakenings" tended to be decreased (p = 0.08). These findings suggest that intake of L-serine before going to bed may improve human sleep.

Effects of Garcinia cambogia extract on serum sex hormones in overweight subjects.

(-) Hydroxycitric acid (HCA), an active ingredient extracted from the Garcinia cambogia fruit rind, has been commonly used as a dietary supplement for weight management. Given the controversy over HCA related testicular toxicity in animal studies, we investigated changes in serum sex hormones levels as an extension of our previous double-blind placebo-controlled trial in human subjects, in which 44 participants received either G. cambogia extract (1667.3 mg/day equivalent to 1000 mg HCA/day) or placebo for 12 weeks. Compared to the placebo group, administration of the extract did not significantly alter the serum testosterone, estrone, and estradiol levels. Similarly, hematology, serum triacylglycerol and serum clinical pathology parameters did not reveal any significant adverse effects. The results of this preliminary investigation indicate that ingestion of G. cambogia extract at dose levels commonly recommended for human use does not affect serum sex hormone levels and blood parameters.

Singlet oxygen quenching activity of human serum.

Singlet oxygen is regarded as contributing to the pathogenesis of various diseases including light-induced skin disorders and inflammatory response. In this study, the correlation between singlet oxygen quenching activity (SOQA) of human serum and blood biochemistry or life-style was evaluated. Healthy volunteers were recruited and carried out a measurement of SOQA by using electron paramagnetic resonance (EPR) and a questionnaire survey about a smoking. It was demonstrated that major quenchers of singlet oxygen in serum are proteins, and small molecular anti-oxidants relatively play a minor role. SOQA of whole sera showed no correlation with protein concentration, but positively correlated with SOQA of small molecular fraction. In vitro studies demonstrated that the decrease of sulfhydryl groups by NO or superoxide significantly attenuated SOQA of albumin. Together, these results may imply that the underlying oxidative condition in each individual influences both small molecular antioxidant states and the sulfhydryl content of serum proteins. SOQA of sera from women with a smoking history was significantly lower compared to non-smoking women, suggesting that the smoking habit impaired the defense mechanism against singlet oxygen.

Effects of garcinia cambogia (Hydroxycitric Acid) on visceral fat accumulation: a double-blind, randomized, placebo-controlled trial.

BACKGROUND: (-)-Hydroxycitric acid (HCA) is an active ingredient extracted from the rind of the Indian fruit Garcinia cambogia. It inhibits adenosine triphosphate citrate lyase and has been used in the treatment of obesity. OBJECTIVE: The primary end point of this study was the effects of 12 weeks of G cambogia extract administration on visceral fat accumulation. The secondary end points were body indices (including height, body weight, body mass index [BMI], waist and hip circumference, and waist-hip ratio) and laboratory values (including total cholesterol, triacylglycerol, and free fatty acid). METHODS: This study was performed according to a double-blind, randomized, placebo-controlled, parallel-group design. Subjects aged 20 to 65 years with a visceral fat area >90 cm(2) were enrolled. Subjects were randomly assigned to receive treatment for 12 weeks with G cambogia (containing 1000 mg of HCA per day) or placebo. At the end of the treatment period, both groups were administered placebo for 4 weeks to assess any rebound effect. Each subject underwent a computed tomography scan at the umbilical level at -2, 0, 12, and 16 weeks. RESULTS: Forty-four subjects were randomized at baseline, and 39 completed the study (G cambogia group, n = 18; placebo group, n = 21). At 16 weeks, the G cambogia group had significantly reduced visceral, subcutaneous, and total fat areas compared with the placebo group (all indices P<0.001). No severe adverse effect was observed at any time in the test period. There were no significant differences in BMI or body weight at week 12, but there were slight numeric decreases in body weight and BMI in men. There were no signs of a rebound effect from week 12 to week 16. CONCLUSION: G cambogia reduced abdominal fat accumulation in subjects, regardless of sex, who had the visceral fat accumulation type of obesity. No rebound effect was observed. It is therefore expected that G cambogia may be useful for the prevention and reduction of accumulation of visceral fat.