Jean Doré

Effects of encapsulated green tea and Guarana extracts containing a mixture of epigallocatechin-3-gallate and caffeine on 24 h energy expenditure and fat oxidation in men

It has been reported that green tea has a thermogenic effect, due to its caffeine content and probably also to the catechin, epigallocatechin-3-gallate (EGCG). The main aim of the present study was to compare the effect of a mixture of green tea and Guarana extracts containing a fixed dose of caffeine and variable doses of EGCG on 24 h energy expenditure and fat oxidation. Fourteen subjects took part to this randomized, placebo-controlled, double-blind, cross-over study. Each subject was tested five times in a metabolic chamber to measure 24 h energy expenditure, substrate oxidation and blood pressure. During each stay, the subjects ingested a capsule of placebo or capsules containing 200 mg caffeine and a variable dose of EGCG (90, 200, 300 or 400 mg) three times daily, 30 min before standardized meals. Twenty-four hour energy expenditure increased significantly by about 750 kJ with all EGCG-caffeine mixtures compared with placebo. No effect of the EGCG-caffeine mixture was observed for lipid oxidation. Systolic and diastolic blood pressure increased by about 7 and 5 mmHg, respectively, with the EGCG-caffeine mixtures compared with placebo. This increase was significant only for 24 h diastolic blood pressure. The main finding of the study was the increase in 24 h energy expenditure with the EGCG-caffeine mixtures. However, this increase was similar with all doses of EGCG in the mixtures.

Reducing weight increases postural stability in obese and morbid obese men

Objective:To investigate the effect of weight loss on balance control in obese and morbid obese men.Methods:In a longitudinal and clinical intervention study, postural stability was measured with a force platform before and after weight loss in men. Weight loss was obtained in obese men (mean body mass index (BMI)=33.0 kg/m2) by hypocaloric diet until resistance and in morbid obese men (mean BMI=50.5 kg/m2) by bariatric surgery. Morbid obese men were tested before surgery, and 3 and 12 months after surgery when they had lost 20 and nearly 50% of initial body weight, respectively. Normal weight individuals (mean BMI=22.7 kg/m2) were tested twice within a 6- to 12-month period to serve as control. Body fatness and fat distribution measures, and posturographic parameters of the center of foot pressure (CP) along the antero-posterior and medio-lateral axes for conditions with and without vision were performed in all subjects.Results:Weight loss averaged 12.3 kg after dieting and 71.3 kg after surgery. Body weight remained unchanged in the control group. After weight loss, nearly all measures of postural stability were improved with and without vision (i.e., CP speed and range in antero-posterior and medio-lateral axes). A strong linear relationship was observed between weight loss and improvement in balance control measured from CP speed (adjusted R 2=0.65, P<0.001).Conclusion:Weight loss improves balance control in obese men and the extent of the improvement is directly related to the amount of weight loss. This should decrease the habitual greater risk of falling observed in obese individuals.

Effect of Lactobacillus rhamnosus CGMCC1.3724 supplementation on weight loss and maintenance in obese men and women.

The present study investigated the impact of a Lactobacillus rhamnosus CGMCC1.3724 (LPR) supplementation on weight loss and maintenance in obese men and women over 24 weeks. In a double-blind, placebo-controlled, randomised trial, each subject consumed two capsules per d of either a placebo or a LPR formulation (1.6 × 10(8) colony-forming units of LPR/capsule with oligofructose and inulin). Each group was submitted to moderate energy restriction for the first 12 weeks followed by 12 weeks of weight maintenance. Body weight and composition were measured at baseline, at week 12 and at week 24. The intention-to-treat analysis showed that after the first 12 weeks and after 24 weeks, mean weight loss was not significantly different between the LPR and placebo groups when all the subjects were considered. However, a significant treatment × sex interaction was observed. The mean weight loss in women in the LPR group was significantly higher than that in women in the placebo group (P = 0.02) after the first 12 weeks, whereas it was similar in men in the two groups (P= 0.53). Women in the LPR group continued to lose body weight and fat mass during the weight-maintenance period, whereas opposite changes were observed in the placebo group. Changes in body weight and fat mass during the weight-maintenance period were similar in men in both the groups. LPR-induced weight loss in women was associated not only with significant reductions in fat mass and circulating leptin concentrations but also with the relative abundance of bacteria of the Lachnospiraceae family in faeces. The present study shows that the Lactobacillus rhamnosus CGMCC1.3724 formulation helps obese women to achieve sustainable weight loss.

Calcium plus vitamin D supplementation and fat mass loss in female very low-calcium consumers: potential link with a calcium-specific appetite control.

This randomized, double-blind, placebo-controlled study was conducted to compare the effect of a 15-week weight-reducing programme ( -2900 kJ/d) coupled with a calcium plus vitamin D (calcium+D) supplementation (600 mg elemental calcium and 5 microg vitamin D, consumed twice a day) or with a placebo, on body fat and on spontaneous energy/macronutrient intake. Sixty-three overweight or obese women (mean age 43 years, mean BMI 32 kg/m2) reporting a daily calcium intake < 800 mg participated in present study. Anthropometric variables, resting energy expenditure and spontaneous energy intake were measured before and after the 15-week programme. The calcium+D supplementation induced no statistically significant increase in fat mass loss in response to the programme. However, when analyses were limited to very low-calcium consumers only (initial calcium intake < or =600 mg/d, n 7 for calcium+D, n 6 for placebo), a significant decrease in body weight and fat mass (P < 0.01) and in spontaneous dietary lipid intake (P < 0.05) was observed in the calcium+D but not in the placebo group. In very low-calcium consumers, change in fat mass was positively correlated with change in lipid intake. During the weight-reducing programme, a calcium+D supplementation was necessary in female overweight/obese very low-calcium consumers to reach significant fat mass loss that seemed to be partly explained by a decrease in lipid intake. We propose that this change in lipid intake could be influenced by a calcium-specific appetite control.

Increased Plasma Levels of Toxic Pollutants Accompanying Weight Loss Induced by Hypocaloric Diet or by Bariatric Surgery

Background: Weight loss reduces the risk of several diseases. Increases of plasma organochlorine and pesticide compounds, however, have been observed with weight loss induced by a dietary intervention and by a gastroplasty. This increased concentration of toxic pollutants could be a side-effect of weight loss and a risk for health problems. The aim of this study was: 1) to observe if there is a relationship between the plasma concentration of organochlorines and BMI at steady state weight, and 2) to determine, after a bariatric surgical intervention, if the magnitude of the weight loss has a direct effect on this concentration. Methods: Weight loss was obtained in obese individuals by a hypocaloric diet program until resistance and in morbidly obese individuals by a bariatric operation (biliopancreatic diversion - duodenal switch [BPD-DS]). Normal-weight individuals were tested to serve as controls. Blood samples were analyzed for organochlorine and pesticide compounds at baseline in all groups, after resistance to weight loss in obese individuals, and at 3 months and 1 year after surgery in morbidly obese individuals. Results: At steady state weight, organochlorine and pesticide compounds were found in all groups, and the sum of all organochlorine compounds correlated with age and not BMI. Weight loss averaged 12.1% of the initial body weight after dieting and 20.9% at 3 months after surgery, respectively. This weight loss yielded significant increases in total plasma organochlorine concentration (increase of 23.8% for obese and 51.8% for morbidly obese individuals). For morbidly obese individuals, the weight loss at 1 year after surgery (46.3%) yielded a 388.2% increase in total plasma organochlorine concentration. Conclusion: Plasma organochlorine concentration increases with weight loss and is related to the magnitude. Future research will have to determine if: 1) this pollutant concentration remains elevated over time and 2) there are long-term effects of this high concentration on health.

Awakening cortisol response in relation to psychosocial profiles and eating behaviors

Awakening cortisol response was measured in 78 men and women, on 3 mornings within a 2-month period. Psychosocial and eating behavior variables were assessed using self-administered questionnaires on anxiety (State-Trait Anxiety Inventory), depression (Beck Depression Inventory), body esteem (Body Esteem Scale for Adolescents and Adults), and eating behaviors (Three-Factor Eating Questionnaire and Eating Disorder Inventory-2). Data on food intake and appetite sensations were also collected using a buffet-type meal test, a 3-day food record and visual analog scales measured before and after a standardized breakfast meal test. In women, high anxiety, disinhibition and hunger scores, as well as poor body esteem and a high weight preoccupation, were negatively correlated to ACR. The factor that appeared to account the most for this inverse relation was emotional susceptibility to disinhibition (r=-0.61, p=0.003). The latter was also negatively associated with the satiety quotient for fullness in response to the standardized breakfast (r=-0.48, p=0.010). In men, ACR was negatively associated with flexible (r=-0.33, p=0.020) and strategic (r=-0.28, p=0.049) restraint behaviors. This study highlights a gender-dependent relationship between ACR, hence the activity of the hypothalamic-pituitary-adrenal axis, and eating behaviors and psychological profiles.

Impact of walking on eating behaviors and quality of life of premenopausal and early postmenopausal obese women.

Objective: Aerobic exercise is known to improve health-related quality of life (QoL). The aim of this study was to compare the effects of a 16-week walking program on eating behaviors and QoL between late premenopausal and early postmenopausal obese and sedentary women, once chronological aging is taken into account. Methods: Sixteen women 49 ± 2 years old and 14 women 53 ± 2 years old, whose body mass index ranged between 29 and 35 kg/m2, were subjected to three sessions per week of 45-minute walking at 60% of their heart rate reserve. Fat mass and lean mass (bioelectrical impedance), cardiorespiratory fitness estimated by maximum oxygen consumption (2-km walking test), eating behaviors (Three-Factor Eating Questionnaire), and QoL, estimated by the Short Form-36 Health Survey, Pittsburgh Sleep Quality Index, and Perceived Stress Scale-10 questionnaires, were recorded before and after exercise. Results: With the exception of a higher attitude of self-regulation in postmenopausal than in premenopausal women (P = 0.05), no between-group differences were observed in body composition, eating behaviors, and QoL at baseline. In all participants, body weight and fat mass decreased, whereas cardiorespiratory fitness increased after walking (0.001 < P < 0.0001). Situational susceptibility was the only eating behavior reduced after training in all women (P = 0.02). Neither the sleep quality index nor the perceived stress score changed in response to endurance exercise. Finally, in all women, Short Form-36 physical and mental scores increased after walking (0.001 < P < 0.05). Conclusions: Despite modest body weight and fat mass losses, a 16-week walking program seems to be sufficient to improve physical and mental well-being, irrespective of menopause status.

Effects of short-term normobaric hypoxia on haematology, muscle phenotypes and physical performance in highly trained athletes

This study aimed to determine the impact of short‐term normobaric hypoxia on physiology and performance in highly trained athletes. Twelve (7 male and 5 female) athletes were randomly assigned into two groups and spent 8 h per night for two consecutive nights a week over 3 weeks under either short‐term normobaric hypoxia (simulating 3636 m altitude, inspired O2= 13%) or in normobaric normoxia in a single‐blind study. Following a 3 week washout period, athletes were then exposed to the other condition. Athletes were tested for maximal oxygen consumption and time to exhaustion on an electromagnetically braked cycle ergometer before and after each treatment in addition to being tested for anaerobic performance (Wingate test) on a modified Monark cycle ergometer. Blood samples were taken throughout the experiment and vastus lateralis muscle biopsies were taken before and after each treatment. Increases in red blood cell count, haematocrit, haemoglobin, platelet number and erythropoietin concentration were observed following short‐term normobaric hypoxia. Except for a modest decrease in phosphofructokinase activity following short‐term normobaric hypoxia, no changes were observed in muscle enzyme activities, buffer capacity, capillary density or morphology. No performance measures were changed following short‐term normobaric hypoxia or normobaric normoxia. Although short‐term normobaric hypoxia exposure increased levels of a number of haematological parameters, this was not associated with improved aerobic or anaerobic performance in highly trained athletes.

Cortisol response to the Trier Social Stress Test in obese and reduced obese individuals

Impact of body weight loss, body fat distribution and the nutritional status on the cortisol response to the Trier Social Stress Test (TSST) was investigated in this study. Fifty-one men (17 non-obese, 20 abdominally obese and 14 reduced obese) and 28 women (12 non-obese, 10 peripherally obese and 6 reduced obese) were subjected to the TSST in fed and fasted states. The TSST response was determined using salivary cortisol measurements. The nutritional status (being fed or fasted) had no effect on the cortisol levels during and following the TSST. Reduced obese men exhibited lower cortisol levels than non-obese men. Cortisol levels in obese men were not different from those of non-obese and reduced obese subjects. In women, there was no significant difference between groups. These finding suggest that weight status in men influences cortisol reactivity to a psychological stress and the different responses seen among genders could be linked to the different fat distributions that characterize men and women.

Impact of Walking on Adipose Tissue Lipoprotein Lipase Activity and Expression in Pre- and Postmenopausal Women

Objective: The aim of this study was to examine regional variation in adipose tissue lipoprotein lipase (AT-LPL) activity and expression in pre-and postmenopausal women, before and after training, once differences in chronological age or obesity degree are taken into account. Methods: Sixteen late pre- and 14 early postmenopausal (49 ± 2 vs. 52 ± 2 years; p < 0.001) moderately obese women (body mass index 29–35 kg/m2) were subjected to a 16-week walking program (3 sessions/week of 45 min at 60% heart rate reserve). Abdominal and femoral AT-LPL activity and expression, fasting lipidlipoprotein profile, body composition, and cardiorespiratory fitness (CRF) were measured before and after our intervention. Statistical analyses were performed using covariance analysis for age differences. Results: AT-LPL activity and expression, lipid-lipoprotein metabolism, body fatness, and CRF were similar at baseline, irrespective of the group considered. Slight reductions in plasma cholesterol and high-density lipoprotein (HDL) cholesterol levels, fat mass and waist girth reductions, CRF increases as well as femoral AT-LPL activity and expression decreases after our intervention were comparable, regardless of menopausal status (0.0001 < p < 0.05). Conclusions: Lipid storage is decreased in the femoral depot after walking, regardless of menopausal status. Reduction in AT-LPL activity or expression does not lead to a more deleterious lipid-lipoprotein profile, despite the modest decrease noted in HDL cholesterol concentrations.