Bacillus subtilis DE111 intake may improve blood lipids and endothelial function in healthy adults.

Cardiovascular disease (CVD) is the leading cause of death in the US and worldwide. By 2030 it is anticipated that CVD will claim the lives of more than 24 million people. Throughout the last decade, researchers have investigated the role of the gut microbiota in the development of CVD. Evidence exists for a positive correlation between Bifidobacterium and vascular function, glucose tolerance, and reduced systemic inflammation. Another probiotic species, Bacillus subtilis, has also been found to reduce cholesterol levels in human and animal models. In light of these data, we examined various measures of cardiovascular health after consumption of Bifidobacterium animalis subsp. lactis strain BL04, with and without a cocktail of Escherichia coli-targeting bacteriophages (marketed as PreforPro), Bacillus subtilis strain DE111 or a maltodextrin-based placebo in a healthy human population. In a randomised, double-blind, placebo-controlled 4-week intervention conducted in individuals 18 to 65 years of age with a body mass index of 20 to 34.9, we saw no significant changes in measured CVD parameters among individuals consuming B. lactis with or without bacteriophages. However, B. subtilis supplementation resulted in a significant reduction in total cholesterol relative to baseline measures (-8 mg/dl; P=0.04, confidence interval (CI): -13.40, -0.19), as well as non-high-density lipoprotein-cholesterol (-11 mg/dl; P=0.01, CI: -12.43, -2.07). In addition we observed trending improvements in endothelial function (P=0.05, CI: -0.003, 0.370) and in low-density lipoprotein-cholesterol (P=0.06, CI:-12.29, 0.2864). Strikingly, these effects were seen in a largely healthy population. These data suggest that B. subtilis supplementation may be beneficial for improving risk factors associated with CVD. Further studies in populations of older adults or those with dyslipidaemia and endothelial dysfunction is warranted.

Relationship of pressure to be thin with gains in body weight and fat mass in adolescents.

BACKGROUND: Sociocultural pressure to be thin is commonly reported by adolescents; yet, to what extent such pressure is associated with weight gain has not been evaluated longitudinally. OBJECTIVE: Examine whether pressure to be thin was positively associated with weight and fat gain in adolescents. METHODS: Participants were 196 healthy adolescent (age 15 ± 1 years old) girls (65%) and boys of varying weights (BMI 25 ± 7 kg/m2 ) studied at baseline and 1-year follow-up. At baseline, adolescents and their mothers reported pressure to be thin by questionnaire. At baseline and follow-up, BMI was calculated, and fat mass was assessed with air displacement plethysmography. Multiple regression was used to examine associations between baseline pressure to be thin and 1-year changes in BMI and fat mass. RESULTS: Accounting for multiple covariates, including baseline BMI or fat, adolescent-reported pressure from parents and peers and mother-reported pressure toward their teen were associated with greater gains in either adolescent BMI or fat (ps < .05). Adolescent weight status was a moderator of multiple effects (ps < .05). CONCLUSIONS: Parental and peer pressure to be thin were associated with increases in BMI and fat mass during adolescence, particularly in heavier adolescents. Further research is necessary to clarify how this association operates reciprocally and to identify underlying explanatory mechanisms.

Blood pressure and blood lipids among vegetarian, semivegetarian, and nonvegetarian African Americans.

Blood pressure (BP) and serum lipids were compared among three dietary groups of Seventh-day Adventist (SDA) African-American adults: vegetarians (VEGs: no consumption of animal flesh, n = 66), semivegetarians (SEMIVEGs: one to three servings of animal flesh per week, n = 56), and nonvegetarians (NONVEGs: daily consumption of animal flesh, n = 45). VEGs had a lower mean waist-to-hip ratio (WHR) and lower dietary intakes of protein, saturated fat, and cholesterol compared with the NONVEGs. Only 16% of the VEGs were confirmed to be hypertensive compared with 35.7% of the SEMIVEGs and 31.1% of the NONVEGs. Independent of differences in WHR, the VEGs had significantly lower concentrations of serum total cholesterol (STC), LDL-C, triglycerides, STC/HDL-C, and LDL-C/HDL-C than the NONVEGs. The SEMIVEGs had lipid values intermediate to the VEG and NONVEG groups. Among African-American SDAs, a vegetarian diet is associated with lower cardiovascular disease risk factors than is an omnivorous diet.

Resting metabolic rate in weight-cycling collegiate wrestlers compared with physically active, noncycling control subjects.

To determine the effect of multiple cycles of weight loss and regain on resting metabolic rate (RMR), we compared RMR between 12 weight-cycling collegiate wrestlers (means age 19.4 y) with a minimum of three previous seasons of weight cycling and 13 weight-stable nonwrestlers of similar weight and body composition (means age 20.6 y). RMR was measured before, during, and after a 6-mo wrestling season. Wrestlers exhibited a significantly higher baseline RMR compared with the control subjects (p less than 0.05). During the season when wrestlers had lost weight for competition, RMR was reduced (p less than 0.05) but was not significantly lower than that of the weight-stable control subjects. After a season of weight cycling and the final weight regain, the wrestler's postseason RMR was similar to preseason values and higher than the postseason RMR of the control subjects (p less than 0.05). Participation in numerous cycles of weight loss and regain did not lower RMR in these competitive athletes, as has been previously suggested.

Metabolic differences between subjects whose blood pressure did or did not respond to oral calcium supplementation.

In a randomized, double-blind, placebo-controlled trial of a 1500 mg/d calcium supplement taken over a 12-wk period, the mean arterial pressure of normotensive adult males (n = 37) was modestly but significantly lowered as compared with a placebo group (n = 38). Within the Ca group only, responders (greater than or equal to 5 mm Hg decrease in mean arterial pressure, n = 14) were compared with nonresponders (less than 5 mm Hg decrease in mean arterial pressure, n = 23). The responders were older (p = 0.002) and exhibited higher mean arterial pressure (p = 0.00001), higher serum parathyroid hormone (p = 0.01), and lower serum total Ca (p = 0.001) at baseline. A stepwise discriminant function analysis revealed that mean arterial pressure and serum total Ca correctly classified 78.38% of the responders and nonresponders and, thus, were the most important determinants of blood pressure response to supplemental Ca.

Resting metabolic rate and postprandial thermogenesis in highly trained and untrained males.

The purpose was to compare the resting metabolic rate (RMR) and thermic effect of a meal (TEM) in exercise trained and untrained individuals. TEM was measured for 180 min and blood samples were drawn for determination of plasma insulin, glucose, triiodothyronine (T3) and thyroxine (T4). Results indicated that highly trained subjects demonstrated a higher RMR when expressed in kilocalories per minute and per kilogram fat-free weight (FFW) than do untrained subjects. TEM was lower in trained (55.8 +/- 3.1 kcal) than in untrained (79.2 +/- 3.7 kcal) subjects. No differences were noted between the two groups for plasma levels of insulin, glucose, T3, and T4. A higher RMR and lower TEM persisted in the trained group compared with the untrained group when groups were matched for FFW and body fat. Results support a higher RMR in endurance athletes and a lower TEM even after control is exerted over differences in body composition.

Interaction of acute changes in exercise energy expenditure and energy intake on resting metabolic rate.

The effects on resting metabolic rate (RMR) of energy intake and exercise energy expenditure were examined in eight trained men under four conditions: 1) high energy flux (HF), 90 min of exercise at 75% VO2max on 3 d while in energy balance; 2) low energy flux (LF), no exercise for 3 d while in energy balance; 3) negative energy balance (NEB), exercise on 3 d while consuming low-flux meals; and 4) positive energy balance (PEB), no exercise for 2 d while consuming high-flux meals. Eight untrained men were studied in LF. There were effects of exercise energy expenditure and energy intake on RMR, and an exercise x diet interaction (P < 0.05). RMR was greater in trained than in untrained subjects only when trained subjects were in HF. These data indicate that RMR is influenced by exercise, energy intake, and their interaction and suggest that higher RMR in trained vs untrained individuals results from acute effects of HF rather than from a chronic adaptation to exercise training.

Iron status in exercising women: the effect of oral iron therapy vs increased consumption of muscle foods.

Forty-seven previously sedentary women participating in a 12-wk moderate aerobic-exercise program were randomly assigned to one of four dietary groups: 50-mg/d iron supplement and a low food-iron diet (50 FE + EX), 10-mg/d iron supplement and a low food-iron diet (10 FE + EX), placebo and unrestricted diet (P + EX), and meat supplement and high food-iron diet (M + EX). A sedentary control group (n = 13) received no dietary interventions. Hematocrit, total iron-binding capacity, and hemoglobin, serum iron, serum ferritin, and serum albumin concentrations were measured every 4 wk. Hemoglobin values decreased at the end of 4 wk in all exercising groups compared with the control group. Iron status in the 50 FE + EX and M + EX groups improved after week 4 as indicated by an increase in serum ferritin, serum iron, and hemoglobin concentrations, and a decline in total iron-binding capacity. Thus, short-term, moderate aerobic exercise resulted in compromised iron status that was offset to varying degrees by ingesting iron or meat supplements. However, meat supplements were more effective in protecting hemoglobin and ferritin status than were iron supplements.

Resting metabolic rate and postprandial thermogenesis in vegetarians and nonvegetarians.

Resting metabolic rate (RMR), thermic effect of a meal (TEM), and associated hormonal changes were studied in vegetarians and nonvegetarians. RMR was established by indirect calorimetry in 12 male vegetarians (VEG) and 11 nonvegetarians (NVEG) of similar body fat and aerobic fitness. Subjects ingested a liquid meal and TEM was measured for 180 min postprandially. Plasma concentrations of glucose, insulin and thyroid hormones (T3 and T4) were determined before and after meal ingestion. Absolute RMR was comparable between VEG and NVEG. However, TEM was lower (p less than 0.01) in VEG (55.8 +/- 3.3 kcal/180 min) vs NVEG (76.4 +/- 3.6). Plasma levels of glucose and insulin were similar between the two groups whereas plasma T3 was slightly but nonsignificantly lower in vegetarians. A vegetarian diet may decrease the postprandial thermic response; this does not support the supposition that an elevated TEM is a factor contributing to the lower body weight in vegetarians than in omnivores.

Aerobic fitness and resting energy expenditure in young adult males.

Ambiguous findings have been reported in previous studies regarding the relationships among aerobic fitness, resting metabolic rate (RMR), and the thermic effect of a meal (TEM). We reexamined the association among these variables in young nonobese men who exhibited a wide range of aerobic fitness levels. RMR was measured after an overnight fast and TEM was assessed for three hours after ingestion of a liquid meal. Preprandial and postprandial plasma levels of insulin, glucose, and thyroid hormones (total T3 and T4) were measured. Daily energy intake was estimated from three-day food diaries, body composition from underwater weighing, and aerobic fitness from a test of VO2 max. Data were analyzed with linear and curvilinear regression analysis, as well as with ANOVA to test for differences among subjects classified by fitness level (ie, untrained, moderately, and highly trained). A significant correlation was found between RMR and VO2 max (r = .77, P less than .01). RMR adjusted for body weight and FFW was higher in highly trained men when compared to moderately and untrained individuals. However, a curvilinear relationship was found between TEM and VO2 max (P less than .05). Subjects who exhibited moderate levels of fitness showed the highest TEM, whereas a lower TEM was noted in untrained and highly trained men. These findings were observed in the absence of differences in plasma concentrations of total T3 and T4 among fitness levels. These findings suggest that highly trained men have a high RMR adjusted for their metabolic size.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of moderate chronic wine consumption on insulin sensitivity and other correlates of syndrome X in moderately obese women.

Epidemiologic studies indicate that alcohol consumption is associated with improved insulin sensitivity; however, scant experimental evidence confirms this observation. To determine the effects of regular moderate wine consumption on insulin sensitivity, 20 overweight women (body mass index [BMI], 29.8 +/- 2.2 kg/m2) participated in a 20-week free-living randomized crossover trial. The subjects, serving as their own controls, consumed wine (190 mL red wine, 13% vol/vol ethanol, 5 days per week) for 10 weeks and abstained for 10 weeks or vice versa. The dependent variables (body weight, BMI, percent body fat, blood pressure, fasting blood glucose and insulin, blood lipids, dietary intake, and insulin sensitivity by intravenous glucose tolerance test [IVGTT]) were measured at the pretest, at the 10-week crossover, and at the 20-week completion of the study. Data were analyzed at the pretest and at completion of the wine drinking and abstention periods of the study using ANOVA by order of treatment. Fasting glucose remained unchanged (mean +/- SD; P > .05) throughout the experiment (pretest, drinking, and abstention, 91.1 +/- 9.2, 91.6 +/- 9.1, and 88.5 +/- 11.2 mg/dL), as did the measures of insulin sensitivity, fasting insulin (pretest, drinking, and abstention, 8.6 +/- 3.3, 8.6 +/- 4.1, and 9.1 +/- 4.7 microU/mg) and the insulin sensitivity index (3.60 +/- 2.96, 3.25 +/- 2.17, and 3.30 +/- 1.84). Body composition and blood lipids also remained unchanged (P > .05) during treatment. Moderate wine consumption at this dose in overweight women did not improve or impair insulin sensitivity, nor did it change any of the known correlates of insulin sensitivity, including body weight and composition, blood lipids, and blood pressure.

The impact of exercise and diet restriction on daily energy expenditure.

In addition to the direct energy cost of physical activity, exercise may influence resting energy expenditure in 3 ways: (a) a prolonged increase in postexercise metabolic rate from an acute exercise challenge; (b) a chronic increase in resting metabolic rate associated with exercise training; and (c) a possible increase in energy expenditure during nonexercising time. It seems apparent that the greater the exercise perturbation, the greater the magnitude of the increase in postexercise metabolic rate. An exercise prescription for the general population that consists of exercise of low (less than 50% VO2max) or moderate intensity (50 to 75% VO2max) does not appear to produce a prolonged elevation of postexercise metabolic rate that would influence body-weight. Inconsistent results have been found with respect to the effects of exercise training and the trained state on resting metabolic rate. Whereas some investigators have found a higher resting metabolic rate in trained than untrained individuals and in individuals after an exercise training programme, other investigators have found no chronic exercise effect on resting metabolic rate. Differences in experimental design, genetic variation and alterations in energy balance may contribute to the discrepant findings among investigators. A relatively unexplored area concerns the influence of exercise training on energy expenditure during nonexercising time. It is presently unclear whether exercise training increases or decreases the energy expenditure associated with spontaneous or nonpurposeful physical activity which includes fidgeting, muscular activity, etc. The doubly labelled water technique represents a methodological advance in this area and permits the determination of total daily energy expenditure. Concomitant with the determination of the other components of daily energy expenditure (resting metabolic rate and thermic effect of a meal), it will now be possible to examine the adaptive changes in energy expenditure during nonexercising time. A plethora of studies have examined the combined effects of diet and exercise on body composition and resting metabolic rate. The hypothesis is that combining diet and exercise will accelerate fat loss, preserve fat-free weight and prevent or decelerate the decline in resting metabolic rate more effectively than with diet restriction alone. The optimal combination of diet and exercise, however, remains elusive. It appears that the combination of a large quantity of aerobic exercise with a very low calorie diet resulting in substantial loss of bodyweight may actually accelerate the decline in resting metabolic rate. These findings may cause us to re-examine the quantity of exercise and diet needed to achieve optimal fat loss and preservation of resting metabolic rate.

Two seasons of weight cycling does not lower resting metabolic rate in college wrestlers.

Over the course of 2 yr, we prospectively studied the effect on resting metabolic rate (RMR) of multiple cycles of weight loss followed by regain in six weight cycling collegiate wrestlers (WC) (mean age = 19.0 yr) compared with 12 weight stable, physically active, nonwrestling controls (C) (mean age = 20.9 yr), whose body composition was similar to the wrestlers. Furthermore, during the second year of the investigation, a group of six nonweight cycling collegiate wrestlers (NWC) (mean age = 18.8 yr) were included in the analyses. The WC had previously undergone at least three seasons of weight cycling and continued this pattern during each year of the study. For the WC, RMR was determined by indirect calorimetry before and after a 6-month season of weight cycling for each of two consecutive years. A similar time frame was followed for measurement of RMR in the C, while for the NWC, pre- and postseason RMRs were measured only during the second year. During the 2 yr, the WC had significantly higher (P < 0.05) pre- and postseason measures of RMR compared with the C. A separate analysis comparing all three groups during the second year showed that RMR was not different for WC and NWC, and that RMR was higher for both wrestling groups compared with C. In this prospective study, weight cycling did not increase the thermogenic efficiency of collegiate wrestlers compared with either nonweight cycling wrestlers or weight stable controls, who were not wrestlers.

Effect of exercise intensity and duration on postexercise energy expenditure.

The purpose of this study was to examine 1) the effect of two exercise intensities of equal caloric output on the magnitude (kcal) and duration of excess postexercise oxygen consumption (EPOC) and 2) the effect of exercise of equal intensity but varying duration on EPOC. Ten trained male triathletes performed three cycle ergometer exercises: high intensity-short duration (HS), low intensity-short duration (LS), and low intensity-long duration (LL). Baseline VO2 was measured for 1 h prior to each exercise condition. Postexercise VO2 was measured continuously until baseline VO2 was achieved. The duration of EPOC was similar for HS (33 +/- 10 min) and LL (28 +/- 14 min), and both were significantly longer (P less than 0.05) than the EPOC following LS (20 +/- 5 min). However, total net caloric expenditure was significantly more (P less than 0.05) for HS (29 +/- 8 kcal) than for either LS (14 +/- 6 kcal) or LL (12 +/- 7 kcal). The exercise conditions used in this study did not produce a prolonged EPOC. However, the exercise intensity was shown to affect both the magnitude and duration of EPOC, whereas the exercise duration affected only the duration of EPOC. Moreover, the duration of EPOC and the subsequent caloric expenditure were not necessarily related. Based on the resulting magnitude of the postexercise energy expenditure, it is possible that EPOC may be of some value for weight control over the long term.

Resting metabolic rate and postprandial thermogenesis by level of aerobic fitness in young women.

Resting metabolic rate (RMR) and the thermic effect of a meal (TEM) were compared among women of three levels of aerobic fitness. Twenty-three euthyroid, eumenorrheic women (aged 18-35 years) were divided into three groups based on VO2 max standardized for fat-free weight (FFW), as determined from a graded exercise test: High Fit (HF): n = 7, VO2 max > 70 ml*kg FFW-1*min-1; Moderately Fit (MF): n = 8, VO2 max = 55-70 ml*kg FFW-1*min-1; and Low Fit (LF): n = 8, VO2 max < 55 ml*kg FFW-1*min-1). At 0700h RMR was measured for 1 h by indirect calorimetry with subjects in a fasted, preovulatory state, having refrained from exercise on the preceding day. The subject then consumed a liquid meal (12 kcal*kg FFW-1) and indirect calorimetry was continued for 3 h to determine the TEM. RMR adjusted for FFW using analysis of covariance was significantly higher (P < 0.05) in the HF group (mean +/- SEM = 1.08 +/- 0.03 kcal*min-1) compared to the MF (0.99 +/- 0.04) and LF (0.90 +/- 0.04) groups. Group differences in the thermic response did not reach statistical significance, although there was a trend for a high TEM in the HF group. There was a positive relationship between RMR and energy flux (average daily kcalorie intake + daily kcaloric expenditure in physical activity). These results suggest that women who exhibit high levels of exercise and aerobic fitness may be less energy efficient during the non-exercise portion of the day then their less active counterparts.

Beyond blood pressure screening: a rationale for promoting the primary prevention of hypertension.

Abstract High blood pressure is a major public health problem in the United States. However, the underlying reasons for the chronic elevation of blood pressure (BP) are unknown in most cases of hypertension (HT), and medical care has focused on lowering already elevated BP, primarily by pharmacologic means. Although an important factor in the development of HT appears to be a genetic predisposition, other potentially modifiable lifestyle risk factors associated with elevated BP have been identified. This article describes the scientific rationale for encouraging health promotion specialists to focus on the primary prevention of abnormally elevated blood pressure. Nonbehavioral risk factors such as increasing age, history of HT, Black ancestry, and consistent BP readings in the higher range of normality, and behavioral factors including dietary excesses and deficiencies, excessive body fat, a sedentary life style, and frequent episodes of unmanageable emotional stress are addressed. Recommendations are made based on scientific evidence supporting the relationships between these risk factors and the development of HT.

Inhibition of prostaglandin synthesis: a possible mechanism for stress-induced hypertension.

Essential hypertension, while considered to be idiopathic, may be due to a variety of physiologic and/or psychologic factors, including stress. A possible mechanism for stress-induced hypertension is the inhibition of prostaglandin (PG) synthesis by the release of corticoids in the stereotypical stress response. PGI2 and PGE2, acting as vasodilators are important antagonists to the pressor effects of norepinephrine. However, a decreased synthesis of these PGs due to higher cortisol levels associated with stress, would negate their vasodilatory action, thus favoring vasoconstriction due to vascular suprasensitivity to norepinephrine. PGF2 alpha, a vasoconstrictor thought to be synthesized in the brain in response to a stressor, may also play a key role in the pathogenesis of hypertension.

Energy expenditure following a bout of non-steady state resistance exercise.

Little is known about the effect of non-steady state resistive exercise on postexercise energy expenditure. Using a counterbalanced design, energy expenditure was measured by indirect calorimetry in six adult males (mean age +/- SD = 24.5 +/- 6.1) for 30 min before and 60 min after a single 42 min bout of weight lifting, and again on a separate day for 30 min before and 60 min after a 42 min control period of quiet sitting. For the exercise condition the subjects performed 4 sets of upper and 3 sets of lower body resistive exercises at weights equivalent to a 12 repetition maximum for each respective lift. Metabolic rate remained significantly elevated at the end of the 60 min recovery period compared to the control condition, although the excess postexercise oxygen consumption accounted for only approximately 19 additional kcal expended. These data suggest that while postexercise metabolic remains elevated for at least one hour following a moderate level of resistive exercise, the caloric cost of this elevation during a one hour recovery period is small and similar to that induced by steady-state exercise of moderate intensity.

Correlates of blood pressure in elementary schoolchildren.

This cross-sectional study determined which anthropometric, dietary, and physical fitness variables were best predictors of blood pressure (BP) in 323 white elementary schoolchildren. Height, weight, triceps, and subscapular skinfold thickness were measured, followed by two resting BP measurements. Cardiorespiratory fitness was assessed by time in a one mile run. A food frequency questionnaire measured habitual dietary intake. Correlational analysis revealed height, weight, body mass index (wt/ht2), and skinfold thicknesses were anthropometric variables associated significantly with both systolic and diastolic blood pressure. Physical fitness was not correlated with BP and, among dietary variables, only estimated daily caloric intake, dietary cholesterol, and nondiscretionary sodium were related to blood pressure. A multiple regression analysis selected weight, body mass index (BMI), and total caloric intake as factors explaining the greatest amount of BP variability. For some individuals, hypertension may originate in childhood, thus, these results could have implications for primary prevention of high blood pressure.