The acute effects of plyometric and sled towing stimuli with and without caffeine ingestion on vertical jump performance in professional soccer players

Background

Post-activation potentiation (PAP) is the phenomenon by which muscular performance is enhanced in response to a conditioning stimulus. PAP has typically been evidenced via improved counter movement jump (CMJ) performance. This study examined the effects of PAP, with and without prior caffeine ingestion, on CMJ performance.

Methods

Twelve male professional soccer players (23?±?5 years) performed two trials of plyometric exercises and sled towing 60 min after placebo or caffeine ingestion (5 mg.kg^??1) in a randomized, counterbalanced and double-blinded design. CMJ performance was assessed at baseline and 1, 3 and 5 min after the conditioning stimulus (T1, T3 and T5, respectively).

Results

Two way ANOVA main effects indicated a significant difference in jump height after the PAP protocol (F[3, 11]?=?14.99, P?<?0.001, partial η2?=?0.577). Analysis also indicated a significant difference in CMJ performance across conditions, with caffeine eliciting a greater response (F[1, 11]?=?10.12, P?=?0.009, partial η2?=?0.479). CMJ height was increased at T1, T3 and T5 in caffeine condition (5.07%, 5.75% and 5.40%, respectively; P?<?0.01) compared to baseline. In the placebo condition, jump performance was increased at T3 (4.94%; P?<?0.01) only. Jump height was higher in caffeine condition on T1, T3 and T5 (P?<?0.05) but not on baseline (P?>?0.05) compared to placebo.

Conclusions

The results of this study suggest that acute plyometric and sled towing stimuli enhances jump performance and that this potentiation is augmented by caffeine ingestion in male soccer players.

     

The influence of frequently consumed beverages and snacks on dental erosion among preschool children in Saudi Arabia

Background

To determine the prevalence of dental erosion and its association to commonly used beverages and snacks among 3 to 5 year old preschool children in Riyadh, Saudi Arabia.

Methods

Three hundred eighty-eight preschool children between 3 and 5 years old were selected from 10 different schools using a cluster random sample selection; there were 184 (47%) boys and 204 (53%) girls. The surfaces of each tooth were examined for erosion, and the level of tooth wear was recorded. Data on the frequently used beverages and snacks were obtained by questionnaires completed by the parents of the preschool children.

Results

Among the 388 children examined, 47% exhibited low erosion, 10% exhibited moderate erosion and 4% exhibited severe erosion. There was no statistically significant difference between boys and girls in terms of the prevalence of erosion. Sixty percent of the children regularly consumed juice drinks. Among daily consumers, 84% of children showed erosion prevalence with strongly significant association (p?<?0.005). Holding the drink in the mouth also showed a significant association with erosion (p?<?0.02).

Conclusion

It was concluded that an association was found between the prevalence of dental erosion and the frequency of citrus and carbonated juice consumed by the preschool children in Saudi Arabia.

     

Efficacy and safety of turmeric and curcumin in lowering blood lipid levels in patients with cardiovascular risk factors: a meta-analysis of randomized controlled trials

Background

Dyslipidemia is an important and common cardiovascular risk factor in the general population. The lipid-lowering effects of turmeric and curcumin are unconfirmed. We performed a meta-analysis to assess the efficacy and safety of turmeric and curcumin in lowering blood lipids in patients at risk of cardiovascular disease (CVD).

Methods

A comprehensive literature search was conducted on PubMed, Embase, Ovid, Medline and Cochrane Library databases to identify randomized controlled trials (published as of November 2016) that assessed the effect of turmeric and curcumin on blood lipid levels including total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG). Pooled standardized mean difference (SMD) with 95% confidence interval (CI) was used to assess the effect.

Results

The analysis included 7 eligible studies (649 patients). Turmeric and curcumin significantly reduced serum LDL-C (SMD = ?0.340, 95% confidence interval [CI]: ?0.530 to ?0.150, P < 0.0001) and TG (SMD = ?0.214, 95% CI: ?0.369 to ?0.059, P = 0.007) levels as compared to those in the control group. These may be effective in lowering serum TC levels in patients with metabolic syndrome (MetS, SMD = ?0.934, 95% CI: ?1.289 to ?0.579, P < 0.0001), and turmeric extract could possibly have a greater effect on reducing serum TC levels (SMD = ?0.584, 95% CI: ?0.980 to ?0.188, P = 0.004); however, the efficacy is yet to be confirmed. Serum HDL-C levels were not obviously improved. Turmeric and curcumin appeared safe, and no serious adverse events were reported in any of the included studies.

Conclusions

Turmeric and curcumin may protect patients at risk of CVD through improving serum lipid levels. Curcumin may be used as a well-tolerated dietary adjunct to conventional drugs. Further research is required to resolve uncertainties related to dosage form, dose and medication frequency of curcumin.

     

Diet quality and therapeutic targets in patients with type 2 diabetes: evaluation of concordance between dietary indexes

Background

This study aimed to evaluate the concordance between two dietary indexes, the Healthy Eating Index (HEI) and the Diabetes Healthy Eating Index (DHEI), in evaluating diet quality and its possible association with therapeutic targets in patients with type 2 diabetes.

Methods

Cross-sectional study of outpatients with type 2 diabetes mellitus treated at a university hospital. Dietary information was obtained from a quantitative food frequency questionnaire (previously validated for use in patients with type 2 diabetes) and converted into daily intakes. Diet quality was assessed using two dietary indexes: HEI (12 components, nine food groups and three moderation components) and DHEI (10 components, six food groups, three nutrient groups, and one for variety of diet). In both indexes, the sum of the scores for each component yields an overall score converted on a scale from 0 to 100%; diet quality is subsequently ranked as low (<51%), needing improvement (51–80%), or high (>80%). Patients underwent clinical and laboratory assessment. Those with fasting blood glucose values 70–130 mg/dL, A1c?<?7%, total cholesterol <200 mg/dL, LDL-cholesterol <100 mg/dL, and triglycerides <150 mg/dL were considered to meet therapeutic targets. All analyses were conducted in PASW Statistics 18.0, and p?<?0.05 deemed significant.

Results

We analyzed 148 patients with type 2 diabetes (73% white, mean age 63.2?±?9.4 years, median diabetes duration 10 [IQR 5–19] years, mean A1c% 8.4?±?2.0%, and mean BMI 30.5?±?4.2 kg/m²). Mean energy intake was 2114?±?649 kcal/day. DHEI scores were 17.0 (95%CI -6.8 to 41.0) points lower than HEI scores (55.9?±?14.2% vs. 72.9?±?10.7%, respectively; P?<?0.001), suggesting there is no agreement (Bland-Altman method), and the Pearson correlation coefficient was 0.55 (P?<?0.001). More patients were classified as having a low-quality diet by the DHEI than by the HEI (38.5% vs. 1.4%; P?<?0.001). A higher proportion of patients (35.7%) with out-of-target total cholesterol levels had a low-quality diet evaluated by the DHEI (P?=?0.03). We did not find associations between overall score of HEI and therapeutic targets.

Conclusions

In its intended population of patients with type 2 diabetes, the DHEI seems to be a more rigorous tool to evaluate association between diet quality and changes in metabolic parameters.

     

Dietary intake of professional Australian football athletes surrounding body composition assessment

Background

Sports Dietitians aim to assist in improving performance by developing nutrition knowledge (NK), enhancing dietary intake and optimising body composition of athletes. In a high-pressure environment, it is important to identify factors that may compromise an athlete’s nutrition status. Body composition assessments are regularly undertaken in sport to provide feedback on training adaptions; however, no research has explored the impact of these assessments on the dietary intake of professional athletes.

Methods

This cross-sectional study assessed dietary intake (7-day food diary), nutrition knowledge (Nutrition for Sport Knowledge Questionnaire) and body composition (Dual-energy X-ray absorptiometry) of 46 professional male Australian football (AFL) athletes during a 2017 pre-season training week (7 days) where body composition assessments were undertaken. Dietary intake was assessed against International Olympic Committee recommendations for professional athletes.

Results

Overall, no athlete met dietary their recommended energy intake (15?±?1.1 vs. 9.1?±?1.8 MJ, respectively) or carbohydrate recommendations (6–10 vs. 2.4?±?0.9 g·kg-1·day-1). Only 54% met protein recommendations. Secondary analyses demonstrated significant associations between education status and energy intake (P <?0.04) and vegetable intake (P <?0.03), with higher levels of education being associated with higher intakes. A moderately positive association was observed between NK scores and meeting estimated energy requirements (r =?0.33, P =?0.03). NK scores were also positively associated with protein (r =?0.35, P =?0.02), fibre (r =?0.51, P =?0.001) and calcium intakes (r =?0.43, P =?0.004).

Conclusions

This research identified that the dietary intake of professional AFL athletes during a pre-season training week where body composition assessments were undertaken did not meet current recommendations. Several factors may influence the dietary intake of AFL athletes, including lower education levels, poor NK and dietary intake restriction surrounding body composition assessment. Athletes may require support to continue with performance-based nutrition plans in periods surrounding body composition assessment.

     

Association of dietary patterns,anthropometric measurements,and metabolic parameters with C-reactive protein and neutrophil-to-lymphocyte ratio in middle-aged and older adults with metabolic syndrome in Taiwan: a cross-sectional study

Background

Metabolic syndrome is commonly associated with inflammation. The underlying factors of inflammation in metabolic syndrome are not fully understood. The objective of the study was to determine the association of dietary patterns, anthropometric measurements, and metabolic parameters with inflammatory markers in middle-aged and older adults with metabolic syndrome in Taiwan.

Methods

A total of 26,016 subjects aged ≥35 y with metabolic syndrome were recruited from Mei Jau institution between 2004 and 2013 for a cross sectional study. Metabolic syndrome was defined by the International Diabetes Federation. Multivariate logistic regression was performed to evaluate the association of dietary patterns, anthropometric measurements, and metabolic parameters with C-reactive protein (CRP) and neutrophil-to-lymphocyte ratio (NLR) in men and women with metabolic syndrome. Crude and adjusted models were analyzed by gender.

Results

The western dietary pattern, obesity, high body fat, high waist or hip circumference, and high waist-to-hip ratio were significantly associated with increased odds ratios of high CRP and NLR in both genders. High systolic or diastolic blood pressure (BP), low high-density lipoprotein-cholesterol (HDL-C), high low-density lipoprotein-cholesterol (LDL-C), high total cholesterol (TC), high serum triglycerides (TG), and high fasting blood glucose (FBG) were significantly correlated with increased odds ratios of high CRP in both genders. Low HDL-C, high LDL-C, high serum TG, and high FBG were significantly associated with increased odds ratios of high NLR in both genders. However, high systolic (OR?=?1.124, 95% CI 1.047–1.206, P?<?0.01) or diastolic BP (OR?=?1.176, 95% CI 1.087–1.273, P?<?0.001) and high TC (OR?=?1.138, 95% CI 1.062–1.220, P?<?0.001) were significantly correlated with increased odds ratios of high NLR only in men.

Conclusions

The western dietary pattern, obese-related anthropometric parameters, and most components of metabolic syndrome are positively associated with CRP levels and NLR in men and women with metabolic syndrome.

     

Citrulline malate supplementation does not improve German Volume Training performance or reduce muscle soreness in moderately trained males and females

Background

Use of supplements to aid performance is common practice amongst recreationally active individuals, including those without a sufficient evidence base. This investigation sought to assess whether acute supplementation with 8 g of citrulline malate (CM) (1.11: 1 ratio) would improve anaerobic performance.

Methods

A randomised double blind placebo control trial was employed, using a counterbalanced design. We recruited recreationally active men and women to take part in an isokinetic chair protocol, based on German Volume Training (GVT) whereby participants attempted to perform 10 sets of 10 repetitions against a force representing 70% of their peak concentric force.

Results

The number of repetitions achieved over the course of the GVT was 94.0?±?7.9 and 90.9?±?13.9 for placebo and CM respectively. There was no significant difference between the placebo and CM treatment for number of repetitions (P?=?0.33), isometric (P?=?0.60), concentric (P?=?0.38), or eccentric (P?=?0.65) peak force following the GVT. Total muscle soreness was significantly higher in the CM compared to the placebo treatment following the GVT protocol over 72 h (P?=?0.01); although this was not accompanied by a greater workload/number of repetitions in the CM group.

Conclusions

We conclude that an acute dose of CM does not significantly affect anaerobic performance using an isokinetic chair in recreational active participants. Practical implications include precaution in recommending CM supplementation. Coaches and athletes should be aware of the disparity between the chemical analyses of the products reviewed in the present investigation versus the manufacturers’ claims.

     

Cardiovascular and inflammatory mechanisms in healthy humans exposed to air pollution in the vicinity of a steel mill

Background

There is a paucity of mechanistic information that is central to the understanding of the adverse health effects of source emission exposures. To identify source emission-related effects, blood and saliva samples from healthy volunteers who spent five days near a steel plant (Bayview site, with and without a mask that filtered many criteria pollutants) and at a well-removed College site were tested for oxidative stress, inflammation and endothelial dysfunction markers.

Methods

Biomarker analyses were done using multiplexed protein-array, HPLC-Fluorescence, EIA and ELISA methods. Mixed effects models were used to test for associations between exposure, biological markers and physiological outcomes. Heat map with hierarchical clustering and Ingenuity Pathway Analysis (IPA) were used for mechanistic analyses.

Results

Mean CO, SO₂ and ultrafine particles (UFP) levels on the day of biological sampling were higher at the Bayview site compared to College site. Bayview site exposures “without” mask were associated with increased (p?<?0.05) pro-inflammatory cytokines (e.g IL-4, IL-6) and endothelins (ETs) compared to College site. Plasma IL-1β, IL-2 were increased (p?<?0.05) after Bayview site “without” compared to “with” mask exposures. Interquartile range (IQR) increases in CO, UFP and SO₂ were associated with increased (p?<?0.05) plasma pro-inflammatory cytokines (e.g. IL-6, IL-8) and ET-1_(1–21) levels. Plasma/saliva BET-1 levels were positively associated (p?<?0.05) with increased systolic BP. C-reactive protein (CRP) was positively associated (p?<?0.05) with increased heart rate. Protein network analyses exhibited activation of distinct inflammatory mechanisms after “with” and “without” mask exposures at the Bayview site relative to College site exposures.

Conclusions

These findings suggest that air pollutants in the proximity of steel mill site can influence inflammatory and vascular mechanisms. Use of mask and multiple biomarker data can be valuable in gaining insight into source emission-related health impacts.

     

The effect of chronic soluble keratin supplementation in physically active individuals on body composition,blood parameters and cycling performance

Background

Keratins are structural, thiol-rich proteins, which comprise 90% of total poultry feather weight. Their favourable amino acid profile suggests the potential for use as a protein source and ergogenic aid for endurance athletes, following treatment to increase digestibility. This study investigated whether 4 weeks of soluble keratin (KER) consumption (0.8 g/kg bodyweight/day) by 15 endurance-trained males would have favourable effects on body composition, blood and cardiorespiratory variables, and cycling performance, compared to casein protein (CAS).

Methods

Supplementation was randomized, blinded and balanced, with a minimum eight-week washout period between trials. An exercise test to measure oxygen consumption during submaximal and maximal cycling exercise was completed at the start at and end of each intervention. Anthropometric (DEXA) and blood measures were made prior to and following each intervention period.

Results

Total body mass and percentage body fat did not change significantly (p?>?0.05). However, a significantly greater increase in bone-free lean mass (LM) occurred with KER compared to CAS (0.88 kg vs 0.07 kg; p?<?0.05). While no change in LM was evident for the trunk and arms, leg LM increased (0.45?±?0.54 kg; p?=?0.006) from baseline with KER. KER was not associated with changes in blood parameters, oxygen consumption, or exercise performance (p?>?0.05).

Conclusions

These data suggest that KER is not useful as an ergogenic aid for endurance athletes but may be a suitable protein supplement for maximizing increases in lean body mass.

     

Novel essential amino acid supplements enriched with L-leucine facilitate increased protein and energy intakes in older women: a randomised controlled trial

Background

Inadequate protein intake (PI), containing a sub-optimal source of essential amino acids (EAAs), and reduced appetite are contributing factors to age-related sarcopenia. The satiating effects of dietary protein per se may negatively affect energy intake (EI), thus there is a need to explore alternative strategies to facilitate PI without compromising appetite and subsequent EI.

Methods

Older women completed two experiments (EXP1 and EXP2) where they consumed either a Bar (565 kJ), a Gel (477 kJ), both rich in EAAs (7.5 g, 40% L-leucine), or nothing (Control). In EXP1, participants (n?=?10, 68?±?5 years, mean?±?SD) consumed Bar, Gel or Control with appetite sensations and appetite-related hormonal responses monitored for one hour, followed by consumption of an ad libitum breakfast (ALB). In EXP2, participants (n?=?11, 69?±?5 years) ingested Bar, Gel or Control alongside an ALB.

Results

In EXP1, EI at ALB was not different (P?=?0.674) between conditions (1179?±?566, 1254?±?511, 1206?±?550 kJ for the Control, Bar, and Gel respectively). However, total EI was significantly higher in the Bar and Gel compared to the Control after accounting for the energy content of the supplements (P?<?0.0005). Analysis revealed significantly higher appetite Area under the Curve (AUC) (P?<?0.007), a tendency for higher acylated ghrelin AUC (P?=?0.087), and significantly lower pancreatic polypeptide AUC (P?=?0.02) in the Control compared with the Bar and Gel. In EXP2, EI at ALB was significantly higher (P?=?0.028) in the Control (1282?±?513 kJ) compared to the Bar (1026?±?565 kJ) and Gel (1064?±?495 kJ). However, total EI was significantly higher in the Bar and Gel after accounting for the energy content of the supplements (P?<?0.007).

Conclusions

Supplementation with either the Bar or Gel increased total energy intake whether consumed one hour before or during breakfast. This may represent an effective nutritional means for addressing protein and total energy deficiencies in older women.

Trial registration

Clinical trial register: retrospectively registered, ISRCTN12977929 on.

     

An empirical investigation of the impact of smoking on body weight using an endogenous treatment effects model approach: the role of food consumption patterns

Background

This study explored the influence of cigarette smoking and food consumption patterns on BMI after adjusting for various socio-demographic characteristics. Since weight-based stereotypes may have an impact on smoking behaviour and both obesity and smoking have been associated with detrimental health effects, an interdependency between them is quite possible.

Methods

Cross-sectional data were collected via a formal standardized questionnaire administered in personal interviews and two additional self-completion questionnaires from a random sample of 3471 German adults. The empirical framework considered potential endogeneity between smoking and body weight by employing an endogenous treatment effects model with an ordered outcome. The estimations derived from the endogenous treatment effects approach were also compared to the univariate ordered probit model results.

Results

Our findings showed that ignoring potential endogeneity may affect both the statistical significance of the smoking estimate and the direction of the influence of smoking on BMI. Smoking was positively associated with BMI in both male (β?=?1.236, p?<?0.01) and female (β?=?0.634, p?<?0.10) participants. Smokers presented a 23.1% higher risk of obesity and a 24.3% lower likelihood of being within a healthy weight range. Male smokers also appeared to have a considerably augmented probability of being obese compared to their female counterparts (23.6% vs 15.1%). The relationship between smoking and BMI may be attributed to dietary practices, since smoking was correlated with poor dietary habits characterized by the frequent intake of more energy-dense foods (meat products and white-toasted bread) and less frequent consumption of healthy food items, such as whole-grain bread, vegetables and fruits. Concerning the impact of eating habits on body weight, frequent consumption of meat products and confectionery was found to have a direct association with BMI in both genders. Furthermore, white-toasted bread consumption was negatively linked with body weight in males (β?=???0.337, p?<?0.01).

Conclusions

Our findings raised questions about the general belief that smoking is an effective weight control tool. Health interventions should be oriented toward a simultaneous decrease in smoking and obesity, since both behaviours seem to be interdependent. Nutrition programmes should also be designed according to the characteristics of different target groups in order to promote a healthy lifestyle.

     

Priority use of medium-chain fatty acids during high-intensity exercise in cross-country skiers

Background

One of the topics discussed in sports science is the use of medium-chain saturated fat as an energy-saving nutrient additive when approaching high-intensity exercise. The purpose of this study was to compare the blood concentrations of medium-chain and long-chain fatty acids (FAs) across different intensity loads.

Methods

Fifteen male highly trained athletes from the Russian cross-country skiing team participated in the study. Blood samples were drawn at rest, at the peak of veloergometric test with a growing exercise load till exhaustion (97–100% VO2max), and after competitions. The plasma FA profile was determined using gas-liquid chromatography.

Results

We observed a substantial increase in the concentrations of capric acid (С10:0) (+?164.1%), lauric acid (С12:0) (+?223.9%), and myristic acid (С14:0) (+?130.2%) in skiers after a sprint distance (1.3?km). A less intense increase in the concentrations of these acids (p?<?0.05) was observed after a middle length distance or cycle exercise «until exhaustion». No significant differences in long-chain saturated FA content relative to baselines during exercise tests or competitions were revealed.

Conclusions

In conclusion, the obtained results demonstrate activation of the lipolysis and the oxidation of medium-chain FA involved in the energy supply for highly trained athletes at maximum exercise loads.

     

A health facility based case-control study on determinants of low birth weight in Dassie town,Northeast Ethiopia: the role of nutritional factors

Background

Low birth weight remains a major public health problem affecting developing countries. Evidence shows that low birth weight has long lasting negative health consequences through its contribution to stunting, mental impairment and non-communicable chronic diseases in later life. Thus, it is worth investigating the role of nutritional factors as determinants of low birth weight to suggest nutritional interventions to curb its negative health outcomes. This study aimed to investigate the determinants of low birth weight with main focus on the role of nutritional factors in Ethiopia.

Methods

A facility-based case-control study was conducted from 3 February to 29 April, 2017. The data were collected using structured, pretested interviewer-administered questionnaire in all public health facilities of Dessie Town. Anthropometric measurements were made following standard procedures for both mothers and their newborns. Consecutive live births of <?2500 g and two succeeding normal weight babies were selected as cases and controls, respectively. Data were entered in to Epi-data software version 3.1, and exported to SPSS version 21, and analyzed using frequency, mean and percentage. Factors with p?<?0.25 during bivariate analyses were entered into a multivariable logistic regression model to determine significant determinants of LBW. Statistical significance was considered at p?<?0.05. Results were reported with odds ratio and 95% CI.

Results

Mean?±?SD of birth weight (g) was 2138?±?207 for cases and 3145?±?415 for controls. After adjusting for potential confounders using multivariable logistic regression analysis, the absence of iron and folate supplementation, receiving no nutritional counseling and consuming no additional meal, maternal undernutrition, maternal anemia and inadequate dietary diversity during the current pregnancy were found to be significant determinants of low birth weight in our study.

Conclusion

Lack of nutritional counseling, absence of additional meal intake and iron and folate supplementation during pregnancy, and maternal undernutrition, maternal anemia and inadequate maternal dietary diversity were significant determinants of low birth weight. The importance of nutritional counseling, improving iron and folate supplementation during pregnancy, and nutritional status of pregnant women need to be strengthened to reduce the incidence of LBW in Ethiopia. In addition, behavioral change communications targeting pregnant women to improve women dietary diversity and their extra meal intake practice need to be enhanced in Ethiopia.

     

Efficacy of a nootropic spearmint extract on reactive agility: a randomized,double-blind,placebo-controlled,parallel trial

Background

Proprietary spearmint extract (PSE) containing a minimum 14.5% rosmarinic acid and 24% total phenolic content, has evinced positive effects on cognition in individuals aged 50–70 with memory impairment after chronic supplementation. To address the growing interest in connecting mental and physical performance, the present study examined whether the nootropic effects of PSE translate into changes in reactive agility following daily supplementation with PSE.

Methods

Utilizing a randomized, double-blind, placebo-controlled, parallel design, healthy, recreationally-active men and women (n?=?142) received 900?mg of PSE or placebo (PLA) daily for 90?days. Reactive agility, our primary outcome, was determined by measuring the number of hits and average reaction time (ART) on a Makoto Arena II, a 360⁰ audio-visual device that measures stationary, lateral, and multi-directional active choice reaction performance. Safety was evaluated using complete blood count, comprehensive metabolic panel, and blood lipids. Measurements were evaluated on days 7, 30, and 90 of supplementation.

Results

An overall treatment effect (p?=?0.019) was evident for increased hits with PSE on the stationary test with footplates, with between group differences at Day 30 (PSE vs. PLA: 28.96?±?2.08 vs. 28.09?±?1.92 hits; p?=?0.040) and Day 90 (PSE vs. PLA: 28.42?±?2.54 vs. 27.02?±?3.55 hits; p?=?0.002). On the same task, ART improved (treatment effect, p?=?0.036) with PSE at Day 7 (PSE vs. PLA: 0.5896?±?0.060 vs. 0.6141?±?0.073?s; p?=?0.049) and Day 30 (PSE vs. PLA: 0.5811?±?0.068 vs. 0.6033?±?0.055?s; p?=?0.049). PSE also significantly increased hits (treatment effect, p?=?0.020) at Day 30 (PSE vs. PLA: 19.25?±?1.84 vs. 18.45?±?1.48 hits; p?=?0.007) and Day 90 (PSE vs. PLA: 19.39?±?1.90 vs. 18.66?±?1.64 hits; p?=?0.026) for the multi-directional test with footplates. Significant differences were not observed in the remaining Makoto tests. PSE was well tolerated as evidenced by no effects observed in the blood safety panels.

Conclusions

The findings of the current study demonstrate that consumption of 900?mg of PSE improved specific measures of reactive agility in a young, active population.

Trial registration

clinicaltrials.gov, NCT02518165. Registered August 7, 2015 – retrospectively registered.

     

Effects of cow’s milk beta-casein variants on symptoms of milk intolerance in Chinese adults: a multicentre,randomised controlled study

Background

A major protein component of cow’s milk is β-casein. The most frequent variants in dairy herds are A1 and A2. Recent studies showed that milk containing A1 β-casein promoted intestinal inflammation and exacerbated gastrointestinal symptoms. However, the acute gastrointestinal effects of A1 β-casein have not been investigated. This study compared the gastrointestinal effects of milk containing A1 and A2 β-casein versus A2 β-casein alone in Chinese adults with self-reported lactose intolerance.

Methods

In this randomised, crossover, double-blind trial, with a 3-day dairy washout period at baseline, subjects were randomised to consume 300 mL of milk containing A1 and A2 β-casein (ratio 58:42; conventional milk) or A2 β-casein alone; subjects consumed the alternative product after a 7-day washout period. Urine galactose was measured at baseline after a 15 g lactose load. Subjects completed 9-point visual analogue scales for gastrointestinal symptoms (borborygmus, flatulence, bloating, abdominal pain, stool frequency, and stool consistency) at baseline and at 1, 3, and 12 h after milk consumption.

Results

A total of 600 subjects were included. All six symptom scores at 1 and 3 h were significantly lower after consuming A2 β-casein versus conventional milk (all P<0.0001). At 12 h, significant differences remained for bloating, abdominal pain, stool frequency, and stool consistency (all P<0.0001). Symptom scores were consistently lower with A2 β-casein in both lactose absorbers (urinary galactose ≥0.27 mmol/L) and lactose malabsorbers (urinary galactose <0.27 mmol/L).

Conclusion

Milk containing A2 β-casein attenuated acute gastrointestinal symptoms of milk intolerance, while conventional milk containing A1 β-casein reduced lactase activity and increased gastrointestinal symptoms compared with milk containing A2 β-casein. Thus, milk-related gastrointestinal symptoms may result from the ingestion of A1 β-casein rather than lactose in some individuals.

Trial registration

NCT02878876, registered August 16, 2016. Retrospectively registered.

     

Walnut consumption in a weight reduction intervention: effects on body weight,biological measures,blood pressure and satiety

Background

Dietary strategies that help patients adhere to a weight reduction diet may increase the likelihood of weight loss maintenance and improved long-term health outcomes. Regular nut consumption has been associated with better weight management and less adiposity. The objective of this study was to compare the effects of a walnut-enriched reduced-energy diet to a standard reduced-energy-density diet on weight, cardiovascular disease risk factors, and satiety.

Methods

Overweight and obese men and women (n =?100) were randomly assigned to a standard reduced-energy-density diet or a walnut-enriched (15% of energy) reduced-energy diet in the context of a behavioral weight loss intervention. Measurements were obtained at baseline and 3- and 6-month clinic visits. Participants rated hunger, fullness and anticipated prospective consumption at 3 time points during the intervention. Body measurements, blood pressure, physical activity, lipids, tocopherols and fatty acids were analyzed using repeated measures mixed models.

Results

Both study groups reduced body weight, body mass index and waist circumference (time effect p <?0.001 for each). Change in weight was ?9.4 (0.9)% vs. -8.9 (0.7)% (mean [SE]), for the standard vs. walnut-enriched diet groups, respectively. Systolic blood pressure decreased in both groups at 3 months, but only the walnut-enriched diet group maintained a lower systolic blood pressure at 6 months. The walnut-enriched diet group, but not the standard reduced-energy-density diet group, reduced total cholesterol and low-density lipoprotein cholesterol (LDL-C) at 6 months, from 203 to 194 mg/dL and 121 to 112 mg/dL, respectively (p <?0.05). Self-reported satiety was similar in the groups.

Conclusions

These findings provide further evidence that a walnut-enriched reduced-energy diet can promote weight loss that is comparable to a standard reduced-energy-density diet in the context of a behavioral weight loss intervention. Although weight loss in response to both dietary strategies was associated with improvements in cardiovascular disease risk factors, the walnut-enriched diet promoted more favorable effects on LDL-C and systolic blood pressure.

Trial registration

The trial is registered at (NCT02501889).

     

Comparison of a sports-hydration drink containing high amylose starch with usual hydration practice in Australian rules footballers during intense summer training

Background

Fluid deficits exceeding 1.6% can lead to physical and cognitive impairment in athletes. Sport drinks used by athletes are often hyper-osmolar but this is known to be suboptimal for rehydration in medical settings and does not utilize colonic absorptive capacity. Colonic absorption can be enhanced by fermentative production of short chain fatty acids (SCFA) from substrates such as high amylose maize starch (HAMS). This study therefore compared, in elite Australian Football League (AFL) players at the height of outdoor summer training, a novel dual-action sports oral rehydration strategy that contained HAMS as well as glucose, to their usual rehydration practices (Control). The primary outcome markers of hydration were hematocrit and body weight.

Methods

A randomized single-blind crossover study was undertaken in thirty-one AFL players; twenty-seven completed the study which was conducted on four days (two days in the Intervention arm and two in Control arm). The Intervention arm was comprised a 50-100 g evening preload of an acetylated HAMS (Ingredion Pty Ltd) followed by consumption of a specially formulated sports oral rehydration solution (SpORS) drink during intense training and recovery. Players followed their usual hydration routine in the Control arm. Quantitative assessments of body weight, hematocrit and urine specific gravity were made at three time-points on each day of training: pre-training, post-training (90 min), and at end of recovery (30–60 min later). GPS tracking monitored player exertion.

Results

Across the three time-points, hematocrit was significantly lower and body weight significantly higher in Intervention compared to Control arms (p <?0.02 and p =?0.001 respectively, mixed effects model). Weights were significantly heavier at all three assessment points for Intervention compared to Control arms (Δ =?0.30?±?0.13, p =?0.02 pre-training; Δ =?0.43?±?0.14, p =?0.002 post training; and Δ =?0.68?±?0.14, p <?0.001 for recovery). Between the pre-training and end-of-recovery assessments, the Control arm lost 0.80 kg overall compared with 0.12 kg in the Intervention arm, an 85% lower reduction of bodyweight across the assessment period.

Conclusion

The combination of the significantly lower hematocrit and increased body weight in the Intervention arm represents better hydration not only at the end of training as well as following a recovery period but also at its commencement. The magnitude of the benefit seems sufficient to have an impact on performance and further studies to test this possibility are now indicated.

Trial registration

Trial is listed on the Australian New Zealand Clinical Trials Registry (ACTRN 12613001373763). 

     

Examining the validity and utility of two secondary sources of food environment data against street audits in England

Background

Secondary data containing the locations of food outlets is increasingly used in nutrition and obesity research and policy. However, evidence evaluating these data is limited. This study validates two sources of secondary food environment data: Ordnance Survey Points of Interest data (POI) and food hygiene data from the Food Standards Agency (FSA), against street audits in England and appraises the utility of these data.

Methods

Audits were conducted across 52 Lower Super Output Areas in England. All streets within each Lower Super Output Area were covered to identify the name and street address of all food outlets therein. Audit-identified outlets were matched to outlets in the POI and FSA data to identify true positives (TP: outlets in both the audits and the POI/FSA data), false positives (FP: outlets in the POI/FSA data only) and false negatives (FN: outlets in the audits only). Agreement was assessed using positive predictive values (PPV: TP/(TP?+?FP)) and sensitivities (TP/(TP?+?FN)). Variations in sensitivities and PPVs across environment and outlet types were assessed using multi-level logistic regression. Proprietary classifications within the POI data were additionally used to classify outlets, and agreement between audit-derived and POI-derived classifications was assessed.

Results

Street audits identified 1172 outlets, compared to 1100 and 1082 for POI and FSA respectively. PPVs were statistically significantly higher for FSA (0.91, CI: 0.89–0.93) than for POI (0.86, CI: 0.84–0.88). However, sensitivity values were not different between the two datasets. Sensitivity and PPVs varied across outlet types for both datasets. Without accounting for this, POI had statistically significantly better PPVs in rural and affluent areas. After accounting for variability across outlet types, FSA had statistically significantly better sensitivity in rural areas and worse sensitivity in rural middle affluence areas (relative to deprived). Audit-derived and POI-derived classifications exhibited substantial agreement (p?<?0.001; Kappa?=?0.66, CI: 0.63–0.70).

Conclusions

POI and FSA data have good agreement with street audits; although both datasets had geographic biases which may need to be accounted for in analyses. Use of POI proprietary classifications is an accurate method for classifying outlets, providing time savings compared to manual classification of outlets.

     

The effect of two β-alanine dosing strategies on 30-minute rowing performance: a randomized,controlled trial

Background

β-alanine (βA) supplementation has been shown to increase intramuscular carnosine content and subsequent high-intensity performance in events lasting <?4?minutes (min), which may be dependent on total, as opposed to daily, dose. The ergogenic effect of βA has also been demonstrated for 2000-m rowing performance prompting interest in whether βA may be beneficial for sustained aerobic exercise. This study therefore investigated the effect of two βA dosing strategies on 30-min rowing and subsequent sprint performance.

Methods

Following University Ethics approval, twenty-seven healthy, male rowers (age: 24?±?2?years; body-height: 1.81?±?0.02?m; body-mass: 82.3?±?2.5?kg; body-fat: 14.2?±?1.0%) were randomised in a double-blind manner to 4?weeks of: i) βA (2.4?g·d^??1, βA1); ii) matched total βA (4.8?g on alternate days, βA2); or iii) cornflour placebo (2.4?g·d^??1, PL). Participants completed a laboratory 30-min rowing time-trial, followed by 3x30-seconds (s) maximal sprint efforts at days 0, 14 and 28 (T1-T3). Total distance (m), average power (W), relative average power (W·kg^??1), cardio-respiratory measures and perceived exertion were assessed for each 10-min split. Blood lactate ([La-]_b mmol·L^??1) was monitored pre-post time-trial and following maximal sprint efforts. A 3-way repeated measures ANOVA was employed for main analyses, with Bonferonni post-hoc assessment (P?≤?0.05).

Results

Total 30-min time-trial distance significantly increased from T1-T3 within βA1 only (7397?±?195?m to 7580?±?171?m, P?=?0.002, ?p²?=?0.196), including absolute average power (194.8?±?18.3?W to 204.2?±?15.5?W, P?=?0.04, ?p²?=?0.115) and relative average power output (2.28?±?0.15?W·kg^??1 to 2.41?±?0.12?W·kg^??1, P?=?0.031, ?p²?=?0.122). These findings were potentially explained by within-group significance for the same variables for the first 10?min split (P?≤?0.01), and for distance covered (P?=?0.01) in the second 10-min split. However, no condition x time interactions were observed. No significant effects were found for sprint variables (P?>?0.05) with comparable values at T3 for mean distance (βA1: 163.9?±?3.8?m; βA2: 161.2?±?3.5?m; PL: 162.7?±?3.6?m), average power (βA1: 352.7?±?14.5?W; βA2: 342.2?±?13.5?W; PL: 348.2?±?13.9?W) and lactate (βA1: 10.0?±?0.9?mmol·L^??1; βA2: 9.2?±?1.1?mmol·L^??1; PL: 8.7?±?0.9?mmol·L^??1).

Conclusions

Whilst daily βA may confer individual benefits, these results demonstrate limited impact of βA (irrespective of dosing strategy) on 30-min rowing or subsequent sprint performance. Further investigation of βA dosage >?2.4?g·d^??1 and/or chronic intervention periods (>?4–8?weeks) may be warranted based on within-group observations.