Meghan A. Brown

Effects of Montmorency tart cherry (Prunus Cerasus L.) consumption on vascular function in men with early hypertension

BACKGROUND Tart cherries contain numerous polyphenolic compounds that could potentially improve endothelial function and reduce cardiovascular disease risk. OBJECTIVE We sought to examine the acute effects of Montmorency tart cherry (MC) juice on vascular function in subjects with early hypertension. DESIGN A placebo-controlled, blinded, crossover, randomized Latin square design study with a washout period of ≥14 d was conducted. Fifteen men with early hypertension [systolic blood pressure (SBP) ≥130 mm Hg, diastolic blood pressure ≥80 mm Hg, or both] received either a 60-mL dose of MC concentrate or placebo. Microvascular reactivity (laser Doppler imaging with iontophoresis), arterial stiffness (pulse wave velocity and analysis), blood pressure, and phenolic acid absorption were assessed at baseline and at 1, 2, 3, 5, and 8 h postconsumption. RESULTS MC consumption significantly lowered SBP (P < 0.05) over a period of 3 h, with peak reductions of mean ± SEM 7 ± 3 mm Hg 2 h after MC consumption relative to the placebo. Improvements in cardiovascular disease risk factors were closely linked to increases in circulating protocatechuic and vanillic acid at 1-2 h. CONCLUSIONS MC intake acutely reduces SBP in men with early hypertension. These benefits may be mechanistically linked to the actions of circulating phenolic acids. This study provides information on a new application of MCs in health maintenance, particularly in positively modulating SBP. This trial was registered at clinicaltrials.gov as NCT02234648.

Calcium Ingestion Suppresses Appetite and Produces Acute Overcompensation of Energy Intake Independent of Protein in Healthy Adults

BACKGROUND Prior evidence suggests that high-calcium intake influences postprandial appetite and insulinemia, possibly due to elevated incretins. In vitro and ex vivo models demonstrate that extracellular calcium and protein synergistically enhance secretion of incretins. This is yet to be shown in humans. OBJECTIVE This study was designed to assess energy intake compensation in response to protein and calcium ingestion. METHODS Twenty healthy adults (13 men; 7 women) completed 4 trials in a randomized, double-blind crossover design separated by ≥48 h. During the trials, each participant consumed a low-calcium and low-protein control preload [(CON); 4 g and 104 mg, respectively], a high-protein preload (PRO; 29 g), a high-calcium preload (CAL; 1170 mg), or a high-protein and high-calcium preload (PROCAL). Blood samples were collected at baseline and 15, 30, 45, and 60 min after preload ingestion to determine insulin and incretin hormone concentrations. Energy intake was assessed by a homogenous test meal 60 min after the preload. Visual analog scales were completed immediately before blood sampling to assess subjective appetite sensations. RESULTS Relative to the CON, the PRO produced 100% (95% CI: 85%, 115%) energy compensation, whereas the CAL produced significant overcompensation [118% (95% CI: 104%, 133%)], which was significantly more positive than with the PRO (P < 0.05). The PROCAL resulted in energy compensation of 109% (95% CI: 95%, 123%), which tended to be greater than with the PRO (P = 0.06). The mean difference in appetite sensations relative to the CON was not significantly different between the PRO (-3 mm; 95% CI: -8, 3 mm), CAL (-5 mm; 95% CI: -9, 0 mm), and PROCAL (-5 mm; 95% CI: -10, -1 mm) (P > 0.05). CONCLUSIONS The addition of protein to a preload results in almost perfect energy compensation, whereas the addition of calcium, with or without protein, suppresses appetite and produces overcompensation of subsequent energy intake. The role of circulating insulin and incretin concentrations in these responses, however, remains unclear. This trial was registered at clinicaltrials.gov as NCT01986036.

Minimal muscle damage after a marathon and no influence of beetroot juice on inflammation and recovery

This study examined whether beetroot juice (BTJ) would attenuate inflammation and muscle damage following a marathon. Using a double blind, independent group design, 34 runners (each having completed ca. ∼16 previous marathons) consumed either BTJ or an isocaloric placebo (PLA) for 3 days following a marathon. Maximal isometric voluntary contractions (MIVC), countermovement jumps (CMJ), muscle soreness, serum cytokines, leucocytosis, creatine kinase (CK), high sensitivity C-reactive protein (hs-CRP), and aspartate aminotransferase (AST) were measured pre, post, and 2 days after the marathon. CMJ and MIVC were reduced after the marathon (P < 0.05), but no group differences were observed (P > 0.05). Muscle soreness was increased in the day after the marathon (BTJ; 45 ± 48 vs. PLA; 46 ± 39 mm) and had returned to baseline by day 2, irrespective of supplementation (P = 0.694). Cytokines (interleukin-6; IL-6, interleukin-8, tumour necrosis factor-α) were increased immediately post-marathon but apart from IL-6 had returned to baseline values by day 1 post. No interaction effects were evident for IL-6 (P = 0.213). Leucocytes increased 1.7-fold after the race and remained elevated 2 days post, irrespective of supplement (P < 0.0001). CK peaked at 1 day post marathon (BTJ: 965 ± 967, and PLA: 1141 ± 979 IU·L-1) and like AST and hs-CRP, was still elevated 2 days after the marathon (P < 0.05); however, no group differences were present for these variables. Beetroot juice did not attenuate inflammation or reduce muscle damage following a marathon, possibly because most of these indices were not markedly different from baseline values in the days after the marathon.

The Effect of a Dairy-Based Recovery Beverage on Post-Exercise Appetite and Energy Intake in Active Females.

This study was designed to assess the effect of a dairy-based recovery beverage on post-exercise appetite and energy intake in active females. Thirteen active females completed three trials in a crossover design. Participants completed 60 min of cycling at 65% V̇O2peak, before a 120 min recovery period. On completion of cycling, participants consumed a commercially available dairy-based beverage (DBB), a commercially available carbohydrate beverage (CHO), or a water control (H2O). Non-esterified fatty acids, glucose, and appetite-related peptides alongside measures of subjective appetite were sampled at baseline and at 30 min intervals during recovery. At 120 min, energy intake was assessed in the laboratory by ad libitum assessment, and in the free-living environment by weighed food record for the remainder of the study day. Energy intake at the ad libitum lunch was lower after DBB compared to H2O (4.43 ± 0.20, 5.58 ± 0.41 MJ, respectively; p = 0.046; (95% CI: −2.28, −0.20 MJ)), but was not different to CHO (5.21 ± 0.46 MJ), with no difference between trials thereafter. Insulin and GLP-17-36 were higher following DBB compared to H2O (p = 0.015 and p = 0.001, respectively) but not to CHO (p = 1.00 and p = 0.146, respectively). In addition, glucagon was higher following DBB compared to CHO (p = 0.008) but not to H2O (p = 0.074). The results demonstrate that where DBB consumption may manifest in accelerated recovery, this may be possible without significantly affecting total energy intake and subsequent appetite-related responses relative to a CHO beverage.

Whey protein hydrolysate supplementation accelerates recovery from exercise-induced muscle damage in females

A number of different forms of protein and their analogues have been investigated for their efficacy in ameliorating exercise-induced muscle damage (EIMD) and recovery. Preliminary data regarding whey protein hydrolysate (WPH) supplementation are promising. However, its efficacy beyond acute eccentric/resistance exercise bouts or longer term training programmes are limited and all investigations have been conducted in male or mixed-sex groups. This study sought to elucidate whether the benefits of WPH previously reported can be demonstrated in females following repeated-sprint exercise. Twenty physically active females were assigned to consume 2 doses of 70 mL WPH or isoenergetic carbohydrate (CHO) for 4 days post-EIMD. Measures of muscle soreness, limb girth, flexibility, muscle function, and creatine kinase were collected before, immediately after, and 24, 48, and 72 h postexercise. Time effects were observed for all variables (p < 0.05) except limb girth, which is indicative of EIMD. Flexibility improved beyond baseline measures following WPH by 72 h, but had failed to recover in the CHO group (p = 0.011). Reactive strength index was higher throughout recovery in the WPH group compared with CHO (p = 0.016). Reductions in creatine kinase were greater following WPH compared with CHO at 48 h post-EIMD (p = 0.031). The findings suggest that 4-day supplementation of WPH is beneficial for reducing symptoms of EIMD and improving recovery of muscle function in physically active females.

Energy Intake and Energy Expenditure of Pre-professional Female Contemporary Dancers

Many athletes in aesthetic and weight dependent sports are at risk of energy imbalance. However little is known about the exercise and eating behaviours of highly trained dance populations. This investigation sought to determine the energy intake and energy expenditure of pre-professional female contemporary dancers. Twenty-five female contemporary dance students completed the study. Over a 7-day period, including five week days (with scheduled dance training at a conservatoire) and two weekend days (with no scheduled dance training at the conservatoire), energy intake (self-reported weighed food diary and 24 h dietary recall) and expenditure (tri-axial accelerometry) were recorded. Mean daily energy intake and expenditure were different over the 7-day period (P = 0.014) equating to an energy deficit of -356 ± 668 kcal·day-1 (or -1.5 ± 2.8 MJ·day-1). Energy expenditure was not different when comparing week and weekend days (P = 0.297). However daily energy intake (P = 0.002), energy availability (P = 0.003), and energy balance (P = 0.004) were lower during the week compared to the weekend, where energy balance became positive. The percentage contribution of macronutrients to total energy intake also differed; with higher fat (P = 0.022) and alcohol (P = 0.020), and lower carbohydrate (P = 0.001) and a trend for lower protein (P = 0.051) at the weekend. Energy balance and appropriate macronutrient intake are essential for maintaining the demands of training, performance and recovery. Whilst aesthetics are important, female contemporary dancers may be at risk of the numerous health and performance impairments associated with negative energy balance, particularly during periods of scheduled training.

Adaptation to Damaging Dance and Repeated-sprint Activity in Women

Abstract Brown, MA, Howatson, G, Keane, KM, and Stevenson, EJ. Adaptation to damaging dance and repeated-sprint activity in women. J Strength Cond Res 30(9): 2574–2581, 2016—The repeated bout effect (RBE) refers to the prophylactic effect from damaging exercise after a single previous bout of exercise. There is a paucity of data examining the RBE in women, and investigations using exercise paradigms beyond isolated eccentric contractions are scarce. In light of the limited literature, this investigation aimed to determine whether 2 different sport-specific exercise bouts would elicit a RBE in women. Twenty-one female dancers (19 ± 1 years) completed either a dance-specific protocol (n = 10) or sport-specific repeated-sprint protocol (n = 11). Delayed-onset muscle soreness (DOMS), limb girths, creatine kinase (CK), countermovement jump height, reactive strength index, maximal voluntary contraction, and 30-meter sprint time were recorded before and 0, 24, 48, and 72 hours after exercise. An identical exercise bout was conducted approximately 4 weeks after the initial bout, during which time the subjects maintained habitual training and dietary behaviors. DOMS and 30-meter sprint time decreased after a second bout of both activities (p = 0.003; = 0.38 and p = 0.008; and = 0.31, respectively). Circulating CK was also lower at 24, 48, and 72 hours after the second bout, independent of group (p = 0.010 and = 0.23). Compared with the repeated-sprint protocol, the magnitude of change in DOMS was greater after a subsequent bout of the dance protocol (p = 0.010 and = 0.19). These data are the first to demonstrate that dance and repeated-sprint activity resulting in muscle damage in women confers a protective effect against muscle damage after a subsequent bout.

Montmorency tart cherry (Prunus cerasus L.) supplementation accelerates recovery from exercise-induced muscle damage in females

Abstract Tart Montmorency cherry concentrate (MC) has been reported to attenuate the symptoms of exercise-induced muscle damage (EIMD) and to accelerate exercise recovery, which has been attributed to its high anti-inflammatory and antioxidant properties. Although these data are promising, there are no data regarding exclusively female populations. Therefore, the aim of this investigation was to examine the efficacy of MC on recovery following EIMD in females. In a randomised, double-blind, placebo-controlled study, twenty physically active females (mean ± SD age 19 ± 1 y; stature 167 ± 6 cm; body mass 61.4 ± 5.7 kg) consumed MC or a placebo (PL) for eight days (30 mL twice per day). Following four days of supplementation, participants completed a repeated-sprint protocol and measures of muscle soreness (DOMS), pain pressure threshold (PPT), limb girth, flexibility, muscle function, and systemic indices of muscle damage and inflammation were collected pre, immediately post (0 h) and 24, 48 and 72 h post-exercise. Time effects were observed for all dependent variables (p < 0.05) except limb girth and high sensitivity C-reactive protein. Recovery of countermovement jump height was improved in the MC group compared to PL (p = 0.016). There was also a trend for lower DOMS (p = 0.070) and for higher PPT at the rectus femoris (p = 0.071) in the MC group. The data demonstrate that MC supplementation may be a practical nutritional intervention to help attenuate the symptoms of muscle damage and improve recovery on subsequent days in females.

Independent and synergistic effects of calcium and protein on appetite and energy intake in humans

There is convincing evidence that a high protein intake supresses appetite and reduces subsequent energy intake; associated with increases in satiety and the release of several gut peptides. Calcium intake may also elicit an improvement in appetite regulation and reduce subsequent energy intake, although the few studies that have assessed its direct impact are controversial. We aimed to assess whether calcium and protein exhibit a synergistic effect on appetite and energy intake as well as influencing these independently. Healthy male (n= 13) and female (n= 7) adults were recruited for the study. In a randomised double-blind, cross-over design each participant completed four trials. Each trial consisted of consuming a porridge based pre-load in a fasted state with differing calcium and protein content (porridge only, CON; high protein, PRO; high calcium, CAL; high protein and calcium, PROCAL). Visual analogue scales were used to determine subjective appetite sensations pre and at 15 min intervals during a 60 min post-prandial period, which was followed by the consumption of a pasta based test-meal ad-libitum. Time-averaged area under the curve subjective appetite ratings and mean food (g) and energy (kJ) intake of the ad-libitum test-meal in each trial were compared using ANOVA.