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1.
Four Days of Blueberry Powder Supplementation Lowers the Blood Lactate Response to Running But Has No Effect on Time-Trial Performance.
Brandenburg, JP, Giles, LV
International journal of sport nutrition and exercise metabolism. 2019;(6):636-642
Abstract
Blueberries are abundant with anthocyanins possessing antioxidant and anti-inflammatory properties. As these properties combat fatigue and promote recovery, blueberry supplementation may enhance performance and recovery. Thus, the objectives were to examine the effects of two blueberry supplementation protocols on running performance, physiological responses, and short-term recovery. Using a randomized, double-blind, placebo (PLA)-controlled crossover design, 14 runners completed an 8-km time trial (TT) after supplementation with 4 days of blueberries (4DAY), 4 days of a PLA, or 2 days of placebo followed by 2 days of blueberries (2DAY). Heart rate and ratings of perceived exertion were monitored during the TT. Blood lactate, vertical jump, reactive strength index, and salivary markers were assessed before and after. No significant differences were observed for time to complete the TT (PLA: 3,010 ± 459 s; 2DAY: 3,014 ± 488 s; 4DAY: 3,011 ± 423 s), heart rate, ratings of perceived exertion, or any of the salivary markers. An interaction effect (p = .027) was observed for blood lactate, with lower post-TT concentrations in 4DAY (5.4 ± 2.0 mmol/L) than PLA (6.6 ± 2.5 mmol/L; p = .038) and 2DAY (7.4 ± 3.4 mmol/L; p = .034). Post-TT decreases in vertical jump height were not different, whereas the decline in reactive strength index was less following 4DAY (-6.1% ± 13.5%) than the other conditions (PLA: -12.6% ± 10.1%; 2DAY: -11.6% ± 11.5%; p = .038). Two days of supplementation did not influence performance or physiological stress. Although 4 days of supplementation did not alter performance, it blunted the increase in blood lactate, perhaps reflecting altered lactate production and/or clearance, and offset the decrease in dynamic muscle function post-TT, as indicated by the reactive strength index differences.
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2.
High doses of sodium bicarbonate increase lactate levels and delay exhaustion in a cycling performance test.
Ferreira, LHB, Smolarek, AC, Chilibeck, PD, Barros, MP, McAnulty, SR, Schoenfeld, BJ, Zandona, BA, Souza-Junior, TP
Nutrition (Burbank, Los Angeles County, Calif.). 2019;:94-99
Abstract
OBJECTIVES It is well established that ingestion of sodium bicarbonate (NaHCO3) causes metabolic alkalosis. However, there is no consensus in terms of optimal NaHCO3 doses leading to enhanced performance. This study aimed to determine the effects of different NaHCO3 doses on performance and lactate clearance in non-professional cyclists. METHODS Twenty-one cyclists performed the following three double-blind trials: 1) ingestion of 0.3 g · kg-1 body weight (BW) of placebo; 2) ingestion of 0.1 g · kg-1 BW NaHCO3 plus 0.2 g · kg-1 BW placebo (0.1 BC); and 3) ingestion of 0.3 g · kg-1 BW NaHCO3 (0.3 BC). Performance was evaluated after warm-up on the bike followed by a performance test until exhaustion. Lactate levels were monitored in blood samples before and immediately after performance tests. RESULTS Lactate levels in the blood were significantly higher after exercise in 0.3 BC and 0.1 BC (15.12 ± 0.92 versus 10.3 ± 1.22 and 13.24 ± 0.87 versus 10.3 ± 1.22 mmol/L; P < 0.05) compared with control. Significant improvements in performance were only identified in 0.3 BC group (76.42 ± 2.14; P = 0.01). CONCLUSIONS The present study found that 0.3 g · kg-1 BW NaHCO3 is effective in improving performance and improving blood lactate levels in cyclists compared with control and 0.1 g · kg-1 BW NaHCO3.
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3.
Hydrogen Rich Water Improved Ventilatory, Perceptual and Lactate Responses to Exercise.
Botek, M, Krejčí, J, McKune, AJ, Sládečková, B, Naumovski, N
International journal of sports medicine. 2019;(14):879-885
Abstract
The potential anti-fatigue and performance benefits of hydrogen rich water (HRW) have resulted in increased research interest over the past 5 years. The aim of this study was to assess physiological and perceptual responses to an incremental exercise protocol after administration of 600 ml HRW within 30 min before exercise. This randomized, double blinded placebo-controlled cross over study included twelve healthy males aged 27.1±4.9 years. The exercise protocol consisted of a 10 min warm-up at 1.0 W.kg-1, followed by 8 min at 2.0, 3.0, and 4.0 W.kg-1, respectively. Cardio-respiratory variables, lactate and ratings of perceived exertion (RPE) were assessed in the last minute of each step. A significantly lower blood lactate was found with HRW (4.0±1.6 and 8.9±2.2 mmol.l-1) compared to Placebo (5.1±1.9 and 10.6±3.0 mmol.l-1) at 3.0, and 4.0 W.kg-1, respectively. Ventilatory equivalent for oxygen and RPE exhibited significantly lower values with HRW (32.3±7.2, and 17.8±1.2 points, respectively) compared to Placebo (35.0±8.4, and 18.5±0.8 points, respectively) at 4 W.kg-1. To conclude, acute pre-exercise supplementation with HRW reduced blood lactate at higher exercise intensities, improved exercise-induced perception of effort, and ventilatory efficiency.
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4.
Syneresis investigations of lacto-fermented sodium caseinate in a mixed model system.
El Bouchikhi, S, Pagès, P, El Alaoui, Y, Ibrahimi, A, Bensouda, Y
BMC biotechnology. 2019;(1):57
Abstract
BACKGROUND The textural characteristics of fermented dairy products are important quality parameters that play a major role in their stability and consumer's acceptance. The aim of this study was to investigate the influence of sodium caseinate, starch, lactose and lactic acid bacteria as ferment on the syneresis in a mixed model system, and to evaluate their impact on the acid gel formation throughout pH and zeta potential monitoring. Accordingly, a protocol was designed to perform an experimental design by using a mixture of the selected factors. RESULTS A significant decrease of syneresis was detected in all mixtures at 8% of sodium caseinate, ranging between a minimum of 1.8% and a maximum of 20.6% compared to the mixtures at 3% of sodium caseinate in which the syneresis decrease had ranged between a minimum of 22.2% and a maximum of 47.8%. The addition of starch had a significant impact on the acidification profile and on the syneresis of the fermented mixed model. Moreover, the monitoring of pH and zeta potential during the lacto-fermentation process has also led to a better understanding of the acid gelation and the syneresis variations. CONCLUSION Syneresis varies very closely with sodium caseinate concentration, starch concentration and also with their association, regardless of the concentrations of lactose and ferment. In fact syneresis could be reduced to an optimum level if a sodium caseinate-starch mixed system is employed: Less syneresis gels could be obtained at a sodium caseinate concentration above 5% if starch is used above 1%.
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5.
The human central nervous system discharges carbon dioxide and lactic acid into the cerebrospinal fluid.
Akaishi, T, Onishi, E, Abe, M, Toyama, H, Ishizawa, K, Kumagai, M, Kubo, R, Nakashima, I, Aoki, M, Yamauchi, M, et al
Fluids and barriers of the CNS. 2019;(1):8
Abstract
BACKGROUND The central nervous system was previously thought to draw oxygen and nutrition from the arteries and discharge carbon dioxide and other metabolic wastes into the venous system. At present, the functional role of cerebrospinal fluid in brain metabolism is not fully known. METHODS In this prospective observational study, we performed gas analysis on venous blood and cerebrospinal fluid simultaneously acquired from 16 consecutive preoperative patients without any known neurological disorders. RESULTS The carbon dioxide partial pressure (pCO2) (p < 0.0001) and lactic acid level (p < 0.001) in the cerebrospinal fluid were significantly higher than those in the peripheral venous blood, suggesting that a considerable proportion of metabolic carbon dioxide and lactic acid is discharged from the central nervous system into the cerebrospinal fluid. The oxygen partial pressure (pO2) was much higher in the cerebrospinal fluid than in the venous blood, corroborating the conventional theory of cerebrospinal fluid circulatory dynamics. The pCO2 of the cerebrospinal fluid showed a strong negative correlation with age (R = - 0.65, p = 0.0065), but the other studied variables did not show significant correlation with age. CONCLUSION Carbon dioxide and lactic acid are discharged into the circulating cerebrospinal fluid, as well as into the venules. The level of carbon dioxide in the cerebrospinal fluid significantly decreased with age.
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6.
The effect of cold ambient temperature and preceding active warm-up on lactate kinetics in female cyclists and triathletes.
Morrissey, MC, Kisiolek, JN, Ragland, TJ, Willingham, BD, Hunt, RL, Hickner, RC, Ormsbee, MJ
Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme. 2019;(10):1043-1051
Abstract
The aim of this study was to evaluate the effect of cold ambient temperature on lactate kinetics with and without a preceding warm-up in female cyclists/triathletes. Seven female cyclists/triathletes participated in this study. The randomized, crossover study included 3 experimental visits that comprised the following conditions: (i) thermoneutral temperature (20 °C; NEU); (ii) cold temperature (0 °C) with no active warm-up (CNWU); and (iii) cold temperature (0 °C) with 25-min active warm-up (CWU). During each condition, participants performed a lactate threshold (LT) test followed by a time to exhaustion trial at 120% of the participant's peak power output (PPO) as determined during prior peak oxygen consumption testing. Power output at LT with CNWU was 10.2% ± 2.6% greater than with NEU, and the effect was considered very likely small (effect size (ES) = 0.59, 95%-99% likelihood). Power output at LT with CNWU was 4.2% ± 5.4% greater than with CWU; however, the effect was likely trivial (ES = 0.25, 75%-95% likelihood). At LT, there were no significant differences between interventions groups in oxygen consumption, blood lactate concentration, heart rate, or rating of perceived exertion. Time to exhaustion at 120% at PPO was 11% longer with CNWU than with CWU (ES = 0.62, respectively), and this effect was likely small. These findings suggest that power output at LT was higher in CNWU compared with NEU. Additionally, time to exhaustion at 120% of PPO was higher in CNWU compared with CWU and no different than NEU; these differences likely result in a small improvement in performance with CNWU versus CWU and NEU.
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7.
Dissimilatory iron and sulfate reduction by native microbial communities using lactate and citrate as carbon sources and electron donors.
Xia, D, Yi, X, Lu, Y, Huang, W, Xie, Y, Ye, H, Dang, Z, Tao, X, Li, L, Lu, G
Ecotoxicology and environmental safety. 2019;:524-531
Abstract
The bacterial (dissimilatory) iron and sulfate reduction (BIR and BSR) are intimately linked to the biogeochemical cycling of C, Fe, and S in acid mine drainage (AMD) environments. This study examined the response of native microbial communities to the reduction of iron and sulfate in bench experimental systems. Results showed that the reduction of ferric iron and sulfate took place when the electron acceptors coexist. Existence of Fe(III) can postpone the reduction of sulfate, but can enhance the reduction rate. Cultures grown in the presence of 10 mM iron can reach the final level of sulfate bio-reduction rate (~100%) after 35 days incubation. 16 S rDNA -based microbial community analysis revealed that the three genera Anaeromusa, Acinetobacter and Bacteroides were dominated in the ferric-reducing conditions. SRB (Desulfobulbus, Desulfosporosinus and Desulfovibrio) were dominated in the sulfate reduction process. Results in this study highlighted the highly coupled nature of C, Fe, and S biogeochemical cycles in AMD and provided insights into the potential of environmental remediation by native microbial.
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8.
Free lactic acid production under acidic conditions by lactic acid bacteria strains: challenges and future prospects.
Singhvi, M, Zendo, T, Sonomoto, K
Applied microbiology and biotechnology. 2018;(14):5911-5924
Abstract
Lactic acid (LA) is an important platform chemical due to its significant applications in various fields and its use as a monomer for the production of biodegradable poly(lactic acid) (PLA). Free LA production is required to get rid of CaSO4, a waste material produced during fermentation at neutral pH which will lead to easy purification of LA required for the production of biodegradable PLA. Additionally, there is no need to use corrosive acids to release free LA from the calcium lactate produced during neutral fermentation. To date, several attempts have been made to improve the acid tolerance of lactic acid bacteria (LAB) by using both genome-shuffling approaches and rational design based on known mechanisms of LA tolerance and gene deletion in yeast strains. However, the lack of knowledge and the complexity of acid-tolerance mechanisms have made it challenging to generate LA-tolerant strains by simply modifying few target genes. Currently, adaptive evolution has proven an efficient strategy to improve the LA tolerance of individual/engineered strains. The main objectives of this article are to summarize the conventional biotechnological LA fermentation processes to date, assess their overall economic and environmental cost, and to introduce modern LA fermentation strategies for free LA production. In this review, we provide a broad overview of free LA fermentation processes using robust LAB that can ferment in acidic environments, the obstacles to these processes and their possible solutions, and the impact on future development of free LA fermentation processes commercially.
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9.
Recent advancements in lactic acid production - a review.
Eş, I, Mousavi Khaneghah, A, Barba, FJ, Saraiva, JA, Sant'Ana, AS, Hashemi, SMB
Food research international (Ottawa, Ont.). 2018;:763-770
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10.
Longer-Period Effects of Bicarbonate/Lactate-Buffered Neutral Peritoneal Dialysis Fluid in Patients Undergoing Peritoneal Dialysis.
Hoshino, T, Kaneko, S, Minato, S, Yanai, K, Mutsuyoshi, Y, Ishii, H, Kitano, T, Shindo, M, Miyazawa, H, Aomatsu, A, et al
Therapeutic apheresis and dialysis : official peer-reviewed journal of the International Society for Apheresis, the Japanese Society for Apheresis, the Japanese Society for Dialysis Therapy. 2018;(6):641-648
Abstract
High concentrations of lactate are considered to contribute to impairment of the peritoneal membrane. We investigated the longer-period effects of bicarbonate/lactate-buffered neutral peritoneal dialysis fluid (PDF) in patients undergoing PD for about 2 years. Patients undergoing PD were changed from a lactate-buffered neutral PDF to a bicarbonate/lactate-buffered neutral PDF. We then investigated the patients' clinical outcomes and peritoneal membrane functions as well as the surrogate markers in the drained dialysate. Fourteen patients undergoing PD were enrolled. Peritonitis was observed in one patient. No other adverse events were observed. Peritoneal function did not change as the ultrafiltration volume decreased. Fibrin degradation products and vascular endothelial growth factor in the drained dialysate decreased while the interleukin level increased. These results suggest that bicarbonate/lactate-buffered neutral PDF may have beneficial effects in terms of peritoneal preservation and can be safely used in patients undergoing PD.