The absorption of orally supplied β-Alanine and its effect on muscle carnosine synthesis in human vastus lateralis
ABSTRACT Beta-alanine in blood-plasma when administered as A) histidine dipeptides (equivalent to 40 mg . kg(-1) bwt of beta-alanine) in chicken broth, or B) 10, C) 20 and D) 40 mg . kg(-1) bwt beta-alanine (CarnoSyn, NAI, USA), peaked at 428 +/- SE 66, 47 +/- 13, 374 +/- 68 and 833 +/- 43 microM. Concentrations regained baseline at 2 h. Carnosine was not detected in plasma with A) although traces of this and anserine were found in urine. Loss of beta-alanine in urine with B) to D) was <5%. Plasma taurine was increased by beta-alanine ingestion but this did not result in any increased loss via urine. Pharmacodynamics were further investigated with 3 x B) per day given for 15 d. Dietary supplementation with I) 3.2 and II) 6.4 g . d(-1) beta-alanine (as multiple doses of 400 or 800 mg) or III) L-carnosine (isomolar to II) for 4 w resulted in significant increases in muscle carnosine estimated at 42.1, 64.2 and 65.8%.
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- "Thus, we could argue that during the 45-jump test anaerobic glycolysis and lactate accumulation were not connected to any major disturbance of buffering capacity , accumulation of lactate, or improved mitochondrial coupling. A possible explanation is that BA supplementation increased carnosine muscle content in subjects and that the proton-sequestering property of the carnosine molecule reduced the drop in muscle pH induced by the anaerobic glycolysis, improving performance (Harris et al. 2006). "
ABSTRACT: β-Alanine (BA) supplementation has become an ergogenic aid amongst competitive athletes to augment intramuscular carnosine content, leading to higher buffer capacity and exercise performance. We investigated 27 regularly trained young males and females who were randomly allocated either to placebo (PL) or BA ingestion for 8 weeks. Every single day, BA or PL (4.0-5.6 g day(-1)) supplements were ingested by participants and associated with a strong plyometric high-intensity training (two sessions per week during the 8 weeks). Before and after training, maximal jump heights were recorded during squat jump (SJ) and countermovement jump (CMJ) and an index of fatigue was recorded as a mean height of 45 consecutive CMJ. Blood lactate was measured at rest, after completing the fatigue test and every 5 min thereafter up to 30 min recovery. After plyometric training, SJ and CMJ were increased, respectively, by 8.8 and 6.4 % in PL group and 9.9 and 11.0 % in BA group (p < 0.01, no difference between groups). Blood lactate reached a maximal value of 9.4 ± 1.6 mmol l(-1) in PL group, and 10.3 ± 1.3 mmol l(-1) in BA group, with a slight better performance in the fatigue test (+8.6 %, p ≤ 0.01) for BA group as compared to PL group. To conclude, 2-month β-alanine supplementation resulted in a slight improvement of explosive force after 45 maximal consecutive jumps in young athletes. However, the practical adequacy of supplementation remains questionable in an active and healthy population.Amino Acids 04/2015; 47(7). DOI:10.1007/s00726-015-1981-6 · 3.29 Impact Factor
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- "Raising muscle carnosine concentrations in humans has been found to be relatively easy by means of chronic oral -alanine administration (Harris et al. 2006), whereas raising plasma carnosine levels seems very difficult in humans owing to the high and human-specific serum carnosinase activity (Everaert et al. 2012). "
ABSTRACT: There is growing in vivo evidence that the dipeptide carnosine has protective effects in metabolic diseases. A critical unanswered question is whether its site of action is tissues or plasma. This was investigated using oral carnosine versus β-alanine supplementation in a high-fat diet rat model. Thirty-six male Sprague-Dawley rats received a control diet (CON), a high-fat diet (HF; 60% of energy from fat), the HF diet with 1.8% carnosine (HFcar), or the HF diet with 1% β-alanine (HFba), as β-alanine can increase muscle carnosine without increasing plasma carnosine. Insulin sensitivity, inflammatory signaling, and lipoxidative stress were determined in skeletal muscle and blood. In a pilot study, urine was collected. The 3 HF groups were significantly heavier than the CON group. Muscle carnosine concentrations increased equally in the HFcar and HFba groups, while elevated plasma carnosine levels and carnosine-4-hydroxy-2-nonenal adducts were detected only in the HFcar group. Elevated plasma and urine N(ε)-(carboxymethyl)lysine in HF rats was reduced by ∼50% in the HFcar group but not in the HFba group. Likewise, inducible nitric oxide synthase mRNA was decreased by 47% (p < 0.05) in the HFcar group, but not in the HFba group, compared with HF rats. We conclude that plasma carnosine, but not muscle carnosine, is involved in preventing early-stage lipoxidation in the circulation and inflammatory signaling in the muscle of rats.Applied Physiology Nutrition and Metabolism 03/2015; 40(9):150331143629004. DOI:10.1139/apnm-2015-0042 · 2.34 Impact Factor
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- " et al . , 2009 ) . With 800 - mg doses ( 10 mg·kg −1 ) , Harris et al . ( 2006 ) reported " mild symptoms of flushing " in two out of four partici - pants , beginning within 20 min and lasting for up to 1 h . With a 1 . 6 - g dose , symptoms were recorded as " significant " in three of four participants ( Harris et al . , 2006 ) . Further work by Harris et al . ( 2006 ) has reported that a single β - alanine doses of 3 . 2 g ( 40 mg·kg −1 ) results in side effects that are perceived as " unpleasant " . The available literature suggests that the incidence and severity of the symptoms appears to follow in a dose - dependent fashion . The symp - toms observed in this study after the acute ingestion of 3"
ABSTRACT: β-alanine is a common ingredient in supplements consumed by athletes. Indeed, athletes may believe that the β-alanine induced paresthesia, experienced shortly after ingestion, is associated with its ergogenic effect despite no scientific mechanism supporting this notion. The present study examined changes in cycling performance under conditions of β-alanine induced paresthesia. Eight competitive cyclists (VO2max = 61.8 ± 4.2 mL·kg·min−1) performed three practices, one baseline and four experimental trials. The experimental trials comprised a 1-km cycling time trial under four conditions with varying information (i.e., athlete informed β-alanine or placebo) and supplement content (athlete received β-alanine or placebo) delivered to the cyclist: informed β-alanine/received β-alanine, informed placebo/received β-alanine, informed β-alanine/received placebo and informed placebo/received placebo. Questionnaires were undertaken exploring the cyclists’ experience of the effects of the experimental conditions. A possibly likely increase in mean power was associated with conditions in which β-alanine was administered (±95% CL: 2.2% ± 4.0%), but these results were inconclusive for performance enhancement (p = 0.32, effect size = 0.18, smallest worthwhile change = 56% beneficial). A possibly harmful effect was observed when cyclists were correctly informed that they had ingested a placebo (–1.0% ± 1.9%). Questionnaire data suggested that β-alanine ingestion resulted in evident sensory side effects and six cyclists reported placebo effects. Acute ingestion of β-alanine is not associated with improved 1-km TT performance in competitive cyclists. These findings are in contrast to the athlete’s “belief” as cyclists reported improved energy and the ability to sustain a higher power output under conditions of β-alanine induced paresthesia.European Journal of Sport Science 01/2015; Epub. DOI:10.1080/17461391.2015.1005696 · 1.55 Impact Factor