Protein synthesis is stimulated by resistance exercise and intake of amino acids, in particular leucine. Moreover, activation of mammalian target of rapamycin complex 1 (mTORC1) signaling by leucine is potentiated by the presence of other essential amino acids (EAA). However, the contribution of the branched-chain amino acids (BCAA) to this effect is yet unknown. Here we compare the stimulatory role of leucine, BCAA, and EAA ingestion on anabolic signaling following exercise. Accordingly, eight trained volunteers completed four sessions of resistance exercise during which they ingested either placebo, leucine, BCAA, or EAA (including the BCAA) in random order. Muscle biopsies were taken at rest, immediately after exercise, and following 90 and 180 min of recovery. Following 90 min of recovery the activity of S6 kinase 1 (S6K1) was greater than at rest in all four trials (Placebo
4.
Branched-chain amino acids are associated with cardiometabolic risk profiles found already in lean, overweight and obese young.
Mangge, H, Zelzer, S, Prüller, F, Schnedl, WJ, Weghuber, D, Enko, D, Bergsten, P, Haybaeck, J, Meinitzer, A
The Journal of nutritional biochemistry. 2016;:123-7
Abstract
Cardiovascular risk is increased in obese subjects. Nevertheless, some overweight and obese remain cardiometabolically healthy (CMH), and normal-weight persons develop cardiovascular disease (CVD). Herein, we investigate the potential of branched-chain amino acids (BCAAs) to identify an increased CVD risk in a cross-sectional study of 666 adults and juveniles (age 25.3±12.8years), classified as lean, overweight or obese. Cardiometabolic groups were defined by cutoffs of systolic blood pressure<130mmHg, diastolic blood pressure<85mmHg, glucose<125mg/dl, triglycerides<150mg/dl, HDL-cholesterol>40mg/dl (males), HDL-cholesterol>50mg/dl (females) and HOMA-IR<5. CMH had ≤1 cutoff, and cardiometabolically abnormal (CMA) had ≥2 cutoffs. Amino acids were measured by high-pressure lipid chromatography after precipitation of serum with perchloric acid and derivatization with o-phthalaldehyde. Valine correlated with 5, leucine correlated with 3 and isoleucine correlated with 5 of the cardiac risk classification factors. Valine and leucine were significantly higher in the obese (P<.001, P=.015, respectively), overweight (P<.001, P=.015, respectively) and lean (P=.024, P=.012, respectively) CMA compared to CMH subjects. Isoleucine showed except of the lean group the same results. Taken together, BCAAs, especially valine and leucine, are proposed as a cardiometabolic risk marker independent of body mass index (BMI) category.
5.
Effects of branched-chain amino acids supplementation in patients with cirrhosis and a previous episode of hepatic encephalopathy: a randomized study.
Les, I, Doval, E, García-Martínez, R, Planas, M, Cárdenas, G, Gómez, P, Flavià, M, Jacas, C, Mínguez, B, Vergara, M, et al
The American journal of gastroenterology. 2011;(6):1081-8
Abstract
OBJECTIVES Protein intake impacts on nutritional status and may determine the recurrence of hepatic encephalopathy (HE). A low-protein diet has been considered the standard treatment after an episode of HE, while branched-chain amino acids (BCAA) have been shown to improve minimal HE. We performed a study to investigate the long-term effects of supplementing a protein-controlled diet with BCAA. METHODS A randomized, double-blind, multicenter study that included 116 patients with cirrhosis and a previous episode of HE was conducted in four tertiary care hospitals. All patients received a standard diet of 35 kcal/kg per day and 0.7 g of proteins/kg per day and a supplement of 30 g of BCAA (BCAA group) or maltodextrin (MDX group) during 56 weeks. RESULTS The actuarial risk of remaining free of HE did not differ between groups (BCAA=47%, MDX=34%, P=0.274), but patients in the BCAA group exhibited a better outcome on two neuropsychological tests and an increase in the mid-arm muscle circumference. Recurrence was associated with low plasma albumin at baseline and a decrease in sodium and an increase in creatinine during follow-up. Patients with recurrence of HE exhibited a lack of improvement in global cognitive function. CONCLUSIONS Diet supplementation with BCAA after an episode of HE does not decrease recurrence of HE. However, supplementation with BCAA improves minimal HE and muscle mass. Identification of risk factors for recurrence of HE may allow the development of new preventive therapies that could decrease the neuropsychological sequelae of repeated episodes of HE.
6.
Inhibitory effect of branched-chain amino acid granules on progression of compensated liver cirrhosis due to hepatitis C virus.
Kobayashi, M, Ikeda, K, Arase, Y, Suzuki, Y, Suzuki, F, Akuta, N, Hosaka, T, Murashima, N, Saitoh, S, Someya, T, et al
Journal of gastroenterology. 2008;(1):63-70
Abstract
BACKGROUND A phase II randomized controlled trial was conducted in patients with compensated liver cirrhosis to investigate the inhibitory effect of branched-chain amino acid (BCAA) granules for oral use (TK-98) on disease progression. METHODS Patients who had compensated liver cirrhosis due to hepatitis C virus with baseline serum albumin levels between 3.6 and 4.5 g/dl were assigned to the TK-98 group, which was treated with BCAA granules (TK-98) for 168 weeks, or to a control group (no treatment). RESULTS No symptoms indicating decompensated cirrhosis, including ascites, edema, and hepatic encephalopathy were reported in either the TK-98 or control group during the study observation period. Hepatocellular carcinoma (HCC) was noted in eight of the 39 patients studied, and of these three received TK-98 (15.8%) and five were untreated (25.0%). A time-to-event analysis for the effect of BCAA therapy on development of HCC revealed no statistically significant differences between the two groups. However, an additional analysis of data from a subgroup with a baseline serum albumin level of <4.0 g/dl showed that the incidence of HCC was likely to be lower in BCAA-treated patients. CONCLUSIONS BCAA may inhibit hepatic carcinogenesis in patients with compensated cirrhosis with a serum albumin level of <4.0 g/dl.
7.
Comparative effects of oral aromatic and branched-chain amino acids on urine calcium excretion in humans.
Dawson-Hughes, B, Harris, SS, Rasmussen, HM, Dallal, GE
Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA. 2007;(7):955-61
Abstract
UNLABELLED In 30 adults, increasing intake of aromatic amino acids increased calcium excretion and serum IGF-1, but not indices of bone turnover, when compared with similar increases in intake of branched-chain amino acids. The mechanisms involved are not certain but these findings suggest a role for the calcium sensor receptor. INTRODUCTION In contrast to branched-chain amino acids (BCAAs), aromatic amino acids (AAAs) bind to the calcium sensing receptor (CaR) and thus have an increased potential to affect calcium homeostasis. In this study we compare the effects of increased intake of AAAs versus BCAAs on calcium excretion, serum IGF-1, markers of bone turnover, and 4-hr calcium excretion after an oral calcium load. METHODS After two weeks on low-protein metabolic diets, 30 healthy subjects were randomized to a fivefold increase in intake of AAAs or BCAAs for two weeks. Changes in calcium excretion and other measures were compared in the two groups. RESULTS With the increase in amino acid intake, 24-hr calcium excretion (P = 0.027), IGF-1 (P = 0.022), and 4-hr calcium excretion after an oral load (P = 0.023) increased significantly in the AAA relative to the BCAA group. Group changes in turnover markers did not differ significantly. CONCLUSION In comparison with BCAAs, AAAs promoted calcium excretion. The calciuria does not appear to result from increases in bone resorption and may occur by increasing calcium absorption. The AAAs also increased circulating levels of IGF-1. Collectively these findings raise the possibility that AAAs may selectively influence calcium homeostasis through their interactions with the CaR.
8.
Branched-chain amino acids enhance the cognitive recovery of patients with severe traumatic brain injury.
Aquilani, R, Iadarola, P, Contardi, A, Boselli, M, Verri, M, Pastoris, O, Boschi, F, Arcidiaco, P, Viglio, S
Archives of physical medicine and rehabilitation. 2005;(9):1729-35
Abstract
OBJECTIVE To investigate whether supplementation with branched-chain amino acids (BCAAs) in patients with severe traumatic brain injury (TBI) improves recovery of cognition and influences plasma concentrations of tyrosine and tryptophan, which are precursors of, respectively, catecholamine and serotonin neurotransmitters in the brain. DESIGN Forty patients with TBI were randomly assigned to 15 days of intravenous BCAA supplementation (19.6g/d) (n=20) or an isonitrogenous placebo (n=20). SETTING Tertiary care rehabilitation setting in Italy. PARTICIPANTS Forty men (mean age, 32+/-15 y) with TBI and 20 healthy subjects (controls) matched for age, sex, and sedentary lifestyle. INTERVENTION Supplementation with BCAAs. MAIN OUTCOME MEASURES Disability Rating Scale (DRS) and plasma concentrations of BCAAs, tyrosine, and tryptophan. RESULTS Fifteen days after admission to the rehabilitation department, the DRS score had improved significantly in both the placebo group (P<.05 vs baseline) and in the BCAA-supplemented group (P<.01 vs baseline). The difference between the 2 groups was significant (P<.004). Plasma tyrosine concentration improved in the group given BCAA supplementation, and tryptophan concentration increased in patients receiving placebo. CONCLUSIONS Supplemental BCAAs enhance the retrieval of DRS without causing negative effects on tyrosine and tryptophan concentration.
9.
The effects of standard and branched chain amino acid enriched solutions on thermogenesis and energy expenditure in unconscious intensive care patients.
Cankayali, I, Demirag, K, Kocabas, S, Moral, AR
Clinical nutrition (Edinburgh, Scotland). 2004;(2):257-63
Abstract
BACKGROUND & AIMS This study aims to compare the effects of standard and branched chain amino acid enriched solutions on thermogenesis and energy expenditure in unconscious and mechanically ventilated intensive care patients. DESIGNS The study was carried out at multidisciplinary intensive care unit. Twenty unconscious and mechanically ventilated patients (18-65 years of age) were included in the study. Patients were hemodynamically stable and all received continuous enteral nutrition. Energy expenditure was calculated using the Harris-Benedict Equation for all of the patients. Patients were randomly assigned to receive a 4h infusion of 0.4 g/kg protein as amino acid solution. Group I (n = 10) received standard amino acid solution and group II (n = 10) received branched chain amino acid enriched solution. Energy expenditure, oxygen consumption and carbon dioxide production were measured by indirect calorimetric method every 30 min during the 4h infusion period and 3h thereafter. Rectal temperature was recorded concomitantly with the metabolic measurements throughout the study. RESULTS There was a statistically significant increase in body temperature during the infusion of amino acid solution between 30 and 210 min in group I and between 30 and 120 min in group II (P <0.05). We observed a significant increase in energy expenditure at 30, 150, 180 and 210 min in group I and at 30-240 min in group II (P <0.05). There were no differences between the two groups in terms of thermogenesis or energy expenditure values during the study (P >0.05). CONCLUSION Thermogenesis and energy expenditure values were increased during the parenteral infusion of both standard amino acid and branched chain amino acid enriched solutions in unconscious intensive care patients without any significance in between.