BCAAs: benefits, dosage, contraindications
Scientific name(s)
Branched-chain amino acids
Family or group:
Amino acids
Indications
Rating methodology
EFSA approval.
Hepatic encephalopathy ✪✪✪✪✪
BCAAs are used in hepatic encephalopathy as an energy source to prevent endogenous protein catabolism and reduce ammonia detoxification in the brain by increasing ammonia metabolism in skeletal muscles. They are recommended for malnourished patients with chronic hepatic encephalopathy who cannot tolerate protein supplementation. The daily intake of BCAAs at a rate of 240 mg/kg (up to 25 grams) in 3 divided doses for a maximum of 3 months seems to improve symptoms, liver function tests, and nitrogen balance in patients with chronic hepatic encephalopathy.
Posologie
Oral route
240 mg/kg
3 - months
Long-term oral branched-chain amino acid treatment in chronic hepatic encephalopathy. A randomized double-blind casein-controlled trial. The Italian Multicenter Study Group
Overview of randomized clinical trials of oral branched-chain amino acid treatment in chronic hepatic encephalopathy
Enteral and parenteral branched chain amino acid-supplemented nutritional support in patients with encephalopathy due to alcoholic liver disease
Branched-chain amino acids for people with hepatic encephalopathy
Sports performance ✪✪✪✪✪
The effects of BCAA intake on physical performance are highly debated. In most studies, oral BCAA intake does not enhance sports performance but seems beneficial in reducing exercise-induced fatigue and perceived effort after prolonged or intense exercise.
Posologie
Oral route
0.17 - 0.3 mg/kg
Effects of branched-chain amino acids supplementation on physiological and psychological performance during an offshore sailing race
Branched-chain amino acids and arginine improve performance in two consecutive days of simulated handball games in male and female athletes: a randomized trial
Nutraceutical effects of branched-chain amino acids on skeletal muscle
Branched-chain amino acid supplementation attenuates muscle soreness, muscle damage and inflammation during an intensive training program
The effects of acute branched-chain amino acid supplementation on recovery from a single bout of hypertrophy exercise in resistance-trained athletes
Branched-chain amino acid supplementation improves cycling performance in untrained cyclists
Branched-chain aminoacid supplementation attenuates a decrease in power-producing ability following acute strength training
Branched-chain amino acids prolong exercise during heat stress in men and women
Influence of ingesting a solution of branched-chain amino acids on perceived exertion during exercise
Cachexia ✪✪✪✪✪
BCAA supplementation in malnourished elderly patients seems to reduce anorexia and improve nutritional indices. BCAAs could compete with tryptophan, a serotonin precursor, for their absorption through the blood-brain barrier. By decreasing serotonin synthesis, BCAAs could increase appetite. Preliminary clinical research conducted in malnourished elderly and hemodialysis patients shows that taking a combination of BCAAs at a dose of 4 grams three times a day improves appetite and caloric intake and increases plasma albumin levels and anthropometric measurements compared to placebo.
Posologie
Oral route
12 g
Cirrhosis ✪✪✪✪✪
A small clinical study shows that taking BCAAs at a rate of 14.4 grams per day for 12 months does not improve survival or liver function in patients with advanced liver cirrhosis but decreases the number of hospitalizations and the prevalence of cachexia and improves quality of life compared to the control group.
Posologie
Oral route
14.4 g
12 - months
Tardive dyskinesia ✪✪✪✪✪
Clinical research conducted in patients taking antipsychotic medications shows that taking a drink containing 222 mg/kg of BCAAs, three times a day for 3 weeks, reduces tardive dyskinesia symptoms (involuntary repetitive movements generally secondary to neuroleptic use) by 30% to 60% compared to placebo.
Posologie
Oral route
222 mg/kg
Alzheimer's disease ✪✪✪✪✪
Observational research has shown that high blood levels of BCAAs are associated with an 11% to 13% lower risk of Alzheimer's disease, except that this association was not significant.
Posologie
Oral route
68 mg/kg
Properties
Metabolic
BCAAs, particularly leucine, act as signaling molecules to stimulate protein synthesis. In fact, leucine, more so than isoleucine and valine, has a regulatory effect on muscle protein metabolism. BCAAs also stimulate protein synthesis in adipose tissue and the liver. At the heart level, they appear to have a specific anabolic effect on cardiac protein metabolism. Moreover, BCAAs seem to stimulate insulin release by pancreatic islet cells, which is necessary for the maximal stimulation of protein synthesis. The sensitivity of BCAAs to stimulate protein synthesis seems to decrease with age.
Usages associés
Musculoskeletal effects
The metabolism of BCAAs occurs largely at the muscular level. Their oxidation releases substrates usable for energy purposes by skeletal muscles and nitrogen atoms intended for the in-situ synthesis of alanine and glutamine. Leucine, more so than isoleucine and valine, has a regulatory effect on muscle protein metabolism.
Usages associés
Neurological
Increased BCAA consumption seems to decrease the synthesis of amino neurotransmitters such as dopamine, norepinephrine, and serotonin. By decreasing serotonin synthesis, BCAAs could increase appetite. BCAAs play a role in the oxidation and synthesis of the excitatory neurotransmitter glutamate. Researchers believe that dietary BCAA intake may be necessary to maintain glutamate reserves in the central nervous system. Finally, BCAAs could reduce plasma phenylalanine by increasing protein synthesis and insulin release, thereby lowering phenylalanine levels in the cerebrospinal fluid. They could thus reduce the symptoms of tardive dyskinesia, which are associated with increased phenylalanine.
Usages associés
Safety dosage
Adult from 18 years: 68 mg/kg
The estimated average requirements (EAR) for BCAAs in adults are 68 mg/kg/day (leucine 34 mg/kg, isoleucine 15 mg/kg, valine 19 mg/kg).
Infant from 1 to 3 months: 98 mg/kg
The estimated average requirements for BCAAs in children are: 1-3 years, 98 mg/kg/day; 4-8 years, 81 mg/kg/day; males 9 to 13 years, 81 mg/kg/day; females 9 to 13 years, 77 mg/kg/day; males 14 to 18 years, 77 mg/kg/day; females 14 to 18 years, 71 mg/kg/day.
Child from 4 to 8 years: 81 mg/kg
The estimated average requirements for BCAAs in children are: 1-3 years, 98 mg/kg/day; 4-8 years, 81 mg/kg/day; males 9 to 13 years, 81 mg/kg/day; females 9 to 13 years, 77 mg/kg/day; males 14 to 18 years, 77 mg/kg/day; females 14 to 18 years, 71 mg/kg/day.
Male from 9 to 13 years: 81 mg/kg
The estimated average requirements for BCAAs for children are: 1-3 years, 98 mg/kg/day; 4-8 years, 81 mg/kg/day; males 9 to 13 years, 81 mg/kg/day; females 9 to 13 years, 77 mg/kg/day; males 14 to 18 years, 77 mg/kg/day; females 14 to 18 years, 71 mg/kg/day.
Female 9 to 13 years: 77 mg/kg
The estimated average requirements for BCAAs for children are: 1-3 years, 98 mg/kg/day; 4-8 years, 81 mg/kg/day; males 9 to 13 years, 81 mg/kg/day; females 9 to 13 years, 77 mg/kg/day; males 14 to 18 years, 77 mg/kg/day; females 14 to 18 years, 71 mg/kg/day.
Male 14 to 18 years: 77 mg/kg
The estimated average requirements for BCAAs for children are: 1-3 years, 98 mg/kg/day; 4-8 years, 81 mg/kg/day; males 9 to 13 years, 81 mg/kg/day; females 9 to 13 years, 77 mg/kg/day; males 14 to 18 years, 77 mg/kg/day; females 14 to 18 years, 71 mg/kg/day.
Female 14 to 18 years: 71 mg/kg
The estimated average requirements for BCAAs for children are: 1-3 years, 98 mg/kg/day; 4-8 years, 81 mg/kg/day; males 9 to 13 years, 81 mg/kg/day; females 9 to 13 years, 77 mg/kg/day; males 14 to 18 years, 77 mg/kg/day; females 14 to 18 years, 71 mg/kg/day.
Precautions
Pregnant woman: avoid
Avoid use due to lack of sufficient and reliable information.
Breastfeeding woman: avoid
Avoid use due to lack of sufficient and reliable information.
