Valine: Functions

Valine has a significant impact on the functions of nerves and muscles.

Valine as an essential amino acid in the central nervous system

Valine is essential for the maintenance of nerve functions. The amino acid may act as a precursor of neurotransmitters (chemical messengers) in intermediary metabolism. Neurotransmitters are essential for nerve impulse transmission. They transmit information from one nerve cell to another. Nerve cells or neurons consist of a cell body with dendrites, an axon and terminal synapses. The latter represent the contact points between individual nerve cells and are the sites of signal transmission. At the end of an axon, transmitter molecules are formed and stored in synaptic vesicles. Action potentials (electrical impulses) entering the synapse cause the release of neurotransmitters into the synaptic cleft – space between the synapse terminal of one neuron and a dendrite of another neuron. Subsequently, the chemical messengers bind to the membrane receptors of the downstream neuron, triggering processes required for information transmission.Amino acids are indispensable components for the synthesis of chemical messengers. Important neurotransmitters are, for example, acetylcholine, serotonin, histamine, glutamate and glutamine as well as the catecholamines adrenaline, noradrenaline and dopamine. These require essential amino acids in particular, such as methionine, tryptophan, histidine and BCAAs, as metabolic precursors for their biosynthesis. In addition to isoleucine, leucine, alanine, aspartate and some aromatic amino acids, valine also serves as a starting building block for the synthesis of glutamate or glutamic acid, a non-essential amino acid. The reaction by which glutamate is formed is called transamination. In this process, the amino group (NH2) of an amino acid, such as valine, alanine or aspartic acid, is transferred to an alpha-keto acid, usually alpha-ketoglutarate. Alpha-ketoglutarate is thus the acceptor molecule. The products of a transamination reaction include glutamate and an alpha-keto acid, such as pyruvate or oxaloacetate. In order for transaminations to occur, special enzymes are required – called transaminases. The two most important transaminases include alanine aminotransferase (ALAT/ALT), also known as glutamate pyruvate transaminase (GPT), and aspartate aminotransferase (ASAT/AST), also known as glutamate oxaloacetate transaminase (GOT). The former catalyzes the conversion of alanine and alpha-ketoglutarate to pyruvate and glutamate. ASAT converts aspartate and alpha-ketoglutarate to oxaloacetate and glutamate. Coenzyme of all transaminases is the vitamin B6 derivative pyridoxal phosphate (PLP). PLP is loosely bound to the enzymes and is essential for optimal transaminase activity. Transamination reactions are localized in liver and other organs. The transfer of alpha-amino nitrogen from valine to an alpha-keto acid by transaminases to form glutamate occurs in muscle. Glutamate represents the dominant excitatory neurotransmitter in the central nervous system. At the same time, glutamate is the most abundant among the free amino acids of the brain. The chemical messenger binds to specific glutamate receptors and can thus control ion channels, especially calcium channels. Glutamatergic synapses and receptors are found in many areas of the brain, especially in the cortex, cerebellum, hippocampus as well as in the amygdala. The latter two brain areas are primarily responsible for functions related to learning and memory. Accordingly, glutamate has the ability to influence complicated concentration and memory processes. Glutamic acid is an essential component of the phenomenon of long-term potentiation, LTP. LTP is a long-term potentiation of synaptic transmission. Among other criteria, long-term potentiation enables complicated learning and memory processes. The essentiality of glutamate in the central nervous system was clearly demonstrated in a multicenter clinical double-blind study. 120 adolescents between the ages of 11 and 16 who suffered from learning difficulties were tested. Patients in the verum group were treated with a glutamate preparation over a period of 8 weeks.They received 600 mg three times daily during weeks 1-2, 400 mg three times daily during weeks 3-6, and 200 mg three times daily during the last two weeks. The adolescents in the verum group showed a significant increase in cerebral performance in contrast to those in the placebo group. Improvement occurred in the following symptoms:

  • Memory
  • Concentration disorders
  • Delaying mental fatigue
  • Resilience
  • Stamina
  • Lack of energy
  • Nervousness
  • Forgetfulness

Based on these positive results, it suggests that further benefits could be achieved by extending the duration of therapy beyond eight weeks. Glutamate is not only neurotransmitter, but also neurotransmitter precursor. By splitting off the carboxyl group (decarboxylation), glutamate can be converted to gamma-aminobutyric acid (GABA). GABA belongs to the biogenic amines and is the most important inhibitory neurotransmitter in the gray matter of the central nervous system. It inhibits neurons in the cerebellum. Furthermore, glutamate is considered the “hub” of amino nitrogen metabolism. It plays a key role in the formation, conversion and degradation of amino acids. Glutamate is the starting substrate for the synthesis of proline, ornithine and glutamine. The latter is an essential amino acid for nitrogen transport in the blood, protein biosynthesis, and for the excretion of protons in the kidney in the form of NH4. In addition, glutamine is important for intestinal mucosal integrity and the immune system.

Valine as an essential amino acid in protein metabolism

Valine, along with the other two branched-chain amino acids isoleucine and leucine, occupies a special function in protein metabolism. The BCAAs are predominantly involved in building new tissue and are very effective in enhancing protein biosynthesis in muscle and liver. In muscle tissue, valine inhibits protein breakdown and promotes the maintenance as well as the build-up of muscle protein – especially during exercise and disease. Valine plays an essential role in:

  • Strength and endurance sports
  • STH secretion
  • Stress
  • Diseases and diet

Valine as an energy supplier in strength and endurance sports

Valine enters the hepatocytes (liver cells) after absorption via the portal vein. There, amino acid breakdown takes place. Ammonia (NH3) is cleaved from valine, producing an alpha-keto acid. Alpha-keto acids can be used directly for energy production or serve as a precursor for other metabolic products. Since valine is a glucogenic amino acid, the alpha-keto acid can be converted to succinyl-coenzyme A. The intermediate of the citrate cycle succinyl-CoA is one of the necessary substrates for gluconeogenesis (new glucose formation) in liver and muscles. Glucose is a carbohydrate, more specifically a monosaccharide (simple sugar). Glucose is stored in the form of glycogen in the liver and muscles. If there is an increased demand for energy, for example during physical exertion, glucose can be mobilized from the stores and used for energy production. The erythrocytes (red blood cells) and the renal medulla are completely dependent on glucose as an energy supplier. The brain only partially, because in starvation metabolism it can obtain up to 80% of energy from ketone bodies. When glucose is broken down in the muscles, ATP (adenosine triphosphate) is formed, the cell’s most important energy carrier. When its phosphate bonds are hydrolytically cleaved by enzymes, ADP or AMP is formed. The energy released in this process enables chemical, osmotic or mechanical work, such as muscle contractions. After processing in the liver, almost 70% of all amino acids entering the blood are BCAAs. They are rapidly absorbed by the muscles. In the first three hours after a protein-rich meal, valine, isoleucine and leucine account for about 50-90% of the muscles’ total amino acid intake. Muscle tissue is made up of 20% protein. The BCAAs are a component of these muscle proteins, which in detail include the contractile proteins actin, myosin, troponin and tropomyosin, the enzymes of energy metabolism, the scaffold protein alpha-actinin and myoglobin. The latter, like the hemoglobin of the blood, can absorb, transport and release oxygen. In this way, myoglobin enables the slowly contracting skeletal muscle to produce energy aerobically.Valine promotes the release of insulin from the beta cells of the pancreas. In addition, the amino acids leucine, isoleucine, arginine and phenylalanine also exhibit insulin-stimulating effects. High insulin concentrations in the blood accelerate amino acid uptake into myocytes – muscle cells. Increased transport of amino acids into myocytes leads to the following processes [1,Kettelhut]:

  • Increased protein buildup in the muscles
  • Rapid decrease in the concentration of the stress hormone cortisol, which promotes muscle breakdown and inhibits amino acid uptake into muscle cells
  • Better storage of glycogen in the myocytes, maintenance of muscle glycogen.

Finally, an intake of foods rich in valine, isoleucine and leucine results in optimal muscle growth and maximum accelerated recovery. For the breakdown and conversion of BCAAs, biotin, vitamin B5 (pantothenic acid) and vitamin B6 (pyridoxine) are essential. Only as a result of a sufficient supply of these vitamins can the branched-chain amino acids be optimally metabolized and used. A deficit of vitamin B6 can lead to a valine deficiency. Several studies show that both endurance sports and strength training require increased protein intake. To maintain a positive nitrogen balance – corresponding to a tissue rebuilding – the daily protein requirement is between 1.2 and 1.4 grams per kg body weight for endurance athletes and 1.7-1.8 g per kg body weight for strength athletes. During endurance sports, especially valine, leucine and isoleucine are used for energy production. The supply of energy from these amino acids increases when the glycogen stores in the liver and muscles become increasingly depleted as physical activity progresses. The reason for this is that the organism initially relies on glucose for energy production during physical exertion. If there is no longer sufficient glucose available, proteins are broken down from the liver and muscles. Finally, endurance athletes should consume sufficient carbohydrates as well as proteins in their diet to prevent protein breakdown. Strength athletes should also ensure a high intake of branched-chain amino acids, especially before training. In this way, the organism does not fall back on its own BCAAs from the muscles during physical exertion and protein catabolism is prevented. The supply of BCAAs is also recommended after training. Valine quickly raises insulin levels after the end of training, stops protein breakdown caused by previous exertion and initiates renewed muscle growth. In addition, BCAAs result in increased fat loss. In order to be able to use valine optimally in terms of muscle building, attention should be paid to the intake of high-quality protein with a high content of valine. A protein is of high quality if it contains essential and non-essential amino acids in a balanced ratio. On the other hand, the proportion of absorbed dietary protein that is retained in the body to meet individual requirements for defined physiological functions plays a role. The joint intake of the branched-chain amino acids in the ratio leucine:isoleucine:valine = 1-2:1:1 in combination with other protein is also recommended. Isolated intake of valine or isoleucine or leucine may temporarily interfere with protein biosynthesis for muscle building. A sole supply of BCAAs should be viewed critically, especially before endurance training, due to oxidation under stress and urea attack. The breakdown of 1 gram of BCAAs produces about 0.5 grams of urea. Excessive urea concentrations put a strain on the organism. Therefore, in connection with BCAAs intake, increased fluid intake is crucial. With the help of plenty of fluid, the urea can be quickly eliminated via the kidneys. Finally, increased intake of valine, isoleucine or leucine should be weighed during endurance exercise. Performance improvements for the endurance athlete only occur when BCAAs are used during altitude training or training in high heat. As a result of a high protein intake or physical stress, high amounts of nitrogen in the form of ammonia (NH3) are produced as a result of protein breakdown. This has a neurotoxic effect in higher concentrations and can result, for example, in hepatic encephalopathy.This condition is a potentially reversible brain dysfunction that results from inadequate liver detoxification function. If BCAAs are taken in the right proportions, they can exert their additive effect and reduce the level of free toxic ammonia in the muscles through increased protein biosynthesis (new protein formation) and reduced protein breakdown – a significant advantage for the athlete. In the liver, arginine and ornithine keep the ammonia concentration at a low level. Scientific studies have shown that administration of 10-20 grams of BCAAs during exercise can delay mental fatigue. However, there is still no evidence that branched-chain amino acids lead to improved performance. Similarly, improved adaptation to exercise has not been demonstrated.

BCAAs for increased STH secretion

Somatotropic hormone (STH) stands for somatotropin, a growth hormone produced in the adenohypophysis (anterior pituitary gland). It is secreted in batches and broken down in the liver within a short time. Subsequently, somatomedins (growth factors) are synthesized. STH and somatomedins are essential for normal growth in length. Especially during puberty, its production is very pronounced. STH affects almost all tissues of the body, especially bones, muscles and liver. Once the genetically determined body size is reached, somatotropin mainly regulates the ratio of muscle mass to fat. Growth hormone is secreted especially in the first hours of deep sleep and in the morning hours shortly before awakening – diurnal rhythm. In addition, increased STH production occurs as a result of energy-consuming processes, such as injuries, emotional stress, fasting and physical training. The reasons for this include low blood glucose levels during fasting or high lactate levels during intense exercise, which stimulate STH secretion. An increased concentration of somatotropin in the blood now causes a decreased uptake of glucose into the cells, which increases the blood glucose level. As a result, more insulin is secreted from the pancreas (pancreas). Somatotropin and insulin work together. Both hormones increase the transport rate of amino acids into the cells of the muscles and liver during increased physical energy requirements and thus promote protein biosynthesis and the formation of new tissue. Furthermore, somatotropin and insulin lead to the mobilization of free fatty acids from the body’s own fat depots, which are used for energy production. This increases the breakdown of fat. To maintain or even increase normal STH production, an adequate supply of B-complex vitamins, especially vitamin B6 (pyridoxine), is important. A deficit of vitamin B6 reduces STH release by up to 50%. In addition, a pyridoxine deficiency negatively affects insulin synthesis. The minerals calcium, magnesium and potassium as well as the trace element zinc also play a significant role in the STH regulatory circuit. As a result, studies have found significantly low secretion of growth hormones and impaired formation of gonadal hormones in individuals suffering from zinc deficiency. Several scientific studies show that supplementation with valine, isoleucine and leucine slightly increased the increase in STH secretion induced by physical exercise. Thus, BCAAs promote anabolic or anticatabolic protein metabolism via increased secretion of somatotropin. The process of building muscle protein is accelerated and fat burning is stimulated – a welcome effect for both athletic and diet-conscious individuals. Such an effect was also supported by a study in which a daily intake of 14 g of branched-chain amino acids over a 30-day period resulted in an increase in lean body mass.

Valine in stress-related situations

During increased physical and exercise stress, such as injury, illness, and surgery, the body breaks down more protein. Increased intake of valine-rich foods can counteract this. Protein catabolism is halted as valine rapidly raises insulin levels, promotes amino acid uptake into cells, and stimulates protein building.Protein anabolism is important for the formation of new body tissues or for the healing of wounds and for increasing resistance to infections. Finally, valine helps to regulate the metabolism and defenses. In this way, important muscle functions can be supported during increased physical stress.

Valine in diseases and diets

Acutely ill or convalescent patients have an increased need for essential amino acids. Due to a frequently inadequate intake of high-quality protein and restricted dietary intake, increased intake of valine, isoleucine, and leucine, in particular, is recommended. BCAAs can accelerate convalescence (recovery). Specific benefits of leucine occur in the following conditions:

  • Fibromyalgia
  • Cirrhosis of the liver
  • Hepatic encephalopathy
  • Coma hepaticum
  • Schizophrenia
  • Phenylketonuria (PKU)
  • Dystones syndrome

FibromyalgiaFibromyalgia is a chronic pain disorder with symptoms of the joint or musculoskeletal system. Patients, especially women between 25 and 45 complain of diffuse pain of the musculoskeletal system especially with exertion, stiffness, easy fatigue, difficulty concentrating, non-restorative sleep, and significantly reduced mental and physical performance. A typical feature of fibromyalgia is specific pressure-dolent areas on the body. Several lines of evidence suggest that, among other factors, a deficiency of BCAAs plays a role in the development of fibromyalgia. Since BCAAs are essential for protein and energy metabolism in the muscle, too low BCAA concentrations lead to a muscular energy deficit, which could be the trigger of fibromyalgia. In addition, significantly decreased serum levels of valine, isoleucine, and leucine can be seen in affected individuals. Accordingly, branched-chain amino acids may counteract the pathogenesis of fibromyalgia as well as favorably influence the treatment of this disease. Liver cirrhosis, hepatic encephalopathy, and coma hepaticumLiver cirrhosis is the end stage of chronic liver disease and develops over a period of years to decades. Patients exhibit a disturbed structure of liver tissue with nodular changes and excessive formation of connective tissue – fibrosis – as a result of progressive tissue loss. Eventually, circulatory disturbances occur, resulting in the inability of portal vein (vena portae) blood from the unpaired abdominal organs to be properly delivered to the liver. The blood thus accumulates at the hepatic portal (portal hypertension/portal hypertension; portal hypertension). Patients with cirrhosis of the liver break down the body’s own proteins, especially muscle mass, more rapidly than healthy individuals. Despite the higher requirement, they must not consume too much protein with food, since their cirrhotic liver can only detoxify the toxic ammonia (NH3) produced by protein breakdown to a limited extent via the urea cycle. If NH3 concentrations are too high, there is a risk of hepatic encephalopathy, a subclinical brain dysfunction resulting from inadequate detoxification function of the liver. Hepatic encephalopathy is characterized by the following features:

  • Mental and neurologic changes
  • Decrease in practical intelligence and ability to concentrate
  • Increased fatigue
  • Reduced fitness to drive
  • Impairment in manual occupations

It is believed that 70% of patients with liver cirrhosis suffer from latent hepatic encephalopathy, the precursor of manifest hepatic encephalopathy. Coma hepaticum is the most severe form of hepatic encephalopathy – stage 4. Nerve damage in the central nervous system results in, among other things, unconsciousness without response to painful stimuli (coma), extinction of muscle reflexes, and muscle rigidity with flexion and extension postures. Patients with and without hepatic encephalopathy usually have reduced plasma concentrations of branched-chain amino acids and increased plasma levels of the aromatic amino acids phenylalanine and tyrosine. In addition, the concentration of free tryptophan shows a slight increase.In addition to accelerated protein breakdown, the cause of this amino acid imbalance could also be the hormonal imbalance between insulin and glucagon that frequently occurs in patients with liver cirrhosis. Insulin is produced in excess amounts due to the underactive liver. This leads to a significantly increased insulin concentration in the serum, which ensures increased transport of amino acids, including valine, to the muscles. In the blood, the valine concentration is consequently lowered. Since BCAAs and the essential amino acid tryptophan use the same transport system in the blood, i.e. the same carrier proteins, tryptophan can occupy many free carriers due to the low serum valine level and be transported toward the blood-brain barrier. L-tryptophan competes with 5 other amino acids at the blood-brain barrier for entry into the nutrient fluid of the brain – namely, the BCAAs and aromatic amino acids phenylalanine and tyrosine. Due to the excess of tryptophan in the brain, phenylalanine, the precursor of catecholamines, such as the stress hormones epinephrine and norepinephrine, is also displaced in addition to tyrosine and the BCAAs. Finally, tryptophan can cross the blood-brain barrier unhindered. Because of phenylalanine displacement, sympathetic activation in the brain is absent, limiting catecholamine synthesis in the adrenal medulla. In the central nervous system, tryptophan is converted to serotonin, which functions as a tissue hormone or inhibitory (inhibitory) neurotransmitter in the central nervous system, intestinal nervous system, cardiovascular system, and blood. The increased levels of tryptophan eventually entail increased serotonin production. In liver dysfunction, excessive amounts of serotonin cannot be broken down, which in turn leads to severe fatigue and even unconsciousness – coma hepaticum. Other authors, however, see another reason for the development of hepatic encephalopathy or coma hepaticum in addition to increased serotonin release. Due to the low serum concentration of BCAAs in liver cirrhosis patients, the aromatic amino acids phenylalanine, tyrosine, and tryptophan can cross the blood-brain barrier and enter the central nervous system without much competition. There, instead of being converted into catecholamines, phenylalanine and tyrosine are converted into “false” neurotransmitters, such as phenylethanolamine and octopamine. Unlike catecholamines, these are not sympathomimetics, i.e., they can exert no or only a very slight excitatory effect at the sympathetic alpha and beta receptors of the cardiovascular system. Tryptophan is increasingly used in the central nervous system for serotonin synthesis. Finally, both factors, the formation of false neurotransmitters and increased serotonin production are held responsible for the occurrence of hepatic encephalopathy and coma hepaticum, respectively. Increased intake of valine prevents increased production of serotonin as well as false neurotransmitters via the mechanism of displacement of tryptophan, phenylalanine, and tyrosine at the blood-brain barrier and inhibition of uptake of these amino acids into the central nervous system. In this way, valine counteracts the occurrence of coma hepaticum. Furthermore, valine helps to keep the ammonia content in the body at a low level. This is a significant advantage for patients with liver cirrhosis, who are unable to detoxify NH3 sufficiently. Ammonia accumulates and in high concentrations promotes the development of hepatic encephalopathy. By stimulating protein biosynthesis in muscular tissues and inhibiting protein breakdown, valine incorporates more ammonia and releases less ammonia. In addition, in both muscle and brain, valine can be converted to glutamate, an important amino acid in nitrogen (N) metabolism, which binds excess ammonia to form glutamine and thus detoxifies it temporarily. For final detoxification, NH3 is converted to urea in the hepatocytes (liver cells), which is eliminated as a non-toxic substance by the kidneys. BCAAs stimulate the urea cycle and thus promote NH3 excretion. The efficacy of valine, isoleucine, and leucine with respect to hepatic encephalopathy was confirmed in a randomized, placebo-controlled, double-blind study.Over a 3-month period, 64 patients were to ingest 0.24 g/kg body weight of branched-chain amino acids daily. The result was a significant improvement in chronic hepatic encephalopathy compared with placebo. In a placebo-controlled double-blind cross-over study, patients in the latent hepatic encephalopathy stage received 1 g protein/kg body weight and 0.25 g branched-chain amino acids/kg body weight daily. Already after a 7-day treatment period, a clear improvement of psychomotor functions, attention, and practical intelligence was observed in addition to a decreased ammonia concentration. Furthermore, a randomized double-blind study over a period of one year evaluated the effectiveness of BCAAs in patients with advanced liver cirrhosis. The result was a lower risk of mortality and morbidity. In addition, the patients’ anorexia nervosa and quality of life were positively affected. The average number of hospitalizations was decreased and liver function was stable or even improved. However, there are also studies that have not demonstrated a significant association between BCAAs and liver disease. Nevertheless, in patients with hepatic dysfunction, supplementation with valine, isoleucine, and leucine is recommended because of their beneficial effects on protein metabolism, especially in patients with impaired protein tolerance. Overview of important effects of branched-chain amino acids on protein metabolism [42:

  • Improvement of nitrogen balance
  • Increase protein tolerance
  • Normalization of the amino acid pattern
  • Improvement of cerebral blood flow
  • Promote ammonia detoxification
  • Improve transaminase levels and caffeine clearance.
  • Positive influence on the mental status

SchizophreniaBecause BCAAs reduce the level of tyrosine in the blood and thus in the central nervous system, valine can be used in orthomolecular psychiatry, for example in schizophrenia. Tyrosine is the precursor of dopamine, a neurotransmitter in the central nervous system from the catecholamine group. An excessively high concentration of dopamine in certain brain areas leads to central nervous hyperexcitability and is associated with the symptoms of schizophrenia, such as ego disorders, thought disorders, delusion, motor restlessness, social withdrawal, emotional impoverishment and weakness of will.PhenylketonuriaWith valine, isoleucine and leucine, specific benefits can also be achieved in the treatment of phenylketonuria – PKU. PKU is an inborn error of metabolism in which the phenylalanine hydroxylase system is defective. Due to the impaired activity of the enzyme phenylalanine hydroxylase, which has tetrahydrobiopterin – BH4 – as a coenzyme, the amino acid phenylalanine cannot be degraded. Mutations of the phenylalanine hydroxylase gene as well as genetic defects of the biopterin metabolism have been identified as the cause of the disease. In affected individuals, the disease can be recognized in the form of elevated serum phenylalanine levels. As a result of the accumulation of phenylalanine in the organism, the concentrations of this amino acid increase in the cerebrospinal fluid and various tissues. At the blood-brain barrier, phenylalanine displaces other amino acids, causing the uptake of valine, isoleucine, leucine, tryptophan, and tyrosine into the central nervous system to decrease, while that of phenylalanine increases. As a result of the amino acid imbalance in the brain, the formation of the catecholamines – epinephrine, norepinephrine and dopamine -, the neurotransmitters serotonin and DOPA, and the pigment melanin, which in humans causes the coloration of the skin, hair or eyes, is reduced to a minimum. Due to melanin deficiency, patients exhibit strikingly pale skin and hair. If infants with phenylketonuria are not treated in time, the above-average phenylalanine concentration in the central nervous system entails neurological-psychiatric disorders. These lead to nerve damage and subsequently to severe mental developmental disorders. Affected individuals have been observed to have intelligence defects, language development disorders, and behavioral abnormalities with hyperactivity and destructiveness. About 33% of patients also suffer from epilepsy – spontaneously occurring seizures.Such severe cerebral disorders can be significantly alleviated or even prevented in patients already on a low-phenylalanine diet by increasing BCAAs intake. A high serum valine level decreases the binding of phenylalanine to transport proteins in the blood and its concentration at the blood-brain barrier, thereby reducing phenylalanine uptake into the brain. Thus, with the help of BCAAs, an abnormally high phenylalanine concentration can be normalized both in the blood and in the brain.Dystones SyndromeFurthermore, with the help of branched-chain amino acids, there are benefits for people with so-called dystonic syndrome (dyskinesia tarda). This condition is characterized, among other things, by involuntary movements of the facial muscles, for example spasmodic sticking out of the tongue, by spasms of the pharynx, spasmodic reclination of the head and hyperextension of the trunk and extremities, torticollis, and torsion-like movements in the neck and shoulder girdle area while maintaining consciousness.DietsDiet-conscious individuals who often have an inadequate supply of protein or who primarily consume foods with a low valine content have an increased need for BCAAs. The intake of valine, isoleucine and leucine should eventually be increased so that in the long term the body does not fall back on its own protein reserves, such as from the liver and muscles. If protein intake is too low, the body’s own protein is converted into glucose and used as an energy source by the brain and other metabolically active organs. Protein loss in the muscles leads to a decrease in energy-consuming muscle tissue. The more a dieting person loses muscle mass, the more the basal metabolic rate or energy expenditure decreases and the body burns fewer and fewer calories. Finally, a diet should aim to preserve muscle tissue or increase it through exercise. At the same time, the proportion of body fat should be reduced. During a diet, BCAAs help to prevent protein breakdown and thus a drop in the basal metabolic rate, as well as to increase fat breakdown. Immune defense is largely maintained. A new study at Arizona State University suggests that a diet high in branched-chain amino acids can increase basal metabolic rate by 90 kilocalories daily. Extrapolated over a year, that would mean a weight loss of about 5 kilograms without calorie reduction or exercise. Furthermore, the branched-chain amino acids are needed in quantities appropriate for maintaining normal plasma albumin levels. Albumin is one of the most important blood proteins and consists of about 584 amino acids, including the BCAAs. Low concentrations of valine, isoleucine, and leucine are associated with a decrease in plasma albumin levels, which lowers the colloid osmotic pressure of the blood. As a result, edema (water retention in the tissues) and impaired diuresis (urine excretion via the kidneys) may occur. Accordingly, diet-conscious individuals can help prevent edema formation themselves with an adequate dietary intake of BCAAs and thus maintain their water balance.