L-Leucine (C 6 H 13 NO 2) is one of three essential branched chain amino acids. The other two are L-Valine and L-Isoleucine. Leucine cannot be produced by the body and must be obtained through food or dietary supplements. It can be found in nuts, brown rice, and whole grains. Leucine makes up about eight percent of all amino acids in the body and is the fourth most concentrated amino acid in muscle tissue.
A distinctive feature of Leucine is that this amino acid plays an important role in protein synthesis. The term "protein synthesis" can be found quite often, even in ordinary articles concerning the formation of muscle mass. However, what is this process? Simply put, it is the formation of new proteins that occurs in skeletal muscle of our body.
If this happens quite intensely, we are talking about hypertrophy of skeletal muscles (their growth), i.e. about the process of increasing our muscle mass. The purpose of this article is to highlight the effects of dietary intake, in particular leucine, on protein synthesis in skeletal muscle after exercise.
Prerequisites
Different types of exercise have different effects on muscle protein metabolism.
- Endurance exercises affect protein metabolism in skeletal muscles in the following way: they reduce anabolic processes (the formation of new proteins) and increase the process of catabolism (protein breakdown) causing myopathy - a decrease in muscle mass.
- Exercise for weight is unique in comparison with other types of physical exercise, since at the time of performing these exercises, along with an increase in the breakdown of proteins in muscles, an effective increase in protein synthesis also occurs.
A common effect in both cases is a negative protein balance (general protein breakdown). Thus, exercise induces protein catabolism in the short term. However, in the long term, exercise can help maintain or increase muscle mass.
Leucine
It has been established that in order to maintain a positive protein balance after physical training, it is necessary to consume proteins, in particular, the amino acid leucine. Until leucine is supplied with food, the protein balance will remain negative.
Leucine is one of the three and is a unique amino acid that promotes muscle protein synthesis. In fact, leucine has about 10 times more influence on the formation of new proteins than any other amino acid!
So how does leucine promote muscle protein synthesis? First, we need to learn more about the processes in the body that leucine activates. Leucine has been shown to activate a major anabolic receptor known as the mammalian target of rapamycin (mTOR protein). mTOR is an amino acid receptor in the cell that is sensitive to the concentration of leucine.
A decrease in the concentration of leucine transmits the mTOR signal that there is currently not enough food for the synthesis of new proteins in the muscles, and mTOR is deactivated. As the concentration of mTOR leucine increases, a signal is sent that there are enough proteins to synthesize new muscle proteins, and mTOR is activated.
MTOR activation
Although researchers are not entirely sure exactly how leucine activates mTOR, mTOR has been found to be sensitive to leucine concentration and levels (lowering ATP levels also deactivates mTOR).
MTOR activation is closely related to increased protein synthesis. mTOR promotes protein synthesis through two different mechanisms.
Mechanism No. 1
Phosphorylation of the binding protein 4E-BP1, which leads to its inactivation. When active, the 4E-BP1 protein binds to the eIF4E protein (initiating factor), preventing it from binding to the next eIF4G protein to form the eIF4E * eIF4G complex.
The formation of this complex is an important factor in starting the process of protein synthesis.
Simply put, mTOR promotes the triggering of protein synthesis by inactivating 4E-BP1, thus allowing the formation of the eIF4E * eIF4G complex, which is an important factor in triggering the protein synthesis process.
It could be explained in more detail, however, this is superfluous. This diagram is pretty simple to understand the process.
Mechanism number 2
mTOR activates the ribosomal protein S6 (known as rpS6 or p70 S6). The rpS6 protein increases the synthesis of components of the protein synthesis chain. Thus, mTOR not only promotes protein synthesis, but also increases the potential for its synthesis.
By analogy, to help understand this process, consider the example of a contractor building a new skyscraper.
mTOR is a contracting organization. The protein you are trying to synthesize is a skyscraper. The components of the protein synthesis chain are the machines (bulldozers, cranes, etc.) that you use to construct a building. And leucine is the funds needed to carry out design work.
With enough cash available (increasing the concentration of leucine), the contractor can not only start building a skyscraper (synthesize protein in muscles), but also buy more cars (increase the number of components needed for synthesis). This, in turn, will increase the power and speed with which the skyscraper (protein synthesized in the muscles) will be erected.
Leucine also promotes protein synthesis by increasing the availability of the eIF4G protein to form the eIF4G * eIF4E complex through phosphorylation of eIF4G.
In simple terms
Let's leave the gems of science aside and talk about what we've learned from the above. How beneficial is leucine supplementation? Or is it perhaps enough to switch to a high protein diet? There is some evidence to support taking leucine even if you consume enough protein in your diet.
Scientists recently conducted an experiment in which three groups of people did weight exercises for forty-five minutes, after which one group of people was given food containing exclusively, another - carbohydrates and about 30 g of protein, and the third - carbohydrates, protein and leucine.
It was found that in the group of people who ate food containing carbohydrates, proteins and leucine, protein catabolism decreased, and protein synthesis in the muscles increased to a greater extent than in the group of people who ate food containing carbohydrates and proteins, and increased even more. degree than in the group of people who ate food containing exclusively carbohydrates.
A possible explanation for these results is associated with the peak increase in plasma leucine concentration that the free form of dietary leucine can achieve. It takes a long time for total protein to travel from the stomach to the small intestine and finally into the bloodstream. Thus, the concentration of proteins in blood plasma rises slowly and plateau-like.
Even when digested quickly, for example, serum leucine can take several hours to be cleared of protein and absorbed into the circulation. In this regard, the concentration of leucine in the blood plasma never reaches a high level.
However, when eating food containing pure leucine, it will be rapidly absorbed into the bloodstream, thus reaching its peak concentration in blood plasma, which will cause a sharp increase in the level of intracellular leucine and activation of the above-mentioned anabolic chain.
Conclusion
In conclusion, we come to the obvious fact that leucine promotes protein synthesis by increasing mTOR activity and phosphorylation of the eIF4G protein.
Leucine has a much more stimulating effect on protein synthesis than any other amino acid. It has been found that protein synthesis also increases in response to a relatively small dose of leucine in food.
It has also been found that adding leucine to foods that are high in protein is much more conducive to muscle protein synthesis.
In any case, it remains to be determined how beneficial it is for athletes and bodybuilders to consume leucine in addition to high protein foods to further increase muscle mass in the long term.
Most athletes are well aware of such a protein supplement for building muscle mass as BCAA... It includes three essential irreplaceable amino acids : isoleucine , valine and leucine. These protein components have similar features, but at the same time, each of them is unique in its own way. Let's get acquainted with the features of leucine in the human body.
Substance information
Leucine is an aliphatic amino acid. Its belonging to the BCAA category is determined by the presence of the branched chain protein component in the structure. The name of the amino acid in science also sounds like 2-amino-4-methylpentanoic acid. In nature, it is found in all natural proteins. This is also indicated by the history of the discovery of organic compounds: in the 20s. the century before last, leucine was first isolated by the European scientist A. Brakonno from the wool and muscles of an animal. Much later, at the beginning of the 20th century, thanks to another researcher, the German G. Fischer, an artificial method of obtaining a substance saw the light. The chemist used the method of contacting 2-bromo-4-methylpentanoic acid with ammonia.
In the human body, leucine does not have the ability to synthesize on its own, and therefore belongs to the group of irreplaceable protein "building blocks". When an amino acid enters the internal environment of the body with food or special dietary supplements, it rushes, first of all, to the pancreas, then to the liver, spleen, and organs of the urinary system. A lot of it is also concentrated in muscle tissue and blood serum.
The amino acid leucine is indicated for use in the form of dietary supplements for people with the following diseases: neuritis, exhaustion, mental disorders, anemia, liver cirrhosis, immunodeficiency, poliomyelitis, Menkes disease, degenerative changes in the muscles. It gives excellent results after injuries and surgeries.
Excess and deficiency of leucine
Leucine must enter the human body every day, and in specific quantities. Experts recommend taking 1 - 1.2 g of an essential amino acid daily if you do not lead an active lifestyle, that is, do not play sports, and are not trying to lose excess weight... Otherwise, you will have to increase the announced dose to 5-10 g. With targeted weight loss, this amount will have to be taken in three passes.
What happens to a person who does not receive leucine regularly, at least in the diet? He develops the negative consequences of a chronic deficiency of a substance: problems in the functioning of the thyroid gland, exhaustion, and impaired renal function. For infants, a lack of leucine is fraught with hypoklycemia, that is, a strong decrease in blood sugar levels; for adolescents - a decrease in the synthesis of somatropin, in other words - inhibition of the growth process.
Alas, an overdose of an essential amino acid is also quite harmful to human health. This is a direct road to intoxication resulting from the oversaturation of body tissues with ammonia. In addition, due to the excessive intake of leucine into the internal environment of the body, protein metabolism is disrupted.
Leucine source foods
Enrichment of the daily diet with leucine is possible due to the inclusion of products containing a protein component in their menu.
First of all, you should pay attention to the treats that are of animal origin. Milk, kefir, sour cream, cheeses, cottage cheese, yogurt, sea and ocean fish, red and black caviar, chicken eggs, diet meats (chicken, turkey, rabbit, lean beef) are all excellent sources of leucine. At the same time, fish and meat fillets in terms of the amount of essential amino acids benefit much more than fermented milk products.
From plant products, which contain enough leucine, it is worth highlighting soybeans, peanuts, sprouted wheat grains, pumpkin seeds, almond and walnuts, brown rice, baker's yeast.
Compound contraindications
The amino acid leucine in the form of a dietary supplement can only be consumed after consulting a doctor. Otherwise, it is real to cause great harm to your health. People suffering from individual intolerance to this organic substance will generally have to abandon even the very idea of taking a drug enriched with leucine.
Athletes are advised to lean on BCAAs. However, the joint intake of leucine with its counterparts - valine and isoleucine - is fraught in some cases with skin allergies and even an increase in blood sugar levels. So be careful!
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There is evidence that chronic diseases of civilization are associated with mTORC hyperactivity, such as acne, obesity, type 2 diabetes, hypertension, Alzheimer's disease, cancer, especially prostate cancer. Today we will start talking about "fast" amino acids, which significantly stimulate mTORС. These are branched-chain amino acids, primarily leucine, let me tell you about its light and dark side. About methionine has already been: .
In the cells of our body, there is a molecular complex that controls the activity of the cell. Its activity is important for the growth of the body and its individual tissues (muscle building). But after 25 years, human growth ends and the excessive activity of this mTOR complex makes harmful, painfully altered cells grow (atherosclerotic plaques, fat, cancer cells and etc.). If a person is actively involved in sports and is exposed to great stress, then he can safely afford a lot of mTOR activity. Imagine that our life is a car ride. If you stupidly press on the gas all the time, you will soon get into an accident. For a long and safe ride, you need to slow down, stop, let other cars pass. Those. our cells need periods of inactive mTOR for our cells to regenerate. Constant stimulation and growth leads to the fact that our cells become "cluttered" and lose sensitivity to the signals of the body, which leads to problems. Foods have different effects on mTOR activity. There are neutral foods that stimulate mTOR in proportion to the number of calories, and there are “fast” foods that stimulate mTOR much more. If a person is growing or physically active for a significant part of the day, then there is no particular harm to him. But if a person has less physical activity, then these foods will lead to the growth of mTOR-dependent diseases, which I talked about earlier. In this regard, the constantly increasing signaling of mTORС1 is recognized as the main driving force behind the development of mTORС1-dependent diseases of civilization. The cell responds to many stimuli (growth factors, nutrients, hormones, etc.), as a result, the mTOR enzyme complex is activated. It is believed that its chronic, out of nowhere, activation contributes to the onset and progression of a number of diseases, such as autism, Alzheimer's disease, parkinsonism and cancer. Now in a series of posts I will talk about the main ways of activating mTOR, today we will talk about proteins and amino acids. And you will see that the division of proteins into "animal" and "vegetable" is not entirely correct from the point of view molecular biology... So, soy and wheat proteins are also "fast" foods that significantly stimulate mTOR. 1. Hormones and growth factors: testosterone, orexin, insulin, IGF-1, etc.
Simple explanation about mTOR.
The main ways of activation (not all!).
3. Physical exercise... mTOR is activated in the brain, muscle and heart, and inhibited in the liver and fat cells, which is beneficial for the body.
4. Inflammation (excess omega-6 fatty acids, disturbed microflora, etc.)
5. Certain substances such as phosphoric acid. It is important to reduce the consumption and creation of phosphoric acid in the body (Orthophosphoric acid is registered as a food additive E338. It is used as an acidity regulator in carbonated drinks, such as Coca-Cola)
Fast foods: milk.
Fast foods contain nutrients that maximally stimulate mTOR by various mechanisms: through glucose, through IGF-1, through a feeding regimen (the more often you eat, the more IGF-1 is produced even with the same number of calories), through the action of leucine and many other mechanisms. The classic fast food is milk and products made from it (cheese, cottage cheese, milk powder, etc.), the consumption of which is growing incredibly quickly. What's more, powdered milk is added to a variety of other foods, from bars and breads to quick cereals and diet food... All dairy products cause a high rise in insulin, IGF-1, stimulate mTOR directly through high levels of leucine and methionine.
Milk is not just food, but it is obviously a highly complex endocrine signaling system that activates mTORC1 through special maternal milk-derived transmitters that are controlled by the mammalian lactation genome: breast-produced BCAAs of milk proteins and exosomal miRs, which lead to increased mTORC1 signals for postpartum growth.
Cow's milk is an extremely potent evolutionary program for the rapid growth of the Bos Taurus (domestic cow) species, which can permanently induce mTORC1 overstimulation in milk drinkers. What's more, the gain in calf weight during the first year of cow's milk (0.7 - 0.8 kg per day) is almost 40 times faster than in human breastfeeding babies (0.2 kg per day)
It is delicious.
Why are these products so popular? It's very simple - they seem delicious to our brains (as well as sugar, fat, salt). The system for the reception of essential amino acids (detection of deficiency or excess) is located in the brain. Here, signals of subsequent feeding behavior are formed, expressed in the preferred eating of balanced feed or the development of a persistent aversion to a diet with a deficiency or imbalance, followed by adaptation and an increase in feed consumption, or the impossibility of adaptation, depending on the severity of the imbalance of essential amino acids.
There is experimental evidence that the anterior piriform cortex (APC) of the brain plays a major role in these reactions. This is where essential amino acid deficiency signals are integrated. To date, it is known that protein kinases are necessary transmitters of signaling impulses in nervous system and the formation of reflexes.
Since dietary amino acid imbalances lead to persistent food aversion, it is suggested that phosphorylation of certain proteins by protein kinases may play an important role in the anorectic response. This is why “fast food” tastes better. But in nature, only the mother (milk) or in limited quantities (eggs) have them.
The branched chain amino acids (BCAAs) leucine, isoleucine and valine have been found to stimulate protein synthesis in skeletal muscle with the same efficiency as a complete mixture of all amino acids. This phenomenon has attracted wide attention of representatives of sports medicine, as it allows you to manage the muscle mass of athletes. Leucine acts through the mTOR protein kinase.
The fastest amino acid is leucine.
Leucine (abbreviated as Leu or L; 2-amino-4-methylpentanoic acid; from the Greek leukos - "white"), is a part of all natural proteins. Leucine is one of the essential amino acids that is not synthesized by the cells of the body, therefore it enters the body exclusively as part of natural food proteins. The absence or lack of leucine in the body can lead to metabolic disorders, stunted growth and development, and a decrease in body weight. Leucine cannot be produced by the body and must be obtained through food or dietary supplements. It can be found in dairy products, meat, wheat, legumes, nuts, brown rice, and whole grains. Leucine makes up about eight percent of all amino acids in the body and is the fourth most concentrated amino acid in muscle tissue.
Lecine has the unique ability to directly stimulate mTOR activity. In addition, leucine stimulates the release of insulin and IGF-1, which also stimulate mTOR. Interestingly, leucine has a much larger effect on protein synthesis than any other amino acid.
One of the most studied paths muscle growth is the serine / threonine protein kinase mTOR (mammalian target of rapamycin), by which leucine activates complex muscle-building pathways. It should be noted that mTOR is highly sensitive to leucine concentration. Leucine has about 10 times more effect on the formation of new proteins than any other amino acid!
The white side of leucine.
The activation of mTOR in muscle is an important factor in muscle growth. Therefore, many athletes recommend the "sucker" feeding style - a newborn baby: liquid food, milk and its derivatives (such as whey protein), a lot of sugar and frequent meals. Of course, all this helps the activation of mTOR. But I want to draw your attention to the fact that the main thing for muscle growth is the selective stimulation of mTOR (only in the muscles). When you play sports, mTOR is stimulated by mechanical growth factor, which is secreted in the muscles and mTOR works there.
It has been scientifically proven that resistance training alone can increase protein synthesis by 40%. When using leucine, this figure rises to 50%. Muscle growth and stimulation are sufficient when mechanical growth factor is activated. Participating in mTOR certainly adds impact, but only if you really "grow". But nutritional stimulation of leucine increases mTOR activity throughout the body and everything from atherosclerotic plaques to acne grows. Of course, there is no problem in short-term stimulation, balance is important, I already wrote about this.
While this may result in a leaner mass over a period of time, leucine has also been shown to be effective in increasing muscle mass in people with low protein intakes and in the elderly (who tend to have muscle protein synthesis impairments). as a result of a therapeutic diet).
The effect of leucine on glucose is not fully understood. Leucine has the ability to lower blood sugar (it can release insulin from the pancreas and also directly stimulate the absorption of glucose by the cell without insulin), but also has the opposite properties (inhibits insulin-stimulated glucose uptake by stimulating ribosomal protein S6 kinase). In cell culture, leucine stimulates glucose uptake for up to 45 minutes. In living systems, the effect of small doses of leucine is insignificant (according to preliminary data, leucine has rehabilitative properties in diabetes mellitus).
In addition, leucine is an effective adjuvant to increase human performance during various diets. Taking leucine and other BCAA amino acids helps athletes reduce body fat, increase muscle mass, increase endurance and improve the quality of the exercises performed during training
A bit of biochemistry... As already sounded, the main mechanism of action of leucine is the activation of the target of rapamycin (TOR), which is referred to as the "target of rapamycin in mammalian cells" (in particular, leucine activates mTORC1, one of the subgroups of the complex). The first intracellular multimolecular signaling complex (mTORC1) consists of several proteins: TOR itself, along with raptor (regulatory-associated protein of TOR), protein GβL, and PRAS40 (proline-rich PKB / AKT substrate 40 kDa)). This complex is activated by leucine supplementation.
Incubation of the cell with leucine activates mTOR without activating protein kinase B, and this effect is identical to the overall increase in intracellular calcium. Interestingly, leucine appears to induce mTOR activity by increasing intracellular calcium, since an increase in calcium and the binding of calmodulin (a protein involved in calcium homeostasis) to hVPS34 is fundamentally important for leucine-induced mTOR activation.
Protein SHP-2 (tyrosine phosphatase) is critical for muscle protein synthesis and is known to limit muscle growth during periods of nutritional deprivation. It signals ribosomal protein S6 kinase (S6K1) by mobilizing intracellular calcium at the highest point of phospholipase C gamma-4 and works by the protein Rheb, which stimulates mTOR. Rheb proteins are known to be positive modulators of mTOR function. Leucine and / or its metabolites increase intracellular calcium, similar to muscle contractions.
The increase in calcium, in turn, activates proteins like mTOR, which then induce muscle protein synthesis. Unlike muscle contractions, this process occurs in all cells and not only in skeletal muscles. In other words, the process is as follows: SHP-2 (currently the farthest protein in the chain) → calcium mobilization → hVPS34 binding to calmodulin → mTORC1 activation (possibly with Rheb) → S6K1 activation → muscle protein synthesis
The black side of leucine.
It is important to understand that mTORC hyperstimulation is caused not by leucine alone, but by a complex of problems (hypercaloricity, excess sugar, total excess of protein, excess omega-6, constant snacks, etc.). The peculiarity of the Western diet is that we eat incredible amounts of leucine in both animal and plant foods. The main sources of leucine are meat, dairy products (including cheese), legumes (soy), wheat, and peanuts. Sound familiar? Often the diet of many people consists of meat, cereals and milk.
With constant stimulation of growth and mTORC activity, cells cease to repair themselves, and autophagy is disrupted. It turned out that the amino acid methionine, as well as the amino acids BCAA (leucine, isoleucine, and valine), stimulate the activity of a signaling protein, mTOR kinase. The activity of the mTOR kinase protein shortens the lifespan due to the fact that this protein activates the synthesis of new proteins in orgasm to the detriment of the "utilization" of old ones, which simply clog the cell. The increased content of old damaged proteins leads to accelerated aging of body cells.
In addition, as I wrote above, with food stimulation, mTORC is stimulated everywhere, including fat cells. So, leucine is the most powerful stimulant of fat accumulation in fat cells (picture below).
Constant overstimulation of mTORС1 contributes to the emergence of chronic diseases of civilization. Epidemic acne is a visible indicator of excess mTORС1, signaling an increased risk of the following diseases of civilization: early puberty, early onset of acne, excessive acne (acne), obesity, type 2 diabetes, cancer, neurodegeneration.
Until recently, a rather weak link was recognized between the consumption of milk and dairy products and the pathogenesis of acne, but now, however, there is significant epidemiological and biochemical evidence supporting the effect of milk and dairy products on increasing insulin- / IGF-1 and worsening acne.
In this regard, it is scary to realize that more than 85% of adolescents in Western countries show acne, while representatives of the non-Western population, such as Kitava, are not affected by this disease and other mTORC1-dependent diseases of civilization. This suggests that most of the Western population lives with overly activated mTORC1 signals, a major pathogenic factor that could possibly set the stage for the development of other more serious diseases of civilization. This finding leads to the conclusion that acne may be an indicator of an increased risk of breast cancer.
Dermatologists advising patients with acne problems, especially young ones, should not only pay attention to the treatment of skin pathologies, but also advise on how to correct the unusual mTORC1 stimulation, aggravated by the Western diet. This is necessary to prevent the more serious mTORC1-dependent diseases of civilization, such as obesity, diabetes and cancer. A comprehensive dietary strategy for treating acne can only be achieved by increasing the consumption of vegetables and fruits, and reducing the amount of food of animal origin.
The study was conducted in the United States under the direction of Walter Longo. The research results are shown in 2014. So among people from 50 to 65 years old, regular consumption of large amounts of cow's milk and dairy products led to an increase in overall mortality and an increase in tumor diseases.
The restriction of foods rich in leucine has an effect that is tantamount to therapeutic fasting and on low-calorie meals, and their lifespan grew. But another group of fruit flies was also planted on a low-calorie diet, but at the same time BCAA amino acids, or one amino acid methionine, were added to their diet. Life extension was not observed in such fruit flies. It was found that it was not low calorie intake that caused life extension, but lower intake of sugar-containing foods + lower intake of BCAA amino acids and methionine. Later, the same results were confirmed in mammals. Methionine and BCAA are amino acids that are part of, first of all, animal protein. Especially a lot of it in cow's milk and dairy products.
Leucine refers to essential amino acids. They are considered to be indispensable nutritional factors. Our body receives essential amino acids from protein products. Each amino acid has a number of unique functions. The body uses the amino acid leucine to make protein.Properties of leucine.
Leucine has a number of important functions necessary for the human body, these include:
- Essential for the normal functioning of the liver;
- In the postoperative period, it is used to restore skin and bones. Promotes rapid wound healing;
- Reduces blood sugar levels. Leucine breaks down to glutamine and alanine, which maintain blood glucose levels;
- Stimulates the growth of muscle tissue and prevents protein breakdown. This is the function of leucine is important for athletes to build muscle.
- Participates in the metabolism of carbohydrates.
- To strengthen the immune system;
- Prevents the onset of fatigue;
- Effective in the fight against excess weight.
Daily rate leucine is 5000 mg for an adult, according to I.M. Skurikhin.
What foods contain leucine.
This is found in protein foods.
To get the daily norm of leucine, you need to eat 200g of millet porridge + 115g of rabbit meat.
At lack of leucine there is a mental disorder.
The reason for the lack of leucine is insufficient intake of vitamin B6 into the body.
Excess leucine causes excess ammonia in the body.
Woman for wound healing, received during childbirth, you need to eat foods rich in leucine.
Leucine for nursing mothers To feed her husband, to keep the house in order, to take care of the baby - all this tires the young mother and leads to constant fatigue and lack of sleep. The easiest way to relieve fatigue is to eat foods that contain essential amino acids, including leucine.
Leucine for children. Every mother is interested in how to protect her child from infections. Not the least role in strengthening the child's immunity is nutrition, and maybe even the first. A child must get all the essential nutrients in their diet, including leucine, in order to be healthy and successful.
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