BLOG SERIES: Nutrient Utilization for Targeted Hypertrophy—The Path of Food from the Mouth to the Muscle Cell, Part 3: Blood and the Liver

Dear blog readers and loyal Peak customers, In the first two parts of my blog series, we saw how food we consume is ultimately transferred into the bloodstream via the mouth, the esophagus, and the intestines. Once there, nutrients must be distributed according to the body’s needs. But who decides which nutrients go where, and how are nutrients transported? I’ll address these questions in Part 3 of my series. Blood: General Information Human blood, also known as liquid tissue, consists of approximately 45% cellular components and 55% plasma. This ratio is crucial for determining the hematocrit value, which provides information about the blood’s viscosity and flow properties. Men generally have a slightly higher cellular content than women. General components of blood include water, proteins, salts, hormones, dissolved gases, nutrients, and metabolic and waste products. Plasma Components In addition to water, the following ions are present in blood plasma:

Sodium

 

Chloride

 

Magnesium

 

Phosphate

 

Calcium

Cellular Components: Classification of Blood Cells a) Erythrocytes (red blood cells) They transport oxygen and carbon dioxide. An increase in erythrocytes occurs during conditions of oxygen deprivation, e.g., during high-altitude training. b) Leukocytes (white blood cells) Leukocytes and their subtypes are responsible for specific and nonspecific immune defense. c) Thrombocytes (blood platelets) Thrombocytes help stop bleeding and thus form the basis of the first phase of wound healing. Functions of the blood a) Transport function: Blood transports oxygen and nutrients to the cells. At the same time, metabolic waste products such as carbon dioxide or lactate are removed via the blood. b) Homeostasis Water and electrolytes are reabsorbed into the blood in the large intestine. Their continuous availability must be ensured there. The blood’s pH level must also be regulated autonomously (normally 7.4). c) Defense function: Blood is part of the immune system. It provides protection and defense against foreign substances and antigens through phagocytes (scavenger cells) and antibodies. d) Constant body temperature: The constant circulation of blood ensures a constant body temperature in humans, which should be approximately 36.5 degrees Celsius. e) Other Functions In the event of injuries, the blood responds by producing clotting factors to close wounds and prevent blood loss. Due to the pressure within the blood vessels, blood also provides structural support to the body. Hormones That Influence Blood Sugar a) Glucocorticoids (Cortisol) Cortisol is produced by the adrenal cortex. It is responsible for raising blood sugar levels. It promotes protein breakdown to provide energy via gluconeogenesis in stressful situations. Cortisol levels can be reduced by managing stress, inducing insulin release, or supplementing with active ingredients such as phosphatidylserine. b) Insulin Insulin is produced by the pancreas (pancreas). It is responsible for lowering blood sugar levels. As an anabolic hormone, it stores carbohydrates, fats, and proteins in muscle and fat cells. Insulin promotes muscle growth but is detrimental when it comes to burning body fat. Increased insulin secretion can be triggered by short-chain carbohydrates, while insulin secretion is reduced when the diet contains a certain amount of fat and/or the carbohydrates are as long-chain as possible. c) Glucagon Glucagon is produced by the pancreas. It is responsible for raising blood sugar levels. Glucagon is the antagonist of insulin. The increase in blood sugar levels occurs through the release of glycogen and body fat. d) Catecholamines: Norepinephrine and epinephrine. These hormones originate in the adrenal medulla. They are released during stressful situations and during intense physical exertion and promote the breakdown of glycogen and fats to provide energy. These hormones are the best allies for fat loss and can be stimulated through exercise or supplements containing caffeine and/or taurine. They have a negative effect on muscle building, however, as activation of the sympathetic nervous system suppresses the feeling of hunger. e) STH (Growth Hormone) is produced by the pituitary gland. It also acts as an antagonist to insulin by raising blood sugar levels. STH increases fatty acid oxidation and glycogen breakdown. It strongly stimulates protein synthesis. It can be stimulated through good sleep, certain supplements, and training with short rest intervals. The amino acid tryptophan, for example, promotes a long period of deep sleep. Citrulline malate or the amino acid combination of arginine-ornithine and lysine are said to stimulate STH. f) T4 (thyroxine) and T3 (triiodothyronine), thyroid hormones, cause an acute increase in blood sugar levels. Thyroid hormone levels are maintained through metabolism-boosting activities and an isocaloric or hypercaloric diet. They support efforts to lose body fat but can also be responsible for the failure of dieting efforts if their secretion is reduced during a hypocaloric diet, thereby slowing down the metabolism. Manipulation of Blood Flow Through Arginine What Is Arginine and What Does It Do? Arginine is a semi-essential amino acid, which means that in certain situations, the body cannot synthesize it on its own and therefore requires an external source. In addition to numerous positive health effects—such as improved wound healing, stimulation of the immune system, and promotion of recovery from reversible diseases and damage to the cardiovascular system, liver, kidneys, and gastrointestinal tract—arginine is particularly popular in bodybuilding due to its vasodilatory effect. How does vasodilation occur? In the endothelial cells—that is, the cells lining the blood vessels—arginine is converted into nitric oxide (NO) with the help of the enzyme NO synthase. NO, in turn, is responsible for dilating the blood vessels. Benefits in Bodybuilding Bodybuilders experience an enhanced “pump” during training. Muscle cells can be better supplied with blood—and thus with the nutrients, anabolic hormones, and oxygen (via red blood cells) it contains. Combining arginine with, for example, essential amino acids, glucose, or creatine is therefore highly beneficial. In particular, the combination of arginine and glucose leads to a significantly increased blood flow rate. Timing of Intake To increase NO production, it is recommended to take it 30–60 minutes before training. Immediate Enhancement or Maximization of Vascularity with Arginine The use of arginine is not always beneficial for developing vascularity, especially when the muscles are not being trained or worked. Reason: Vasodilation can lead to a drop in blood pressure. This effect is rather unfavorable for achieving a full, pumped appearance in the muscles. Other NO boosters: In addition to arginine, the following supplements also increase NO production:

• Citrulline malate
• Pycnogenol
• Vitamin C

The Liver Functions The liver is responsible for maintaining metabolism. This includes the maintenance, synthesis, and breakdown of energy stores, cell structures, and fluid balance. The liver is also responsible for the production of blood clotting factors. Bile acids, which aid in fat digestion, are initially produced in the liver. Hormone precursors are also formed in the liver. Important detoxification processes in the body also take place in the liver, such as urea synthesis—which is crucial for protein digestion—and the breakdown of alcohol. The liver also serves as an important vitamin store. Metabolic phases of the liver a) Absorption phase Nutrients pass from the intestine into the liver Carbohydrates Glucose present in the blood is stored as glycogen in the liver or, when needed, transported from there to the muscles. Excess carbohydrates are converted into fat in the liver and can thus be stored in adipose tissue. Proteins: Amino acids are mostly used in the liver for the synthesis of protein compounds, which then enter the bloodstream as plasma proteins. Fat: Fat reaches the liver from the lymph and is converted there into lipoproteins. In this form (as a fat-protein compound), they are released into the blood and can thus be transported to adipose tissue. Summary: Absorption Phase During the absorption phase, nutrients are stored as energy-rich compounds in various depots. Nutrient Storage Depots 1. Liver glycogen: Its capacity is approximately 80–120 g and is available to supply the organs when food intake is insufficient. 2. Muscle glycogen: Approximately 300 g is stored here. If muscle mass is high, this value can rise to as much as 500 g. Triglyceride stores Virtually an infinite amount of energy can be stored in subcutaneous fat. The average amount of stored fat is 14,500 g in a 70-kg person, which is approximately 135,000 kcal. b) Post-absorption phase: Mobilization of glycogen and stored fat. No nutrient transport from the intestine to the liver. Process: The liver’s glycogen stores are “depleted.” Glycogen is converted to glucose so it can be transported via the blood to the organs. When glycogen reserves are depleted, amino acids, glycerol, and lactic acid are converted into glucose through the process of gluconeogenesis. IMPORTANT: Glycogen stored in the muscles can no longer be used by the body to stabilize blood sugar. The pathway of glucose into the muscles is, so to speak, a one-way street. Increased gluconeogenesis from amino acids inevitably leads to muscle breakdown as energy requirements rise. Summary: Post-absorption phase. In this phase, stored energy reserves are drawn upon to maintain a constant blood sugar level and ensure a steady supply of energy to the organs. Liver and Carbohydrate Metabolism. Depending on the current metabolic state and nutritional status:

• The liver forms glycogen from glucose (storage)
• The liver converts glucose into fatty acids (storage)
• The liver converts fructose into galactose and glycerol (diet-dependent)
• The liver distributes glucose to the body’s tissues (as needed)
• The liver produces glucose from amino acids, lactate, and glycerol (diet-dependent)

The liver’s primary goal is to maintain a constant blood glucose level The Liver and Amino Acid Balance Using incoming amino acids, the liver stabilizes the amino acid level in the blood. When there is an excess, protein structures are synthesized at an increased rate. This process is known as protein synthesis, which is explained in detail in Part 4. Excess nitrogen is converted by the liver into urea and thus detoxified. The Liver and Muscle Building As described above, the liver acts as the distributor of nutrients arriving via the blood or lymph. If the organs and blood are supplied with sufficient glucose and amino acids, nutrients can be used in response to a training stimulus to replenish glycogen stores depleted during training and to rebuild or strengthen damaged protein structures. It is therefore one of the fundamental tasks of a bodybuilder to ensure an adequate supply of nutrients in order to create an anabolic environment in the body—specifically in the muscles. This is achieved through a solid nutritional foundation and, furthermore, through supplements that provide the body with a balanced supply of nutrients that CANNOT be obtained through a normal diet. Sufficient protein protects the muscles from having to release amino acids that have already been incorporated into them in order to maintain stable blood sugar levels or supply the organs. Protein powders are particularly well-suited for this purpose, as they provide the amount needed by bodybuilders. IMPORTANT: Without an appropriately intense training stimulus, the liver receives no signals to increase the transport of protein and glucose to the muscles! Summary: We have seen that our blood is responsible for transporting all nutrients, active substances, and oxygen to their destinations and, in return, removing metabolic waste products. Blood flow can be modified through supplements so that MORE nutrients and oxygen reach the muscles FASTER, and toxins and waste products leave the muscles FASTER. When using these supplements, it’s important to find the right balance and not follow the “more is better” approach. The liver is, so to speak, the “brain” of metabolism. It controls the distribution of nutrients and alternates between storage and release phases. Through targeted nutrition, supplementation, and training, you can ensure that the liver transports more nutrients to the muscle cells so they can be utilized there for hypertrophy. The bodybuilder’s goal must also be to utilize and manipulate the hormones that influence blood sugar levels according to their specific objectives, since the liver distributes its substrates based on these signals. The fourth and final part will now focus on the metabolism of the muscle cell. It describes how nutrients enter the muscle and which mechanisms are involved. A major topic in Part 4 is protein synthesis. In short, in Part 4 we conclude our journey of nutrients into the muscle cell. Finally, actual muscle building takes place! Until then, I wish you every success and hope you enjoy reading. Best regards, Holger Gugg www.body-coaches.de