The Liver And Blood Glucose Levels
Tweet Glucose is the key source of energy for the human body. Supply of this vital nutrient is carried through the bloodstream to many of the body’s cells. The liver produces, stores and releases glucose depending on the body’s need for glucose, a monosaccharide. This is primarily indicated by the hormones insulin - the main regulator of sugar in the blood - and glucagon. In fact, the liver acts as the body’s glucose reservoir and helps to keep your circulating blood sugar levels and other body fuels steady and constant. How the liver regulates blood glucose During absorption and digestion, the carbohydrates in the food you eat are reduced to their simplest form, glucose. Excess glucose is then removed from the blood, with the majority of it being converted into glycogen, the storage form of glucose, by the liver’s hepatic cells via a process called glycogenesis. Glycogenolysis When blood glucose concentration declines, the liver initiates glycogenolysis. The hepatic cells reconvert their glycogen stores into glucose, and continually release them into the blood until levels approach normal range. However, when blood glucose levels fall during a long fast, the body’s glycogen stores dwindle and additional sources of blood sugar are required. To help make up this shortfall, the liver, along with the kidneys, uses amino acids, lactic acid and glycerol to produce glucose. This process is known as gluconeogenesis. The liver may also convert other sugars such as sucrose, fructose, and galactose into glucose if your body’s glucose needs not being met by your diet. Ketones Ketones are alternative fuels that are produced by the liver from fats when sugar is in short supply. When your body’s glycogen storage runs low, the body starts conserving the sugar supplies fo Continue reading >>
6. Regulation Of Blood Glucose
Processes in which simple substances are built into more complex ones. Requires energy. Processes in which complex organic compounds are broken down into simple ones. Reactions that produce energy that is stored for later release in a molecule called ATP. Why must blood glucose levels be regulated? Glucose is the preferred energy source for the brain, and must be supplied constantly to it. Explain briefly how nutrients are used to supply energy to the body glucose is an important intermediate compound in the interconversions of carbohydrates, lipids and proteins. These conversions can occur after digestion and virtually all the molecules in the body are continually being broken down and rebuilt breakdown of glycogen in the liver to glucose. formation of glucose in the liver from fat and protein molcules polysaccharides and disaccharides are hydrolysed into monosaccharides glucose, fructose and galactose. Virtually all fructose and galactose is then converted in the liver to glucose. Carbohydrates in the form of glucose or glycogen are important energy sources. Glucose is the preferred energy source for cells, and the fate of absorbed glucose depends on the current energy needs of the body. If cells need immediate energy then glucose absorbed after a meal is oxidised within the cells. Surplus glucose is converted to glycogen or fat for storage, or excreted in urine. Glucose can be converted to glycogen and stored in the liver and skeletal muscle. Glucose metabolism changes frequently between the formation of glycogen (glycogenesis) and the breakdown of glycogen (glycogenolysis). glycogen, the storage carbohydrate is broken down (glycogenolysis) in the liver to glucose. Glucose in the liver is catabolised via glycolysis, krebs cycle and electron transport chain. The oxid Continue reading >>
Does Carbohydrate Become Body Fat?
Dear Reader, Ah, poor carbohydrates, maligned by diets such as Atkins’ and the ketogenic diet. However, carbohydrates are your body’s main source of energy — in fact your muscles and brain cells prefer carbs more than other sources of energy (triglycerides and fat, for example). To answer your question: research completed over the last several decades suggests that if you are eating a diet that is appropriate for your levels of daily activity, little to no carbohydrate is converted to fat in your body. For most people (unless you have a metabolic disorder) when you eat carbs they are digested, broken down to glucose, and then transported to all the cells in your body. They are then metabolized and used to support cellular processes. If you’re active and eating appropriately for your activity level, most of the carbs you consume are more or less burned immediately. There are two caveats here: first, if you’re eating a lot more calories per day than you are burning, then yes, your liver will convert excess calories from carbohydrate into fats; second, not all carbs are created equal. If you consume too many calories from simple sugars like sucrose and fructose (think sugary sodas sweetened by sugar and high fructose corn syrup) then your body will more readily take some of those sugars and turn them into triglycerides (fat) in your liver. What happens to excess calories that come from carbs? The answer depends on several things: what kind of carbs you consumed, your genetics, as well as how many extra calories we’re talking about. For those who eat a well-balanced diet and have no metabolic disorders, excess dietary carbohydrates are converted by the liver into complex chains of glucose called glycogen. Glycogen is stored in liver and muscle cells and is a sec Continue reading >>
How Fat Cells Work
In the last section, we learned how fat in the body is broken down and rebuilt into chylomicrons, which enter the bloodstream by way of the lymphatic system. Chylomicrons do not last long in the bloodstream -- only about eight minutes -- because enzymes called lipoprotein lipases break the fats into fatty acids. Lipoprotein lipases are found in the walls of blood vessels in fat tissue, muscle tissue and heart muscle. Insulin When you eat a candy bar or a meal, the presence of glucose, amino acids or fatty acids in the intestine stimulates the pancreas to secrete a hormone called insulin. Insulin acts on many cells in your body, especially those in the liver, muscle and fat tissue. Insulin tells the cells to do the following: The activity of lipoprotein lipases depends upon the levels of insulin in the body. If insulin is high, then the lipases are highly active; if insulin is low, the lipases are inactive. The fatty acids are then absorbed from the blood into fat cells, muscle cells and liver cells. In these cells, under stimulation by insulin, fatty acids are made into fat molecules and stored as fat droplets. It is also possible for fat cells to take up glucose and amino acids, which have been absorbed into the bloodstream after a meal, and convert those into fat molecules. The conversion of carbohydrates or protein into fat is 10 times less efficient than simply storing fat in a fat cell, but the body can do it. If you have 100 extra calories in fat (about 11 grams) floating in your bloodstream, fat cells can store it using only 2.5 calories of energy. On the other hand, if you have 100 extra calories in glucose (about 25 grams) floating in your bloodstream, it takes 23 calories of energy to convert the glucose into fat and then store it. Given a choice, a fat cell w Continue reading >>
How Sugar Makes You Fat
Look at how many grams of sugar are in what you’re eating (on the nutritional label). Now divide that number by 4. That’s how many teaspoons of pure sugar you’re consuming. Kinda scary, huh? Sugar makes you fat and fatfree food isn’t really free of fat. I’ve said it before in multiple articles, but occasionally, I’ve had someone lean over my desk and say “How in the heck does sugar make you fat if there’s no fat in it?”. This article will answer that puzzler, and provide you with some helpful suggestions to achieve not only weight loss success, but improved body health. First, let’s make some qualifications. Sugar isn’t inherently evil. Your body uses sugar to survive, and burns sugar to provide you with the energy necessary for life. Many truly healthy foods are actually broken down to sugar in the body – through the conversion of long and complex sugars called polysaccharides into short and simple sugars called monosaccharides, such as glucose. In additions to the breakdown products of fat and protein, glucose is a great energy source for your body. However, there are two ways that sugar can sabotage your body and cause fat storage. Excess glucose is the first problem, and it involves a very simple concept. Anytime you have filled your body with more fuel than it actually needs (and this is very easy to do when eating foods with high sugar content), your liver’s sugar storage capacity is exceeded. When the liver is maximally full, the excess sugar is converted by the liver into fatty acids (that’s right – fat!) and returned to the bloodstream, where is taken throughout your body and stored (that’s right – as fat!) wherever you tend to store adipose fat cells, including, but not limited to, the popular regions of the stomach, hips, but Continue reading >>
Lecture 14: Introduction To Metabolic Regulation
Lecture 14: Introduction to metabolic regulation If you lose the printed handout, you can download another copy here. The "purpose" of metabolism is to supply the energy and raw materials that the body needs to stay alive and reproduce. Not only must these systems operate efficiently in "ideal" situations, but they must also handle shortages and unexpected demands: fighting, natural disasters, pregnancy, lactation, famine, injury and disease. Metabolic control mechanisms are complex, but they normally work very well. They are essential for survival. 1) It is of central importance to keep blood glucose close to 5mM. This is essential for normal cerebral functions. The brain can and does use other fuels, such as ketones and amino acids, but only glucose can cross the blood-brain barrier in sufficient quantities to support normal activity. Confusion and coma supervene if blood glucose falls below 3mM, serious vascular damage follows through protein glycation if it exceeds 8mM for significant periods. Long-term damage caused by protein glycation includes ulcers, kidney failure, blindness, strokes and ischaemic heart disease. Glycation is the non-enzymatic condensation of the aldehyde and ketone groups in sugars with amino groups in proteins to initially yield Schiff bases. These then undergo further chemical reactions to produce "advanced glycation end products" or AGEs. Kumar & Clarke rather confusingly call this process "glycosylation" in chapter 19. Strictly speaking this term is not chemically accurate, but it is widely used. Glycation damages collagen in blood vessel walls, increasing their stiffness, and leading to inflammation and atherosclerosis. This process is now considered to be the major contributor to diabetic pathology, and this has resulted in greater clini Continue reading >>
Physiology • Glucose in the blood is derived from three main sources: ○ ▪ Glucose is the end-product of carbohydrate digestion, absorbed by enterocytes. ▪ Increased blood glucose concentrations occur 2 to 4 hours after a meal in simple-stomached animals. ○ Hepatic production ▪ Gluconeogenesis and glycogenolysis within hepatic cells produce glucose when metabolically necessary. □ Gluconeogenesis converts noncarbohydrate sources, primarily amino acids (from protein) and glycerol (from fat), in simple-stomached animals. □ Glycogenolysis converts glycogen (poly-glucose) stored in hepatocytes to glucose through hydrolysis. ▪ Gluconeogenesis and glycogenolysis within hepatic cells produce glucose when metabolically necessary. □ Gluconeogenesis converts noncarbohydrate sources, primarily amino acids (from protein) and glycerol (from fat), in simple-stomached animals. □ Glycogenolysis converts glycogen (poly-glucose) stored in hepatocytes to glucose through hydrolysis. ○ ▪ Gluconeogenesis and glycogenolysis within renal epithelial cells can result in the formation of glucose when metabolically necessary. • The plasma concentration of glucose is controlled by a number of hormones, in particular, insulin and glucagon. The physiology of glucose homeostasis is controlled primarily by insulin release in response to elevated glucose levels (postprandial), although in birds, glucagon appears to serve as the primary regulator. Significant species variations in glucose levels have been noted. In general, levels are lowest in reptiles (60 to 100 mg/dL) and highest in birds (200 to 500 mg/dL), with mammals in between (100 to 200 mg/dL). Glucose that is not needed for energy is stored in the form of glycogen as a source of potential energy, readily available whe Continue reading >>
The Conversion Of Carbohydrates To Triglycerides
Eating a diet high in simple carbohydrates can raise your level of triglycerides—fats carried in the blood and stored in fat cells. The body turns carbohydrates into glucose to use for fuel, but will store excess glucose as fat. High levels of triglycerides can increase your risk for heart disease. Triglycerides are fats. You eat triglycerides in the form of foods such as butters and oil, but your body also makes triglycerides from excess calories, especially from alcohol or from the simple carbohydrates found in sugar-rich foods. Triglycerides help transport cholesterol, which is essential for brain and nerve function, to your cells. Trigylcerides also carry glucose, or blood sugar, to your fat cells. Carbohydrates in the Diet Dietary carbohydrates fall into two categories: simple carbohydrates, or sugars, and complex carbohydrates, or starch and fiber. Most of the simple carbohydrates in the American diet come from sugar, or sucrose, and high-fructose corn syrup, used to sweeten a wide variety of foods. Fruit juices also contribute simple sugars. Whole fruit contains simple sugars, but also contains fiber, which helps slow down the digestion of glucose. All carbohydrates supply the body with glucose, which is used for immediate energy needs and stored as glycogen in the liver and muscle cells. Eating too many simple carbohydrates is harmful, according to the Cleveland Clinic. How Carbs Turn into Fat Your body digests simple sugars and refined carbohydrates such as white rice and white flour rapidly, causing a spike in blood glucose. This causes the pancreas to release more insulin. When your body has more glucose than it needs for energy and has reached its storage capacity for glycogen, the increased insulin prompts the liver to convert glucose into triglycerides, Continue reading >>
Can Fats Be Turned Into Glycogen For Muscle?
The amount of fat in the average diet and the amount of stored fat in the average body make the notion of converting that fat into usable energy appealing. Glycogen, a form of energy stored in muscles for quick use, is what the body draws on first to perform movements, and higher glycogen levels result in higher usable energy. It is not possible for fats to be converted directly into glycogen because they are not made up glucose, but it is possible for fats to be indirectly broken down into glucose, which can be used to create glycogen. Relationship Between Fats and Glycogen Fats are a nutrient found in food and a compound used for long-term energy storage in the body, while glycogen is a chain of glucose molecules created by the body from glucose for short-term energy storage and utilization. Dietary fats are used for a number of functions in the body, including maintaining cell membranes, but they are not used primarily as a source of fast energy. Instead, for energy the body relies mostly on carbohydrates, which are converted into glucose that is then used to form glycogen. Turning Fats Into Glucose Excess glucose in the body is converted into stored fat under certain conditions, so it seems logical that glucose could be derived from fats. This process is called gluconeogenesis, and there are multiple pathways the body can use to achieve this conversion. Gluconeogenesis generally occurs only when the body cannot produce sufficient glucose from carbohydrates, such as during starvation or on a low-carbohydrate diet. This is less efficient than producing glucose through the metabolizing of carbohydrates, but it is possible under the right conditions. Turning Glucose Into Glycogen Once glucose has been obtained from fats, your body easily converts it into glycogen. In gl Continue reading >>
How Are Carbohydrates Converted Into Fat Deposits?
How are carbohydrates converted into fat deposits? There are two ways that carbohydrates and body fat interact. One is directly by turning into body fat, and the other is via insulin. Turning into body fat is like adding fat into the fat cells, whereas carbohydrates spiking insulin does not add anything to fat cells per se, but hinders the release. The former is like a + equation, where the latter is a double negative which results in something that seems positive. There is a process called de novo lipogenesis (literally: Creation of fat from non-fat sources) that can occur in the body. This process turns glucose into lipids, which are then stored as body fat. This process is normally quite inefficient in the body  , which suggests that carbohydrates cannot be stored as fat to a high degree. The process can be upregulated (enhanced) if dietary fat comprised almost none of the diet (lesser than 10%, as a rough estimate), if carbohydrate intake is excessively high for a period of a few days, or if one follows an obesogenic diet (diet that is likely to make you fat) for a prolonged period of time.    Carbohydrates spike insulin , which is a hormone that mediates glucose metabolism. Insulin is not good or bad, insulin is insulin. It can be thought of as a lever that switches the body from fat burning mode into carbohydrate burning mode. This allows carbohydrates (and glycogen) to be burnt at a greater rate, but directly reduces the ability of fat to be lost. Overall metabolic rate (calories burnt over the course of a day) does not change significantly, just where the calories come from. When insulin is spiked in presence of ingested dietary fat, the dietary fat can go into body fat stores and not be released since glucose from glycogen is being used in place of Continue reading >>
Protein: Metabolism And Effect On Blood Glucose Levels.
Abstract Insulin is required for carbohydrate, fat, and protein to be metabolized. With respect to carbohydrate from a clinical standpoint, the major determinate of the glycemic response is the total amount of carbohydrate ingested rather than the source of the carbohydrate. This fact is the basic principle of carbohydrate counting for meal planning. Fat has little, if any, effect on blood glucose levels, although a high fat intake does appear to contribute to insulin resistance. Protein has a minimal effect on blood glucose levels with adequate insulin. However, with insulin deficiency, gluconeogenesis proceeds rapidly and contributes to an elevated blood glucose level. With adequate insulin, the blood glucose response in persons with diabetes would be expected to be similar to the blood glucose response in persons without diabetes. The reason why protein does not increase blood glucose levels is unclear. Several possibilities might explain the response: a slow conversion of protein to glucose, less protein being converted to glucose and released than previously thought, glucose from protein being incorporated into hepatic glycogen stores but not increasing the rate of hepatic glucose release, or because the process of gluconeogenesis from protein occurs over a period of hours and glucose can be disposed of if presented for utilization slowly and evenly over a long time period. Continue reading >>
The Basic Food Groups: The Insulin/fat Connection
The Insulin/Fat Connection The primary source of body fat for most Americans is not dietary fat but carbohydrate, which is converted to blood sugar and then, with the aid of insulin, to fat by fat cells. Remember, insulin is our main fatbuilding hormone. Eat a plate of pasta. Your blood sugar will rise and your insulin level (if you have type 2 diabetes or are not diabetic) will also rise in order to cover, or prevent, the jump in blood sugar. All the blood sugar that is not burned as energy or stored as glycogen is turned into fat. So you could, in theory, acquire more body fat from eating a high-carbohydrate “fat-free” dessert than you would from eating a tender steak nicely marbled with fat. Even the fat in the steak is more likely to be stored if it is accompanied by bread, potatoes, corn, and so on. The fatty-acid building blocks of fats can be metabolized (burned), stored, or converted by your body into other compounds, depending on what it requires. Consequently, fat is always in flux in the body, being stored, appearing in the blood, and being converted to energy. The amount of triglycerides (the storage form of fat) in your bloodstream at any given time will be determined by your heredity, your level of exercise, your blood sugar levels, your diet, your ratio of visceral (abdominal) fat to lean body mass (muscle), and especially by your recent consumption of carbohydrate. The slim and fit tend to be very sensitive (i.e., responsive) to insulin and have low serum levels not only of triglycerides but insulin as well. But even their triglyceride levels will increase after a high-carbohydrate meal, as excess blood sugar is converted to fat. The higher the ratio of abdominal fat (and, to a lesser degree, total body fat) to lean body mass, the less sensitive to i Continue reading >>
Does Fat Convert To Glucose In The Body?
Your body is an amazing machine that is able to extract energy from just about anything you eat. While glucose is your body's preferred energy source, you can't convert fat into glucose for energy; instead, fatty acids or ketones are used to supply your body with energy from fat. Video of the Day Fat is a concentrated source of energy, and it generally supplies about half the energy you burn daily. During digestion and metabolism, the fat in the food you eat is broken down into fatty acids and glycerol, which are emulsified and absorbed into your blood stream. While some tissues -- including your muscles -- can use fatty acids for energy, your brain can't convert fatty acids to fuel. If you eat more fat than your body needs, the extra is stored in fat cells for later use. Fat has more than twice as many calories per gram as carbs and protein, which makes it an efficient form of stored energy. It would take more than 20 pounds of glycogen -- a type of carbohydrate used for fuel -- to store the same amount of energy in just 10 pounds of fat. Your Body Makes Glucose From Carbs Almost all the glucose in your body originated from carbohydrates, which come from the fruit, vegetables, grains and milk in your diet. When you eat these carb-containing foods, your digestive system breaks them down into glucose, which is then used for energy by your cells. Any excess glucose is converted into glycogen, then stored in your muscles and liver for later use. Once you can't store any more glucose or glycogen, your body stores any leftover carbs as fat. Glucose is your brain's preferred source of energy. However, when glucose is in short supply, your brain can use ketones -- which are derived from fat -- for fuel. Since your brain accounts for approximately one-fifth of your daily calori Continue reading >>
How Our Bodies Turn Food Into Energy
All parts of the body (muscles, brain, heart, and liver) need energy to work. This energy comes from the food we eat. Our bodies digest the food we eat by mixing it with fluids (acids and enzymes) in the stomach. When the stomach digests food, the carbohydrate (sugars and starches) in the food breaks down into another type of sugar, called glucose. The stomach and small intestines absorb the glucose and then release it into the bloodstream. Once in the bloodstream, glucose can be used immediately for energy or stored in our bodies, to be used later. However, our bodies need insulin in order to use or store glucose for energy. Without insulin, glucose stays in the bloodstream, keeping blood sugar levels high. Insulin is a hormone made by beta cells in the pancreas. Beta cells are very sensitive to the amount of glucose in the bloodstream. Normally beta cells check the blood's glucose level every few seconds and sense when they need to speed up or slow down the amount of insulin they're making and releasing. When someone eats something high in carbohydrates, like a piece of bread, the glucose level in the blood rises and the beta cells trigger the pancreas to release more insulin into the bloodstream. When insulin is released from the pancreas, it travels through the bloodstream to the body's cells and tells the cell doors to open up to let the glucose in. Once inside, the cells convert glucose into energy to use right then or store it to use later. As glucose moves from the bloodstream into the cells, blood sugar levels start to drop. The beta cells in the pancreas can tell this is happening, so they slow down the amount of insulin they're making. At the same time, the pancreas slows down the amount of insulin that it's releasing into the bloodstream. When this happens, Continue reading >>
When Does Glucose Convert To Fat?
Despite the fact that eating a jelly doughnut seems to deposit fat directly on your hips, converting sugar to fat is actually a relatively complex chemical process. Sugar conversion to fat storage depends not only upon the type of foods you eat, but how much energy your body needs at the time you eat it. Video of the Day Your body converts excess dietary glucose into fat through the process of fatty acid synthesis. Fatty acids are required in order for your body to function properly, playing particularly important roles in proper brain functioning. There are two kinds of fatty acids; essential fatty acids and nonessential fatty acids. Essential fatty acids refer to fatty acids you must eat from your diet, as your body cannot make them. Nonessential fatty acids are made through the process of fatty acid synthesis. Fatty Acid Synthesis Fatty acids are long organic compounds having an acid group at one end and a methyl group at the other end. The location of their first double bond dictates whether they are in the omega 3, 6, or 9 fatty acid family. Fatty acid synthesis takes place in the cytoplasm of cells and requires some energy input. In other words, your body actually has to expend some energy in order to store fat. Glucose is a six-carbon sugar molecule. Your body first converts this molecule into two three-carbon pyruvate molecules through the process of glycolysis and then into acetyl CoA. When your body requires immediate energy, acetyl CoA enters the Citric Acid Cycle creating energy molecules in the form of ATP. When glucose intake exceeds your body's energy needs--for example, you eat an ice-cream sundae and then go relax on the sofa for five hours--your body has no need to create more energy molecules. Therefore, acetyl CoA begins the process of fatty acid syn Continue reading >>