What Happens To Glucose In The Liver?

You And Your Hormones

What is insulin? Insulin is a hormone made by an organ located behind the stomach called the pancreas. Here, insulin is released into the bloodstream by specialised cells called beta cells found in areas of the pancreas called islets of langerhans (the term insulin comes from the Latin insula meaning island). Insulin can also be given as a medicine for patients with diabetes because they do not make enough of their own. It is usually given in the form of an injection. Insulin is released from the pancreas into the bloodstream. It is a hormone essential for us to live and has many effects on the whole body, mainly in controlling how the body uses carbohydrate and fat found in food. Insulin allows cells in the muscles, liver and fat (adipose tissue) to take up sugar (glucose) that has been absorbed into the bloodstream from food. This provides energy to the cells. This glucose can also be converted into fat to provide energy when glucose levels are too low. In addition, insulin has several other metabolic effects (such as stopping the breakdown of protein and fat). How is insulin controlled? When we eat food, glucose is absorbed from our gut into the bloodstream. This rise in blood glucose causes insulin to be released from the pancreas. Proteins in food and other hormones produced by the gut in response to food also stimulate insulin release. However, once the blood glucose levels return to normal, insulin release slows down. In addition, hormones released in times of acute stress, such as adrenaline, stop the release of insulin, leading to higher blood glucose levels. The release of insulin is tightly regulated in healthy people in order to balance food intake and the metabolic needs of the body. Insulin works in tandem with glucagon, another hormone produced by the pan Continue reading >>

How Does The Liver Control Glucose In The Blood?

Your body needs a constant supply of glucose, or sugar, for cells to have energy, so it requires a readily available reservoir to keep blood glucose in balance. One of the liver’s main roles in the body is controlling the amount of glucose circulating in the blood. By storing excess glucose as glycogen and creating new glucose from proteins and fat byproducts, the liver is able to maintain balanced glucose levels in your body at all times. Video of the Day When you eat carbohydrates, the body releases glucose into the bloodstream immediately, triggering the production of insulin. The body cannot be in a state of constant consumption, so when insulin levels are high enough, the body links long chains of glucose together into a compound called glycogen, which is then stored in the liver and the muscles. The liver uses this stored glucose energy as its main reservoir for releasing glucose into the bloodstream when levels drop. Breakdown of Glycogen Blood glucose levels drop when you're not eating, such as during sleep or between meals. This low blood sugar signals the liver to produce glucose and release it back into the bloodstream. The liver favors glycogen as its primary source since it is efficiently broken down into glucose in a process known as glycogenolysis. In this process, the liver breaks the bonds that hold glucose molecules together as glycogen, degrading most but not all of the glycogen molecule. Effects of Insulin Resistance When your body is chronically subjected to high levels of blood sugar and insulin, such as after you've eaten an excessive amount of foods high in sugar, it develops a resistance to the hormone, and the liver cannot respond properly, eventually leading to type-2 diabetes if the resistance is not controlled. According to a study publish Continue reading >>

What Happens To Excess Protein?

Li Z, Treyzon L, Chen S, Yan E, Thames G, Carpenter CL. Protein-enriched meal replacements do not adversely affect liver, kidney or bone density: an outpatient randomized controlled trial. Nutr J 2011;9(1):72. BACKGROUND: There is concern that recommending protein-enriched meal replacements as part of a weight management program could lead to changes in biomarkers of liver or renal function and reductions in bone density. This study was designed as a placebo-controlled clinical trial utilizing two isocaloric meal plans utilizing either a high protein-enriched (HP) or a standard protein (SP) meal replacement in an outpatient weight loss program. Subjects/methods: 100 obese men and women over 30 years of age with a body mass index (BMI) between 27 to 40 kg/m2 were randomized to one of two isocaloric weight loss meal plans 1). HP group: providing 2.2 g protein/kg of lean body mass (LBM)/day or 2). SP group: providing 1.1 g protein/kg LBM/day. Meal replacement (MR) was used twice daily (one meal, one snack) for 3 months and then once a day for 9 months. Body weight, lipid profiles, liver function, renal function and bone density were measured at baseline and 12 months. CONCLUSIONS: These studies demonstrate that protein-enriched meals replacements as compared to standard meal replacements recommended for weight management do not have adverse effects on routine measures of liver function, renal function or bone density at one year. Continue reading >>

Glycogenesis, Glycogenolysis,

Biosynthesis of Glycogen: The goal of glycolysis, glycogenolysis, and the citric acid cycle is to conserve energy as ATP from the catabolism of carbohydrates. If the cells have sufficient supplies of ATP, then these pathways and cycles are inhibited. Under these conditions of excess ATP, the liver will attempt to convert a variety of excess molecules into glucose and/or glycogen. Glycogenesis: Glycogenesis is the formation of glycogen from glucose. Glycogen is synthesized depending on the demand for glucose and ATP (energy). If both are present in relatively high amounts, then the excess of insulin promotes the glucose conversion into glycogen for storage in liver and muscle cells. In the synthesis of glycogen, one ATP is required per glucose incorporated into the polymeric branched structure of glycogen. actually, glucose-6-phosphate is the cross-roads compound. Glucose-6-phosphate is synthesized directly from glucose or as the end product of gluconeogenesis. Link to: Interactive Glycogenesis (move cursor over arrows) Jim Hardy, Professor of Chemistry, The University of Akron. Glycogenolysis: In glycogenolysis, glycogen stored in the liver and muscles, is converted first to glucose-1- phosphate and then into glucose-6-phosphate. Two hormones which control glycogenolysis are a peptide, glucagon from the pancreas and epinephrine from the adrenal glands. Glucagon is released from the pancreas in response to low blood glucose and epinephrine is released in response to a threat or stress. Both hormones act upon enzymes to stimulate glycogen phosphorylase to begin glycogenolysis and inhibit glycogen synthetase (to stop glycogenesis). Glycogen is a highly branched polymeric structure containing glucose as the basic monomer. First individual glucose molecules are hydrolyzed fr Continue reading >>

What Happens To Sugar In Your Body?

Look on virtually any store shelf at your local grocery store, and you’ll see our love affair with sugar. Products you never thought would contain sugar are chock-full of the stuff. You might not even see “sugar” in the ingredient list, but it’s there! Agave nectar, barley malt, blackstrap molasses, brown rice syrup, cane juice, and the list goes on and on… all sugar and much of it high on the glycemic index, which is a measure of a food’s effect on your blood sugar. We crave sugar because it’s a carbohydrate that gives our body energy. Unfortunately, most Americans don’t exercise enough to put those carbohydrates to work fueling our bodies. Almost all scientific data recommends that we lower our average daily intake of sugar, but most of us fail to do so. Perhaps a look into your body and what happens to it when you eat sugar will help you understand why nutritionists recommend you put down that chocolate chip muffin. Dopamine. And It Feels So Good Whenever you eat something sweet, your brain releases a neurotransmitter called dopamine, which makes you feel happy. Eaten too frequently, sugar can desensitize this brain chemical and make it more difficult to feel satisfied after eating a sugary treat. Eventually, you need more and more sugar just to get the same effect. In the last few years, the scientific community has jumped on the idea that sugar is just as addictive as drugs like heroin and cocaine. Although those claims probably feature some hyperbole, those sentiments don’t seem so incredible once you learn what happens to sugar in your body. When You Eat Sugar Your body is designed to process sugar and turn it into energy by breaking it down into glucose or fructose. When you eat sugar in small doses, your pancreas releases insulin that grabs th Continue reading >>

Insulin Levels Signal The Liver Whether More Glucose Is Needed

To understand what happens as your blood sugar deteriorates from normal to pre-diabetes, and finally, to full-fledged diabetes you first need to understand how blood sugar control works in a normal body. The most important factor here is the role played by special cells called beta cells. These tiny cells are scattered through an organ called the pancreas which is located just under your stomach. The job of the beta cell is to produce insulin, store it, and release it into the blood stream at appropriate times. You can learn how blood sugar fluctuates during the day in people with normal blood sugar, those with mildly diabetic blood sugars, and those with full fledged Type 2 Diabetes on this page: Blood Sugar Throughout the Day. Healthy beta-cells are continually making insulin, storing it within the cell in little granules you can see in the illustration above. This insulin is released into the blood stream in two different fashions. Some of it is secreted into the blood continually. This is called basal insulin. The rest is secreted only when blood sugars rise, which happens mostly after you eat foods containing carbohydrates. This kind of insulin is secreted in two separate phases. Let's look more closely at these different ways the pancreas secretes insulin. Basal Insulin Release The beta-cells of a healthy person who has not eaten in a while release a small amount of insulin into the blood stream throughout the day and night in the form of very small pulses every few minutes. This is called "basal insulin release." Maintaining this steady supply of insulin is important. It allows the cells of the body to utilize blood sugar even if some time has passed since a meal. Insulin Levels Signal the Liver Whether More Glucose is Needed The steady insulin level as another f Continue reading >>

How Is Excess Glucose Stored?

The human body has an efficient and complex system of storing and preserving energy. Glucose is a type of sugar that the body uses for energy. Glucose is the product of breaking down carbohydrates into their simplest form. Carbohydrates should make up approximately 45 to 65 percent of your daily caloric intake, according to MayoClinic.com. Video of the Day Glucose is a simple sugar found in carbohydrates. When more complex carbohydrates such as polysaccharides and disaccharides are broken down in the stomach, they break down into the monosaccharide glucose. Carbohydrates serve as the primary energy source for working muscles, help brain and nervous system functioning and help the body use fat more efficiently. Function of Glucose Once carbohydrates are absorbed from food, they are carried to the liver for processing. In the liver, fructose and galactose, the other forms of sugar, are converted into glucose. Some glucose gets sent to the bloodstream while the rest is stored for later energy use. Once glucose is inside the liver, glucose is phosphorylated into glucose-6-phosphate, or G6P. G6P is further metabolized into triglycerides, fatty acids, glycogen or energy. Glycogen is the form in which the body stores glucose. The liver can only store about 100 g of glucose in the form of glycogen. The muscles also store glycogen. Muscles can store approximately 500 g of glycogen. Because of the limited storage areas, any carbohydrates that are consumed beyond the storage capacity are converted to and stored as fat. There is practically no limit on how many calories the body can store as fat. The glucose stored in the liver serves as a buffer for blood glucose levels. Therefore, if the blood glucose levels start to get low because you have not consumed food for a period of time Continue reading >>

Glycogen Metabolism

Glycogen is a readily mobilized storage form of glucose. It is a very large, branched polymer of glucose residues (Figure 21.1) that can be broken down to yield glucose molecules when energy is needed. Most of the glucose residues in glycogen are linked by α-1,4-glycosidic bonds. Branches at about every tenth residue are created by α-1,6-glycosidic bonds. Recall that α-glycosidic linkages form open helical polymers, whereas β linkages produce nearly straight strands that form structural fibrils, as in cellulose (Section 11.2.3). Glycogen is not as reduced as fatty acids are and consequently not as energy rich. Why do animals store any energy as glycogen? Why not convert all excess fuel into fatty acids? Glycogen is an important fuel reserve for several reasons. The controlled breakdown of glycogen and release of glucose increase the amount of glucose that is available between meals. Hence, glycogen serves as a buffer to maintain blood-glucose levels. Glycogen's role in maintaining blood-glucose levels is especially important because glucose is virtually the only fuel used by the brain, except during prolonged starvation. Moreover, the glucose from glycogen is readily mobilized and is therefore a good source of energy for sudden, strenuous activity. Unlike fatty acids, the released glucose can provide energy in the absence of oxygen and can thus supply energy for anaerobic activity. The two major sites of glycogen storage are the liver and skeletal muscle. The concentration of glycogen is higher in the liver than in muscle (10% versus 2% by weight), but more glycogen is stored in skeletal muscle overall because of its much greater mass. Glycogen is present in the cytosol in the form of granules ranging in diameter from 10 to 40 nm (Figure 21.2). In the liver, glycoge Continue reading >>

Controlling Blood Sugar Levels

Glucose is a sugar needed by cells for respiration. It is important that the concentration of glucose in the blood is maintained at a constant level. Insulin, a hormone secreted by the pancreas, controls blood sugar levels in the body. It travels from the pancreas to the liver in the bloodstream. As with other responses controlled by hormones, the response is slower but longer lasting than if it had been controlled by the nervous system. Blood sugar levels- Higher tier What happens when glucose levels in the blood become too high or too low glucose level effect on pancreas effect on liver effect on glucose level too high insulin secreted into the blood liver converts glucose into glycogen goes down too low insulin not secreted into the blood liver does not convert glucose into glycogen goes up Use the animation to make sure you understand how this works. You have an old or no version of flash - you need to upgrade to view this funky content! Go to the WebWise Flash install guide Diabetes is a disorder in which the blood glucose levels remain too high. There are two main types of diabetes: Type 1, which usually develops during childhood Type 2, which usually develops in later life. The table summarises some differences between Type 1 and Type 2 diabetes. Some differences between Type 1 and Type 2 diabetes Type 1 diabetes Type 2 diabetes Who it mainly affects Children and teenagers. Adults under the age of 40. Adults, normally over the age of 40 (there is a greater risk in those who have poor diets and/or are overweight). How it works The pancreas stops making enough insulin. The body no longer responds to its insulin. How it is controlled Injections of insulin for life and an appropriate diet. Exercise and appropriate diet. When treating Type 1 diabetes, the dosage of in Continue reading >>

What Is Glucagon?

Blood sugar levels are an important part of overall health. When blood sugar levels drop, an individual may feel lethargic. If they drop too low, the individual may become disoriented, dizzy or even pass out. Blood sugar control involves a complex system of hormones, and one of those hormones is glucagon. Glucagon is a hormone that works with other hormones and bodily functions to control glucose levels in the blood. It comes from alpha cells found in the pancreas and is closely related to insulin-secreting beta cells, making it a crucial component that keeps the body’s blood glucose levels stable. What does glucagon do? Although secreted by the pancreas, glucagon directly impacts the liver as it works to control blood sugar levels. Specifically, glucagon prevents blood glucose levels from dropping to a dangerous point by stimulating the conversion of stored glycogen to glucose in the liver. This glucose can be released into the bloodstream, a process known as glycogenolysis. Secondly, glucagon stops the liver from consuming some glucose. This helps more glucose to enter the bloodstream, rather than being consumed by the liver, to keep levels stable. Finally, glucagon works in a process known as gluconeogenesis, which is the production of glucose in the amino acid molecules. In each of these processes, glucagon and insulin work together. Insulin will prevent glucose levels from increasing to a point that is too high, while glucagon prevents it from dropping too low. Glucagon production is stimulated when an individual eats a protein-rich meal, experiences a surge in adrenaline, or has a low blood sugar event. Potential problems with glucagon function Glucagon function is crucial to proper blood glucose levels, so problems with glucagon production will lead to problems Continue reading >>

Blood Sugar Or Blood Glucose: What Does It Do?

Blood sugar, or blood glucose, is sugar that the bloodstream carries to all the cells in the body to supply energy. Blood sugar or blood glucose measurements represent the amount of sugar being transported in the blood during one instant. The sugar comes from the food we eat. The human body regulates blood glucose levels so that they are neither too high nor too low. The blood's internal environment must remain stable for the body to function. This balance is known as homeostasis. The sugar in the blood is not the same as sucrose, the sugar in the sugar bowl. There are different kinds of sugar. Sugar in the blood is known as glucose. Blood glucose levels change throughout the day. After eating, levels rise and then settle down after about an hour. They are at their lowest point before the first meal of the day, which is normally breakfast. How does sugar get into the body's cells? When we eat carbohydrates, such as sugar, or sucrose, our body digests it into glucose, a simple sugar that can easily convert to energy. The human digestive system breaks down carbohydrates from food into various sugar molecules. One of these sugars is glucose, the body's main source of energy. The glucose goes straight from the digestive system into the bloodstream after food is consumed and digested. But glucose can only enter cells if there is insulin in the bloodstream too. Without insulin, the cells would starve. After we eat, blood sugar concentrations rise. The pancreas releases insulin automatically so that the glucose enters cells. As more and more cells receive glucose, blood sugar levels return to normal again. Excess glucose is stored as glycogen, or stored glucose, in the liver and the muscles. Glycogen plays an important role in homeostasis, because it helps our body function du Continue reading >>

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 >>

Fasting Physiology – Part Ii

There are many misconceptions about fasting. It is useful to review the physiology of what happens to our body when we eat nothing. Physiology Glucose and fat are the body’s main sources of energy. If glucose is not available, then the body will adjust by using fat, without any detrimental health effects. This is simply a natural part of life. Periods of low food availability have always been a part of human history. Mechanisms have evolved to adapt to this fact of Paleolithic life. The transition from the fed state to the fasted state occurs in several stages. Feeding – During meals, insulin levels are raised. This allows uptake of glucose into tissues such as the muscle or brain to be used directly for energy. Excess glucose is stored as glycogen in the liver. The post-absorptive phase – 6-24 hours after beginning fasting. Insulin levels start to fall. Breakdown of glycogen releases glucose for energy. Glycogen stores last for roughly 24 hours. Gluconeogenesis – 24 hours to 2 days – The liver manufactures new glucose from amino acids in a process called “gluconeogenesis”. Literally, this is translated as “making new glucose”. In non-diabetic persons, glucose levels fall but stay within the normal range. Ketosis – 2-3 days after beginning fasting – The low levels of insulin reached during fasting stimulate lipolysis, the breakdown of fat for energy. The storage form of fat, known as triglycerides, is broken into the glycerol backbone and three fatty acid chains. Glycerol is used for gluconeogenesis. Fatty acids may be used for directly for energy by many tissues in the body, but not the brain. Ketone bodies, capable of crossing the blood-brain barrier, are produced from fatty acids for use by the brain. After four days of fasting, approximately 75 Continue reading >>

Ketosis, Ketones, And How It All Works

Ketosis is a process that the body does on an everyday basis, regardless of the number of carbs you eat. Your body adapts to what is put in it, processing different types of nutrients into the fuels that it needs. Proteins, fats, and carbs can all be processed for use. Eating a low carb, high fat diet just ramps up this process, which is a normal and safe chemical reaction. When you eat carbohydrate based foods or excess amounts of protein, your body will break this down into sugar – known as glucose. Why? Glucose is needed in the creation of ATP (an energy molecule), which is a fuel that is needed for the daily activities and maintenance inside our bodies. If you’ve ever used our keto calculator to determine your caloric needs, you will see that your body uses up quite a lot of calories. It’s true, our bodies use up much of the nutrients we intake just to maintain itself on a daily basis. If you eat enough food, there will likely be an excess of glucose that your body doesn’t need. There are two main things that happen to excess glucose if your body doesn’t need it: Glycogenesis. Excess glucose will be converted to glycogen and stored in your liver and muscles. Estimates show that only about half of your daily energy can be stored as glycogen. Lipogenesis. If there’s already enough glycogen in your muscles and liver, any extra glucose will be converted into fats and stored. So, what happens to you once your body has no more glucose or glycogen? Ketosis happens. When your body has no access to food, like when you are sleeping or when you are on a ketogenic diet, the body will burn fat and create molecules called ketones. We can thank our body’s ability to switch metabolic pathways for that. These ketones are created when the body breaks down fats, creating Continue reading >>

What Happens To Food In Your Body?

Just thinking about eating causes your body to start secreting insulin, a hormone that helps keep blood sugar (glucose) under control. Insulin is made by the pancreas. As you eat, more insulin is released, in response to the carbohydrates in the meal. Insulin is released when you eat protein-rich foods, but at a slower rate. If your pancreas is functioning properly, the amount of carbohydrates in what you’re eating usually determines how much insulin is released. As you digest carbohydrates, they go into the blood stream as glucose. To keep blood sugar levels under control, insulin signals the cells in your body to take in glucose from the blood stream. The cells use some of glucose for energy and store some for later use. The way glucose is stored depends on the type of cell doing the storing. Muscle cells store glucose as glycogen. Liver cells store some glucose as glycogen and convert some to fat. Fat cells store glucose as fat. As glucose is removed from the blood stream, insulin levels go down and your cells start using fat for fuel instead of glucose. This is why you can go for long stretches – overnight, for example, when you’re sleeping, without eating. Your cells rely on fat for fuel. There are two types of body fat: fatty acids and triglycerides. Fatty acids are small enough to move in and out of cells and be used as fuel for cells. Fat is stored inside fat cells as triglycerides, three fatty acids bound together. Triglycerides are too big to flow through cell membranes and so are stored for future use. Insulin also plays a major role in telling your body when to store and use fat and protein. It does this by affecting the actions of two enzymes, lipoprotein lipase (LPL) and hormone-sensitive lipase (HSL). LPL sits on the surface of cells and pulls fat o Continue reading >>