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How Are Ketone Bodies Used For Energy?

Ketosis, Ketones, And How It All Works

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 >>

Ketone Bodies

Ketone Bodies

Ketone bodies Acetone Acetoacetic acid (R)-beta-Hydroxybutyric acid Ketone bodies are three water-soluble molecules (acetoacetate, beta-hydroxybutyrate, and their spontaneous breakdown product, acetone) that are produced by the liver from fatty acids[1] during periods of low food intake (fasting), carbohydrate restrictive diets, starvation, prolonged intense exercise,[2], alcoholism or in untreated (or inadequately treated) type 1 diabetes mellitus. These ketone bodies are readily picked up by the extra-hepatic tissues, and converted into acetyl-CoA which then enters the citric acid cycle and is oxidized in the mitochondria for energy.[3] In the brain, ketone bodies are also used to make acetyl-CoA into long-chain fatty acids. Ketone bodies are produced by the liver under the circumstances listed above (i.e. fasting, starving, low carbohydrate diets, prolonged exercise and untreated type 1 diabetes mellitus) as a result of intense gluconeogenesis, which is the production of glucose from non-carbohydrate sources (not including fatty acids).[1] They are therefore always released into the blood by the liver together with newly produced glucose, after the liver glycogen stores have been depleted (these glycogen stores are depleted after only 24 hours of fasting)[1]. When two acetyl-CoA molecules lose their -CoAs, (or Co-enzyme A groups) they can form a (covalent) dimer called acetoacetate. Beta-hydroxybutyrate is a reduced form of acetoacetate, in which the ketone group is converted into an alcohol (or hydroxyl) group (see illustration on the right). Both are 4-carbon molecules, that can readily be converted back into acetyl-CoA by most tissues of the body, with the notable exception of the liver. Acetone is the decarboxylated form of acetoacetate which cannot be converted Continue reading >>

Ketone Bodies As A Fuel For The Brain During Starvation

Ketone Bodies As A Fuel For The Brain During Starvation

THE STATUS OF OUR KNOWLEDGE OF STARVATION AND BRAIN METABOLISM IN HUMANS WHEN I BEGAN MY RESEARCH This story begins in the early 1960s when the general level of knowledge about whole-body metabolism during human starvation was grossly deficient. This was partly caused by a lack of accurate and specific methods for measuring hormones and fuels in biological fluids, which became available about 1965.11 Rigidly designed protocols for studying human volunteers or obese patients, who underwent semi- or total starvation for prolonged periods of time, were not widely employed, and much of the published data regarding metabolic events during starvation were not readily accessible. To complicate matters further, a great deal of the available data was confusing because much of the supposition regarding mechanisms used by the body to survive prolonged periods of starvation was based upon information that was obtained from nonstandardized and often erroneous procedures for studying metabolism. For example, the rate of urinary nitrogen excretion during starvation was sometimes confounded by the consumption of carbohydrate during the studies. Today, students of biochemistry take for granted the fact that tissues of the human body have a hierarchy of fuel usage. They know that the brain, an organ devoted to using glucose, can switch to use ketone bodies during prolonged starvation (2–3 days), thus sparing glucose for other tissues (i.e. red blood cells must use glucose as a fuel; without mitochondria, they have no choice!). However, this fundamental insight into human metabolism was not recognized in the early 1960s, when my research in this area began. How this simple but fundamental fact that ketone bodies provide critical fuels for the brain was discovered and its implication for Continue reading >>

Ketosis

Ketosis

There is a lot of confusion about the term ketosis among medical professionals as well as laypeople. It is important to understand when and why nutritional ketosis occurs, and why it should not be confused with the metabolic disorder we call ketoacidosis. Ketosis is a metabolic state where the liver produces small organic molecules called ketone bodies. Most cells in the body can use ketone bodies as a source of energy. When there is a limited supply of external energy sources, such as during prolonged fasting or carbohydrate restriction, ketone bodies can provide energy for most organs. In this situation, ketosis can be regarded as a reasonable, adaptive physiologic response that is essential for life, enabling us to survive periods of famine. Nutritional ketosis should not be confused with ketoacidosis, a metabolic condition where the blood becomes acidic as a result of the accumulation of ketone bodies. Ketoacidosis can have serious consequences and may need urgent medical treatment. The most common forms are diabetic ketoacidosis and alcoholic ketoacidosis. What Is Ketosis? The human body can be regarded as a biologic machine. Machines need energy to operate. Some use gasoline, others use electricity, and some use other power resources. Glucose is the primary fuel for most cells and organs in the body. To obtain energy, cells must take up glucose from the blood. Once glucose enters the cells, a series of metabolic reactions break it down into carbon dioxide and water, releasing energy in the process. The body has an ability to store excess glucose in the form of glycogen. In this way, energy can be stored for later use. Glycogen consists of long chains of glucose molecules and is primarily found in the liver and skeletal muscle. Liver glycogen stores are used to mai Continue reading >>

Ketones: Your Brain’s Preferred Fuel Source

Ketones: Your Brain’s Preferred Fuel Source

Ketones have long been touted as a superior fuel source for the brain that possesses a wide array of cognitive benefits. Our brains are made up of two types of cells, neurons, and glial cells, and both are imperative for our brains to function properly (1). Under normal physiological conditions, the principle energy source utilized by the brain cells is glucose (2). Glucose transporters saturate brain capillaries to allow glucose to cross the blood-brain barrier. Once in the brain, glucose is metabolized to pyruvate which enters the mitochondria of the brain cells to ultimately generate energy through aerobic metabolism (3). However, ketone bodies may also provide energy to the brain through different mechanisms. Brain Fuel In addition to glucose, brain cells can derive energy from monocarboxylates which include lactate and the ketone bodies beta-hydroxybutyrate (β-HB) and acetoacetate (AcAc) (2). It is controversial whether or not lactate can be used as a fuel source in the brain; however, many laboratories have reported that BHB is a major fuel supplier for the brain, especially under specific physiological conditions (3,4). BHB and glucose do not nourish the brain uniformly but rather have specific areas of localization. BHB accumulates primarily in the pituitary and pineal glands, as well as in portions of the hypothalamus, and the lower cortical layers (4). Physiological conditions that elevate BHB and consequently provide increased energy to the aforementioned areas of the brain include starvation, fasting, pregnancy, prolonged exercise, uremia, during the prenatal period, infancy, during the chronic consumption of a high fat/low carbohydrate ketogenic diet, and possibly even ketone supplementation (4). Ketones: Brain’s Utilization Capacity Low circulating gluc Continue reading >>

Brain: Ketone Metabolism

Brain: Ketone Metabolism

Definition The three ketone bodies are acetone, acetoacetic acid, and beta-hydroxybutyric acid. Ketone bodies are derived from the incomplete oxidation of fatty acids in the liver and are used for energy (ATP generation) in the heart and brain. Ketone bodies are transported from the liver to other tissues, where acetoacetate and beta-hydroxybutyrate can be reconverted to acetyl-CoA to produce energy, via the Krebs cycle. The brain gets its energy from ketone bodies when insufficient glucose is available, such as during fasting and starvation. In the event of low blood glucose, most other tissues have additional energy sources besides ketone bodies (such as fatty acids), but the brain does not. After the diet has been changed to lower blood glucose for 3 days, the brain gets 30% of its energy from ketone bodies. After about 40 days, this goes up to 70% (during the initial stages the brain does not burn ketones, since they are an important substrate for lipid synthesis in the brain). By using alternative fuels, the demand for glucose is reduced and muscle proteins are spared further degradation. Subspecialty Keyword history See Also: Sources PubMed Continue reading >>

Oncology Letters 14: 673-680, 2017

Oncology Letters 14: 673-680, 2017

Abstract. Normal and cancerous cells are suggested to have differential utilization of fatty acids and ketone bodies, which could be exploited in cancer therapy. The present study exam- ined the effect of 3-hydroxybutyric acid (3-HBA), which is a ketone body generating acetyl-CoA, and lauric acid (LAA, C12:0), which is a medium-chain saturated fatty acid trans- located to mitochondria in a carnitine-independent manner to produce acetyl-CoA, on the energy metabolism of mouse CT26 colon cancer cells. In CT26 cells expressing 3-HBA and LAA transporters, 3-HBA and LAA reduced cell prolif- eration, mitochondrial volume and lactate production, and increased oxidative stress, particularly in low-glucose condi- tions. Concurrent treatment with 3-HBA and LAA under glucose starvation had a synergistic effect on cell growth inhibition. In addition, LAA and LAA + 3-HBA promoted an imbalance in the expression of enzymes in the electron transport chain. These findings suggested that treatment with 3-HBA and/or LAA during glucose starvation may reprogram energy metabolism and decrease the proliferation of cancer cells. Introduction The difference in energy production between cancer cells and normal cells is considered to be one of the available targets for the treatment of cancer (1). Unlike normal cells, cancer cells obtain energy mostly via glycolysis, while mitochondrial oxidative phosphorylation is reduced (2). As tumor cells actively proliferate, they require a constant energy supply and it has been postulated that they switch to aerobic glycolysis characterized by rapid ATP production, which is known as the Warburg effect (2). It is hypothesized that the purpose of the Warburg effect is to avoid the excessive generation of reactive oxygen species (ROS) during oxidative phosphory Continue reading >>

Lipid Metabolism

Lipid Metabolism

on on Fats (or triglycerides) within the body are ingested as food or synthesized by adipocytes or hepatocytes from carbohydrate precursors ([link]). Lipid metabolism entails the oxidation of fatty acids to either generate energy or synthesize new lipids from smaller constituent molecules. Lipid metabolism is associated with carbohydrate metabolism, as products of glucose (such as acetyl CoA) can be converted into lipids. Lipid metabolism begins in the intestine where ingested triglycerides are broken down into smaller chain fatty acids and subsequently into monoglyceride molecules (see [link]b) by pancreatic lipases, enzymes that break down fats after they are emulsified by bile salts. When food reaches the small intestine in the form of chyme, a digestive hormone called cholecystokinin (CCK) is released by intestinal cells in the intestinal mucosa. CCK stimulates the release of pancreatic lipase from the pancreas and stimulates the contraction of the gallbladder to release stored bile salts into the intestine. CCK also travels to the brain, where it can act as a hunger suppressant. Together, the pancreatic lipases and bile salts break down triglycerides into free fatty acids. These fatty acids can be transported across the intestinal membrane. However, once they cross the membrane, they are recombined to again form triglyceride molecules. Within the intestinal cells, these triglycerides are packaged along with cholesterol molecules in phospholipid vesicles called chylomicrons ([link]). The chylomicrons enable fats and cholesterol to move within the aqueous environment of your lymphatic and circulatory systems. Chylomicrons leave the enterocytes by exocytosis and enter the lymphatic system via lacteals in the villi of the intestine. From the lymphatic system, the chylo Continue reading >>

Ketone Bodies: A Review Of Physiology, Pathophysiology And Application Of Monitoring To Diabetes.

Ketone Bodies: A Review Of Physiology, Pathophysiology And Application Of Monitoring To Diabetes.

Abstract Ketone bodies are produced by the liver and used peripherally as an energy source when glucose is not readily available. The two main ketone bodies are acetoacetate (AcAc) and 3-beta-hydroxybutyrate (3HB), while acetone is the third, and least abundant, ketone body. Ketones are always present in the blood and their levels increase during fasting and prolonged exercise. They are also found in the blood of neonates and pregnant women. Diabetes is the most common pathological cause of elevated blood ketones. In diabetic ketoacidosis (DKA), high levels of ketones are produced in response to low insulin levels and high levels of counterregulatory hormones. In acute DKA, the ketone body ratio (3HB:AcAc) rises from normal (1:1) to as high as 10:1. In response to insulin therapy, 3HB levels commonly decrease long before AcAc levels. The frequently employed nitroprusside test only detects AcAc in blood and urine. This test is inconvenient, does not assess the best indicator of ketone body levels (3HB), provides only a semiquantitative assessment of ketone levels and is associated with false-positive results. Recently, inexpensive quantitative tests of 3HB levels have become available for use with small blood samples (5-25 microl). These tests offer new options for monitoring and treating diabetes and other states characterized by the abnormal metabolism of ketone bodies. Continue reading >>

Ketone Body

Ketone Body

ketone body n. Any of three compounds, acetoacetic acid, acetone, and beta-hydroxybutyric acid, that are ketones or derivatives of ketones and are intermediate products of fatty acid metabolism. Ketone bodies accumulate in the blood and urine when fats are being used for energy instead of carbohydrates, as in individuals affected by starvation or uncontrolled diabetes mellitus. Also called acetone body. American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved. ketone body n (Biochemistry) biochem any of three compounds (acetoacetic acid, 3-hydroxybutanoic acid, and acetone) produced when fatty acids are broken down in the liver to provide a source of energy. Excess ketone bodies are present in the blood and urine of people unable to use glucose as an energy source, as in diabetes and starvation. Also called: acetone body Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014 ke′tone bod′y n. any of several compounds, as acetoacetic acid, acetone, and hydroxybutyric acid, that are intermediate in the metabolism of fatty acids and are produced in excessive amounts under certain abnormal conditions, as in diabetes mellitus. Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved. Noun 1. ketone body - a ketone that is an intermediate product of the breakdown of fats in the body; any of three compounds (acetoacetic acid, acetone, and/or beta-hydroxybutyric acid) found in excess in blood and urine of persons with meta Continue reading >>

Ketone Bodies Formed In The Liver Are Exported To Other Organs

Ketone Bodies Formed In The Liver Are Exported To Other Organs

Ketone Bodies In human beings and most other mammals, acetyl-CoA formed in the liver during oxidation of fatty acids may enter the citric acid cycle (stage 2 of Fig. 16-7) or it may be converted to the "ketone bodies" acetoacetate, D-β-hydroxybutyrate, and acetone for export to other tissues. (The term "bodies" is a historical artifact; these compounds are soluble in blood and urine.) Acetone, produced in smaller quantities than the other ketone bodies, is exhaled. Acetoacetate and D-β-hydroxybutyrate are transported by the blood to the extrahepatic tissues, where they are oxidized via the citric acid cycle to provide much of the energy required by tissues such as skeletal and heart muscle and the renal cortex. The brain, which normally prefers glucose as a fuel, can adapt to the use of acetoacetate or D-β-hydroxybutyrate under starvation conditions, when glucose is unavailable. A major determinant of the pathway taken by acetyl-CoA in liver mitochondria is the availability of oxaloacetate to initiate entry of acetyl-CoA into the citric acid cycle. Under some circumstances (such as starvation) oxaloacetate is drawn out of the citric acid cycle for use in synthesizing glucose. When the oxaloacetate concentration is very low, little acetyl-CoA enters the cycle, and ketone body formation is favored. The production and export of ketone bodies from the liver to extrahepatic tissues allows continued oxidation of fatty acids in the liver when acetyl-CoA is not being oxidized via the citric acid cycle. Overproduction of ketone bodies can occur in conditions of severe starvation and in uncontrolled diabetes. The first step in formation of acetoacetate in the liver (Fig. 16-16) is the enzymatic condensation of two molecules of acetyl-CoA, catalyzed by thiolase; this is simply Continue reading >>

Bcii: Ketone Bodies

Bcii: Ketone Bodies

Sort The major site of formation of acetoacetate from fatty acids is the: a. adipose tissue. b. intestinal mucosa. c. kidney. d. liver. e. muscle. d. liver. Ketone bodies are formed in the liver and transported to the extrahepatic tissues mainly as: a. acetoacetyl-CoA. b. acetone. c. beta-hydroxybutyric acid. d. beta-hydroxybutyryl-CoA. e. lactic acid. b. acetone. Continue reading >>

Ketones

Ketones

Ketones are a beneficial product of fat metabolism in the body. When carbohydrate intake is restricted, it lowers blood sugar and insulin levels. As insulin levels fall and energy is needed, fatty acids flow from the fat cells into the bloodstream and are taken up by various cells and metabolized in a process called beta-oxidation. The end result of beta-oxidation is a molecule called acetyl-coA, and as more fatty acids are released and metabolized, acetyl-coA levels in the cells rise. This causes a sort of metabolic “feedback loop” which triggers liver cells to shunt excess acetyl-Coa into ketogenesis, or the making of ketone bodies. Once created, the liver dumps the ketone bodies into the blood stream and they are taken up by skeletal and heart muscle cells at rates of availability. In addition, the brain begins to use ketones as an alternate fuel when blood levels are high enough to cross the blood brain barrier. Testing Laboratory Microbiology - Air Quality - Mold Asbestos - Environmental - Lead emsl.com There are three major types of ketone bodies present in the human blood stream when the metabolic process of ketosis is dominant: Acetoacetate (AcAc) is created first β-hydroxybutyrate (BHB) is created from acetoacetate Acetone is a spontaneously created side product of acetoacetate In times of starvation, or a low carbohydrate intake resulting in low insulin levels, ketone bodies supply up to 50% of the energy requirements for most body tissues, and up to 70% of the energy required by the brain. Glucose is the main source of fuel for neurons when the diet is high in carbohydrates. But when carbs are restricted, ketogenesis becomes the primary fuel process for most cells. During fasting or low carbohydrate intake, levels of ketone bodies in the blood stream can Continue reading >>

Ketone Bodies Metabolism

Ketone Bodies Metabolism

1. Metabolism of ketone bodies Gandham.Rajeev Email:[email protected] 2. • Carbohydrates are essential for the metabolism of fat or FAT is burned under the fire of carbohydrates. • Acetyl CoA formed from fatty acids can enter & get oxidized in TCA cycle only when carbohydrates are available. • During starvation & diabetes mellitus, acetyl CoA takes the alternate route of formation of ketone bodies. 3. • Acetone, acetoacetate & β-hydroxybutyrate (or 3-hydroxybutyrate) are known as ketone bodies • β-hydroxybutyrate does not possess a keto (C=O) group. • Acetone & acetoacetate are true ketone bodies. • Ketone bodies are water-soluble & energy yielding. • Acetone, it cannot be metabolized 4. CH3 – C – CH3 O Acetone CH3 – C – CH2 – COO- O Acetoacetate CH3 – CH – CH2 – COO- OH I β-Hydroxybutyrate 5. • Acetoacetate is the primary ketone body. • β-hydroxybutyrate & acetone are secondary ketone bodies. • Site: • Synthesized exclusively by the liver mitochondria. • The enzymes are located in mitochondrial matrix. • Precursor: • Acetyl CoA, formed by oxidation of fatty acids, pyruvate or some amino acids 6. • Ketone body biosynthesis occurs in 5 steps as follows. 1. Condensation: • Two molecules of acetyl CoA are condensed to form acetoacetyl CoA. • This reaction is catalyzed by thiolase, an enzyme involved in the final step of β- oxidation. 7. • Acetoacetate synthesis is appropriately regarded as the reversal of thiolase reaction of fatty acid oxidation. 2. Production of HMG CoA: • Acetoacetyl CoA combines with another molecule of acetyl CoA to produce β-hydroxy β-methyl glutaryl CoA (HMC CoA). • This reaction is catalyzed by the enzyme HMG CoA synthase. 8. • Mitochondrial HMG CoA is used for ketogenesis. Continue reading >>

Benefits Of Fueling Your Body With Ketones

Benefits Of Fueling Your Body With Ketones

Why Ketones are a better fuel source than glucose Where do our bodies get the energy to fuel our activities of daily living? Glucose is the main fuel source of our bodies, but there is another type of fuel that is available to our bodies, ketones. Ketones are a natural by-product of fat metabolism. When the body has run out of glucose to use as fuel it will switch fuel sources and start converting fat into fatty acids and then into ketones. Our bodies were designed to use this duel source of energy based on how we lived in the caveman days. In the summer and spring when food was plentiful, cavemen would eat more food and pack on the extra and store it as fat. Then in the fall and winter when food was scarce, the cavemen would live off that extra stored fat. Nowadays, since food supply is plentiful all year around and there is no physiological need or demand to live off the stored fat, thus we may just keep packing it on, all year around. What are the differences between ketones and glucose as a source of energy? Research suggests that ketones are a better, cleaner source of energy for the body and actually provide more energy than glucose. Unlike glucose, ketones do not depend on insulin to get into the cells for use. Ketones produce less carbon dioxide and free radicals than when the body uses glucose as a fuel source thus are less toxic for our body, making it a cleaner fuel source. Unfortunately, ketones are harder energy source for our bodies to tap into since they require your body to be in either a starvation mode or at least be in a state of very low in carbohydrates. Nowadays, the most common way of getting the body to produce ketones, or be in a state of ketosis, is by being on a very low carb diet i.e. a ketogenic diet. Typically, a ketogenic diet consists of Continue reading >>

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