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 Are Ketones?
With the gradual resurgence of low-carb diets in recent years, the word “ketones” is thrown around a lot. But many people aren’t really aware of the details. What are ketones, really? And what do they do in the body? There can be a lot of misinformation regarding the answers to these questions, so read on for a full overview of ketones and their role in a ketogenic diet. Ketones, also known as “ketone bodies,” are byproducts of the body breaking down fat for energy that occurs when carbohydrate intake is low. Here’s how it works: When there isn’t a sufficient level of available glucose — which is what the body uses for its main source of fuel — and glycogen levels are depleted, blood sugar and insulin are lowered and the body looks for an alternative source of fuel: in this case, fat. This process can happen when a person fasting, after prolonged exercise, during starvation, or when eating a low-carb, ketogenic diet. And when the body begins breaking down fats for energy like this, a process known as beta-oxidation, ketones are formed for use as fuel for the body and brain. This is known as ketosis. People following a ketogenic diet specifically reduce their carbohydrate intake for this reason: to create ketones for energy. Many people use the benefits of ketosis — less reliance on carbs and more burning of fat — to possibly help lower blood pressure, reduce cravings, improve cholesterol, increase weight loss, improve energy, and more. TYPES OF KETONE BODIES So, what else about ketones do we need to know? To start, there are technically three types of ketone bodies: Acetoacetate (AcAc) Beta-hydroxybutyric acid (BHB) Acetone Both acetoacetate and beta-hydroxybutyrate are responsible for transporting energy from the liver to other tissues in the body Continue reading >>
Excess ketones are dangerous for someone with diabetes... Low insulin, combined with relatively normal glucagon and epinephrine levels, causes fat to be released from fat cells, which then turns into ketones. Excess formation of ketones is dangerous and is a medical emergency In a person without diabetes, ketone production is the body’s normal adaptation to starvation. Blood sugar levels never get too high, because the production is regulated by just the right balance of insulin, glucagon and other hormones. However, in an individual with diabetes, dangerous and life-threatening levels of ketones can develop. What are ketones and why do I need to know about them? Ketones and ketoacids are alternative fuels for the body that are made when glucose is in short supply. They are made in the liver from the breakdown of fats. Ketones are formed when there is not enough sugar or glucose to supply the body’s fuel needs. This occurs overnight, and during dieting or fasting. During these periods, insulin levels are low, but glucagon and epinephrine levels are relatively normal. This combination of low insulin, and relatively normal glucagon and epinephrine levels causes fat to be released from the fat cells. The fats travel through the blood circulation to reach the liver where they are processed into ketone units. The ketone units then circulate back into the blood stream and are picked up by the muscle and other tissues to fuel your body’s metabolism. In a person without diabetes, ketone production is the body’s normal adaptation to starvation. Blood sugar levels never get too high, because the production is regulated by just the right balance of insulin, glucagon and other hormones. However, in an individual with diabetes, dangerous and life-threatening levels of ketone Continue reading >>
Ketosis, Ketone Bodies, And Ketoacidosis – An Excerpt From Modern Nutritional Diseases, 2nd Edition
The following text is excerpted from Lipids (Chapter 8) of Modern Nutritional Diseases, 2nd Edition. Ketone Bodies and Ketosis: Ketones are organic chemicals in which an interior carbon in a molecule forms a double bond with an oxygen molecule. Acetone, a familiar chemical, is the smallest ketone possible. It is composed of three carbons, with the double bond to oxygen on the middle carbon. Biological ketone bodies include acetone, larger ketones, and biochemicals that can become ketones. The most important of the ketone bodies are hydroxybutyrate and acetoacetate, both of which are formed from condensation of two acetyl CoA molecules. Acetone is formed from a nonenzymatic decarboxylation of acetoacetate. Ketone bodies are fuel molecules that can be used for energy by all organs of the body except the liver. The production of ketone bodies is a normal, natural, and important biochemical pathway in animal biochemistry (17, p. 577). Small quantities of ketone bodies are always present in the blood, with the quantity increasing as hours without food increase. During fasting or carbohydrate deprivation, larger amounts of ketone bodies are produced to provide the energy that is normally provided by glucose. Excessive levels of circulating ketone bodies can result in ketosis, a condition in which the quantity of circulating ketone bodies is greater than the quantity the organs and tissues of the body need for energy. People who go on extremely low-carbohydrate diets to lose a large excess of body fat usually go into a mild ketosis that moderates as weight is lost. There is no scientific evidence that a low-carbohydrate diet is capable of producing sufficient ketone bodies to be harmful. Excess ketone bodies are excreted by the kidneys and lungs. Exhaled acetone gives the brea Continue reading >>
What Are Ketone Bodies And Why Are They In The Body?
If you eat a calorie-restricted diet for several days, you will increase the breakdown of your fat stores. However, many of your tissues cannot convert these fatty acid products directly into ATP, or cellular energy. In addition, glucose is in limited supply and must be reserved for red blood cells -- which can only use glucose for energy -- and brain tissues, which prefer to use glucose. Therefore, your liver converts many of these fatty acids into ketone bodies, which circulate in the blood and provide a fuel source for your muscles, kidneys and brain. Video of the Day Low fuel levels in your body, such as during an overnight fast or while you are dieting, cause hormones to increase the breakdown of fatty acids from your stored fat tissue. These fatty acids travel to the liver, where enzymes break the fatty acids into ketone bodies. The ketone bodies are released into the bloodstream, where they travel to tissues that have the enzymes to metabolize ketone bodies, such as your muscle, brain, kidney and intestinal cells. The breakdown product of ketone bodies goes through a series of steps to form ATP. Conditions of Ketone Body Utilization Your liver will synthesize more ketone bodies for fuel whenever your blood fatty acid levels are elevated. This will happen in response to situations that promote low blood glucose, such as an overnight fast, prolonged calorie deficit, a high-fat and low-carbohydrate diet, or during prolonged low-intensity exercise. If you eat regular meals and do not typically engage in extremely long exercise sessions, the level of ketone bodies in your blood will be highest after an overnight fast. This level will drop when you eat breakfast and will remain low as long as you eat regular meals with moderate to high carbohydrate content. Ketone Bodi Continue reading >>
Ketone Body Formation
Ketone body formation occurs as an alternative energy source during times of prolonged stress e.g. starvation. It occurs in the liver from an initial substrate of: long chain fatty acids; the fatty acids undergo beta-oxidation by their normal pathway within mitochondria until acetyl-CoA is produced, or ketogenic amino acids; amino acids such as leucine and lysine, released at times of energy depletion, are interconverted only to acetyl-CoA Then, three molecules of acetyl-CoA are effectively joined together in three enzyme steps sequentially catalyzed by: acetyl CoA acetyltransferase HMG-CoA transferase HMG-CoA lyase Coenzyme A is regenerated and the ketone body acetoacetate is formed. Finally, acetoacetate is reduced to another ketone body, D-3-hydroxybutyrate, in a reaction catalyzed by 3-hydroxybutyrate dehydrogenase. This requires NADH. The oxidate state of the liver is such that the forward reaction is generally favoured; this results in more hydroxybutyrate being formed than acetoacetate. Continue reading >>
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 >>
Diabetes And Ketones
Tweet The presence of high levels of ketones in the bloodstream is a common complication of diabetes, which if left untreated can lead to ketoacidosis. Ketones build up when there is insufficient insulin to help fuel the body’s cells. High levels of ketones are therefore more common in people with type 1 diabetes or people with advanced type 2 diabetes. If you are suffering from high levels of ketones and seeking medical advice, contact your GP or diabetes healthcare team as soon as possible. What are ketones? Ketones are an acid remaining when the body burns its own fat. When the body has insufficient insulin, it cannot get glucose from the blood into the body's cells to use as energy and will instead begin to burn fat. The liver converts fatty acids into ketones which are then released into the bloodstream for use as energy. It is normal to have a low level of ketones as ketones will be produced whenever body fat is burned. In people that are insulin dependent, such as people with type 1 diabetes, however, high levels of ketones in the blood can result from taking too little insulin and this can lead to a particularly dangerous condition known as ketoacidosis. How do I test for ketones? Ketone testing can be carried out at home. The most accurate way of testing for ketones is to use a blood glucose meter which can test for ketones as well as blood glucose levels. You can also test urine for ketone levels, however, the testing of urine means that the level you get is representative of your ketone levels up to a few hours ago. Read about testing for ketones and how to interpret the results Who needs to be aware of ketones? The following people with diabetes should be aware of ketones and the symptoms of ketoacidosis: Anyone dependent on insulin – such as all people Continue reading >>
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 during periods of low food intake (fasting), carbohydrate restrictive diets, starvation, prolonged intense exercise,, 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. 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). 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). 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 >>
Diabetic Ketoacidosis- Enzyme For Ketones Formation?
Case details A 54- year-old man with Type 1 diabetes is referred to an ophthalmologist for evaluation of developing cataract. Blood chemistry results are shown below- Fasting blood glucose 198 mg/dl Hemoglobin A 15 gm/dl Hemoglobin A 1c 10% of total Hb Urine ketones Positive Urine glucose Positive Which of the following enzymes is most strongly associated with ketones formation in this patient? A) Pyruvate dehydrogenase complex B) Thioesterase C) Thiophorase D) Thiokinase E) Thiolase. The correct answer is- E- Thiolase. Out of the given options thiolase is the only enzyme involved in the ketogenesis. The process of ketogenesis starts from the action of thiolase. In fact, the actual specific enzyme for ketogenesis is HMG Co A Synthase (mitochondrial isoform) which is not mentioned in the given options. Ketone bodies Acetoacetate, D (-3) -hydroxybutyrate (Beta hydroxy butyrate), and acetone are often referred to as ketone bodies (figure-1). Figure-1- Acetoacetate is the primary ketone body, the other ketone bodies are derived from it. The term “ketones” is actually a misnomer because beta-hydroxybutyrate is not a ketone and there are ketones in blood that are not ketone bodies, e.g., pyruvate, fructose. Ketogenesis takes place in liver using Acetyl co A as a substrate or a precursor molecule. Enzymes responsible for ketone body formation are associated mainly with the mitochondria. Steps of synthesis Acetoacetate (First ketone body) is formed from acetyl CoA in three steps (Figure-2). 1) Two molecules of acetyl CoA condense to form Acetoacetyl CoA. This reaction, which is catalyzed by thiolase, is the reverse of the thiolysis step in the oxidation of fatty acids. 2) Acetoacetyl CoA then reacts with acetyl CoA and water to give 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) Continue reading >>
The term “ketone bodies” refers primarily to two compounds: acetoacetate and β‐hydroxy‐butyrate, which are formed from acetyl‐CoA when the supply of TCA‐cycle intermediates is low, such as in periods of prolonged fasting. They can substitute for glucose in skeletal muscle, and, to some extent, in the brain. The first step in ketone body formation is the condensation of two molecules of acetyl‐CoA in a reverse of the thiolase reaction. The product, acetoacetyl‐CoA, accepts another acetyl group from acetyl‐CoA to form β‐hydroxy‐β‐hydroxymethylglutaryl‐CoA (HMG‐CoA). HMG‐CoA has several purposes: It serves as the initial compound for cholesterol synthesis or it can be cleaved to acetoacetate and acetyl‐CoA. Acetoacetate can be reduced to β‐hydroxybutyrate or can be exported directly to the bloodstream. Acetoacetate and β‐hydroxybutyrate circulate in the blood to provide energy to the tissues. Acetoacetate can also spontaneously decarboxylate to form acetone: Although acetone is a very minor product of normal metabolism, diabetics whose disease is not well‐managed often have high levels of ketone bodies in their circulation. The acetone that is formed from decarboxylation of acetoacetate is excreted through the lungs, causing characteristic “acetone breath.” Continue reading >>
How Are Ketones Formed?
Ketones are a very important functionnal group in organic chemistry, and thus there are several ways to prepare them, the 2 most common being oxidations, and reductions. The first is straightforward. You can oxidize a secondary alcohol to a ketone. There are a lot of reagents that can do that, the most practical are probably the hypervalent iodine reagents (IBX, Dess-Martin periodinane, although the latter is more used for oxidation of primary alcohol to the aldehyde). Chromium and Manganese oxides can also be used, in some cases. Then there are the methodologies which will cleave a double bond and give you two ketones, like ozonolysis, or Osmium oxide reaction on double bonds. The second is a bit more devious: because it doesn't look like a typical reduction. But when a organocopper, organizinc or organomagnesium reagent (or other organometallic reagents, these are just the most commonly used in the lab), when they react with an acid derivative, it is a reduction ( the oxidation of the carbon goes from +3 to +2). Possibilities include reaction of the organometallic reagent with anhydrides or acyl chlorides, possibly catalyzed by a transition metal (Ni, Pd, Co, Fe…), reactions with Weinreb amides , or with morpholine amides, in the case of Grignard reagents. Remember that you cannot use directly an ester and a Grignard, apart from the 2 aforementioned cases, the ketone will be more reactive and thus the Grignard will react with the ketone as soon as it is formed, to form the tertiary alcohol. You can use carbonylation reactions. In these reactions, you use a nucleophile (typically an organostannane, but other can be used), an electrophile (usually an aryl or vinyl halide), under carbon monoxide atmosphere, with a Palladium catalyst. There's also the Pauson-Khand react Continue reading >>
To gain a better understanding of ketosis and the ketogenic diet, it is important to take a look at the physiology behind the diet. If you recall from the article What is a Ketogenic Diet? the goal of a ketogenic diet is to induce ketosis by increasing ketone body production. A key step in understanding the diet is to learn what ketosis is, what are ketones and what do they do. “Normal” Metabolism Learning the basics of the various metabolic processes of the body will better your ability to understand ketosis. Under the normal physiological conditions that are common today, glucose is our body’s primary source of energy. Following ingestion, carbohydrates are broken down into glucose and released into the blood stream. This results in the release of insulin from the pancreas. Insulin not only inhibits fat oxidation but also acts as a key holder for cells by allowing glucose from the blood to be shuttled into cells via glucose transporters (GLUT). The amount of insulin required for this action varies between individuals depending on their insulin sensitivity. Once inside the cell, glucose undergoes glycolysis, a metabolic process that produces pyruvate and energy in the form of adenosine triphosphate (ATP). Once pyruvate is formed as an end product of glycolysis, it is shuttled into the mitochondria, where it is converted to acetyl-CoA by pyruvate dehydrogenase. Acetyl-CoA then enters the TCA cycle to produce additional energy with the aid of the electron transport chain. Since glucose is so rapidly metabolized for energy production and has a limited storage capacity, other energy substrates, such as fat, get stored as triglycerides due to our body’s virtually infinite fat storage capacity. When a sufficient source of carbohydrates is not available, the body adap Continue reading >>
Clinical Review: Ketones And Brain Injury
Abstract Although much feared by clinicians, the ability to produce ketones has allowed humans to withstand prolonged periods of starvation. At such times, ketones can supply up to 50% of basal energy requirements. More interesting, however, is the fact that ketones can provide as much as 70% of the brain's energy needs, more efficiently than glucose. Studies suggest that during times of acute brain injury, cerebral uptake of ketones increases significantly. Researchers have thus attempted to attenuate the effects of cerebral injury by administering ketones exogenously. Hypertonic saline is commonly utilized for management of intracranial hypertension following cerebral injury. A solution containing both hypertonic saline and ketones may prove ideal for managing the dual problems of refractory intracranial hypertension and low cerebral energy levels. The purpose of the present review is to explore the physiology of ketone body utilization by the brain in health and in a variety of neurological conditions, and to discuss the potential for ketone supplementation as a therapeutic option in traumatic brain injury. Introduction Ketogenesis is the process by which ketone bodies (KB), during times of starvation, are produced via fatty acid metabolism. Although much feared by physicians, mild ketosis can have therapeutic potential in a variety of disparate disease states. The principle ketones include acetoacetate (AcAc), β-hydroxybutyrate (BHB) and ace-tone. In times of starvation and low insulin levels, ketones supply up to 50% of basal energy requirements for most tissues, and up to 70% for the brain. Although glucose is the main metabolic substrate for neurons, ketones are capable of fulfilling the energy requirements of the brain. The purpose of the present review is to e Continue reading >>
What Is Ketone? - Definition, Structure, Formation & Formula
Background of Ketone Did you know that our friend aldehyde has a very close relative named ketone? By definition, a ketone is an organic compound that contains a carbonyl functional group. So you may be wondering if aldehydes and ketones are relatives, what makes them different? Well, I am glad you asked because all you have to remember is this little guy: hydrogen. While aldehyde contains a hydrogen atom connected to its carbonyl group, ketone does not have a hydrogen atom attached. There are a few ways to know you are encountering a ketone. The first is by looking at the ending of the chemical word. If the suffix ending of the chemical name is '-one,' then you can be sure there is a ketone present in that compound. Want to know another way to tell if a ketone is lurking around the corner? By its physical property. Ketones have high boiling points and love water (high water solubility). Let's dig a little deeper with the physical property of a ketone. The oxygen in a ketone absolutely loves to take all the electrons it can get its hands on. But, by being an electron-hogger, oxygen's refusal to share creates a sticky situation where some atoms on the ketone have more or less charge than others. In chemistry, an electron-hogging atom is referred to as being electronegative. An electronegative atom is more attractive to other compounds. This attractiveness, called polarity, is what contributes to ketones' physical properties. Structure & Formula Ketones have a very distinct look to them; you can't miss it if you see them. As shown in Diagram 1, there are two R groups attached to the carbonyl group (C=O). Those R groups can be any type of compound that contains a carbon molecule. An example of how the R group determines ketone type is illustrated in this diagram here. The Continue reading >>