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Why Are Ketones Produced?

What Are Ketone Bodies And Why Are They In The Body?

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 >>

Urine Tests For Diabetes: Glucose Levels And Ketones

Urine Tests For Diabetes: Glucose Levels And Ketones

The human body primarily runs on glucose. When your body is low on glucose, or if you have diabetes and don’t have enough insulin to help your cells absorb the glucose, your body starts breaking down fats for energy. Ketones (chemically known as ketone bodies) are byproducts of the breakdown of fatty acids. The breakdown of fat for fuel and the creation of ketones is a normal process for everyone. In a person without diabetes, insulin, glucagon, and other hormones prevent ketone levels in the blood from getting too high. However, people with diabetes are at risk for ketone buildup in their blood. If left untreated, people with type 1 diabetes are at risk for developing a condition called diabetic ketoacidosis (DKA). While rare, it’s possible for people with type 2 diabetes to experience DKA in certain circumstances as well. If you have diabetes, you need to be especially aware of the symptoms that having too many ketones in your body can cause. These include: If you don’t get treatment, the symptoms can progress to: a fruity breath odor stomach pain trouble breathing You should always seek immediate medical attention if your ketone levels are high. Testing your blood or urine to measure your ketone levels can all be done at home. At-home testing kits are available for both types of tests, although urine testing continues to be more common. Urine tests are available without a prescription at most drugstores, or you can buy them online. You should test your urine or blood for ketones when any of the following occurs: Your blood sugar is higher than 240 mg/dL. You feel sick or nauseated, regardless of your blood sugar reading. To perform a urine test, you urinate into a clean container and dip the test strip into the urine. For a child who isn’t potty-trained, a pa Continue reading >>

Ketone Bodies

Ketone Bodies

Overview Structure two types acetoacetate β-hydroxybutyrate β-hydroxybutyrate + NAD+ → acetoacetate + NADH ↑ NADH:NAD+ ratio results in ↑ β-hydroxybutyrate:acetoacetate ratio 1 ketone body = 2 acetyl-CoA Function produced by the liver brain can use ketones if glucose supplies fall >1 week of fasting can provide energy to body in prolonged energy needs prolonged starvation glycogen and gluconeogenic substrates are exhausted can provide energy if citric acid cycle unable to function diabetic ketoacidosis cycle component (oxaloacetate) consumed for gluconeogenesis alcoholism ethanol dehydrogenase consumes NAD+ (converts to NADH) ↑ NADH:NAD+ ratio in liver favors use of oxaloacetate for ketogenesis rather than gluconeogenesis. RBCs cannot use ketones as they lack mitochondria Synthesis occurs in hepatocyte mitochondria liver cannot use ketones as energy lacks β-ketoacyl-CoA transferase (thiophorase) which converts acetoacetate to acetoacetyl under normal conditions acetoacetate = β-hydroxybutyrate HMG CoA synthase is rate limiting enzyme Clinical relevance ketoacidosis pathogenesis ↑ ketone levels caused by poorly controlled type I diabetes mellitus liver ketone production exceeds ketone consumption in periphery possible in type II diabetes mellitus but rare alcoholism chronic hypoglycemia results in ↑ ketone production presentation β-hydroxybutyrate > acetoacetate due to ↑ NADH:NAD+ ratio acetone gives breath a fruity odor polyuria ↑ thirst tests ↓ plasma HCO3 hypokalemia individuals are initially hyperkalemic (lack of insulin + acidosis) because K leaves the cells overall though the total body K is depleted replete K in these patients once the hyperkalemia begins to correct nitroprusside urine test for ketones may not be strongly + does not detect 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 >>

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 Metabolism

Ketone Body Metabolism

Ketone body metabolism includes ketone body synthesis (ketogenesis) and breakdown (ketolysis). When the body goes from the fed to the fasted state the liver switches from an organ of carbohydrate utilization and fatty acid synthesis to one of fatty acid oxidation and ketone body production. This metabolic switch is amplified in uncontrolled diabetes. In these states the fat-derived energy (ketone bodies) generated in the liver enter the blood stream and are used by other organs, such as the brain, heart, kidney cortex and skeletal muscle. Ketone bodies are particularly important for the brain which has no other substantial non-glucose-derived energy source. The two main ketone bodies are acetoacetate (AcAc) and 3-hydroxybutyrate (3HB) also referred to as β-hydroxybutyrate, with acetone the third, and least abundant. Ketone bodies are always present in the blood and their levels increase during fasting and prolonged exercise. After an over-night fast, ketone bodies supply 2–6% of the body's energy requirements, while they supply 30–40% of the energy needs after a 3-day fast. When they build up in the blood they spill over into the urine. The presence of elevated ketone bodies in the blood is termed ketosis and the presence of ketone bodies in the urine is called ketonuria. The body can also rid itself of acetone through the lungs which gives the breath a fruity odour. Diabetes is the most common pathological cause of elevated blood ketones. In diabetic ketoacidosis, high levels of ketone bodies are produced in response to low insulin levels and high levels of counter-regulatory hormones. Ketone bodies The term ‘ketone bodies’ refers to three molecules, acetoacetate (AcAc), 3-hydroxybutyrate (3HB) and acetone (Figure 1). 3HB is formed from the reduction of AcAc i 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 >>

Ketone Ester Effects On Metabolism And Transcription

Ketone Ester Effects On Metabolism And Transcription

Abstract Ketosis induced by starvation or feeding a ketogenic diet has widespread and often contradictory effects due to the simultaneous elevation of both ketone bodies and free fatty acids. The elevation of ketone bodies increases the energy of ATP hydrolysis by reducing the mitochondrial NAD couple and oxidizing the coenzyme Q couple, thus increasing the redox span between site I and site II. In contrast, metabolism of fatty acids leads to a reduction of both mitochondrial NAD and mitochondrial coenzyme Q causing a decrease in the ΔG of ATP hydrolysis. In contrast, feeding ketone body esters leads to pure ketosis, unaccompanied by elevation of free fatty acids, producing a physiological state not previously seen in nature. The effects of pure ketosis on transcription and upon certain neurodegenerative diseases make approach not only interesting, but of potential therapeutic value. PRODUCTION OF KETONE BODIES Ketone bodies are formed in the liver from free fatty acids released from adipose tissue. As the blood concentration of free fatty acids increases, concentration of blood ketone bodies is correspondingly increased (1, 2). Ketone bodies serve as a physiological respiratory substrate and are the physiological response to prolonged starvation in man (3, 4), where the blood level of ketones reaches 5–7 mM (5). If the release of free fatty acids from adipose tissue exceeds the capacity of tissue to metabolize them, as occurs during insulin deficiency of type I diabetes or less commonly in the insulin resistance of type II diabetes, severe and potentially fatal diabetic ketoacidosis can occur, where blood ketone body levels can reach 20 mM or higher (2) resulting in a decrease in blood bicarbonate to almost 0 mM and blood pH to 6.9. Diabetic ketoacidosis, which is a Continue reading >>

Ketones

Ketones

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 >>

The Fat-fueled Brain: Unnatural Or Advantageous?

The Fat-fueled Brain: Unnatural Or Advantageous?

Disclaimer: First things first. Please note that I am in no way endorsing nutritional ketosis as a supplement to, or a replacement for medication. As you’ll see below, data exploring the potential neuroprotective effects of ketosis are still scarce, and we don’t yet know the side effects of a long-term ketogenic diet. This post talks about the SCIENCE behind ketosis, and is not meant in any way as medical advice. The ketogenic diet is a nutritionist’s nightmare. High in saturated fat and VERY low in carbohydrates, “keto” is adopted by a growing population to paradoxically promote weight loss and mental well-being. Drinking coffee with butter? Eating a block of cream cheese? Little to no fruit? To the uninitiated, keto defies all common sense, inviting skeptics to wave it off as an unnatural “bacon-and-steak” fad diet. Yet versions of the ketogenic diet have been used to successfully treat drug-resistant epilepsy in children since the 1920s – potentially even back in the biblical ages. Emerging evidence from animal models and clinical trials suggest keto may be therapeutically used in many other neurological disorders, including head ache, neurodegenerative diseases, sleep disorders, bipolar disorder, autism and brain cancer. With no apparent side effects. Sound too good to be true? I feel ya! Where are these neuroprotective effects coming from? What’s going on in the brain on a ketogenic diet? Ketosis in a nutshell In essence, a ketogenic diet mimics starvation, allowing the body to go into a metabolic state called ketosis (key-tow-sis). Normally, human bodies are sugar-driven machines: ingested carbohydrates are broken down into glucose, which is mainly transported and used as energy or stored as glycogen in liver and muscle tissue. When deprived of d Continue reading >>

Blood Ketones

Blood Ketones

On This Site Tests: Urine Ketones (see Urinalysis - The Chemical Exam); Blood Gases; Glucose Tests Elsewhere On The Web Ask a Laboratory Scientist Your questions will be answered by a laboratory scientist as part of a voluntary service provided by one of our partners, the American Society for Clinical Laboratory Science (ASCLS). Click on the Contact a Scientist button below to be re-directed to the ASCLS site to complete a request form. If your question relates to this web site and not to a specific lab test, please submit it via our Contact Us page instead. Thank you. Continue reading >>

Ketones And Exercise – What You Need To Know

Ketones And Exercise – What You Need To Know

A researcher on diabetes and exercise describes why exercise elevates risk of DKA for people with Type 1 diabetes. In a new set of guidelines for Type 1 diabetes and exercise, I and my fellow researchers warn that people with Type 1 diabetes need to monitor for elevated levels of ketones during exercise. If you have Type 1 and exercise regularly, testing for ketones could save your life. Ketones develop in our bodies when we mobilize fat as fuel. Fat is an important energy source that is used by the body at rest and during exercise. Ketones are a general term in medicine used to describe the three main ketone bodies that the liver produces – acetoacetate, beta-hydroxybutyrate, and acetone. Read “Too Many with Type 1 Don’t Test for Ketones.” sponsor Ketone bodies help fuel the brain and skeletal muscle during times of prolonged fasting or starvation, so in a way ketones are very important for survival. We actually have enough stored fat to generate energy for days, but this can cause a number of metabolic problems, the most important of which is ketoacidosis. In Type 1 diabetes, ketone levels can rise even without starvation, if insulin levels drop too much and levels of other hormones like glucagon and catecholamines rise. This rise in ketone levels in diabetes can cause a life-threatening condition called diabetic ketoacidosis (DKA). Read “How DKA Happens and What to Do About it.” The symptoms of ketoacidosis include: A lack of energy, weakness, and fatigue Nausea and vomiting, stomach pain, decreased appetite Rapid weight loss Decreased perspiration, foul or fruity breath Altered consciousness, mild disorientation or confusion Coma sponsor The reasons for developing high ketone levels in Type 1 diabetes include: Missed insulin injections Failure of insulin 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 >>

Ketones In Gestational Diabetes

Ketones In Gestational Diabetes

As part of your gestational diabetes management, your doctor may ask you to test for ketones in your morning urine. If you have gestational diabetes, you should know about insulin, glucose, and ketones. When you eat, your body breaks down foods into usable sources of energy. Glucose is the sugar that results. Your body needs glucose for energy and your baby needs it to grow. In order to get glucose out of your blood and into your cells, insulin is required. Insulin is a hormone that you produce in your pancreas. "In gestational diabetes, hormones produced during pregnancy can interfere with insulin and make it hard to use glucose. If the pancreas cannot produce enough insulin to overcome the effects of the hormones, the blood sugar will rise," explains Louise McDonald, RN, clinical manager of maternity and pediatrics at Cleveland Clinic Home Care. "The body cannot use sugar without enough insulin. That causes the body to break down fats as a source of energy. Ketones are the waste products that are left over when the body burns some of its own fat for fuel. The ketones pass from the bloodstream into the urine," says McDonald. Why Are Ketones Important in Gestational Diabetes? The treatment of gestational diabetes is aimed at keeping your blood sugar under control. This is done with a combination of diet, exercise, and sometimes insulin treatment. Finding ketones in your urine is a warning sign that your blood sugar control is out of balance. High blood sugar. If you are taking in more sugar in your diet than your insulin can manage, your blood sugar goes up. This is dangerous for you and your baby. If your baby is exposed to more sugar then the baby needs, the baby will grow too fast. This condition, called macrosomia, can lead to problems during delivery. Low blood sug Continue reading >>

Diabetes And Ketones

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 >>

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