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The Body Can Make Glucose From Fatty Acids True Or False

Metabolism And Energetics

Metabolism And Energetics

Metabolism basically refers to all the chemical reactions within the body used to produce energy. This involves a complex set of processes that convert fuels into specialised compounds loaded with energy. In the body, the primary final agent to produce energy is called adenosine triphosphate (ATP) . When ATP is broken down or used by cells huge amounts of energy is released. This energy is essential for cells to grow and divide, synthesise important compounds, for muscles to contract and numerous other important functions. Metabolism therefore produces energy to perform all the functions of different tissues within the body. Metabolism works by breaking down foods in the diet or compounds in the body into their smaller components. These can then enter into special reactions to produce ATP. The left over components are recycled by the body and used to regenerate the original compounds. The body has three main types of molecules it uses for energy: Carbohydrates: These are the sugar type compounds in the body. Carbohydrates come from foods such as bread, cereal, potatoes, fruits and sugar-containing foods or bevarages. When carbohydrates are digested in the gastrointestinal system they are broken down into smaller molecules such as glucose (a simple sugar). The main storage sites for carbohydrates in the body are the liver and muscles. Lipids: This basically refers to fats (such as cholesterol) from the diet or stored in adipose tissue (in other words the body fat). Lipids are broken down into smaller components called fatty acids for energy. Therefore lipids are really just chains of fatty acids joined together. Proteins: These make up nearly three quarters of all the solid materials in the body. Proteins are thus the basic structural components in the body. They are ma Continue reading >>

Chapter 5 Fats, Oils, And Other Lipids

Chapter 5 Fats, Oils, And Other Lipids

Nutrition & You, 4e (Blake) 1) Lipids contain all the following elements except A) nitrogen. B) carbon. C) hydrogen. D) oxygen. Answer: A Page Ref: 146 Skill: Knowledge Learning Outcome: 5.1 Section: 5.1 2) The two essential fatty acids are A) monoglycerides and diglycerides. B) cholesterol and trans fatty acids. C) linoleic acid and alpha-linolenic acid. D) PUFAs and MUFAs. Answer: C Page Ref: 148 Skill: Knowledge Learning Outcome: 5.1 Section: 5.1 3) Which of the following terms encompasses all of the other listed terms? A) LDL B) HDL C) lipoprotein D) VLDL Answer: C Page Ref: 153 Skill: Knowledge Learning Outcome: 5.2 Section: 5.2 4) Which of the following types of lipoprotein contains the highest percentage of protein? A) VLDL B) HDL C) LDL D) chylomicron Answer: B Page Ref: 153 Skill: Comprehension Learning Outcome: 5.2 Section: 5.2 5) Phospholipids are made up of how many fatty acid chains? A) 4 B) 3 C) 2 D) 1 Answer: C Page Ref: 146 Skill: Knowledge Learning Outcome: 5.1 Section: 5.1 6) The phosphate-containing head of a phospholipid attracts water and is thus said to be A) polar. B) nonpolar. C) hydrophobic. D) None of the answers is correct. Answer: A Page Ref: 149, 150 Skill: Knowledge Learning Outcome: 5.1 Section: 5.1 7) Sterols contain how many glycerol and fatty acid groups? A) 3 B) 5 C) 0 D) 2 Answer: C Page Ref: 150 Skill: Knowledge Learning Outcome: 5.1 Section: 5.1 8) A fatty acid that has a single double bond is called a A) unsaturated fatty acid. B) polyunsaturated fatty acid. C) monounsaturated fatty acid. D) saturated fatty acid. Answer: C Page Ref: 148 Skill: Knowledge Learning Outcome: 5.1 Section: 5.1 9) Which of the following lipids is a precursor for both vitamin D and testosterone? A) cholesterol B) alpha-linolenic acid C) eicosanoids D) satu Continue reading >>

Dynamic Adaptation Of Nutrient Utilization In Humans

Dynamic Adaptation Of Nutrient Utilization In Humans

Most cells use glucose for ATP synthesis, but there are other fuel molecules equally important for maintaining the body's equilibrium or homeostasis. Indeed, although the oxidation pathways of fatty acids, amino acids, and glucose begin differently, these mechanisms ultimately converge onto a common pathway, the TCA cycle, occurring within the mitochondria (Figure 1). As mentioned earlier, the ATP yield obtained from lipid oxidation is over twice the amount obtained from carbohydrates and amino acids. So why don't all cells simply use lipids as fuel? In fact, many different cells do oxidize fatty acids for ATP production (Figure 2). Between meals, cardiac muscle cells meet 90% of their ATP demands by oxidizing fatty acids. Although these proportions may fall to about 60% depending on the nutritional status and the intensity of contractions, fatty acids may be considered the major fuel consumed by cardiac muscle. Skeletal muscle cells also oxidize lipids. Indeed, fatty acids are the main source of energy in skeletal muscle during rest and mild-intensity exercise. As exercise intensity increases, glucose oxidation surpasses fatty acid oxidation. Other secondary factors that influence the substrate of choice for muscle include exercise duration, gender, and training status. Another tissue that utilizes fatty acids in high amount is adipose tissue. Since adipose tissue is the storehouse of body fat, one might conclude that, during fasting, the source of fatty acids for adipose tissue cells is their own stock. Skeletal muscle and adipose tissue cells also utilize glucose in significant proportions, but only at the absorptive stage - that is, right after a regular meal. Other organs that use primarily fatty acid oxidation are the kidney and the liver. The cortex cells of the Continue reading >>

General, Organic & Biological Chemistry, 5e

General, Organic & Biological Chemistry, 5e

(Timberlake) Chapter 24 Metabolic Pathways for Lipids and Amino Acids 24.1 Multiple-Choice Questions 1) The digestion of fats begins in the A) mouth. B) stomach. C) small intestine. D) large intestine. E) pancreas. Answer: C Objective: 24.1 Global Outcomes: GO2 2) The digestion of fats begins when the fat globules are A) emulsified by bile salts. B) attacked by protease enzymes to form smaller fat globules. C) converted to lipoproteins for greater solubility. D) hydrolyzed to glucose and amino acids. E) hydrolyzed to glycerol and fatty acids. Answer: A Objective: 24.1 Global Outcomes: GO2 3) Fatty acids and glycerol are produced from the metabolism of A) lipids. B) proteins. C) carbohydrates. D) amino acids. E) glucose. Answer: A Objective: 24.1 Global Outcomes: GO2 4) Most of the energy stored in the human body is in the form of A) glycogen. B) glucose. C) muscle tissue. D) triacylglycerols. E) the amino acid pool. Answer: D Objective: 24.1 Global Outcomes: GO2 5) Fat cells are known as A) lysosomes. B) adipocytes. C) glycerides. D) islet cells. E) monoacylglycerols. Answer: B Objective: 24.1 Global Outcomes: GO2 6) The small droplets of fat that are the first step in the digestion of dietary fats are called A) emulsions. B) detergents. C) bile drops. D) lipoproteins. E) micelles. Answer: E Objective: 24.1 Global Outcomes: GO2 7) The action of pancreatic lipase on triacylglycerols produces A) emulsions. B) micelles. C) monoacylglycerols and free fatty acids. D) high-density lipoproteins. E) low-density lipoproteins. Answer: C Objective: 24.1 Global Outcomes: GO2 8) A chylomicron is a A) lipase. B) digestive enzyme. C) triacylglycerol. D) transport lipoprotein. E) storage protein. Answer: D Objective: 24.1 Global Outcomes: GO2 9) Fatty acids are not a source of energy f 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 >>

Adipose Tissue

Adipose Tissue

Ann L. Albright and Judith S. Stern Department of Nutrition and Internal Medicine University of California at Davis Davis, CA USA Morphology and Development of Adipose TissueAdipose-Tissue MetabolismAdipose Tissue DistributionDefinition and Causes of ObesityFurther Reading Albright, A.L. and Stern, J.S. (1998). Adipose tissue. In: Encyclopedia of Sports Medicine and Science, T.D.Fahey (Editor). Internet Society for Sport Science: 30 May 1998. Adipose tissue is specialized connective tissue that functions as the major storage site for fat in the form of triglycerides. Adipose tissue is found in mammals in two different forms: white adipose tissue and brown adipose tissue. The presence, amount, and distribution of each varies depending upon the species. Most adipose tissue is white, the focus of this review. White adipose tissue serves three functions: heat insulation, mechanical cushion, and most importantly, a source of energy. Subcutaneous adipose tissue, found directly below the skin, is an especially important heat insulator in the body, because it conducts heat only one third as readily as other tissues. The degree of insulation is dependent upon the thickness of this fat layer. For example, a person with a 2-mm layer of subcutaneous fat will feel as comfortable at 15°C as a person with a 1-mm layer at 16°C. Adipose tissue also surrounds internal organs and provides some protection for these organs from jarring. As the major form of energy storage, fat provides a buffer for energy imbalances when energy intake is not equal to energy output. It is an efficient way to store excess energy, because it is stored with very little water. Consequently, more energy can be derived per gram of fat (9 kcal.gm-1) than per gram of carbohydrate (4 kcal.gm-1) or protein (4 kcal.g Continue reading >>

Popular Study Materials From Nutrition 251

Popular Study Materials From Nutrition 251

Size: 177 A) they are needed in larger amounts than the nonessential amino acids. B) they provide energy to the body, while nonessential amino acids do not. C) they are more important than the nonessential amino acids. D) they must be supplied in the diet. A) eggs B) steak C) bread D) orange soda E) hotdog A) has at least some of each essential amino acid B) contains all essential and nonessential amino acids C) is used solely for the manufacture of bodily protein D) contains all the essential amino acids in a pattern which is proportional to human needs A) So that high quality and low quality protein are mixed. B) Because this reduces fats from meat and poultry by mixing with heart healthy fats from the other subgroups. C) To reduce the cost of weekly menus that contain mostly protein from high cost meats such as beef and poultry. D) To reduce the intake of grilled beef and poultry which may contain carcinogens from the grilling process. A) Creamy peanut butter B) Milk C) Parmesan cheese D) Ground beef A) Conversion to nonessential amino acids B) Conversion to niacin, a B vitamin C) Regulation of fluid balance D) Transport nutrients into cells E) Answers A and B above A) Proteins that facilitate chemical reactions B) Proteins that are not altered by the reactions they facilitate C) Chemical messengers that are secreted from one tissue, travels through the body, and cause a change in a target tissue. D) Options A and B above E) Options A, B and C above. Using Matt's dietary analysis from your study questions, it indicates he consumed 170% of his RDA for protein and 13% of his total kcalories from protein. Based on this information, which of the following is the best conclusion? A) Matt met his RDA for protein, but did not meet the Acceptable Maconutrient Distribution Ra Continue reading >>

Nutrition Ch. 7

Nutrition Ch. 7

Front Back .Wirisformula{ margin:0 !important; padding:0 !important; vertical-align:top !important;} Metabolism The sum total of all the chemcial reactions that go on in living cells. Energy metabolism includes all the reactions by which the body obtains and spends energy from food. Example: Nutrients provide the body with FUEL and follows them through a series of reactions that release energy from their chemical bonds. As the bonds break, they release energy in a controlled version of the process by which wood burns in a fire. Energy metabolism All of the chemical reactions through which the human body acquires and spends energy from food Anabolism Small compounds joined together to make largers ones; energy must be used in order to do this Ana = up Catabolism Larger compounds BROKEN down into smaller ones; energy is RELEASED kata = down Coupled reactions Energy released from the breakdown of a large compounds is used to drive other reactions ATP Adenosine triphosphate; energy currency of the body -- produced when large compounds are broken down ATP is used to make large compounds from smaller ones. Ribosomes Cellular machinery used to make proteins Mitochondria Where energy is derived from fat, CHO, protein via TCA cycle, electron transport chain Coenzyme Complex organic molecules that work with enzymes to facilitate the enzymes' activity. Many coenzymes have B vitamins as part of their structures. co = with Cofactor The general term for substances that facilitate enzyme action is cofactors; they include both organic coenzymes such as vitamins and inorganic substances such as minerals Enzymes Protein catalysts - proteins that facilitate chemical reactions without being changed in the process Metalloenzyme Enzymes that contain one or more minerals as part of their stru Continue reading >>

We Really Can Make Glucose From Fatty Acids After All! O Textbook, How Thy Biochemistry Hast Deceived Me!

We Really Can Make Glucose From Fatty Acids After All! O Textbook, How Thy Biochemistry Hast Deceived Me!

Biochemistry textbooks generally tell us that we can’t turn fatty acids into glucose. For example, on page 634 of the 2006 and 2008 editions of Biochemistry by Berg, Tymoczko, and Stryer, we find the following: Animals Cannot Convert Fatty Acids to Glucose It is important to note that animals are unable to effect the net synthesis of glucose from fatty acids. Specficially, acetyl CoA cannot be converted into pyruvate or oxaloacetate in animals. In fact this is so important that it should be written in italics and have its own bold heading! But it’s not quite right. Making glucose from fatty acids is low-paying work. It’s not the type of alchemy that would allow us to build imperial palaces out of sugar cubes or offer hourly sweet sacrifices upon the altar of the glorious god of glucose (God forbid!). But it can be done, and it’ll help pay the bills when times are tight. All Aboard the Acetyl CoA! When we’re running primarily on fatty acids, our livers break the bulk of these fatty acids down into two-carbon units called acetate. When acetate hangs out all by its lonesome like it does in a bottle of vinegar, it’s called acetic acid and it gives vinegar its characteristic smell. Our livers aren’t bottles of vinegar, however, and they do things a bit differently. They have a little shuttle called coenzyme A, or “CoA” for short, that carries acetate wherever it needs to go. When the acetate passenger is loaded onto the CoA shuttle, we refer to the whole shebang as acetyl CoA. As acetyl CoA moves its caboose along the biochemical railway, it eventually reaches a crossroads where it has to decide whether to enter the Land of Ketogenesis or traverse the TCA cycle. The Land of Ketogenesis is a quite magical place to which we’ll return in a few moments, but n Continue reading >>

Nutrition 7

Nutrition 7

Home > Preview Of the components listed below,______________is/are not part of the ATP molecule a) adenine b) ribose c) glucose d) three phosphate In glycolysis, glucose is converted to a) pyruvate b) acetyl-CoA c) glycogen d) fat The TCA cycle is initiated by the reaction a) pyruvate + oxaloacetate > acetyl-CoA b) pyruvate + acetyl-CoA > citric acid c) acetyl-CoA + oxaloacetate > citric acid d) acetyl-CoA + citric acid > oxaloacetate The end products of glucose catabolism are a) ATP, ADP, and NAD b) ATP, CO2, and O2 c) NAD, FAD, and H2O d) ATP, CO2, and H2O True/False (support your answer with an explanation) Acetyl-CoA is the "pivotal" point of the TCA cycle because it can either be used to make glucose or to produce energy False Acetyl-CoA is a 2-carbon molecule, which cannot be converted back to pyruvate (a 3-carbon molecule), and so it cannot make glucose. It is the "pivotal" point of the TCA cycle because other substance that are convertible to acetyl-CoA can enter the energy production cycle or be converted to fats for storage at this point Fatty acids are catabolized to produce energy by a) sequential breakdown to form acetyl-CoA, which then enters the TCA cycle b) beta-oxidation to form pyruvate, which then enters the TCA cycle c) hydrolysis to form glycerol, which then enters glycolysis d) beta-oxidation to form oxaloacetate, which then enters the TCA cycle The nitrogen from excess protein in the diet is excreted as a) ammonia b) water c) amino acids d) urea False Ketone bodies are normal metabolites of the body. At low levels of production, the body can metabolize the ketone bodies. In conditions of fasting or in diabetes, ketone production can increase beyond the body's ability to metabolize ketone bodies. The result is ketosis, which, in its mild form can c Continue reading >>

Metabolism

Metabolism

Sort Catabolism Degradation from large complex molecules to smaller simple ones: 1) Carbohydrate Catabolism: a) Glycolysis b) Penthose Phosphate Passway c) Kerbs Cycle (Cytric Acid Cycle) d) Electron transport Chain e) Glycogenolysis 2) Lipid Catabolism a) β oxidation b) Ketone metabolism c) Cholestrol catabolism 3) Protein Catabolism 4) Nucleic Acid Catabolism Glycolysis: Definition and Enzymes Converts Glucose to Pyruvate (or Lactate in anaerobic conditions) Net energy yield: 2 ATP, 2 NADH Steps: 1) Glucose ---> Glucose-6p 2) Glucose-6p <---> Fructose-6p 3) Fructose-6p ---> Fruktose-1,6 bisphosphate --- 4) Fruktose-1,6 bisphosphate <--->Glyceraldehyde-3p + DHAP 4-a) Glyceraldehyde-3p <---> DHAP 5) Glyceraldehyde-3p <---> 1,3-Biphosphoglycerate 6) 1,3-Biphosphoglycerate <---> 3-Phosphoglycerate 7) 3-Phosphoglycerate <---> 2-Phosphoglycerate 8) 2-Phosphoglycerate ----> Phosphoenylpyruvate (PEP) 9) PEP ---> Pyruvate Enzymes: 1) Hexokonase (Glucokinase in liver), 2) Glucose 6-p isomerase (Phosphoglucose isomerase) 3) PFK, 4) Aldolase, 4-a) Triose-phosphate isomerase, 5) Glyceraldehyde-phosphate dehydrogenase, 6) Phosphoglycerate kinase, 7) Phosphoglycerate mutase, 8) Enolase, 9) Pyruvate Kinase Hexokinase, PFK and Pyruvate Kinase are irreversible and regulatory PFK is Rate Limiting Step ATP is used in steps 1 & 3 NADH produced in 5 ATP produced in 6 & 9 Glycolysis: regulators 1) Hexokinase inhibited by:G6P (In Liver: Glucokinase regulated by: Glucokinase regulatory protein: GKRP) 2) PFK-1 Stimulated by AMP & Fructose-2,6-bisphosphate⁰ and inhibited by ATP & Citrate PFK-2 stimulated by Insukine and inhibited by Glucagon 3) Pyruvate kinase activated by: fructose-1,6-bisphosphate and Insuline⁰, Inhibited by ATP, Acetyl-CoA, Glucagon⁰ and Alanine⁰ ⁰Liver specific G Continue reading >>

Essential Fatty Acids

Essential Fatty Acids

Linoleic acid (LA), an omega-6 fatty acid , and -linolenic acid (ALA), an omega-3 fatty acid, are considered essential fatty acids because they cannot be synthesized by humans. (More information) The long-chain omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), can be synthesized from ALA, but due to low conversion efficiency, it is recommended to consume foods rich in EPA and DHA. (More information) Both omega-6 and omega-3 fatty acids are important structural components of cell membranes , serve as precursors to bioactive lipid mediators, and provide a source of energy. Long-chain omega-3 polyunsaturated fatty acids ( PUFA in particular exert anti-inflammatory effects; it is recommended to increase their presence in the diet. (More information) Both dietary intake and endogenous metabolism influence whole body status of essential fatty acids. Genetic polymorphisms in fatty acid synthesizing enzymes can have a significant impact on fatty acid concentrations in the body. (More information) DHA supplementation during pregnancy may reduce the risks of early premature birth (birth before 34 weeks' gestation) and very low birth weight (<1.5 kg [<3 pounds 5 ounces]). (More information) DHA is important for visual and neurological development. However, supplementation with long-chain during pregnancy or early infancy appears to have no significant effect on children's visual acuity, neurodevelopment, and physical growth. (More information) Replacing saturated fat in the diet with omega-6 lowers total blood cholesterol ; yet, randomized controlled trials have failed to demonstrate cardiovascular benefits in healthy people and people at risk for or with type 2 diabetes mellitus . Long-chain omega-3 PUFA supplementation may be useful to reduce mort Continue reading >>

Myths About Keto: Whats True & Whats False?

Myths About Keto: Whats True & Whats False?

Myths About Keto: Whats True & Whats False? Wouldnt it be nice to live in a world where the answers to all our health questions were black and white, (Eat this, and you will feel good; dont eat this, or you will not feel good)? Unfortunately, health is not black and white, and often we have to navigate through the grey areas to find the truth. MYTH #1: A ketogenic diet increases your risk for cardiovascular disease This myth is centred around the misinformation that saturated fat and cholesterol are the main causes of heart disease. Despite being shown that dietary cholesterol does not raise blood cholesterol1 and saturated fat has little correlation to heart disease,2 there is still a stigma around both. Cardiovascular risk does not boil down to a single biomarker, but rather encompasses a host of factors such as age, sex, total cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, smoking, blood pressure, glycemic control, and more. Several of these risk factors may be mitigated by lifestyle changes. Low-density lipoprotein (LDL) cholesterol, as opposed to high-density lipoprotein (HDL) cholesterol, often gets a bad rap because the general understanding about cholesterol is that LDL cholesterol is the bad cholesterol, and HDL cholesterol is the good cholesterol. While this isnt entirely misleading, what is misleading is referring to these as absolutes. LDL is usually misrepresented as the single factor that determines ones risk for cardiovascular disease (CVD), when in fact there is more to the LDL and CVD risk story much of which is still uncovered. The danger lies with the small, dense LDL particles (as opposed to large, buoyant LDL particles),3 which have been shown to be associated with CVD.4 It is not uncommon to see a rise in total LDL levels Continue reading >>

Volatile Fatty Acids

Volatile Fatty Acids

Larry R. Engelking, in Textbook of Veterinary Physiological Chemistry (Third Edition) , 2015 Propionate, a volatile fatty acid (VFA) produced from microbial carbohydrate digestion in ruminants and other herbivores (see Chapter 54), is a major hepatic gluconeogenic substrate. The percentage of glucose derived from propionate in the liver varies with diet (and species), from a maximum of about 70% under heavy grain feeding in ruminants, to very little during starvation. The importance of propionate as a gluconeogenic substrate is illustrated by the observation that the lactating udder of the goat may utilize 60-85% of glucose produced by the liver for milk production. In contrast to propionate, acetate and butyrate, the other two major VFAs produced through microbial carbohydrate digestion, do not contribute carbon atoms directly to the net synthesis of glucose. Certain glucogenic amino acids (namely isoleucine, valine, threonine, and methionine), the terminal 3 carbons of odd-chain fatty acids undergoing mitochondrial -oxidation, and the -aminoisobutyrate generated from thymine degradation, can also enter hepatic gluconeogenesis at the level of propionyl-CoA. While the former may be quantitatively significant to carnivores, and to all animals during starvation, the latter two are not since: Few odd-chain fatty acids exist in mammalian organisms (with the exception of ruminant animals; see Chapter 54), and Only small amounts of -aminoisobutyrate normally become available to the liver through pyrimidine degradation (see Chapter 17). Entry of propionate into gluconeogenesis (as well as amino acids that are converted to propionyl-CoA), requires pantothenate (a source of coenzyme A.SH), vitamin B12, and biotin (see Fig. 37-1). These vitamins are normally synthesized by micro Continue reading >>

Nbpns

Nbpns

INDICATIONS:If the GI tract works,useit;partial/trophic GI feeds as possible.Parenteral nutrition should only be used when there is a clear indication. Energy & nutrient requirements & delivery True/False: Patients on TPN usually need higher caloric intakes (relative to body weight). This is FALSE. Patient on TPN frequently have several factors contributing to lower calorie needs. First, there is usually decreased energy expenditure from activity compared to healthy peers. Second, there may be additional limitations on activity such as is seen with sedation and mechanical ventilation. And third, with the infusion of nutrients directly into the veins, the energy expenditure related to the thermic effect of food is eliminated. The thermogenic effect of feeding can contribute to 7 - 10% of energy expenditure. So, even though patients on parenteral nutrition are often critically ill, their energy needs will not necessarily be higher. Sources of Energy in parenteral solutions: Protein (amino acids):4 kcal/g (g N = protein g/6.25) True or False: Dextrose should provide the main exogenous energy source during TPN. This is TRUE. Intravenous dextrose suppresses the endogenous breakdown of protein for energy, provides an easily oxidized substrate, and provides the primary fuel for the brain, red and white bloods cells, and for wounds. IV dextrose should be the main source of exogenous energy: it suppresses gluconeogenesis and provides easily oxidized substrate; Start at D10-12.5%;by 2.5% per day (2.5 g/kg/d) until reach goal of ~ 50-60% of total kcal Glucose loadis dependent on concentration & rate (g/kg/d or mg/kg/min); max hepatic oxidation rates are highest in young infant (18 g/kg/d12.5 mg/kg/min), lowest in adults (4.3 g/kg/d3.0 mg/kg/min); exceeding these may result in com Continue reading >>

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