What Will Happen to a Protein Being Synthesized if an Essential Amino Acid Is Missing?
Essential Amino Acid
The limiting amino acrid is the essential amino acid present in the lowest amount in a protein when compared to the content of that same amino acid in a reference poly peptide, usually egg white.
From: Medical Biochemistry , 2017
Nutrient Requirements/Nutritional Support in Premature Neonate
Richard J. Martin MBBS, FRACP , in Fanaroff and Martin's Neonatal-Perinatal Medicine , 2020
Intravenous Amino Acrid Mixtures
The start parenteral amino acid solutions used in neonates were hydrolysates of fibrin or casein. Concerns about these first-generation solutions included high concentrations of glycine, glutamate, and aspartate; the presence of unwanted peptides; and high acidity. Reports of hyperammonemia and acidosis in the early 1970s were associated with the use of these first-generation solutions in neonates. Although amino acid solutions have been significantly modified, the perceived risks associated with the protein hydrolysates linger, contributing to the hesitancy by some clinicians to administrate early on parenteral amino acids.
The second generation of amino acid solutions consisted of crystalline amino acid mixtures (FreAmine 3, Travasol, Aminosyn). The amino acrid pattern of these mixtures reflects that of high-quality dietary proteins with large amounts of glycine and alanine, absence of glutamate and aspartate, and absence or poor solubility of tyrosine and cysteine.
The newest solutions include modifications of crystalline amino acids for employ in pediatric patients. The currently available solutions include modifications of crystalline amino acids for use in pediatric and neonatal patients (Table 41.1). TrophAmine was originally formulated to match plasma amino acrid concentrations of healthy term, breastfed infants; Premasol is identical in limerick to TrophAmine. The composition of Primene, available outside the Usa, was derived from fetal and neonatal cord claret concentrations. Both TrophAmine and Premasol supply a mixture of L-tyrosine and North-acetyltyrosine. The bioavailability of N-acetyltyrosine, nonetheless, has been questioned. Neither Aminosyn-PF nor Primene supplies a substantial amount of tyrosine. Cysteine is non supplied by nearly amino acrid solutions, because information technology is not stable for long periods of time in solution. Still, cysteine hydrochloride tin can exist added during the compounding process just prior to delivery of the solution.
Information technology is no surprise that the platonic limerick of intravenous amino acrid mixtures is unknown. Although these solutions are widely used in the neonatal intensive care unit, normative data on plasma amino acid concentrations, particularly in ELBW infants, has not been established. Whether the goal should be to lucifer amino acid concentrations of term, breastfed infants or another standard is not known. Clearly, the ultimate goal is to accomplish plasma amino acid concentrations in response to provision of parenteral nutrition that optimize both growth and neurodevelopment without toxicity. To optimize nutrition and growth, especially in a premature baby, the requirements for specific amino acids demand to exist more precisely defined.
Several amino acids may be "conditionally essential" in premature infants. That is, the babe's ability to synthesize these amino acids de novo may be less than needed for functional metabolic demands. Cysteine, tyrosine, and arginine are often considered conditionally essential amino acids for premature infants.
miRNAs as Nutritional Targets in Aging
Robin A. McGregor , Dae Y. Seo , in Molecular Basis of Diet and Aging, 2016
miRNAs Modulated past Poly peptide
Essential amino acids (EAAs) are well established as stiff stimulators of muscle poly peptide synthesis and therefore are particularly useful in medical foods and supplements designed to maintain or increase skeletal musculus mass [63]. EAAs have been shown to modulate miRNA levels in skeletal musculus too [64]. A written report in young men found that ingestion of 10 k of EAAs increased the expression of mature miR-499, miR-208b, miR-23a, and miR-one transcripts, as well as pri-miR-206 afterward 3 h [64]. These EAA-induced changes were accompanied by alteration of muscle growth related genes [64]. No studies take investigated the fourth dimension class of changes in miRNA expression levels afterward feeding EAAs, other amino acids, or different types of proteins. By studies have shown that whey poly peptide, casein poly peptide, soy poly peptide can all stimulate muscle protein synthesis in humans; leucine is a specially potent anabolic agent [65]. Future studies are needed to define how and which miRNAs are modulated by whole proteins from different nutrient sources, as well equally individual amino acids.
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Poly peptide Metabolism
John Eastward. Hall PhD , in Guyton and Hall Textbook of Medical Physiology , 2021
Essential and Nonessential Amino Acids
Ten of the amino acids ordinarily present in animal proteins tin be synthesized in the cells, whereas the other 10 either cannot exist synthesized or are synthesized in quantities too small-scale to supply the body'south needs. This second grouping of amino acids that cannot exist synthesized is chosen the essential amino acids . Utilise of the word "essential" does not hateful that the other ten "nonessential" amino acids are not required for the formation of proteins but merely that the others arenot essential in the diet because they can be synthesized in the body.
Synthesis of the nonessential amino acids depends mainly on the formation of advisable α-keto acids, which are the precursors of the respective amino acids. For case,pyruvic acid, which is formed in big quantities during the glycolytic breakdown of glucose, is the keto acrid precursor of the amino acidalanine. And then, by the process oftransamination, an amino radical is transferred to the α-keto acid, and the keto oxygen is transferred to the donor of the amino radical. This reaction is shown inFigure 70-3. Notation that alanine is formed afterward the amino radical is transferred to the pyruvic acid from glutamic acid. Amino radicals tin can be transferred fromasparagine, aspartic acid,andglutamine. Glutamine is nowadays in the tissues in big quantities, and one of its principal functions is to serve as an amino radical storehouse.
Note likewise that the reactions are reversible so that transfer of amino groups tin also occur during degradation of amino acids, equally discussed later.
Transamination is promoted by several enzymes, among which are theaminotransferases, which are derivatives of pyridoxine, one of the B vitamins (Bvi). Without this vitamin, the amino acids are poorly synthesized, and protein formation cannot proceed commonly.
Glucose Homeostatis and the Pathogenesis of Diabetes Mellitus
Manda L. Orgeron , ... Thomas West. Gettys , in Progress in Molecular Biology and Translational Scientific discipline, 2014
one Rationale for Study of Dietary Methionine Restriction
The essential amino acids (EAAs) (due east.g., methionine, lysine, leucine, isoleucine, tryptophan, valine, threonine, phenylalanine, and histidine) cannot be synthesized endogenously, so 10–20 mg/kg body weight of each must be obtained in the diet each twenty-four hours from consumed protein. Moreover, dietary protein sources must contain the full assortment of EAAs because proteins deficient in ane or more EAAs apace produce an aversive feeding response that results in a significant decrease in consumption of the diet. Semisynthetic diets absent-minded a single EAA have been used to explore the sensing and signaling mechanisms that mediate the behavioral and physiological responses to EAA deprivation. 1–6 An of import implication of this work is that dietary amino acids are functioning much like receptor ligands in the sense that specific concentration ranges engage signaling systems linked to molecular responses that have biochemical and physiological consequences. An of import distinction is that the absence of an EAA (e.yard., EAA impecuniousness) is the bespeak that initiates the full signaling response, suggesting that limitation of an EAA must achieve some threshold of restriction for triggering the response. This assumption has been supported by substantial empirical evidence, merely the somewhat surprising finding is that dietary restriction (DR) of EAAs inside narrowly divers ranges has proven highly beneficial to metabolic condition and overall health. In particular, the benign responses that result from restricting normal intakes of dietary methionine within a defined range are the subject field of this chapter.
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Energy metabolism
Jeannette Naish MBBS MSc FRCGP , in Medical Sciences , 2019
Essential amino acids (see alsoClinical box 3.17)
Some individual amino acids must be conserved for protein synthesis because, apart from collagen, all 20 of those that form proteins must be nowadays together for protein synthesis. This applies particularly to the essential amino acids, which cannot be synthesised fast enough for requirements in the trunk and must be obtained from food (see Fig. 3.17 andCh. 16).
The hepatic extraction of the branched-chain amino acids that cannot be synthesised past humans is less than the extraction of the other amino acids. Furthermore, although used for hepatic protein synthesis, these essential amino acids are not degraded to any corking extent by the liver, so they are found in higher concentrations in peripheral blood than other amino acids. Whereas they typically constitute approximately xv%–xx% of dietary protein, valine, leucine and isoleucine stand for at least 70% of the full amino acids entering the general circulation after a meal.
Valine, leucine and isoleucine are, therefore, taken up by skeletal muscle to a greater extent than the other amino acids, bookkeeping for lx%–lxxx% of the total amino acid uptake by muscle. Branched-chain amino acids that are non used for protein synthesis can be oxidised in the muscles to provide energy.
The use of the branched-concatenation amino acids preferentially past musculus underlies their inclusion in parenteral feeding solutions for patients in situations of negative nitrogen balance (e.1000. stress, trauma, burns), where there is excessive poly peptide breakdown (run intoCh. 16).
Amino Acid Modifications
Larry R. Engelking , in Textbook of Veterinarian Physiological Chemistry (Third Edition), 2015
Essential and Nonessential Amino Acids
Essential amino acids, which generally have a longer half-life than the nonessential ones, are those that are required in the diet since the body cannot synthesize them in acceptable amounts to maintain protein biosynthesis ( Table three-1 ). If even i essential (or nones-sential) amino acid is absent, the remaining 19 cannot be used, and they get catabolized thus leading to a negative nitrogen residue. Essential amino acids vary depending on species and age.
Adults and Young | Boosted for Young |
---|---|
Isoleucine | Arginine |
Leucine | Glycine (Chickens) |
Lysine | Histidine |
Methionine | |
Phenylalanine | |
Taurine (Cats) | |
Threonine | |
Tryptophan | |
Valine |
The branched-concatenation amino acids, (leucine, isoleucine and valine) are routinely oxidized in muscle tissue, and phenylalanine is needed for hepatic tyrosine biosynthesis {which is and so used for catecholamine biosynthesis (e.thou., dopamine, norepinephrine and epinephrine) in nerve tissue, as well as thyroid hormone biosynthesis}. Methionine is needed for cysteine formation, and tryptophan is used for serotonin (5-hydroxytryptamine) and melatonin germination. Most nonessential amino acids can be interconverted with carbohydrate metabolites through aminotransferase (i.e., transamination) reactions (run across Chapter 9). However, there are no in vivo aminotransferase reactions for lysine and threonine, and, in addition, histidine, phenylalanine and methionine are not metabolized to whatever significant extent by these reactions. Hence, they are all "essential" dietary amino acids.
The ordinary diet of domestic animals usually contains more than adequate amounts of both essential and nonessential amino acids. Therefore, these categories are of practical significance only in affliction, when specific supplements are administered, or when one is designing an animal nutrition. If, for any reason, dietary amino acid supply is insufficient, the need to synthesize specific proteins for vital physiologic deportment results in a redistribution of amino acids among proteins. For example, hemoglobin (Hb) is degraded to the extent of most 1%/day as erythrocytes die, a loss normally balanced past resynthesis. In amino acid deficiency, relatively less Hb is synthesized because the caste of anemia is more tolerable than a deficiency of certain other proteins. Additionally, there is a definite sequence in which body proteins are lost during starvation in order to maintain the blood glucose concentration (see Chapter 76).
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Engineering science the biosynthesis of depression molecular weight metabolites for quality traits (essential nutrients, health-promoting phytochemicals, volatiles, and aroma compounds)
Fumihiko Sato , Kenji Matsui , in Found Biotechnology and Agriculture, 2012
Essential amino acids
Essential amino acrid biosynthesis is strictly regulated by some key enzymes, such as dihydrodipicolinate synthase (DHDPS) in lysine (Lys) biosynthesis, and anthranilate synthase in tryptophan (Trp) synthesis ( Figure 28.3A,B). Thus, introduction of a mutant enzyme gene without feedback regulation is critical to better the content of essential amino acids.
The first successful increases in Lys content in the seeds of canola and soybean plants were accomplished by the introduction of Lys-feedback-insensitive bacterial DHDPS and aspartokinase (AK) enzymes encoded past the Corynebacterium dapA cistron and a mutant Escherichia coli lysC cistron (Falco et al., 1995). The expression of Corynebacterium DHDPS resulted in more than a 100-fold increase in the aggregating of free Lys in the seeds of canola, and the full seed Lys content approximately doubled. The expression of Corynebacterium DHDPS plus Lys-insensitive E. coli AK in soybean transformants similarly increased the complimentary Lys level by several hundred-fold and the total seed Lys content past as much as 5-fold. Yet, genes should be linked to a plastid transit peptide and expressed from a seed-specific promoter in transgenic canola and soybean seeds, since these biosyntheses occur in plastids in seeds.
The start successful applied science of Lys biosynthesis as well illustrated enhanced catabolism: the accumulation of α-amino adipic acrid in canola and saccharopine in soybean. This indicates that applied science can influence catabolism through the modification of biosynthesis (Zhu and Galili, 2003). Transgenic Arabidopsis expressing the feedback-insensitive DHDPS in a knockout mutant in the Lys catabolism pathway showed a synergistic 80-fold increase in the seed-free Lys level compared to a unmarried trait line; a single DHDPS over-expresser and a Lys catabolism mutant contained, respectively, only 12- and 5-fold higher levels of seed-free Lys than wild-blazon plants.
A feedback-insensitive α-subunit of rice anthranilate synthase is another successful application of the accumulation of tryptophan (Trp; Wakasa et al., 2006). The amount of complimentary Trp in transgenic rice seeds was increased past about ii orders of magnitude compared with that in wild-blazon, and the total Trp content was also increased. However, information technology is possible that the marked overproduction of Trp might reduce spikelet fertility, yield, and seed germination ability, although agronomic traits varied among lines. Interestingly, no substantial changes in the amounts of other phenolic compounds were detected, except for near a 2-fold increase in indole acerb acid in the transgenic seeds.
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Industrial Biotechnology and Article Products
D.M. Wuest , ... Yard.H. Lee , in Comprehensive Biotechnology (2nd Edition), 2011
three.52.iii.1 Amino Acids
Amino acids, essential components of living organisms, play an important role in diet and wellness maintenance in both humans and animals. The amino acid industry has a long history, and improvements of product processes via metabolic engineering accept been used for most l years. Among the 20 amino acids, 9 essential amino acids ( l-valine, l-leucine, l-isoleucine, fifty-lysine, l-threonine, fifty-methionine, fifty-histidine, l-phenylalanine, and l-tryptophan) are non synthesized in animals and humans and must be ingested from nutrient [35]. Therefore, a peachy need for amino acids first occurred in the food-processing industry equally nutritional supplements, food additives, and creature feed additives. In improver, l-glutamic acrid serves equally a flavor enhancer, and l-aspartic acrid and 50-phenylalanine are precursors of the peptide sweetener aspartame. More recently, the need for amino acids has expanded to the pharmaceutical and corrective industries and has been introduced as raw materials for the chemical synthesis of herbicides.
All xx amino acids are annually manufactured in different market volumes through different processes as shown in Table ii . The production of amino acids has dramatically increased as a outcome of the success of cost-effective production and downstream processes in the past decade, and they are now the second largest category in the global marketplace for fermentation products (later on antibiotics), at approximately $iv.5 billion estimated in 2004 and growing with an annual rate of 7% [16]. Amino acids are traditionally fabricated by extraction, chemical synthesis, bacterial fermentation, and enzymatic conversion. The choice of a manufacturing process depends on many factors including cost of raw materials, bachelor technologies, market value, and ecology impact. Compared to chemical synthesis, bacterial fermentation has unique advantages including utilization of renewable raw materials, less toxic byproducts, and college stability. However, bacterial fermentation has its own disadvantages, such every bit oxidation of sulfur-containing amino acids, production of circuitous byproducts, and occasional outbreak of bacteriophage infection. To appointment, near L-amino acids are commercially produced past fermentation using central metabolic and amino acid pathways. The production of amino acids can be greatly improved by rational metabolic engineering science. For example, Ikeda and Katsumata (1993) greatly increased l-phenylalanine product in Corynebacterium glutamicum past overexpression of the pheA gene from E. coli [21], and Guillouet et al. (1999) expressed the Eastward. coli catabolic threonine dehydratase in C. glutamicum resulting in increased l-isoleucine production [17].
Amino acid | Estimated product (ton/year) | Process | Uses |
---|---|---|---|
l-glutamic acid | 1 000 000 | Fermentation | Flavor enhancer, neurotransmitter, precursor for the synthesis of the inhibitory GABA in GABA-ergic neurons |
l-lysine HCL | 850 000 | Fermentation | Food supplement, antiviral for Herpes simplex, anticancer |
d,50-methionine | 350 000 | Chemical synthesis | Methyl donor, intermediate in the biosynthesis of cysteine, carnitine, taurine, lecithin, phosphatidylcholine, and other phospholipids, precursor of ethylene, urinary acidifier, treatment of laminitis in horses, antioxidant |
Glycine | 22 000 | Chemical synthesis | Pharmaceutical, buffering amanuensis in antacids, analgesics, antiperspirants, cosmetics, and toiletries |
l-phenylalanine | 8 000 | Fermentation, chemical synthesis | Nutritional supplement, forerunner for the synthesis of nutrient additives and pharmaceuticals (aspartame, HIV protease inhibitor, anti-inflammatory drugs) |
l-aspartic acid | vii 000 | Enzymatic method | Precursor for the synthesis of aspartame, pharmaceutical application (stamina and free energy) |
l-threonine | 7 000 | Fermentation | Feed supplement |
50-tryptophan | two 000 | Fermentation, enzymatic method | Nutritional supplement, feed condiment, food additive, infusion liquid, antidepressant, treatment of pellagra, sleep induction |
l-cysteine | 1 500 | Fermentation, extraction, enzymatic method | Pharmaceutical |
d,50-alanine | ane 500 | Fermentation, chemical synthesis | Flavor enhancer, sweetener |
l-glutamine | 1 300 | Fermentation | Pharmaceutical, treatment of serious illnesses including injury, trauma, burns, and treatment-related side effects of cancer too as in wound healing for postoperative patients |
l-arginine | 1 200 | Fermentation | Flavor enhancer, growth hormone releaser, precursor of nitric oxide |
l-valine | 500 | Fermentation | Component of cosmetics and pharmaceutical, feed additive, infusion liquid, dietary production, precursor in the chemical synthesis of herbicides |
l-leucine | 500 | Fermentation, extraction | Component of cosmetics and pharmaceutical, feed additive, infusion liquid, dietary product, forerunner in the chemical synthesis of herbicides |
50-isoleucine | 400 | Fermentation | Component of cosmetics and pharmaceutical, feed additive, infusion liquid, dietary product, forerunner in the chemical synthesis of herbicides |
50-histidine | 400 | Fermentation | Pharmaceutical |
l-proline | 350 | Fermentation | Pharmaceutical |
l-serine | 200 | Fermentation | Pharmaceutical |
l-tyrosine | 120 | Extraction | Raw material for l-DOPA product, treatment of Basedow'south disease, dietary supplement |
adapted from M. Ikeda [20] with modifications and updates
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Biotechnologies for the Management of Genetic Resources for Food and Agriculture
Preetmoninder Lidder , Andrea Sonnino , in Advances in Genetics, 2012
F Food preservation and product of food and feed ingredients
Fermentation is a cost–constructive food preservation procedure that tin can also enhance the flavor, aroma, and texture of food, enrich its nutritional quality and digestibility, detoxify contaminated food, and decrease cooking time and fuel requirements (Liu et al., 2011b). In many developing countries, fermented foods serve every bit of import dietary constituents and are produced primarily at the household and village level. Equally such, the majority of small fermentations are based on spontaneous processes, resulting from the activities of a variety of microorganisms associated with the raw food fabric and the environs. The majority of fermented foods in Africa are produced by spontaneous fermentation, for example, Cingwada (fermented cassava) in E and Cardinal Africa, Kenkey (fermented maize) in Ghana, and Owoh (fermented cotton seed) in West Africa (FAO, 2011e). However, limitations include enhanced lag stage of microbial growth associated with contamination of competing microorganisms, that is, higher probability of spoilage, variable product quality, and lower product yield (Holzapfel, 2002).
Starter cultures are preparations of live microorganisms that are added to initiate and/or accelerate fermentation processes (FAO, 2011e). The starter culture may be obtained through the do of back slopping (addition of a sample from a previous successful fermentation batch) or may be a "defined starter culture" consisting of unmarried or multiple strains usually produced past pure culture maintenance and propagation nether aseptic conditions (FAO, 2011e). Examples of fermented foods produced using a back-slopping process include fermented cereals and grains in Africa and fermented fish sauces and vegetables in Asia (FAO, 2011e). Strains selected for defined starter cultures should possess several desirable metabolic traits, lack toxicogenic activity, and also be suitable for large-calibration product (Gänzle, 2009). Defined starter cultures allow procedure standardization together with lowered health risks and oft contain adjunct cultures to inhibit pathogenic or nutrient-spoilage organisms and to improve product quality (Mendoza et al., 2011; Settanni and Moschetti, 2010).
Lactic acid bacteria are the predominant microorganisms in a preponderance of nutrient fermentations. They convert carbohydrates either to lactic acid alone or carbon dioxide and ethanol in addition to lactic acid and are responsible for many products such as fermented sausage, all fermented milks, pickled vegetables, and sour dough bread (Flores and Toldra, 2011; Liu et al., 2011b; Steinkraus, 2002). Acetic acrid bacteria are of import in the nutrient manufacture due to their ability to oxidize sugars and alcohols into organic acids and are used in the product of vinegar and in cocoa and coffee fermentations (Sengun and Karabiyikli, 2011). A third grouping of bacteria, belonging to the genus Bacillus, hydrolyze proteins to amino acids and peptides and release ammonia. Such alkaline fermentations of plant seeds every bit well as legumes provide poly peptide-rich condiments especially in Africa and Asia (Parkouda et al., 2009). Yeast fermentations, more often than not involving Saccharomyces species, result in the formation of ethanol and carbon dioxide from sugar and are widely used for the production of leavened bread and fermented beverages such equally wines and beers (Sicard and Legras, 2011).
Fermentation that leads to the nutritional fortification of traditional foods can accept a profound impact on the diets of people in developing countries that depend largely on ane staple, such as cassava, maize, or rice, for subsistence. For case, fermentation of rice to produce tape ketan in Republic of indonesia results in a doubling of protein content and enrichment with lysine, an essential amino acrid. Similarly, pulque that is produced by the fermentation of agave juice in Mexico is rich in vitamins like thiamine, riboflavin, niacin, biotin, and pantothenic acid ( Steinkraus, 2002).
Essential amino acids, produced by microbial fermentation, are also utilized to supplement grain-based livestock feeds, both to increase productivity and to decrease the excretion of nitrogen from the animals into the surroundings (FAO, 2011c). Currently, the almanac global utilise of l-lysine, the first limiting amino acid for pigs and the second limiting amino acid after methionine for poultry, is estimated to be 900,000 tons followed by 65,000 tons for l-threonine and 1900 tons for 50-tryptophan (Kim, 2010). Feed grade fifty-valine is marketed in the EU, while 50-glutamine, also produced through fermentation processes, is available in South America and selected Asian countries (Kim, 2010). Additionally, exogenous microbial enzymes are increasingly being incorporated in animal feeds. Supplemental phytase, the most extensively used feed enzyme, improves utilization of phosphorus every bit well as other minerals in pigs and poultry and tin can reduce phosphorus excretion by upwardly to 50% (Singh et al., 2011b). Phytase has recently also been approved for utilize in salmonid feed in the EU. 184 Other exogenous enzymes included as feed additives to better digestion are xylanases, glucanases, proteases, and amylases (FAO, 2011c).
Microbial enzymes, manufactured by fermentation under controlled weather condition, are commonly employed in the food processing manufacture. For instance, α-amylases are applied for converting starch into fructose and glucose syrups (Souza and Magalhães, 2010), proteases such equally chymosin are used in cheese-making, pectinases are utilized for extraction, description and concentration of fruit juices, and tannases are used for the production of instantaneous tea (Aguilar et al., 2008). Microorganisms are likewise used to generate volatile flavor chemicals that possess desirable backdrop such as antimicrobial and antioxidant activities in addition to sensory properties, and more than 100 odor chemicals are available commercially (Berger, 2009). In recent years, there has been a growing interest in exploiting microbial fermentation processes for the product of bioethanol and biodiesel (Cheng and Timilsina, 2010; Demain, 2009; Ruane et al., 2010; Shi et al., 2011).
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Oral and Enteral Supplements in Kidney Disease and Kidney Failure
Noel J. Cano , in Nutritional Management of Renal Illness, 2013
Indications for Oral Nutritional Supplements and Enteral Nutrition in Conservatively Treated CKD
Essential amino acrid and ketoacid preparations that are given with very low protein diets and prescribed equally role of the regular diet for such patients are not addressed in this chapter (see Chapter 14) [20]. Guidelines for protein, energy intakes and for some mineral and vitamin needs are given in other capacity in this book [8,14,17]. An energy intake of at least 30–35 kcal/kg BW/day is associated with a better nitrogen balance and is recommended in conservatively treated CKD patients. When spontaneous feeding cannot run into these requirements, ONS may be useful to ensure that the recommended intakes are met, to prevent the occurrence of PEW, or to care for this status. ONS and EN with specialized formulas have been recommended for protein-energy wasted CKD patients [8]. Polymeric nutritive mixtures which are protein and electrolyte-restricted and which have high energy density are available. A number of these diets are shown to be well tolerated and able to meliorate poly peptide and calorie intakes [21]. However, their effects on nutritional parameters, morbidity and survival accept non been studied. Because such formulas are not available in every state, standard ONS and EN that are used for people without kidney disease are often employed for CKD patients with PEW. The prescription of such supplements should take into account their protein, phosphorus, sodium and potassium content.
In add-on to its utilize for patients with PEW, EN is indicated in CKD patients who are unable to consume fairly, cannot accept sufficient ONS for their needs, who take acute stress conditions or who take certain neurological diseases, dementia, or pharyngeal or esophageal obstruction [viii,22]. EN is starting time administered through a nasogastric tube. When EN is planned to last more than 1 month, a perendoscopic or radiologic gastrostomy should be considered.
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