Substrates in clinical nutrition Ilze Jagmane Latvian Society of Parenteral and Enteral Nutrition September, 2013
Introduction Food contains one or more of the following nutrients: Water Carbohydrate Lipids Protein Vitamins Minerals, trace elements
Macro & micro nutrients Energy Nitrogen Co-factors Co-enzymes Macronutrients: Carbohydrate Fat Protein Water Micronutrients: Vitamins Minerals and trace elements
Caloric content of macronutrients and alcohol Carbohydrates: 1 g = 4 calories Fat: 1 g = 9 calories Proteins: 1 g = 4 calories Alcohol: 1 g = 7 calories
Carbohydrates Monosaccharide Disaccharides Ooligosaccharides Glucose, Fructose, Galactose Sucrose = glucose + fructose Lactose = glucose + galactose Maltose = glucosa + glucose Maltodextrins Polysaccharides Dietary fibre Starch, glycogen Soluble Insoluble Cellulose Hemicellulose Lignin Pectin, gums, mucilage, Some hemicelluloses
Protein Made up of amino acids 20 different types of amino acids Amino Acids as source of Nitrogen Essential Amino Acids: Isoleucine, leucine, lysine, methionine, phenylalanine, valine, threonine, tryptophan, histidine HCl pepsin Chymotripsin Trypsin Dietary proteins Stomach Polypeptides Small intestine Free aminoacids and very small peptides (mainly dipeptides) Absorbtion
Functions of proteins Synthesis Enzymes Hormones Antibodies Fluid and electrolyte balance Acid base balance Transportation Energy Basics in clinical nutrition, ESPEN 2004, 2011.
Dietary lipids are ingested as: triglycerides phospholipids sterols Free fatty acids: saturated unsaturated polyunsaturated Essential fatty acids: Linoleic - Linolenic Lipids Bile Pancreatic lipase Dietary fats Stomach Small intestine Free fatty acids and monoglycerides Absorbtion
Fatty acids and triglicerides Methyl group terminal Saturated fatty acids Monounsaturated fatty acid Carboxyl group Palmitic acid (16:0) Double bond -9 Oleic acid (18:1, -9) Glycerol + Free fatty acid Polyunsaturated fatty acids -6-3 Linoleic acid (18:2, -6) Triglyceride Alfa Linolenic acid (C 18:3, ω 3)
Functions of lipids Energy storage and metabolism Structural component of biological membranes Hormons and signaling molecules Carriers of fat- soluble vitamins (A, D, E, K) Modulate immune function Precursors of eicosanoids Basics in clinical nutrition, ESPEN 2004, 2011.
The most important lipo- and cyclooxygenase products Anti-inflammatory mediators Leukotrienes of 5 series (LTB 5, LTC 5, LTD 5 ) ω-3 Eucosapentaenoic acid (EPA) Prostanoids of 3 series (TXA 3, PGE 3, PGI 3 ) Lipoxygenase Cyclooxygenase Leukotrienes of 4 Series (LTB 4, LTC 4, LTD 4 ) ω-6 Arachidonic acid (AA) Prostanoids of 3 series (TXA 2, PGE 2, PGI 2 ) Pro-inflammatory mediators
Ratio omega-3: omega-6 Paleolithic: omega-3: omega-6 = 1:1 Today: omega-3: omega-6 = 1:8-12 Recommendations: omega-3: omega-6 = 1:1-4
Related to: Energy requirements expenditure the ability to metabolize substrates correctly Direct or indirect calorimetry Harris-Benedict formula: Males: 66 + (13.7x BW) +(5xH)-(6.8x A) Females: 655 + (9.6xBW) + (1.7xH) - (4.7xA) A - Age (y) BW - Body weight (kg) H - Height (cm) 1 kcal / kg/ h for unstressed, resting male subjects Basics in clinical nutrition, ESPEN 2004, 2011
Energy requirements Energy expenditure does not exceed 2400 kcal a day Overfeeding during acute illness may be associated with complications 20-25 kcal /kg BW /day during the acute and initial phase of critical illness 25-30 kcal /kg BW /day anabolic recovery phase Basics in clinical nutrition, ESPEN 2004, 2011 ESPEN guidelines on enteral nutrition. Clinical Nutrition (2006) 25, 210-223
Composition of parenteral formulas Total parenteral nutrition all nutrient needs provided intravenously Supplementary parenteral nutrition some food via GI tract and the rest infused parenterally PROTEIN, FAT, CHO, vitamins, minerals which form?
Carbohydrates Glucose is the major circulating carbohydrate fuel Provide 50-55 % of calories Carbohydrate 4-6 g / kg a day Minimum 160-200 g / 24 h Max recommended infusion rate is 5 mg/kg/min Avoid hyperglycaemia Basics in clinical nutrition, ESPEN 2004, 2011.
Lipids Provide 20-40 % of non protein calories Not recommended for patients with hypertriglyceridemia (> 4-5 mmol/l) Infuse slowly 0.1-0.15 g / kg / h Monitor plasma triglyceride levels Ideal lipid emulsion - should be easily metabolized, anti- inflammatory, should not increase inflammatory or oxidant stress and should not be immunosuppressive Basics in clinical nutrition, ESPEN 2004, 2011. Grimble R. Clin Nutr 2005.
Lipid emulsions Long - chain triglycerides (LCT) Medium - chain triglycerides (MCT) LCT+MCT mixtures Structured lipid emulsions Fish oil or olive oil based lipid emulsions SMOF-emulsion Basics in clinical nutrition, ESPEN 2004, 2011. Fürst P. J. Nutr. 128: 789-796, 1998. Wirtitsch M. Et al. Clin. Nutrition. 26: 302-313, 2007
Protein Basic requirement of AA is 0,8 1 g /kg/day Up to 1,5-2,0 g / kg /day if severe catabolism, extensive protein loss, severe malnutrition Amino acid solutions of different concentrations and mixtures Some AA are conditionally essential Some AA mixtures contain electrolytes Ratio: 150 kcal : 1g N Basics in clinical nutrition, ESPEN 2004, 2011.
Micronutrients and vitamins Parenteral formulas: commercial preparations Enteral formulas: 100 % RDA or more
Enteral formulas Categories of enteral formulas: Polymeric formulas: Standard, High protein, Energy dense, Fibre enriched Oligomeric and monomeric formulas Special (disease specific) formulas: Liver, Renal, Immunomodulatory, Pulmonary formula, Diabetic formula
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