- Email: [email protected]
Is there a role for specific nutrients?
E-4
Cardio-respiratory failure Aim
To examine critically the place of nutritional support in the evidence-based care of cardio-respiratory failure.
Wasting - types and causes DR STEFAN ANKER Clinical Cardiolog~ National Heart and Lung Institute, London SW3 6L'( England e-mail·[email protected]. uk
No short paper received.
Is there a role for specific nutrients? DR PEGGY BORUM Professor of Human Nutrition, University of Florida, Gainesville, Florida 32611, USA e-mail' prb@ufledu
organ dysfunction implies that the organ dysfunction results in altered nutrient requirements that can be supplied to the patient in some form to meet those requirements, or that a specific compound is both a nutrient and a pharmacological agent that can be supplied to the patient to meet both needs.
Learning objectives
• Contrast nutrient supplementation with pharmacological use of a nutrient. • List factors altering energy metabolism in cardiorespiratory failure. • Describe conditionally essential nutrients. Key words: fuel sources; carbohydrate; lipid; conditionally essential nutrients
Oxygen and fuel source It is often stated that COPD patients have increased energy expenditure, but not all data confirm this statement. Data from different studies implicate factors including cytokines, leptin, and insulin resistance in the alteration of both protein and energy metabolism. Impaired pulmonary function with poor oxygen delivery to the blood plus impaired cardiac function with poor delivery of blood to the cells can clearly result in oxygen deficiency at the tissue level. There are no anaerobic pathways to provide energy from fatty acids. Although the A TP derived from anaerobic metabolism of glucose is less than from aerobic metabolism, glucose can provide energy during reduced oxygen availability. However, the oxidation of glucose will produce more carbon dioxide to be removed by the impaired pulmonary function. Thus one may speculate that
Cardio-respiratory failure metabolic issues
Cardio-respiratory failure is found in a variety of patient populations, but the wasted, elderly patient with severe exercise intolerance is typically envisioned. These chronic obstructive pulmonary disease (COPD) patients have varying stages of mUltiple organ dysfunction including impaired pulmonary function, cardiac function, skeletal muscle function, renal function and hepatic function. The heterogeneity of the population is significant. Nutrients are the only substrates that are available to the body for maintenance and healing. Suggesting that specific nutrients have a role in treating patients with J 17
glucose supplementation would provide energy for exercising muscle, but adversely affect breathing. Published data indicate that not all muscles respond the same. Histologic and metabolic data show that peripheral muscles undergo a shift from oxidative to glycolytic energy metabolism, whereas the opposite is observed in the diaphragm (1). Other investigators have shown no significant difference in metabolism or exercise capacity after a fat-rich or carbohydrate-rich supplement. But surprisingly, the change in shortness of breath (postprandial compared with preprandial) was significantly greater after the fat-rich supplement (2). A systematic review of patients with COPD suggests that those with marginal ventilatory reserve might benefit from a high fat dietary regimen but there was no long term increase in body weight (3). Carbohydrate and lipid are the two macronutrients provided in the diet for energy sources. Frequently energy metabolism is described as switching from one of these macronutrients to the other as though cell metabolism consisted of several forks in pathways using either carbohydrate or lipid depending on the physiological state of the cell. This assumption is often extended to pathophysiological states. Traditionally diabetes has been considered a disease of carbohydrate metabolism. However more thoughtful evaluation of data and the addition of new data suggest that our understanding of type 2 diabetes would be enhanced if we considered a more lipocentric approach rather than only considering a glucocentric approach (4). The lesson is that an integration of carbohydrate, lipid, and protein metabolism comprises cellular metabolism. Branched chain amino acid metabolism (particularly leucine metabolism) is altered in COPD patients and is associated with low muscle mass and high insulin concentrations (5). Elucidation of this metabolic integration is needed to enable the optimal use of altered macronutient intake in patient care.
of the high malonyl-CoA concentration in heart and muscle (8). Should glutathione or carnitine supplementation be considered for patients with cardio-respiratory failure? Conditionally essential nutrients are nutrients not required in the diet by healthy young adults, but required in the diet during certain physiological conditions. Dietary requirement of a particular nutrient may be the result of different physiological conditions or factors. Often a multifactorial route leads to a nutrient becoming a dietary requirement. A nutrient may also be a compound used for pharmacological purposes at a dose larger than found in any known natural diet. Although individual nutrients consumed in a natural diet by a healthy young adult are not usually consumed in concentrations that cause harm, the same nutrient administered via a different route or at elevated concentrations to a patient with less than optimal organ function may be harmful to the patient. In addition, administration of "specific nutrients" may significantly increase the cost of medical care and may interact with one of the medications received by the patient. A very real limitation in patient care is our ability to assess any altered nutrient requirement in an individual patient with one or many organ impairments. Ifwe can detect altered metabolism in a patient, another limitation in patient care is the selection of the dose and route of administration of the specific nutrient.
References I. Gosker HR. Wouters E F M, van der Vusse G 1, Schols A M W 1. Skeletal muscle dysfunction in chronic obstructive pulmonary disease and chronic heart failure: underlying mechanisms and therapy perspectives. Am 1 Clin Nutr 2000; 71(5): 1033-1047 2. Vermeeren MAP, Wouters E F, Nelissen L H, van Lier A, Hofman Z, Schols A M. Acute effects of different nutritional supplements on symptoms and functional capacity in patients with chronic obstructivepulmonary disease. Am 1 Clin Nutr 2001; 73(2): 295-301 3. Ferreira I M, Brooks D. Lacasse Y. Goldstein R S. Nutritional intervention in COPD - A systematic overview. Chest 2002; 119(2): 353-363. 4. McGarry 1 D. Dysregulation of fatty acid metabolism in the etiology of type 2 diabetes. Diabetes 2002; 51(1): 7-18. Ref ID: 41417 5. Engelen M P K 1, Wouters E F M, Deutz N E P, Menheere P P C A. Schols A M W 1. Factors contributing to alterations in skeletal muscle and plasma amino acid profiles in patients with chronic obstructive pulmonary disease. Am 1 Clin Nutr 2000; 72(6): 1480-1487 6. Engelen M P K 1, Schols A M W J. Does 1 D. Deutz N E P. Wouters E F M. Altered glutamate metabolism is associated with reduced muscle glutathione levels in patients with emphysema American 10urnal of Respiratory and Critical Care Medicine 2000: 103(1): 98-103 7. Longnus S L, Wambolt R B, Barr R L. Lopaschuk G D, Allard M F. Regulation of myocardial fatty acid oxidation by substrate supply. American 10urnal of Physiology-Heart and Circulatory Physiology 2001; 281(4): HI561-HI567. 8. Eaton S. Bartlett K. Quant P A. Carnitine palmitoyl transferase I and the control of beta-oxidation in heart mitochondria. Biochem Biophys Res Commun 2001; 285(2): 537-539
Conditionally essential nutrients
Oxidative stress is associated with dysfunction of organs such as heart and skeletal muscle. Muscles of patients with (COPD) have lower concentrations of glutamate and lower concentrations of glutathione. It has been suggest that increased glycolysis may decrease the glutamate concentrations which are needed for the synthesis of glutathione (6). During non-stressful conditions and when substrates are present at physiological concentrations, myocardial substrate supply is proposed as the primary mechanism responsible for alterations in fatty acid oxidation rates. However these patients experience metabolic stress which may lead to additional involvement of intracellular regulatory pathways (7). Although not rate-limiting in vitro, carnitine palmitoy I transferase is probably rate-limiting in vivo because
118
Cardio-respiratory failure Aim
To examine critically the place of nutritional support in the evidence-based care of cardio-respiratory failure.
Wasting - types and causes DR STEFAN ANKER Clinical Cardiolog~ National Heart and Lung Institute, London SW3 6L'( England e-mail·[email protected]. uk
No short paper received.
Is there a role for specific nutrients? DR PEGGY BORUM Professor of Human Nutrition, University of Florida, Gainesville, Florida 32611, USA e-mail' prb@ufledu
organ dysfunction implies that the organ dysfunction results in altered nutrient requirements that can be supplied to the patient in some form to meet those requirements, or that a specific compound is both a nutrient and a pharmacological agent that can be supplied to the patient to meet both needs.
Learning objectives
• Contrast nutrient supplementation with pharmacological use of a nutrient. • List factors altering energy metabolism in cardiorespiratory failure. • Describe conditionally essential nutrients. Key words: fuel sources; carbohydrate; lipid; conditionally essential nutrients
Oxygen and fuel source It is often stated that COPD patients have increased energy expenditure, but not all data confirm this statement. Data from different studies implicate factors including cytokines, leptin, and insulin resistance in the alteration of both protein and energy metabolism. Impaired pulmonary function with poor oxygen delivery to the blood plus impaired cardiac function with poor delivery of blood to the cells can clearly result in oxygen deficiency at the tissue level. There are no anaerobic pathways to provide energy from fatty acids. Although the A TP derived from anaerobic metabolism of glucose is less than from aerobic metabolism, glucose can provide energy during reduced oxygen availability. However, the oxidation of glucose will produce more carbon dioxide to be removed by the impaired pulmonary function. Thus one may speculate that
Cardio-respiratory failure metabolic issues
Cardio-respiratory failure is found in a variety of patient populations, but the wasted, elderly patient with severe exercise intolerance is typically envisioned. These chronic obstructive pulmonary disease (COPD) patients have varying stages of mUltiple organ dysfunction including impaired pulmonary function, cardiac function, skeletal muscle function, renal function and hepatic function. The heterogeneity of the population is significant. Nutrients are the only substrates that are available to the body for maintenance and healing. Suggesting that specific nutrients have a role in treating patients with J 17
glucose supplementation would provide energy for exercising muscle, but adversely affect breathing. Published data indicate that not all muscles respond the same. Histologic and metabolic data show that peripheral muscles undergo a shift from oxidative to glycolytic energy metabolism, whereas the opposite is observed in the diaphragm (1). Other investigators have shown no significant difference in metabolism or exercise capacity after a fat-rich or carbohydrate-rich supplement. But surprisingly, the change in shortness of breath (postprandial compared with preprandial) was significantly greater after the fat-rich supplement (2). A systematic review of patients with COPD suggests that those with marginal ventilatory reserve might benefit from a high fat dietary regimen but there was no long term increase in body weight (3). Carbohydrate and lipid are the two macronutrients provided in the diet for energy sources. Frequently energy metabolism is described as switching from one of these macronutrients to the other as though cell metabolism consisted of several forks in pathways using either carbohydrate or lipid depending on the physiological state of the cell. This assumption is often extended to pathophysiological states. Traditionally diabetes has been considered a disease of carbohydrate metabolism. However more thoughtful evaluation of data and the addition of new data suggest that our understanding of type 2 diabetes would be enhanced if we considered a more lipocentric approach rather than only considering a glucocentric approach (4). The lesson is that an integration of carbohydrate, lipid, and protein metabolism comprises cellular metabolism. Branched chain amino acid metabolism (particularly leucine metabolism) is altered in COPD patients and is associated with low muscle mass and high insulin concentrations (5). Elucidation of this metabolic integration is needed to enable the optimal use of altered macronutient intake in patient care.
of the high malonyl-CoA concentration in heart and muscle (8). Should glutathione or carnitine supplementation be considered for patients with cardio-respiratory failure? Conditionally essential nutrients are nutrients not required in the diet by healthy young adults, but required in the diet during certain physiological conditions. Dietary requirement of a particular nutrient may be the result of different physiological conditions or factors. Often a multifactorial route leads to a nutrient becoming a dietary requirement. A nutrient may also be a compound used for pharmacological purposes at a dose larger than found in any known natural diet. Although individual nutrients consumed in a natural diet by a healthy young adult are not usually consumed in concentrations that cause harm, the same nutrient administered via a different route or at elevated concentrations to a patient with less than optimal organ function may be harmful to the patient. In addition, administration of "specific nutrients" may significantly increase the cost of medical care and may interact with one of the medications received by the patient. A very real limitation in patient care is our ability to assess any altered nutrient requirement in an individual patient with one or many organ impairments. Ifwe can detect altered metabolism in a patient, another limitation in patient care is the selection of the dose and route of administration of the specific nutrient.
References I. Gosker HR. Wouters E F M, van der Vusse G 1, Schols A M W 1. Skeletal muscle dysfunction in chronic obstructive pulmonary disease and chronic heart failure: underlying mechanisms and therapy perspectives. Am 1 Clin Nutr 2000; 71(5): 1033-1047 2. Vermeeren MAP, Wouters E F, Nelissen L H, van Lier A, Hofman Z, Schols A M. Acute effects of different nutritional supplements on symptoms and functional capacity in patients with chronic obstructivepulmonary disease. Am 1 Clin Nutr 2001; 73(2): 295-301 3. Ferreira I M, Brooks D. Lacasse Y. Goldstein R S. Nutritional intervention in COPD - A systematic overview. Chest 2002; 119(2): 353-363. 4. McGarry 1 D. Dysregulation of fatty acid metabolism in the etiology of type 2 diabetes. Diabetes 2002; 51(1): 7-18. Ref ID: 41417 5. Engelen M P K 1, Wouters E F M, Deutz N E P, Menheere P P C A. Schols A M W 1. Factors contributing to alterations in skeletal muscle and plasma amino acid profiles in patients with chronic obstructive pulmonary disease. Am 1 Clin Nutr 2000; 72(6): 1480-1487 6. Engelen M P K 1, Schols A M W J. Does 1 D. Deutz N E P. Wouters E F M. Altered glutamate metabolism is associated with reduced muscle glutathione levels in patients with emphysema American 10urnal of Respiratory and Critical Care Medicine 2000: 103(1): 98-103 7. Longnus S L, Wambolt R B, Barr R L. Lopaschuk G D, Allard M F. Regulation of myocardial fatty acid oxidation by substrate supply. American 10urnal of Physiology-Heart and Circulatory Physiology 2001; 281(4): HI561-HI567. 8. Eaton S. Bartlett K. Quant P A. Carnitine palmitoyl transferase I and the control of beta-oxidation in heart mitochondria. Biochem Biophys Res Commun 2001; 285(2): 537-539
Conditionally essential nutrients
Oxidative stress is associated with dysfunction of organs such as heart and skeletal muscle. Muscles of patients with (COPD) have lower concentrations of glutamate and lower concentrations of glutathione. It has been suggest that increased glycolysis may decrease the glutamate concentrations which are needed for the synthesis of glutathione (6). During non-stressful conditions and when substrates are present at physiological concentrations, myocardial substrate supply is proposed as the primary mechanism responsible for alterations in fatty acid oxidation rates. However these patients experience metabolic stress which may lead to additional involvement of intracellular regulatory pathways (7). Although not rate-limiting in vitro, carnitine palmitoy I transferase is probably rate-limiting in vivo because
118