Journal of Parenteral and Enteral Nutrition http://pen.sagepub.com/ Micronutrient Supplementation in Adult Nutrition Therapy: Practical Considerations Krishnan Sriram and Vassyl A. Lonchyna JPEN J Parenter Enteral Nutr 2009 33: 548 originally published online 19 May 2009 DOI: 10.1177/0148607108328470 The online version of this article can be found at: http://pen.sagepub.com/content/33/5/548 Published by: http://www.sagepublications.com On behalf of: The American Society for Parenteral & Enteral Nutrition Additional services and information for Journal of Parenteral and Enteral Nutrition can be found at: Email Alerts: http://pen.sagepub.com/cgi/alerts Subscriptions: http://pen.sagepub.com/subscriptions Reprints: http://www.sagepub.com/journalsReprints.nav Permissions: http://www.sagepub.com/journalsPermissions.nav >> Version of Record - Aug 27, 2009 OnlineFirst Version of Record - May 19, 2009 What is This? Downloaded from pen.sagepub.com by Karrie Derenski on April 1, 2013 Review Journal of Parenteral and Enteral Nutrition Volume 33 Number 5 September/October 2009 548-562 Micronutrient Supplementation in © 2009 American Society for Parenteral and Enteral Nutrition 10.1177/0148607108328470 Adult Nutrition Therapy: http://jpen.sagepub.com hosted at Practical Considerations http://online.sagepub.com Krishnan Sriram, MD, FRCS(C) FACS1; and Vassyl A. Lonchyna, MD, FACS2 Financial disclosure: none declared. Preexisting micronutrient (vitamins and trace elements) defi- for selenium (Se) and zinc (Zn). In practice, a multivitamin ciencies are often present in hospitalized patients. Deficiencies preparation and a multiple trace element admixture (containing occur due to inadequate or inappropriate administration, Zn, Se, copper, chromium, and manganese) are added to par- increased or altered requirements, and increased losses, affect- enteral nutrition formulations. Most enteral nutrition prepara- ing various biochemical processes and resulting in organ dys- tions also contain adequate amounts of vitamins and trace function, poor wound healing, and altered immune status with elements, although bioavailability may be an issue. Detailed deleterious sequelae. Guidelines for the 13 essential vitamins information about individual micronutrient use specifically in and 10 essential trace elements have been established. These hospitalized adult patients receiving nutrition therapy will be recommendations, however, are applicable to healthy adults and discussed, emphasizing the practical and clinical aspects. not to critically ill patients, in whom decreased serum levels Clinicians are encouraged to think of micronutrients not as may indicate actual deficiencies or a deficiency due to redistri- nutritional supplements alone but also as therapeutic agents bution. Benefits of supplementation over and above the daily and nutraceuticals. (JPEN J Parenter Enteral Nutr. 2009;33: requirements, which may not result in increased serum levels, 548-562) are also unclear and may, in fact, be detrimental. Vitamin requirements are increased in disease states, but a similar rec- ommendation for trace elements has not been initiated except Keywords: micronutrients; trace elements; vitamins he purpose of this review is to highlight practical Preexisting micronutrient deficiencies, especially zinc considerations in the use of micronutrient supple- (Zn), iron (Fe), selenium (Se), and vitamins A, B, and C, T mentation as part of short-term nutrition therapy are often present in critically ill patients.1 In addition, defi- in adults. The term micronutrient includes vitamins and ciencies may occur due to the inadequate or inappropriate trace elements. Vitamins are organic substances not syn- administration of micronutrients during nutrition therapy thesized by the body and necessary for normal metabo- or because of increased requirements or increased bodily lism. They are divided into water soluble or fat soluble losses.2,3 These deficiencies can be expected to deleteri- and those with or without coenzyme function. Trace ele- ously affect various biochemical processes and enzyme ments are metals present in very minute quantities in the functions, leading to organ dysfunction, muscle weakness, body; they are essential for normal metabolic functions poor wound healing, and altered immune status. and are cofactors of enzymes or form an integral part of The U.S. Food and Nutrition Board first prepared the the structure of specific enzymes. daily nutrient requirements more than a half century ago and established the Recommended Dietary Allowance (RDA). The RDA has since been modified numerous times and now includes the 13 essential vitamins (4 fat From the 1Division of Surgical Critical Care, Department of soluble and 9 water soluble)4 and the following trace ele- Surgery, John H. Stroger Jr. Hospital of Cook County, and ments: copper (Cu), chromium (Cr), cobalt (Co), Fe, flu- 2Department of General Surgery, Rush University Medical Center, Chicago, Illinois. oride (Fl), iodine (I), molybdenum (Mo), manganese (Mn), Se, and Zn.5 These recommendations, supported by Received for publication February 25, 2008; accepted for pub- lication July 9, 2008. publications from several organizations, are typically applicable to the general healthy population. Address correspondence to: Krishnan Sriram, MD, FRCS(C), FACS, Stroger Hospital of Cook County, Surgical Critical Over the past decade, the Institute of Medicine has Care/Dept of Surgery, Chicago, IL 60612; e-mail: ksri- developed a new set of dietary requirements known as [email protected]. the Dietary Reference Intake (DRI).6 Table 1, based on Downloaded from pen.sagepub.com548 by Karrie Derenski on April 1, 2013 Micronutrients in Adults / Sriram, Lonchyna 549 Table 1. Dietary Reference Intakes6 EAR RDA AI UL Fat-soluble vitamins A 300-625 μg RAE 700-900 μg RAE 3000 μg RAE D 5-10 μg 50 μg E 12 mg 15 mg 1000 mg K 90-120 μg Water-soluble vitamins C (ascorbic acid) 60-75 mg 75-90 mg 2000 mg B (folate) 320 μga 400 μg 1000 μg Niacin 11-12 mgb 14-16 mg 35 mg B2 (riboflavin) 0.9-1.1 mg 1.1-1.3 mg B1 (thiamine) 0.9-1.0 mg 1.1-1.2 mg B6 (pyridoxine) 1.1-1.4 mg 1.3-1.7 mg 100 mg μ μ B12 (cobalamin) 2.0 g 2.4 g Pantothenic acid 5 mg Biotin 30 μg Trace elements Zinc 6.8-9.4 mg 8-11 mg 40 mg Selenium 45 μg 55 μg 400 μg Copper 700 μg 900 μg 10 000 μg Chromium 20-35 μg Manganese 1.8-2.3 mg Cells are left blank where no data are available. EAR, Estimated Average Requirement (the nutrient needs of 50% of the population [age and gender specific]); RDA, Recommended Dietary Allowance (the nutrient needs of 98% of the population; RDA = EAR + 2 standard deviations); AI, Adequate Intake (the recommended daily nutrient intake); UL, tolerable Upper Limit (the highest average daily nutrient intake level above which side effects occur); RAE, retinol activity equivalent (1 μg RAE = 1 μg retinol, 12 μg β-carotene, or 24 μg α-carotene). 1 IU of vitamin A = 0. 344 μg. aAs dietary folate equivalent (DFE). 1 DFE = 1 μg food folate = 0.6 μg of folic acid. bAs niacin equivalent (NE). 1 g of niacin + 60 mg of tryptophan. information obtained from this 2006 publication, provides mandated by the USFDA. The American Society for the DRI for the micronutrients discussed in this review. Parenteral and Enteral Nutrition (A.S.P.E.N.) has estab- DRIs are further categorized as Estimated Average lished guidelines for the administration of parenteral Requirement (EAR), RDA, Adequate Intake (AI), and tol- trace element additives.11 Tables 2 and 3 summarize erable Upper Limit (UL) and are explained in the caption the current recommendations for administration of vita- to Table 1. These figures serve to provide us with reference mins and trace elements to patients requiring nutrition ranges but are applicable only to enteral intake and to sta- support. ble patients. In practice, a multivitamin preparation (including vita- Micronutrient requirements in critically ill patients min K) and a multiple trace element admixture (containing are unknown.7 Decreased serum levels may not indicate Zn, Se, Cu, Cr, and Mn) are added to parenteral nutrition actual deficiencies but just redistribution. The decrease (PN) formulations. Most standard commercially available in serum levels may actually be a beneficial and adaptive enteral nutrition (EN) preparations already contain the RDA response,8 as some vitamins at high doses function as of vitamins. Table 4 lists the recommendations for vitamins pro-oxidants. Benefits of supplementation, which may and trace elements of interest in critical care practice.12 not result in increased serum levels, are also unclear.9 However, the composition of commercially available However, the United States Food and Drug Admini- trace element preparations in the United States is far from stration (FDA), as early as 1984, recognizing that par- ideal, especially for long-term use, as shown in a recent study enteral vitamins are a requirement for the maintenance of on autopsy specimens obtained from patients with short the body’s reparative and defensive processes, wrote into bowel on long-term PN.13 Tissue levels of Cu, Mn, and Cr law the content and dosage of a parenteral multivitamin were elevated, suggesting that better trace element admix- supplement. In 2000, the doses of vitamins B1, B6, C, and tures, available in several other countries, should be approved folic acid were increased, and vitamin K was added to the and made available in the United States. This study also formulations (for a total of 13 vitamins).10 However, a recommended that the daily