September 2009 Issue

Pediatric Specialty Formulas in Enteral Nutrition
By Marissa R. Beck
Today’s Dietitian
Vol. 11 No. 9 P. 16

Whether a clinical, community, or private practice dietitian, you can benefit from understanding the use of specialty formulas in enteral nutrition (EN). When children cannot consume enough food over an extended period of time, many will become candidates for tube feeding. Some of these children will require an individualized combination of certain formulas. According to the 2009 American Society for Parenteral and Enteral Nutrition clinical guidelines, the use of specific nutrients reportedly has significant therapeutic applications for children who need enteral support. When standard fixed ratios do not meet nutrition needs, specialty formulas are the next best option for today’s pediatric population.

Indications for Specialty Formulas
Children with developmental disabilities, inborn errors of metabolism, or chronic health problems, such as pulmonary disease, have more frequent feeding problems. Acute respiratory distress syndrome (ARDS) is a common pediatric fulminant lung condition where there is increased inflammation, accumulation of fluid in the alveolar air sacs, low blood oxygen, and respiratory distress. Due to the increased inflammation of the lung parenchyma, there is greater need for anti-inflammatory components in an enteral feed. Special formulas are also indicated for improving wound healing. Certain inherited metabolic diseases require nutrition support when there is an inborn error in the metabolism of amino acids, beta-oxidation, organic acids, and galactose.

Specific Nutrients and Their Roles
Some ingredients in specialty formulas include glutamine, arginine, and omega-3 and omega-6 fatty acids.

Glutamine is the body’s most abundant amino acid, considered “conditionally essential” because it can be manufactured in the body, but not in adequate amounts during extreme physical stress. Most glutamine is stored in muscles, followed by the lungs, and has the capacity to cross the blood-brain barrier.

Arginine is another conditionally essential amino acid because the body usually cannot produce enough of it during stressful times. Arginine’s major role is in cell production and body tissue healing.

Essential fatty acids (EFAs) are important for normal brain function, bone health, stimulation of skin and hair growth, regulation of metabolism, and maintenance of reproductive processes. Both omega-3 and omega-6 fatty acids are currently used in specialty formulas. EPA and DHA are omega-3s, and gamma-linolenic acid (GLA) is an omega-6 found primarily in plant-based oils. Linoleic acid is converted to GLA in the body, but GLA is the form found in many specialty formulas.

Research Review
With their share of benefits, specialty formulas appear to be quite, well, special. Researchers began studying the benefits of supplementing with glutamine, arginine, and omega-3 fatty acids in an enteral feed more than a decade ago. Studies to date continue to yield encouraging results.

Recently, scientists examined the effect of glutamine to promote tissue integrity and enhance the immune system for a 2008 issue of Pediatrics. Glutamine-enriched EN in very–low-birth-weight infants has shown that glutamine may decrease allergic diseases later in life. Another clinical study observed the effects of an enteral supplement with glutamine on protein metabolism in patients who were severely burned and indicated that the supplementation could abate the degree of glutamine depletion, promote protein synthesis, improve wound healing, and reduce hospital stay.1

Although more research must be conducted regarding arginine and sepsis, there are many well-designed studies examining arginine’s wound-healing abilities. Researchers performed a double-blind, randomized, placebo-controlled trial of enteral arginine supplementation in children who were burned. All children (aged 1 to 5) were admitted within 48 hours of a moderate-to-deep burn injury covering 10% to 40% of their body. The benefits of arginine for the immune system did not appear to be related to a metabolic response; however, an arginine-supplemented feed improved lymphocyte production in these children, demonstrating the usefulness of arginine supplementation.2 

EFAs from fish oils and borage oils have shown that EN with EPA (from sardine oil) and GLA (from borage oil) may reduce pulmonary inflammation and improve oxygenation and clinical outcomes in patients with ARDS.3 Omega-3 fatty acid-supplemented formulas have been studied in ARDS, and research has demonstrated that these formulas can reduce the inflammatory response. One large, randomized, controlled trial in patients with ARDS showed that compared with conventional formulas, specialty formulas are correlated with a decrease in the number of days on mechanical ventilation, a decrease in organ failure, and a decrease in length of stay in intensive care.4 Observations thus far suggest that specialty formulas containing omega-3 fatty acids may hold promise for patients with ARDS.

There have, however, been other clinical trials in which specialty formula supplementation has not yielded hopeful findings. Researchers studied the effects of specialty formulas in acute pancreatitis and found no evidence that EN supplemented with glutamine, arginine, and omega-3 fatty acids had any beneficial effect on infectious complications, mortality, or length of hospital stay compared with standard EN.5

The Bottom Line
Children with chronic conditions or trauma are likely to benefit from the use of specialty enteral formulas supplemented with glutamine, arginine, and omega-3 fatty acids. Some studies are promising, such as those examining the use of these special formulas for children with ARDS, but not all conditions benefit from the extra supplementation.
Before initiating specialty enteral formulas, dietitians should show mature clinical judgment, know the indications and contraindications for each disease, and assess whether their patient could benefit from the use of a specialty formula. 

— Marissa R. Beck is in the dietetic internship program at Teachers College, Columbia University and is eligible to take the registration exam.

References
1. Peng X, Yan H, You Z, Wang P, Wang S. Clinical and protein metabolic efficacy of glutamine granules-supplemented enteral nutrition in severely burned patients. Burns. 2005;31(3):342-346.

2. Marin VB, Rodriguez-Osiac L, Schlessinger L, Villegas J, Lopez M, Castillo-Duran C. Controlled study of enteral arginine supplementation in burned children: impact on immunologic and metabolic status. Nutrition. 2006;22(7-8):705-712.

3. Singer P, Shapiro H. Enteral omega-3 in acute respiratory distress syndrome. Curr Opin Clin Nutr Metab Care. 2009;12(2):123-128.

4. Gadek JE, DeMichele SJ, Karlstad MD, et al. Effect of enteral feeding with eicosapentaenoic acid, gamma-linolenic acid, and antioxidants in patients with acute respiratory distress syndrome. Enteral Nutrition in ARDS Study Group. Crit Care Med. 1999;27(8):1409-1420.

5. Petrov MS, Atduev VA, Zagainov VE. Advanced enteral therapy in acute pancreatitis: is there a room for immunonutrition? A meta-analysis. Int J Surg. 2008;6(2):119-124.