Immune-enhancing Diets Research Articles

Invited commentary: New roles for immune-enhancing diets

Surgery 2002; 132:815-6.

Omega-3 fatty acids in immune-enhancing enteral diets selectively increase blood flow to the ileum by a bile acid dependent mechanism

Background. The immune-enhancing diet (IED) (Impact, Novartis Corp, Minneapolis, Minn) initiates a delayed and sustained increase in blood flow to the ileum and gut-associated lymphoid tissue. The immune-enhancing benefits of Impact (Novartis Corp) are attributed to the addition of L-arginine, fish oil (FO), and RNA fragments to a standard enteral diet. The sustained increase in blood flow to the gut-associated lymphoid tissue during IED exposure might account for these immune effects. We hypothesized that the increase in ileal blood flow with IED might be a result of ileal ω-3 fatty acid absorption in the ileum by a bile-dependent mechanism. Methods. Male Sprague-Dawley rats (200 g-230 g) were anesthetized and cannulated for microsphere measurement of whole organ blood flow. Rats received gastric gavage (2 mL) with either IED, an isocaloric, isonitrogenous control diet (CD) (Boost, Mead-Johnson, Evansville, Ind), CD plus menhaden FO (CD+FO), or CD+FO plus bile duct ligation (BDL). Blood flow was determined at baseline and 30, 60, and 120 minutes after short-term gavage. Results. Baseline blood flow and central hemodynamics were comparable in all groups. In the ileum, at 120 minutes postgavage, blood flow was increased by IED and CD+FO compared with baseline and CD. BDL prevented the increase in blood flow in the CD+FO+BDL rats. All groups exhibited differences in splanchnic blood flow distribution after gavage: CD and CD+FO+BDL increased blood flow compared with baseline early in the proximal gut and spleen. IED and CD+FO produced a delayed, sustained hyperemia to the distal gut. Conclusions. Gastrointestinal blood flow distribution after feeding is dependent on nutrient composition. These findings suggest that ω-3 fatty acids are the components of the enteral IED, Impact (Novartis Corp), which produce the increased blood flow to the terminal ileum and its contiguous gut-associated lymphoid tissue. Our data suggests that an intact enterohepatic bile pathway is needed for the IED blood flow effect. (Surgery 2002;132:673-81.)

Immunonutrition in Critical Illness

Immunonutrition is an emerging therapy that has been the focus of a number of clinical trials. Manipulation of the immune system has the substantial potential to modify disease outcome, particularly in regard to infectious complications. Many studies have examined the effects of nutritional formulas supplemented with arginine, n-3 fatty acids, structured lipids, and nucleotides compared with standard enteral feeding. Unfortunately, because of marked heterogeneity between studies, only limited consensus has been reached. Some randomized studies have shown that immune-enhanced nutritional formulas can reduce postoperative infectious complications in surgical patients with gastrointestinal or head and neck cancer and may be effective when provided preoperatively as well. A few studies show no benefit, but none demonstrated higher infection rates in this population, which is reinforced by the finding from three separate meta-analyses of overall benefit. 1‐3 Therefore, for surgical patients with gastrointestinal/head and neck cancer, the evidence is reasonably strong in favor of the use of immunonutrition, particularly in malnourished patients. In trauma and critically ill patients, the data are less clear, and no overall recommendation in favor of immunonutrition was made recently by Dr Heyland 4 in a review of the evidence (this issue of NCP). There are three large published studies in intensive care unit (ICU) patients, all using the same immune-enhancing diet, which differ in many ways, with only one showing a significant improvement in morbidity and mortality overall. 5‐7 There was a clear trend toward increased mortality with the immune-enhancing diet in the earliest study. 5 Dr

Immunonutrition in patients after multiple trauma.

Severe trauma threatens the life of the victim, both directly and indirectly via immunological dysregulation during the subsequent clinical course. Inflammatory or infectious episodes may complicate the clinical course and ultimately result in sepsis and multiple organ failure, which have mortality rates of up to 80%. Immunomodulatory intervention aims to ameliorate the early hyperinflammatory phase (systemic inflammatory response syndrome, SIRS) to avoid the development of sepsis. One of the immunomodulation strategies is enteral feeding supplemented with specific nutrients, such as glutamine, n-3-polyunsaturated fatty acids, and nucleotides ('immunonutrition'), because changes in the GALT (gut-associated lymphoid tissue) immune response may contribute to intestinal dysfunction and increase susceptibility to post injury gut-derived sepsis. In a prospective, randomized, double-blind, controlled study in twenty-nine patients suffering severe trauma we were able to show that immunonutrition (arginine, n-3-fatty acids, and nucleotides) significantly reduces the number of SIRS days per patient, and also lowers the multiple organ failure (MOF) score on day 3 and days 8-11 (P<0.05). Other studies have reported a reduction in septic complications and MOF rates, shortened hospital stay, and reduction in the use of antibiotics in patients randomized to the immune-enhancing diet. This improved clinical outcome was reflected in a reduction in hospital costs. In the recovery period after trauma (1-72 h after injury) a limitation of the inflammatory response of immunocompetent cells must be achieved as quickly as possible (<72 h). The only strategy available to clinicians caring for trauma patients is immunonutrition, and this should be strongly considered as a rational approach improving immune function and reducing septic complications in critically ill or injured patients.

Immune-modulatory actions of arginine in the critically ill.

Current trials of immune-enhancing diets suggest several beneficial clinical effects. These products are associated with a reduction in infectious risk, ventilator days, ICU and hospital stay. However, methodological weaknesses limit the inferences we can make from these studies. Furthermore, improvements in outcomes were largely seen in surgical patients and in patients who tolerated critical amounts of formula. We propose that the beneficial findings cannot easily be extrapolated to other patient populations since there is suggestion from clinical trials that the sickest patients, especially those with severest appearances of sepsis, shock and organ failure may not benefit or may even be harmed. In these conditions we hypothesize that systemic inflammation might be undesirably intensified by immune-enhancing nutrients like arginine in critically ill patients. In this paper, we review the purported effects of arginine on the immune system and organ function to understand the scientific rationale for its inclusion into enteral feeding products. We conclude that patients with the most severe appearances of the systemic inflammatory response syndrome should not receive immune-enhancing substrates which may aggravate systemic inflammation and worsen clinical outcomes.

Parenteral nutrition with n-3 lipids in sepsis.

Dietary supplements of n-3 fatty acids have long been used to influence chronic inflammatory disorders. Recent studies with an immune-enhancing diet partly based on n-3 fatty acids report beneficial effects in patients with acute hyper-inflammatory diseases, such as the sepsis syndrome or adult respiratory distress syndrome (ARDS). The possible suppression of exaggerated leucocyte activity, the improvement of microcirculatory events, as well as the opportunity to administer intravenous lipids enriched in n-3 fatty acids signal the possibility of a combination of parenteral caloric support and pharmacological intervention. Using parenteral administration of fish oil-based lipids, a new rapid and highly effective anti-inflammatory agent may allow the option to alter the immune status in hyper-inflammatory diseases such as sepsis and ARDS.

Should immunonutrition become routine in critically ill patients? A systematic review of the evidence.

Several nutrients have been shown to influence immunologic and inflammatory responses in humans. Whether these effects translate into an improvement in clinical outcomes in critically ill patients remains unclear. To examine the relationship between enteral nutrition supplemented with immune-enhancing nutrients and infectious complications and mortality rates in critically ill patients. The databases of MEDLINE, EMBASE, Biosis, and CINAHL were searched for articles published from 1990 to 2000. Additional data sources included the Cochrane Controlled Trials Register from 1990 to 2000, personal files, abstract proceedings, and relevant reference lists of articles identified by database review. A total of 326 titles, abstracts, and articles were reviewed. Primary studies were included if they were randomized trials of critically ill or surgical patients that evaluated the effect of enteral nutrition supplemented with some combination of arginine, glutamine, nucleotides, and omega-3 fatty acids on infectious complication and mortality rates compared with standard enteral nutrition, and included clinically important outcomes, such as mortality. Methodological quality of individual studies was scored and necessary data were abstracted in duplicate and independently. Twenty-two randomized trials with a total of 2419 patients compared the use of immunonutrition with standard enteral nutrition in surgical and critically ill patients. With respect to mortality, immunonutrition was associated with a pooled risk ratio (RR) of 1.10 (95% confidence interval [CI], 0.93-1.31). Immunonutrition was associated with lower infectious complications (RR, 0.66; 95% CI, 0.54-0.80). Since there was significant heterogeneity across studies, we examined several a priori subgroup analyses. We found that studies using commercial formulas with high arginine content were associated with a significant reduction in infectious complications and a trend toward a lower mortality rate compared with other immune-enhancing diets. Studies of surgical patients were associated with a significant reduction in infectious complication rates compared with studies of critically ill patients. In studies of critically ill patients, studies with a high-quality score were associated with increased mortality and a significant reduction in infectious complication rates compared with studies with a low-quality score. Immunonutrition may decrease infectious complication rates but it is not associated with an overall mortality advantage. However, the treatment effect varies depending on the intervention, the patient population, and the methodological quality of the study.

Immune-enhancing diets: products, components, and their rationales.

Immune-enhancing diets: products, components, and their rationales.

The effects of immune-enhancing diets (IEDs) on mortality, hospital length of stay, duration of mechanical ventilation, and other parameters.

The effects of immune-enhancing diets (IEDs) on mortality, hospital length of stay, duration of mechanical ventilation, and other parameters.

The use of immune enhancing diet in head injury.

Journal of Parenteral and Enteral NutritionVolume 25, Issue 2S p. S27-S29 The Use of Immune Enhancing Diet in Head Injury Robert G. Martindale MD, PhD, Robert G. Martindale MD, PhD Department of Surgery, Medical College of Georgia, Augusta, Georgia, [email protected]Search for more papers by this authorGail A. Cresci MS, RD, CNSD, Gail A. Cresci MS, RD, CNSD Department of Surgery, Medical College of Georgia, Augusta, GeorgiaSearch for more papers by this author Robert G. Martindale MD, PhD, Robert G. Martindale MD, PhD Department of Surgery, Medical College of Georgia, Augusta, Georgia, [email protected]Search for more papers by this authorGail A. Cresci MS, RD, CNSD, Gail A. Cresci MS, RD, CNSD Department of Surgery, Medical College of Georgia, Augusta, GeorgiaSearch for more papers by this author First published: 01 March 2001 https://doi.org/10.1177/014860710102500207Citations: 8AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume25, Issue2SMarch 2001Pages S27-S29 RelatedInformation

Use of immune-enhancing diets in burns.

Use of immune-enhancing diets in burns.

Immune function and organ failure. Immunomodulation with nutritional support--an update

Today, substrates with immunomodulatory effects are not only identified in all groups of macronutrients, but also in the domains of vitamins and traceelements. Mainly they interfere with 3 areas of the immune response: 1. the mucosal barrier function, 2. the cellular defense function, and 3. the local or systemic inflammatory response. Enteral formulas enriched with immune-enhancing diets are already in clinical use to encounter "immunoparalysis" of cellular defense during critical illness. Considering defined outcome variables, indeed, current clinical studies point out some improvements. Using an evidence based approach, a grade A recommendation was proclaimed for its broad clinical use. For defined subgroups of patients, however, presenting with most severe appearances of SIRS and consecutive organ failure, the current concept of enteral immunonutrition remains to be a matter of debate, and the evidence of clinical benefits persist to be questionable.

Immune-enhancing Diets

Immune-enhancing Diets

Translocação bacteriana: efeito de dieta imunoestimuladora em ratos com oclusão intestinal

Este estudo tem por objetivo avaliar a ocorrência de translocação bacteriana em ratos submetidos a oclusão intestinal e verificar a capacidade de uma dieta imunoestimuladora em reduzir a incidência de translocação bacteriana nestes animais. Foram utilizados 24 ratos da linhagem Wistar, adultos, machos, pesando entre 180 e 240g, que foram divididos em três grupos, contendo oito animais cada. Ao grupo C (Controle) foi oferecida uma ração padrão para ratos, ao grupo I (Imunomodulação), uma dieta imunoestimuladora, e ao grupo D (Desnutrição) foi oferecida uma dieta padrão com a metade da oferta. Após sete dias, todos os animais foram submetidos a oc1usão intestinal por ligadura do íleo terminal. Após 18 horas da operação, com técnica asséptica, o abdome foi aberto e foram retirados 6ml de sangue da veia cava inferior, para determinação da glicemia, albumina e contagem de leucócitos. O baço, fígado e linfonodo mesentérico foram removidos separadamente, para estudo rnicrobiológico, e segmento do jejuno proximal, para estudo histológico. A ingesta calórica foi semelhante nos grupos C e I e a metade no grupo D. A média de glicemia foi inferior no grupo D. As culturas do linfonodo mesentérico, baço e fígado foram positivas em todos os animais do grupo D, em 58,3% dos ratos do grupo I e em 66,6% dos ratos do grupo C. As alterações histológicas foram mínimas quando comparados os três grupos. Conclui-se que a translocação bacteriana ocorre em ratos submetidos a oclusão intestinal e que o suporte nutricional com dieta imunoestimuladora é capaz de reduzir a incidência de translocação bacteriana em ratos com oclusão intestinal.

A Randomized Trial of Isonitrogenous Enteral Diets After Severe Trauma

The authors randomized patients to an enteral diet containing glutamine, arginine, omega-3 fatty acids, and nucleotides or to an isonitrogenous, isocaloric diet to investigate the effect of septic outcome. A third group of patients, without enteral access but eligible by severity of injury, served as unfed controls and were studied prospectively to determine the risk of infection. Laboratory and clinical studies suggest that diets containing specialty nutrients, such as arginine, glutamine, nucleotides, and omega-3 fatty acids, reduce septic complications. Unfortunately, most clinical trials have not compared these diets versus isonitrogenous, isocaloric controls. This prospective, blinded study randomized 35 severely injured patients with an Abdominal Trauma Index > or = 25 or a Injury Severity Score > or = 21 who had early enteral access to an immune-enhancing diet ([IED] Immun-Aid, McGaw, Inc., Irvine, CA; n = 17) or an isonitrogenous, isocaloric diet (Promote [Ross Laboratories, Columbus, OH] and Casec [Mead-Johnson Nutritionals, Evansville, IN]; n = 18) diet. Patients without early enteral access but eligible by severity of injury served as contemporaneous controls (n = 19). Patients were evaluated for septic complications, antibiotic usage, hospital and intensive care unit (ICU) stay, and hospital costs. Two patients died in the treatment group and were dropped from the study. Significantly fewer major infectious complications (6%) developed in patients randomized to the IED than patients in the isonitrogenous group (41%, p = 0.02) or the control group (58%, p = 0.002). Hospital stay, therapeutic antibiotics, and the development of intra-abdominal abscess was significantly lower in patients receiving the IED than the other two groups. This improved clinical outcome was reflected in reduced hospital costs. An IED significantly reduces major infectious complications in severely injured patients compared with those receiving isonitrogenous diet or no early enteral nutrition. An IED is the preferred diet for early enteral feeding after severe blunt and penetrating trauma in patients at risk of subsequent septic complications. Unfed patients have the highest complication rate.