Immunonutrition--supplementary amino acids and fatty acids ameliorate immune deficiency in critically ill patients.

BACKGROUND: Immunonutrition with omega-3 fatty acids and the "conditionally essential" amino acids arginine, glutamine, cysteine, and taurine can enhance the immune response in critically ill patients. This is due to the immunomodulating properties of these nutrients. Immunonutrition is especially important when a patient's immune response is compromised, as is the case post-operatively or after trauma. Immune deficiency is severely aggravated in sepsis and the systemic inflammatory response syndrome (SIRS). The resulting metabolic stress is characterized by glycolysis, lipolysis, and proteolysis, which may escalate to an hypercatabolic response or "autocannabilism." Catabolic metabolism results in insufficiency of both specific and unspecific immunocompetent cells. CONCLUSIONS: Immunonutrition should be started early in such patients for an optimal beneficial effect, preferably via the enteral route. It should include medium chain and long chain triglycerides, polyunsaturated omega-3 and omega-6 fatty acids (in the ratio 1:2), olive oil, and conventional amino acid preparations supplemented with the conditionally essential amino acids arginine, glutamine, cysteine, and taurine.

Dietary supplementation and immunocompetence in housebound elderly subjects.

Immune function, particularly cell-mediated immunity (CMI), declines with age and it has been suggested that this may be secondary to the impaired nutritional status often found in the elderly. In the present study a balanced nutritional supplement consisting of several macro- and micro-nutrients was administered daily to 27 housebound elderly (aged 70-85 years) for 12 weeks. Thirty-one matched subjects served as a control group. Delayed cutaneous hypersensitivity (DCH) to seven recall antigens was measured using the Mérieux Multitest CMI device and total numbers of lymphocytes, B-cells, T-cells and T-cell sub-populations were determined using monoclonal antibodies. These tests and several indices of nutritional status were measured before and at the end of the 12-week study. Before supplementation 19% of the entire group of subjects were anergic and another 19% hypoergic, values greater than expected for healthy elderly subjects. A weak association (P = 0.056) was shown between plasma zinc concentration and the number of positive skin test responses. Supplementation had minimal effect on DCH, resulting in a significant (P < 0.05) increase only in the sum of positive indurations. Pre-study numbers of total lymphocytes and lymphocyte sub-populations were as expected for healthy elderly subjects, but a correlation was found between plasma selenium concentrations (mean 1.07, range 0.64-1.66 mumol/l) and the numbers of CD4 lymphocytes (P < 0.01). Supplementation did not result in a significant change in any of the lymphocyte populations.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of nutrition in the management of malnutrition and immune dysfunction of trauma.

Current nutrition support improves patient outcome in trauma patients. It appears to do so by limiting the adverse effects of specific nutrient or generalized nutrient deficiencies. Immunosuppression, however, continues as a significant clinical problem. This immunosuppression appears to be part of the inflammatory response that accompanies trauma, and in part, to represent the need for conditional nutrients in this setting. Three nutrients that are being evaluated include arginine, uracil as ribonucleic acid and omega-3 polyunsaturated fatty acids. Animal studies report improved immune function. Early clinical trials are reporting improved immune function and patient outcomes.

Reversibility of age associated NK defect by endocrinological and/or nutritional intervention.

Several abnormalities arise at the level of NK cell function in both rodents and humans with increasing age. The age-related changes are not irreversible alterations since they can be reversed either by endocrinological or nutritional approaches, suggesting that age-related microenvironmental changes may play a relevant role in the age-related immune deterioration. Whether endocrine and nutritional factors have an additive effect or act through the same intracellular mechanisms remains to be established, though the first possibility seems more likely since the action of TSH and thyroid hormones is specifically directed towards lymphokine-boosted NK activity, while AL are able to prevent age-associated defect of basal NK cytotoxicity.