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TOP NUTRITION NEWSLETTER Volume 5 No 9:September 2002

Editorial

This is the ninth issue of TOP NUTRITION NEWSLETTER in 2002. In this issue the following topics are updated for your interest.

The effect of glutamine-supplemented total parenteral nutrition on nitrogen economy depends on severity of diseases in surgical patients
Dietary fats and 16-year coronary heart disease mortality in a cohort of men and women in Great Britain
Enteral nutrition in surgical patients.
Intradialytic parenteral nutrition improves protein and energy homeostasis in chronic hemodialysis patients.

Any comments or suggestions to include the interesting topics are welcomed for future issues.

Dr Shwe Win
Editor

The effect of glutamine-supplemented total parenteral nutrition on nitrogen economy depends on severity of diseases in surgical patients

Reference: Clin Nutr 2002:21(3):213-218.

Background: Gln is an important substrate for enterocyte and rapid proliferation cells. Studies have
shown that parenteral supplementation of Gln maintains the intracellular Gln pool, improves
nitrogen balance and shortens hospital stay. However, some studies showed Gln-supplemented
TPN had no effect on restoring the Gln pool in critically ill patients.

Objective: To evaluate the effect of glutamine (Gln) dipeptide supplementation of total parenteral nutrition (TPN) on postoperative nitrogen balance and immune response of patients undergoing surgery.

Methods: This study is a prospective, randomized double-blind clinical trial. APACHE II score and TISS were used to evaluate the patients after admission. Forty-eight patients with major abdominal surgery were allocated to two groups to receive isonitrogenous (0.228 g nitrogen/kg/day) and isoenergetic (30 kcal/kg/day) TPN for 6 days. Two groups (Conv and Ala-Gln) were further divided to high (APACHE[ges]6) and low (APACHE <6) groups. Control group (Conv) received 1.5 g amino acids/kg/day, whereas the Ala-Gln group received 0.972 g amino acids/kg/day and 0.417 g of L -alanyl- L -glutamine (Ala-Gln)/kg/day. Blood samples were collected on day 1 and day 6 after surgery for plasma amino acid and CD4, CD8 cell and T lymphocyte analysis. Cumulative nitrogen balance were also measured on day 2, 3, 4, 5 postoperatively. Results: Although there was a tendency to have better cumulative nitrogen balance on the postoperative days in the Ala-Gln group, no significant difference was observed between two groups. However, a better significant cumulative nitrogen balance was observed on the 2nd, 3rd and 5th postoperative day in the Ala-Gln group than in the Conv group in patients with APACHE II <6, whereas no significant difference was noted in patients with APACHE II [ges] 6. No difference in urine 3-methylhistidine excretion were observed between the 2 groups. Patients in the Ala-Gln group had significant higher T lymphocyte and CD4 cells than did those in the Conv group.

Conclusion: TPN supplemented with Gln dipeptide had beneficial effect on enhancing the immune response. However, the effect of Ala-Gln administration on improving nitrogen economy was only observed in patients with low APACHE II scores. These results may indicate that Gln required for reversing the catabolic condition may depend on the characteristics and severity of the diseases.

Dietary fats and 16-year coronary heart disease mortality in a cohort of men and women in Great Britain

Reference: European Journal of Clinical Nutrition, 2002,56(8):786-792

Objective: The paper aims to investigate the relationships of dietary fats to subsequent coronary heart disease (CHD) mortality in men and women while taking account of other CHD-related behaviours.

Design: A cohort of randomly selected men and women were interviewed in 1984–85 and monitored subsequently for 16 y for deaths. The interview covered health, health-related behaviours, physical measurements, socio-demographic details and a dietary
questionnaire. Appropriate exclusions left 1225 men and 1451women aged 40–75 with 98 and 57 CHD deaths, respectively. Saturated, polyunsaturated and total fat intakes were estimated.

Setting: The sample was randomly selected from households in Great Britain. The interviews took place in participants' own homes.

Results: Not consuming alcohol, smoking, not exercising and being socially disadvantaged were related to high saturated fat intake and CHD death. Cox survival analyses adjusting for these factors found that a level of saturated fat 100 g per week higher corresponded to a relative risk for CHD death for men of 1.00 (0.86–1.18) and 1.40 (1.09–1.79) for women. This difference between the effects of saturated fat in men and women was statistically significant (P=0.019). Results are also reported for total fat and the relative effects of polyunsaturated and saturated fats.

Conclusions: Strong evidence was found for the within cohort relationship of dietary fat and CHD death in women while no evidence was found for a relationship in men. Possible explanations for this are discussed.

Enteral nutrition in surgical patients.

Reference: Surg Today 2002;32(8):672-8.

PURPOSE: Malnutrition is well-recognized as a potential cause of increased morbidity and
mortality in surgical patients; however, enteral and parenteral nutritional support given pre- and
postoperatively have been shown to decrease these rates. We conducted a prospective study to assess the short-term efficacy of oral dietary supplementation in malnourished patients undergoing major abdominal surgery.

METHODS: Sixty patients undergoing major abdominal surgery were divided according to nutritional risk index into borderline (BM), moderately (MM), and severely (SM) malnourished categories. The patients in each category were randomly divided into a treatment group (TG) and a control group (CG). TG patients were given an oral sip feed containing 500 kcal of energy and 16.66 g of protein in addition to their daily oral intake. The differences in nutritional intake, in terms of energy and protein, and the changes in nutritional status, as assessed by anthropometric, biochemical, and hematological values, complication rates, and duration of stay were compared.

RESULTS: The supplemented feeds were well tolerated and the total caloric and protein intake in the TG was significantly higher than in the CG, at 1798 vs 1182 kcal ( P < 0.01), protein 55.71 vs 39.48 g ( P < 0.01), respectively. Weight loss in the SM patients was significantly less in the TG than in the CG, at 2.15 vs 4.6 kg ( P < 0.001), respectively. Complications developed in 7 of the 30 TG patients and in 10 of the 30 CG patients, with maximum reduction seen in the SM category (7 in the CG vs 4 in the TG).

CONCLUSIONS: Patients with severe malnutrition are likely to develop large energy
deficits postoperatively, resulting in loss of body mass and a higher incidence of infective
complications. Oral nutritional supplements are well tolerated by these patients, and help to
improve their energy and routine intake and reduce the risk of complications.

Intradialytic parenteral nutrition improves protein and energy homeostasis in chronic hemodialysis patients.

Reference: J Clin Invest 2002;110(4):483-92.

Decreased dietary protein intake and hemodialysis-associated protein catabolism are among
several factors that predispose chronic hemodialysis (CHD) patients to protein calorie
malnutrition. Since attempts to increase protein intake by dietary counseling are usually
ineffective, intradialytic parenteral nutrition (IDPN) has been proposed as a potential therapeutic approach in malnourished CHD patients. In this study, we examined protein and energy homeostasis during hemodialysis in seven CHD patients at two separate hemodialysis sessions, with and without IDPN administration. Patients were studied 2 hours before, during, and 2 hours following a hemodialysis session, using a primed constant infusion of L-(1-(13)C) leucine and L-(ring-(2)H(5)) phenylalanine. Our results showed that IPDN promoted a large increase in whole-body protein synthesis and a significant decrease in whole-body proteolysis, along with a significant increase in forearm muscle protein synthesis. The net result was a change from an essentially catabolic state to a highly positive protein balance, both in whole-body and forearm muscle compartments. We conclude that the provision of calories and amino acids during hemodialysis with IDPN acutely reverses the net negative whole-body and forearm muscle protein balances, demonstrating a need for long-term clinical trials evaluating IDPN in malnourished CHD patients.