Stacey J. Bell

Dietary modification of Chyle composition in chylothorax

Nutrition support has played a major role in the treatment of chylothorax, both to prevent malnutrition and to minimize chyle production and flow. This report evaluates chyle composition in a patient with chylothorax who was placed on a low-fat diet, medium-chain triglyceride diet, and total parenteral nutrition in sequence. Both triglyceride content and volume of chyle declined, but drainage persisted, ultimately requiring thoracic duct ligation. The chyle triglyceride while on total parenteral nutrition, which presumably originates from both the intestine and plasma, contained more long-chain unsaturated fatty acids than the circulating serum triglyceride. Of particular interest was the detection of an appreciable amount of medium-chain fatty acids in the chyle triglyceride, constituting 20% of the triglyceride fatty acids when an enteral formulation with medium-chain triglyceride as a sole fat source was administered. The finding of almost threefold more decanoic acid (C10:0) than octanoic acid (C8:0), despite the presence of considerably more octanoic acid in the original diet, suggests that trioctanoin may be a preferable medium-chain triglyceride substrate for the nonsurgical treatment of chylothorax.

Dietary fish oil and cytokine and eicosanoid production during human immunodeficiency virus infection

BACKGROUND Dietary fish oil (FO) has been shown to modulate the immune system. The purpose of this study was to explore the effects of FO supplementation on the production of dienoic eicosanoids and cytokines in patients with human immunodeficiency virus (HIV) infection. METHODS This was a randomized, prospective, double-blind study that included homosexual males with HIV infection. Patients were asked to consume voluntarily five food bars daily containing FO (n = 10) or safflower oil (SO) (n = 9) for 6 weeks. At baseline and week 6, plasma was obtained to measure incorporation of omega-3 fatty acids. At baseline, week 3, and week 6, measurements were made of changes in dienoic eicosanoids and cytokines from lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells (PBMC) or spontaneously releasing cells. RESULTS In the FO group but not the SO group, there was increased incorporation of the omega-3 fatty acid docosahexaenoic acid (DHA) into the phospholipids of the fatty acids of the plasma. In the FO group, there was a significant decrease (p = .01) in 6-keto prostaglandin (PG) F1 alpha released from PBMC. There was a significant increase (p = .01) in interleukin (IL)-6 released from the PBMC in the FO group between baseline and week 3 and between week 3 and week 6. At week 6, there was significantly more IL-6 (p = .01) released from the PBMC in the FO group compared with the SO group. There was no change in CD4 cell counts by analysis of variance. CONCLUSIONS The FO-containing food bars were well tolerated and allowed incorporation of omega-3 fatty acids to occur. Despite evidence of significant metabolic effects on eicosanoid and cytokine production, widespread clinical use of FO for HIV-infected patients is not warranted without further study, particularly given the trend toward a decline in CD4 cell numbers at this dose and with this type of fish oil.

Glutamine Content of Whole Proteins: Implications for Enteral Formulas

In two recent clinical trials in surgical patients, supplementation of total parenteral nutrition with daily doses of 12 or 20 g of glutamine resulted in a diminished loss of free glutamine in skeletal muscle tissue. Studies in animals exploring the use of both enteral and parenteral glutamine supplementation suggest that glutamine may be an essential nutrient in the maintenance of gut structure and function during critical illness. These findings have led to heightened interest in the glutamine content of enteral formulas. This article describes a method for estimating the glutamine content of whole-protein enteral formulas. The average amount of glutamine in selected, whole-protein formulas ranges from a minimum of 3.55 g/4200 kJ to a maximum of 5.15 g/4200 kJ. Although it is still too early to define the safest and most effective dose of glutamine, there are two points regarding glutamine supplementation that clearly merit further investigation: no clinical trials have been conducted to assess the potential benefits of glutamine supplementation of an enteral diet or to assess the effects of using diets containing protein-bound glutamine rather than free glutamine.

Body composition changes in patients with human immunodeficiency virus infection

Malnutrition characterized by weight loss and often extreme wasting generally develops when patients progress from infection with human immunodeficiency virus (HIV) to AIDS. There is evidence that before the development of AIDS, HIV-infected patients without weight loss show early signs of malnutrition, defined as an increase in the ratio of extracellular mass (ECM) to body cell mass (BCM). As part of a dietary intervention study, body composition measurement were obtained at baseline and after 6 wk in 18 patients with HIV infection and CD4 counts between 140 and 740 cells/mm3. Only one patient had a prior weight loss (3.7 kg); patients gained 2 pounds after 3 wk of dietary supplementation of 500 kcal daily. Bioelectrical impedance was used to measured body compartments. The average ECM/BCM ratio (0.77 +/- 0.13) was within the normal range (0.83 +/- 0.16) indicating the absence of malnutrition by this criterion. Most measurements of BCM (kg) approximated normal values, while several for BCM (kg) exceeded normal. BCM (kg) correlated poorly with the ECM/BCM ratio (r2 = 0.08; P = 0.11) in contrast to ECM (kg), which was well correlated (r2 = 0.82; P = 0.00). In addition, there was a significant correlation of body mass index (BMI) with the ECM/BCM ratio (r2 = 0.38; P = 0.00) and with ECM (r2 = 0.244; P = 0.003) indicating that overweight patients may be more likely to be considered malnourished than normal weight patients using this ratio. Without use of bioelectrical impedance, these subtle changes might be missed. Once significant weight loss has occurred coupled with decreases in BCM (kg), the ECM/BCM ratio may be more reflective of malnutrition. These conjectures will require prospective evaluation, but for now it seems reasonable to include bioelectrical impedance as a potentially useful tool in the evaluation of malnutrition in this population.

Review: Overview of Gastrointestinal Disorders Due to Diabetes Mellitus: Emphasis on Nutritional Support

Gastrointestinal disorders associated with diabetes mellitus have a prevalence rate of 30 to 75%. The most prominent disorders are gastroparesis, diarrhea, and constipation. Severity of symptoms range from mild to severe with the most affected patients being at risk for the development of protein calorie malnutrition. An historical review of the major studies which defined the diagnosis, pathophysiology, and prevalence of these disorders is presented. Guidelines for accurate nutritional assessment, which is essential to the decision to initiate nutritional therapy in this difficult to assess population, are also included. Current methods devised for treatment of diabetic gastroparesis and related disorders are presented. Emphasis is placed on recent developments in nutritional support techniques which make it possible to meet the energy requirements of all such patients. Practical outlines for glucose control in patients receiving TPN or enteral feeding and guidelines for transitioning from parenteral feeding to an oral diet are also presented.

Nutritional Management of Hypoglycemia

PURPOSE People with type 1 diabetes who follow an intensive management program have an increased risk of hypoglycemia, particularly overnight. New strategies for the nutritional management of hypoglycemia are essential. METHODS The unique properties of foods that affect blood glucose are reviewed, with special attention to a new medical food bar designed to reduce the incidence of nocturnal hypoglycemia. RESULTS All carbohydrate-containing foods affect blood glucose, but each causes a different rise in concentration. Consuming a variety of conventional foods with different glycemic indices can help control hypoglycemia. A new medical food bar that provides a sequential triphasic release of glucose from sucrose, protein, and uncooked cornstarch can help control blood glucose levels. CONCLUSIONS Hypoglycemia can be avoided by consuming foods with varying glycemic indices. A new medical food bar that provides sequential release of glucose into the bloodstream may also help control blood glucose levels.

Resting Energy Expenditure, Caloric Intake, and Short-Term Change in HIV Infection and AIDS C. GRUNFELD, M. PANGE, L. SHIMIZU, ET AL American Journal of Clinical Nutrition 55:455-460, 1992

Patients with AIDS often develop malignancies and secondary infections that cause weight loss. To examine the etiology of this weight loss, the investigators examined patients with HIV, AIDS, and AIDS plus secondary infection (AIDS-SI) for resting energy expenditure (REE), caloric intake, and short-term weight change over a 28-day period. Although caloric intake during that period for HIV positive and AIDS patients was similar to that of control subjects, it was 36% lower for AIDS-SI patients. The HIV positive and AIDS subjects showed no short-term change in weight, whereas the AIDS-SI subjects demonstrated a 5% weight loss. The HIV positive, AIDS, and AIDS-SI groups exhibited an increase over controls in REE of 11%, 25%, and 29%, respectively. Thus, the AIDS-SI patients consumed 17% fewer calories than would be needed to support the elevated REE, which accounted for the weight loss over the 28 days. Consequently, a hypermetabolic effect caused by the existence of a secondary infection coupled with the HI...

Megestrol acetate in patients with AIDS-related cachexia J. H. VON ROENN, D. ARMSTRONG, D. P. KOTLER, ET AL Ann Intern Med 121:393-399, 1994

Weight loss occurs in almost all patients with human immunodeficiency virus (HIV) infection, and its causes are multifactorial. One of the most common causes is anorexia, and there are presently two drugs available for these patients: megestrol acetate (Megace; Bristol-Myers Oncology Division, Princeton, NJ) and dronabinol (Marinol; Roxane Labs, Columbus, OH). A randomized, double-blind, placebo-controlled, multicenter study using megestrol acetate is reviewed here.1 The purpose of this study was to compare the effects of different doses of the drug on weight gain and other parameters in acquired immunodeficiency syndrome (AIDS) patients who presented with weight loss. In an outpatient setting, 270 patients were evaluated for safety of the drug. Only 195 patients could be used for evaluation of both safety and efficacy. The megestrol acetate was administered at 100, 400, or 800 mg daily for 12 weeks. Patients had lost either 20% or their premorbid weight or were ≤90% of their ideal body weight. No one was...

Early Changes of Body Composition in Human Immunodeficiency Virus-Infected Patients: Tetrapolar Body Impedance Analysis Indicates Significant Malnutrition

In this study the investigators examined alterations in body composition and the prevalence of diarrhea in HIV-infected subjects. By using tetrapolar body impedance analysis (RJL-Akern BIA 109:Data-input, Frankfurt/Main, Germany), body composition was measured in 533 subjects, including 193 men aged 21 to 70 years, who had tested positive for HIV-1 antibodies and 340 age- and sex-matched control subjects. HIV-infected patients were grouped according to the Walter Reed (WR) classification of HIV disease stages.1 Total body water, extracellular mass (ECM), body fat, body cell mass (BCM), and ECM/BCM ratio were determined. Relative to control subjects, the body weight and body mass index (BMI) of WR 3 through WR 5 (n = 85) and WR 6 (n = 83) subjects were significantly decreased ( p < .29 and P < .001, respectively), whereas WR 2 (n = 26) subjects exhibited no decline in either body weight or BMI. However, all HIV-infected subjects, including those classified as WR 2, displayed both a statistically significan...

Gastric Emptying in Humans: Influence of Different Regimens of Parenteral Nutrition S. BURSZTEIN-DE MYTTENAERE, K. M. GIL, S. B. HEYMSFIELD, ET AL Am J Clin Nutr 60:244-248, 1994

Controversy exists in the literature regarding the effect of parenteral nutrition on appetite. Earlier, several authors showed that healthy adult males receiving IV nutrition reduced their voluntary food intake by an amount that approximated 80% of the IV calories. 1 This finding suggested a postabsorptive control of oral food intake. In view of this observation, the authors of this study sought to answer two questions: does parenteral nutrition decrease gastric emptying and does the administration of branched-chain amino acids (BCAAs) alter the rate of gastric emptying?Nine healthy male volunteers between the ages of 20 and 31 years with a mean weight of 72 ± 10 kg were studied. Basal energy requirements were calculated using the Harris-Benedict equation and were estimated to be approximately 1765 kcal/d. All subjects were maintained on a diet consisting solely of an oral liquid supplement composed of 40% carbohydrate, 20% protein, and 40% fat (Ensure, Ross Labs, Columbus, OH). Each subject served as his...