Energy expenditure during continuous intragastric infusion of fuel

Influence of intragastric formula infusion rate on resting thermogenesis was evaluated in 24 healthy subjects. Metabolic rate (M) was measured by indirect calorimetry following an overnight fast. Subgroups then received a continuous intragastric infusion of a formula diet at three levels: submaintenance (mean +/- SEM, 1.02 +/- 0.04 times fasting M, n = 6), maintenance (1.39 +/- 0.01 times fasting M, n = 20), or supramaintenance (2.77 +/- 0.2 times fasting M, n = 14). Formula inflow was started in the evening, and intraprandial M was measured throughout the following day. Relative to fasting, submaintenance and maintenance infusions produced no detectable change in M. With supramaintenance infusion, M increased significantly (10.1%, p less than 0.05) above fasting level. Hence during continuous formula infusion a rise in M above fasting occurs only when rate of energy infusion exceeds rate of thermal energy losses. These results have implications in regard to energetic efficiency of continuous fuel infusion relative to intermittent food or formula ingestion.     

Beta-glucuronidase and hyperbilirubinemia in breast-fed versus formula-fed babies.

Breast milk and formula milk and the corresponding serum samples from 20 breast-fed babies, 20 formula-fed babies, and their mothers were examined at 3 days of age for beta-glucuronidase enzyme. Serum indirect bilirubin levels were also examined for all the infants. Serum indirect bilirubin concentrations were significantly higher (p < 0.001) in breast-fed (4.87 +/- 2.4 mg/dl) than in formula-fed infants (1.04 +/- 0.5 mg/dl). beta-glucuronidase activity in formula milk was negligible, while that in human milk was considerable (468.26 +/- 220.8 Sigma units/ml) and was correlated (p < 0.05) with that in the serum of the breast-fed (66.13 +/- 18.1 Sigma units/ml) than in formula fed infants (52.08 +/- 11.9 Sigma units/ml) and a significant (p < 0.05) correlation was found between its serum level and serum indirect bilirubin in both breast and formula fed infants. Also in breast-fed infants serum bilirubin concentrations were related to beta-glucuronidase activity in breast milk (p < 0.05): Breast milk beta-glucuronidase--by facilitating intestinal reabsorption of bilirubin--seems to be an important factor in the neonatal hyperbilirubinemia of breast-fed babies.     

Nutritional support of the dysphagic patient: methods, risks, and complications of therapy

The indications, methods, and complications of nutritional support of 90 patients admitted with a primary complaint of dysphagia were reviewed. Patients were divided into two groups based on etiology of dysphagia (central neurologic vs local mechanical dysfunction). All patients on admission exhibited marked malnutrition with an average weight loss of 12 +/- 9.8% body weight, serum transferrin 165 +/- 60.1 mg/dl, and albumin 3.2 +/- 0.85 mg/dl. All patients were placed on either enteral (63%) or parenteral (37%) nutrition. Twenty-seven percent of all patients suffered a complication of nutritional therapy. Patients with nasoenteric tubes had a 10% complication incidence (aspiration or endotracheal placement of tube) resulting in a 30% mortality rate; significantly higher (p less than 0.05) than seen with other modalities. Any form of upper enteric feeding (nasoenteric or gastrostomy) was associated with significantly increased (p less than 0.01) risk of aspiration pneumonia. It is concluded that patients admitted to hospital with dysphagia as the major complaint suffer from severe malnutrition, and that upper gastrointestinal intubation should not be employed for feeding until the dysphagia has resolved.     

Continuous nasoenteric feeding: bioenergetic and metabolic response during recovery from semistarvation

The bioenergetic and metabolic response to continuous nasoenteric feeding was examined under balance conditions for up to 22 d in 12 stable undernourished medical patients. Each subject received a fixed inflow of the mixed-fuel formula at rates of one to three times maintenance energy requirement. The pooled results were used to develop a composite profile of physiologic changes during recovery from semistarvation. Body weight, whole-body gas exchange, minute ventilation, thermal and chemical energy losses, and balances of energy, nitrogen, potassium, and sodium changed as a function of formula infusion rate and duration of feeding. These component measurements allowed calculation of such classic bioenergetic efficiency terms as digestible, metabolizable, and net energy as functions of infused energy (IE, kcal.kg fat free body mass-1.h-1: 0.96IE, 0.93IE, and 6.7 [1 - e-0.16IE], respectively) and the energy content of weight gain (means +/- SD; early, 4.2 +/- 3.5 kcal/g, and later, 7.4 +/- 3.6 kcal/g). Continuous nasoenteric feeding provides a unique opportunity to define previously unexplored dietary and metabolic interrelations in humans.     

Zinc tolerance test in uremia: effect of calcitriol supplementation

The effect of 1,25(OH)2D3 on zinc absorption was indirectly determined in hemodialysis patients using the oral zinc tolerance test. The increment in plasma zinc and the area under the curve following an oral zinc load of 25 mg were studied in seven patients, before and after 6 weeks of therapy with 1 microgram/day of 1,25(OH)2D3 [Rocaltrol(R)]. Before therapy, fasting plasma zinc, 2 hour plasma zinc, and the area under the curve (AUC) were subnormal (hemodialysis patients vs normals: 96 +/- 2 vs 105 +/- 3 micrograms/dl, p less than 0.05, 161 +/- 8 vs 222 +/- 16 micrograms/dl, p less than 0.025, and 188 +/- 25 vs 302 +/- 33 micrograms hr/dl, p less than 0.025, respectively). Following Rocaltrol, serum calcium level increased (8.9 +/- .12 to 9.8 +/- .4 mg/dl, p less than 0.05), parathyroid hormone levels decreased (20.4 +/- 8.9 to 13.6 +/- 7.2 ng/ml, p less than 0.05), but there was no significant change in fasting plasma zinc, 2 hour plasma zinc, or AUC (89 +/- 3 micrograms/dl, 149 micrograms/dl, and 176 +/- 18 micrograms hr/dl, respectively). These results suggest that short-term 1,25(OH)2D3 therapy had no significant impact on zinc absorption or plasma zinc level in uremics.     

Effects of short-term aerobic conditioning and high cholesterol feeding on plasma total and lipoprotein cholesterol levels in sedentary young men

The plasma total cholesterol (TC) and lipoprotein cholesterol concentrations of sedentary young men (n = 23) were determined during 4 wk of controlled feeding and 6 wk of supervised aerobic conditioning. Subjects were assigned to dietary treatments of 400 mg cholesterol per day (M) or 1400 mg cholesterol per day (H); both diets had a P/S ratio of about 0.6. Dietary groups M and H were subdivided into exercise (MX and HX) and sedentary (MS and HS) groups. Compared to the sedentary groups, MX and HX exhibited significant (p less than 0.01) improvements in cardiorespiratory fitness. After 2 and 4 wk of high cholesterol feeding, group HS exhibited significant (p less than 0.05) elevations in TC (+30 +/- 7 and +32 +/- 9 mg/dl) with nonsignificant increases in very low-density lipoprotein cholesterol and low-density lipoprotein cholesterol. Group HX exhibited consistent weekly increases in high-density lipoprotein cholesterol (HDL-C) (from 46 +/- 3 mg/dl, the base level, to 53 +/- 4 mg/dl at wk 4) with aerobic conditioning. By combining exercise and sedentary group data at each level of dietary cholesterol it was shown that TC and HDL-C levels significantly (p less than 0.05) increased by the 4th wk of high cholesterol feeding. The TC/HDL-C ratio significantly (p less than 0.05) increased for the sedentary subjects as compared to all the exercising subjects by wk 4 of controlled feeding.     

Comparison of a high-protein disease-specific enteral formula with a high-protein enteral formula in hyperglycemic critically ill patients

AIMS: To determine whether a specific high-protein enteral formula with a similar caloric percentage of fat and carbohydrates achieves greater control over glycemic levels and reduces insulin requirements in hyperglycemic critically ill patients when compared to a control high-protein enteral formula. DESIGN: A prospective, randomized, controlled, single-blind trial in two University Hospital Intensive Care Units in Spain. METHODS: We enrolled 50 patients with diabetes mellitus or stress hyperglycemia with basal glycemia > or =160 mg/dl and indication for enteral nutrition > or =5 days. Patients with severe kidney failure, liver failure or obesity were excluded from the study. In the first 48 h of admission, after randomization, 26 patients received the study diet and 24 patients received the control diet. The variables were monitored for 14 days. The Harris-Benedict formula with a fixed stress factor of 1.2 was used to calculate caloric needs. Insulin was administered by continuous infusion. An intention-to-treat analysis was performed. RESULTS: On admission, there were no differences between the study and control group in plasma glucose levels (mg/dl) (190.9+/-45 vs 210.3+/-63) and capillary glucose levels (mg/dl) (226.1+/-73 vs 213.8+/-67). After the feeding trial, there were differences between the study and control group in plasma glucose levels (mg/dl) (176.8+/-44 vs 222.8+/-47, P=0.001), capillary glucose levels (mg/dl) (163.1+/-45 vs 216.4+/-56, P=0.001), insulin requirements/day (IU) 8.73 (2.3-27.5) vs 30.2 (21.5-57.1) (P=0.001), insulin/received carbohydrates (UI/g) 0.07 (0.02-0.22) vs 0.18 (0.11-0.35) (P=0.02) and insulin/received carbohydrates/kg 0.98 (0.26-3.59) vs 2.13 (1.44-4.58) (P=0.04). These differences remain in a day-to-day comparison. There were no differences in the analytical tests, or in digestive or infectious complications. Intensive Care Unit length of stay, mechanical ventilation and mortality were similar in both groups. CONCLUSIONS: Hyperglycemic critically ill patients fed with a high-protein diet with a similar caloric percentage of fat and carbohydrates show a significant reduction in plasma glucose levels, capillary glucose levels and insulin requirements in comparison to patients on a conventional high-protein diet. This better glycemic control do not modify Intensive Care Unit length of stay, infectious complications, mechanical ventilation and mortality.     

Lipoprotein changes when a reported diet is tested in distance runners

Diet records previously recorded by distance runners indicated that runners consumed considerably more calories, largely as carbohydrates, than did inactive controls. We examined the effect of this reported diet on the serum lipids and lipoproteins of active men. Ten male runners ran 16 km daily and were provided defined diets containing 3587 +/- 233 kcal/day (mean +/- SD) and composed of 53% (486 +/- 31 g/day) carbohydrates, 15% (134 +/- 8 g/day) protein, and 32% (131 +/- 9 g/day) fat for 21 days. Serum samples were obtained before and during the diet period. Low-density lipoprotein cholesterol fell 5 +/- 12 mg/dl before (p = NS) and 15 +/- 13 mg/dl (p less than 0.01) during the diet. High-density lipoprotein (HDL) cholesterol did not change during the week before, but decreased 6 +/- 2 mg/dl (p less than 0.001) while subjects consumed the defined diet. This decrease was due to a 7 +/- 6 mg/dl (p less than 0.01) fall in HDL2 cholesterol (1.063 less than rho less than 1.125 g/ml). Alterations in HDL cholesterol were accompanied by reductions in apo A-1, the major HDL apoprotein. After 14 days on the defined diet no additional changes in serum lipids occurred. Lipoprotein changes of this magnitude were unexpected and suggest that the diet diaries used to design the defined diet were unreliable or that factors not accounted for in diet records had significant effects in these subjects.     

Leptin response to glucocorticoid occurs at physiological doses and is abolished by fasting

OBJECTIVE: To examine the effects of graded doses of hydrocortisone (HC) on leptin secretion, and determine the effect of fasting. RESEARCH METHODS AND PROCEDURES: This was a randomized, placebo-controlled, crossover study, with a 1-week "washout" period between interventions. Eight healthy subjects [age = 36 +/- 2.3 years (+/-SE), body mass index = 31.5 +/- 1.6 kg/m(2)] completed the dose-response study in which an intravenous infusion of saline (placebo) or HC (30 or 100 mg) was administered for 24 hours. Four healthy subjects (age = 35.2 +/- 3.0 years, body mass index = 27.1 +/- 2.1 kg/m(2)) completed the fasting study, which entailed continuous infusion of saline, HC (300 mg/24 hours) in the fed state, or HC (300 mg/24 hours) with total caloric deprivation for 24 hours. Blood sampling was performed every 1 to 2 hours for measurement of leptin, cortisol, insulin, and glucose levels. RESULTS: Peak hyperleptinemia occurred after 16 hours of HC infusion; peak/baseline leptin levels were 129% (placebo), 140% (30 mg of HC for 24 hours, p = 0.05), and 185% (100 mg of HC for 24 hours, p < 0.01). During infusion of HC (300 mg/24 hours or placebo), the peak/baseline plasma leptin levels were 16.1 +/- 5.8/12.8 +/- 5.9 ng/mL (placebo with food, 126%), 14.6 +/- 6.0/12.5 +/- 6.5 ng/mL (HC fasting, 117%), and 32.5 +/- 12.5/12.0 +/- 8.4 ng/mL (HC with food, 271%, p < 0.001). DISCUSSION: Leptin secretory responses occur at physiological doses of HC, are obliterated by fasting, and thus may be of metabolic significance.     

Efficacy of tube feeding in supplying energy requirements of hospitalized patients

During a 6-week period, all adult patients in a university hospital receiving ready-to-feed nasoenteric tube feeding formula were prospectively studied. The study objective was to determine each patient's caloric intake from tube feeding relative to their energy needs and to identify factors causing decreased feeding intake. Each of 35 patients was visited at least once daily to determine their volumetric intake of tube feeding formula. Daily review of patient care records and nursing interviews were used to identify interruptions in therapy. Patient's basal energy expenditures (BEE) were calculated using the Harris-Benedict equation. Calorie goals were set by members of the Nutrition Support Service or clinical dietitians. Intakes averaged 1095 +/- 41 Kcal (SEM) per day or 61% of their mean calorie goal of 1791 +/- 41 Kcal. Mean daily calorie intake was statistically different (p less than 0.05) from mean energy goal on patient study days 1 through 5, 7, and 8. Only 16 of the 35 patients achieved an intake of 100% of their energy goal on any day of therapy. Calorie goals averaged 1.4 times BEE. Mean daily calorie intake did not exceed BEE until study day 10. Eighteen % of potential feeding time was lost due to temporary feeding interruptions; primarily inadvertent extubation (4.6%), gastrointestinal intolerance (4.7%), medical procedures requiring discontinuation of feeding (2.8%), and feeding tube positioning difficulties (1.5%). In addition, physicians ordered only 75% of calculated energy goals. These data indicate that tube feeding therapy, when provided under usual hospital conditions, does not meet patient's energy requirements.     

Overfeeding: cardiovascular and metabolic response during continuous formula infusion in adult humans

The cardiovascular and metabolic response to continuous nasoenteric formula infusion was monitored in eight healthy men during three consecutive 1-wk balance periods: maintenance-stabilization, overfeeding at twice the maintenance infusion rate, and postoverfeeding return to maintenance infusion. Elemental balance, thermogenic, and stable-isotope studies carried out throughout protocol identified 1) two distinct phases during overfeeding (early, days 1-4, and late, days 4-7); 2) changes in extracellular fluid (sodium balance) as the major determinant of overfeeding weight gain; 3) individual differences in percentage of excess fuels retained during overfeeding (76-87%), derived from variation in both digestive and thermogenic processes; and 4) a sustained physiologic response during the postoverfeeding period. These initial findings suggest that individuals differ in response to overfeeding and that specific aspects of this variation are amenable to future study. In addition, the timing of observed fluid, metabolic, and cardiovascular changes during overfeeding suggests specific strategies aimed at preventing refeeding circulatory complications.     

Enteral feeding in the hypoalbuminemic patient

Previous studies have correlated intolerance of isotonic, intact protein enteral solutions with hypoalbuminemia. The purpose of this retrospective study was to determine whether the level of serum albumin (SA) influenced tolerance of such an enteral nutrient solution (ENS). All patients who received Entrition during 1987 for a minimum of 48 hr were studied for the first 10 days of enteral feeding. Documentation included SA, medications, stool frequency, gastric residuals (GR), and daily caloric intake. ENS intolerance was defined as greater than 3 stools/day for greater than 48 hr or GR greater than twice the hourly infusion rate for greater than 48 hr. Patients were categorized into two groups: those with SA greater than or equal to 2.5 g/dl (group I) and those with SA less than 2.5 g/dl (group II). Of 88 patients studied, 48 (86%) in group I and 28 (88%) in group II tolerated the ENS. Eight (14%) in group I and 4 (12%) in group II experienced ENS intolerance. There was no statistically significant difference in the frequency of ENS intolerance between these two groups (p less than 0.05). Also, 97% of all those with a SA less than 2.5 g/dl were fed 80% or more of their estimated caloric requirements. We concluded that ENS tolerance was not affected by the SA level and patients with hypoalbuminemia (SA less than 2.5 g/dl) could be fed enterally.     

Hypocaloric diets and ketogenesis in the management of obese gestational diabetic women.

The extent to which given levels of caloric restriction will improve glycemic status but increase plasma ketone bodies in gestational diabetic women has received little attention. After reviewing the underlying physiology, we present data on two feeding studies investigating the question. In the first, a weight-maintaining approximately 2400-kcal/day diet was fed on a metabolic ward to 12 gestational diabetic women for 1 week. In the second week, subjects were randomized to a continuation of the 2400-kcal/day diet or to a 1200-kcal/day diet. Twenty-four-hour mean glucose levels remained unchanged in the control group but declined in the calorie-restricted group (6.7 mM or 121 mg/dl in week 1 vs 5.4 mM or 97.3 mg/dl in week 2) (p less than 0.01). Nine-hour overnight fasting plasma insulin also declined but oral glucose tolerance did not improve with caloric restriction. Fasting plasma beta-hydroxybutyrate rose in the calorie-restricted group, along with an increase in ketonuria, but not in the control group. A second study compared the impact of a 33% calorie-restricted diet or insulin to a full-calorie diet in a similar 2-week experimental design and measured hepatic glucose output and insulin sensitivity with dideuterated glucose before and during an insulin clamp. Diet in three subjects improved fasting and 24-hr mean glucose by 22 and 10%, respectively, whereas prophylactic insulin in three subjects produced 0 and 4% reductions, respectively. On average, ketonuria after a 9-hr fast declined to an equivalent degree with both treatments. Hepatic glucose output and insulin sensitivity were not statistically significantly altered by gestational diabetes or the therapeutic interventions compared to nondiabetic normal weight or obese pregnant controls. In conclusion, 50% caloric restriction improves glycemic status in obese women with gestational diabetes but is associated with an increase in ketonuria, which is of uncertain significance. An intermediate 33% level of caloric restriction (to 1600-1800 kcal daily) may be more appropriate in dietary management of obese woman with gestational diabetes mellitus and more effective than prophylactic insulin. Further studies are required to confirm these findings.     

Hypocaloric diets and ketogenesis in the management of obese gestational diabetic women.

The extent to which given levels of caloric restriction will improve glycemic status but increase plasma ketone bodies in gestational diabetic women has received little attention. After reviewing the underlying physiology, we present data on two feeding studies investigating the question. In the first, a weight-maintaining approximately 2400-kcal/day diet was fed on a metabolic ward to 12 gestational diabetic women for 1 week. In the second week, subjects were randomized to a continuation of the 2400-kcal/day diet or to a 1200-kcal/day diet. Twenty-four-hour mean glucose levels remained unchanged in the control group but declined in the calorie-restricted group (6.7 mM or 121 mg/dl in week 1 vs 5.4 mM or 97.3 mg/dl in week 2) (p less than 0.01). Nine-hour overnight fasting plasma insulin also declined but oral glucose tolerance did not improve with caloric restriction. Fasting plasma beta-hydroxybutyrate rose in the calorie-restricted group, along with an increase in ketonuria, but not in the control group. A second study compared the impact of a 33% calorie-restricted diet or insulin to a full-calorie diet in a similar 2-week experimental design and measured hepatic glucose output and insulin sensitivity with dideuterated glucose before and during an insulin clamp. Diet in three subjects improved fasting and 24-hr mean glucose by 22 and 10%, respectively, whereas prophylactic insulin in three subjects produced 0 and 4% reductions, respectively. On average, ketonuria after a 9-hr fast declined to an equivalent degree with both treatments. Hepatic glucose output and insulin sensitivity were not statistically significantly altered by gestational diabetes or the therapeutic interventions compared to nondiabetic normal weight or obese pregnant controls. In conclusion, 50% caloric restriction improves glycemic status in obese women with gestational diabetes but is associated with an increase in ketonuria, which is of uncertain significance. An intermediate 33% level of caloric restriction (to 1600-1800 kcal daily) may be more appropriate in dietary management of obese woman with gestational diabetes mellitus and more effective than prophylactic insulin. Further studies are required to confirm these findings.     

Nutritional status of middle-aged and elderly females in Kentucky in two seasons: Part 1. Body weight and related factors

Middle-aged and elderly females aged between 51 and 86 years volunteered for this study. In June and July, 147 females were studied; data collected through interview included general socioeconomic information, health history, use of medication, and a 7-day food intake. During the same 7-day period, physical activity level was measured for each person by use of a pedometer. On the 8th day, anthropometric measurements were conducted and fasting blood was analyzed for certain hormones and related metabolites. In the following January and February, the same group was surveyed again and the same measurements were repeated. Of the initial 147 subjects, 130 persons completed the winter survey. A comparison of the summer and winter data indicated some significant differences: mean body weight increased in winter from 70.4 +/- 12.7 to 71.1 +/- 13.5 kg (p less than or equal to 0.05); energy intake was raised from 1450 +/- 384 to 1549 +/- 372 kcal (p less than or equal to 0.01); physical activity decreased from 10.9 +/- 8.2 to 8.5 +/- 5.4 miles/week (p less than or equal to 0.01); and serum free thyroxine (T4) fell from 1.72 +/- 0.27 to 1.64 +/- 0.27 ng/dl. These results together with other data suggest that more attention should be addressed to seasonal fluctuations involved in body weight maintenance.     

Short-term effects of fat emulsion on serum lipids in postoperative patients

The effect of short-term infusion of intravenous fat on serum lipids was assessed in 23 patients who had elective cancer operations and were given 20% Intralipid for 5 days postoperatively as part of a standard total parenteral nutrition regimen. Serum lipids were measured prior to, during and after the 5-day infusion period. The percentage of cholesterol as high-density lipoproteins (HDL) fell from a mean preinfusion value of 34.7 +/- 2.8 to 27.9 +/- 2.5 (p less than 0.05), while the percentage of cholesterol as low-density lipoproteins (LDL) increased from 40.7 +/- 2.2 to 46.8 +/- 3.4 (p less than 0.05). Serum triglycerides fell significantly (p less than 0.01) from 106.2 +/- 13.7 mg/dl to 64.6 +/- 8.8 mg/dl at 3 days, being 85.3 +/- 3.7 mg/dl at 5 days. No significant change in percent cholesterol as very low-density lipoproteins (VLDL), or levels of serum total cholesterol or phospholipids occurred. Lipoprotein X was detectable in six patients after 5 days. To study triglyceride clearance 1.7 g/kg of fat emulsion was infused over 8 hr and serial blood samples obtained. Within 3 hr of stopping the fat infusion, triglyceride levels had fallen to preinfusion values.     

The effects of marked caloric restriction on lipoprotein lipase-activators in obese subjects

Lipoprotein lipase plays a major role in the clearance of triglyceride rich lipoproteins, chylomicrons and very low density lipoproteins, from the circulation and also contributes to production of high density lipoproteins. To be functional lipoprotein lipase requires an activator which is present in the serum. Generally, serum triglyceride correlates positively with serum lipoprotein lipase-activator levels. During caloric restriction both serum triglyceride and adipose tissue liproprotein activity decrease. Affect of caloric restriction on serum lipoprotein lipase activator levels in not known.In this study we have evaluated the effect of marked caloric restriction on the levels of serum triglyceride, total cholesterol high-density lipoprotein cholesterol and lipoprotein lipase-activator in morbidly obese subjects. Initially, twenty subjects were included in the study. Twenty subjects consumed a 320kcal protein supplemented modified fast diet for three weeks, fourteen subjects for seven weeks and eight subjects for eleven weeks. Weight loss was continuous throughout the study. Serum triglycerides decreased during the first three weeks (Baseline 156±9 mg/dl, third week 119±9 mg/dl, p<0.01), followed by a plateau between third and fifth weeks and a small increase, from the fifth through the eleventh weeks. At eleven weeks serum triglycerides were not significantly lower than at the onset of caloric restriction. Serum total-cholesterol changed similarly showing a rapid and significant decline during the first five weeks, a plateau between fifth and seventh weeks and a small increase between ninth to eleventh weeks. However, at eleven weeks, serum cholesterol was significantly lower (Baseline 216±13 mg/dl, eleventh week 140±5 mg/dl, p<0.01). Serum high-density lipoprotein cholesterol level decreased significantly only in female subjects (Baseline 53±2 mg/dl, third week 37±2 mg/dl, p<0.01). Serum lipoprotein lipase-activator level increased steadily reaching approximately 200% of initial levels at week eleven (p<0.01).Thus, it appears that severe caloric restriction in morbidly obese subjects was associated with a significant decrease in the serum total cholesterol, a significant decrease in HDL-cholesterol in women. These decreases seen in serum lipids were limited to the first five weeks despite a continuous weight loss throughout this study. Serum lipoprotein lipase-activator level increased steadily and changes in serum lipoprotein lipase activator levels did not follow the changes in serum triglyceride levels during the caloric restriction.     

Serum concentrations of retinol and retinyl esters in adults in response to mixed vitamin A and carotenoid containing meals

Previous studies using spectrophotometric methods for vitamin A analysis concluded that fasting prior to blood collection is not necessary for determining vitamin A status of children or young adult subjects. We measured the effect of mixed vitamin A and carotenoid containing meals with less than 3, 50, and 100% of the recommended dietary allowance (RDA) for vitamin A on serum concentrations of retinyl esters, retinol, and carotenoids in elderly and young adults after an overnight fast. Retinyl ester concentrations rose significantly in both age groups with a numerically higher rise over baseline in the elderly subjects: 6.0 +/- 0.9 micrograms/dl for elderly (p less than 0.001), 5.0 +/- 0.5 micrograms/dl for young (p less than 0.001) at 50% RDA; 9.0 +/- 1.3 micrograms/dl for elderly (p less than 0.001) and 6.8 +/- 1.6 micrograms/dl for young (p less than 0.05) at 100% RDA. We conclude that in both young and elderly adults, but especially in the elderly, fasting conditions are necessary for the accurate assessment of vitamin A status if spectrophotometric methods are used for measuring vitamin A.     

Existence of consistent hypo- and hyperresponders to dietary cholesterol in man

Hyper- and hyporesponsiveness of serum cholesterol to dietary cholesterol is an established concept in animals but not in man. The authors studied the stability of the individual response of serum cholesterol to dietary cholesterol in three controlled experiments in 1982. The subjects were volunteers from the general population living in or near Wageningen, the Netherlands. Each experiment had a low-cholesterol baseline period (121, 106, and 129 mg/day in experiments 1, 2, and 3, respectively) and a high-cholesterol test period (625, 673, and 989 mg/day). Duplicate portion analysis showed that dietary cholesterol was the only variable. The 94 healthy men and women who completed experiment 1 showed an increase (mean +/- standard deviation (SD] in serum cholesterol of 0.50 +/- 0.39 mmol/liter (19 +/- 15 mg/dl). Seventeen putative hyperresponders, defined by their response in experiment 1, were retested in experiments 2 and 3; they showed responses of 0.28 +/- 0.38 mmol/liter (11 +/- 15 mg/dl) and 0.82 +/- 0.35 mmol/liter (32 +/- 14 mg/dl), respectively. Fifteen hyporesponders, selected in experiment 1, showed responses in experiments 2 and 3 of 0.06 +/- 0.35 mmol/liter (2 +/- 14 mg/dl) and 0.47 +/- 0.26 mmol/liter (18 +/- 10 mg/dl), significantly lower than the corresponding values for hyperresponders. The standardized regression coefficient for individual responses in experiment 2 on those in experiment 1 was beta = 0.34 (p = 0.03, n = 32); the corresponding regression coefficient for experiment 3 and experiment 1 was 0.53 (p less than 0.01). After correction for intraindividual fluctuations the true responsiveness distribution was found to have a between-subject standard deviation of about 0.29 mmol/liter (11 mg/dl). This implies that if the mean response to a certain dietary cholesterol load amounts to e.g., 0.58 mmol/liter (22 mg/dl), then the 16% of subjects least susceptible to diet will experience a rise of only 0.29 mmol/liter (11 mg/dl) or less, while in the 16% of subjects most susceptible to diet, serum cholesterol will rise by 0.87 mmol/liter (34 mg/dl) or more. The authors conclude that modest differences in responsiveness of serum cholesterol to dietary cholesterol do exist in man, and that the wide scatter of responses observed in single experiments is largely due to chance fluctuations.     

Congestive heart failure: clinical management by use of continuous nasoenteric feeding

Congestive heart failure (CHF) is often associated with undernutrition. Although loss of lean tissue may be detrimental to the host, a protective effect is conveyed as cardiac demands are reduced by lower whole-body oxygen consumption (VO2) and circulating fluid volume. The aim of this study was to determine if continuous nasoenteric feeding could promote an anabolic state with increments in lean tissue in moderate-severe CHF patients without adversely effecting cardiac performance. Undernourished CHF patients on a metabolic ward were fed a formula diet infused intragastrically for 2 wk. The energy infusion rate was maintained at 1.4-1.8 X measured resting metabolic rate. During the infusion period, body weight, elemental balances, VO2, and cardiac function (echocardiography) were monitored. Results showed a loss in weight and extracellular fluid, gain in lean body mass (eg, + delta N and delta K), unaltered VO2, and unchanged cardiac function. Cardiac cachexia is therefore safely and effectively manageable by maintenance or repletional levels of nasoenteric feeding.