Development of a measure of attitude toward nutrition in patient care

BACKGROUND

Development of reliable measures of medical student and resident attitudes about nutrition in patient care is needed before the effects of educational interventions or clinical experience can be gauged. This report describes the systematic development of a measure of attitude toward nutrition in patient care. It presents evidence about scale reliability and the absence of response bias that endorses the trustworthiness of data from the measure.

METHODS

An eight-step attitude scale development procedure was used to create the Nutrition In Patient care Survey (NIPS). Data from five samples of first- and second-year medical students and first-year medical residents were subjected to factor analysis (PA2, varimax rotation), reliability analyses, and statistical analyses to test for demographic bias in the attitude data.

RESULTS

A 45-item attitude measure was developed that contains five subscales derived from the factor analysis: (1) nutrition in routine care (NRC, 8 items); (2) clinical behavior (CB, 20 items); (3) physician-patient relationship (PPR, 8 items); (4) patient behavior/motivation (PBM, 3 items); and (5) physician efficacy (PE, 6 items). Each subscale yields reliable data in terms of internal consistency (alpha coefficients) and stability (test-retest reliability). Medical student and resident demographic variables have negligible influence on attitude scores.

DISCUSSION

The NIPS subscales yield reliable data that can be used to assess outcomes in evaluation research on educational or clinical interventions or to predict patient care practices. Systematic attitude scale development increases the likelihood that the resulting measures will produce useful, trustworthy data.

Obesity and quality of life

The focus of this review is the impact of obesity and weight loss on quality of life. A focus on quality of life broadens the scope of treatment efficacy beyond weight loss and provides a patient-centered perspective. The concept of quality of life is defined, and both general and obesity-specific measures are reviewed. It is clear that obesity confers negative consequences on both the physical and psychosocial aspects of quality of life, especially among the severely obese. The effects of weight loss appear to be favorable, although few studies have examined non-surgical interventions. Future studies would be enhanced by assessing a variety of approaches to weight loss by using both general and obesity-specific measures of quality of life and conducting follow-up studies to assess the effects of weight regain on quality of life.

Evaluation of the obese patient. Practical considerations

The evaluation process for obesity uses the same framework of a history, physical examination and interpretation of selected laboratory and diagnostic tests that are used for other chronic care patient encounters. What makes this evaluation process different is knowing how to take an obesity focused history, what to examine, and which tests to order. An assessment of risk status is then determined based on the National Heart, Lung, and Blood Institute Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults. Other important aspects of the evaluation process include determining the patient's goals, expectations, and motivation for weight loss along with support systems and/or barriers to behavior change.

Single- and multifrequency models for bioelectrical impedance analysis of body water compartments

The 1994 National Institutes of Health Technology Conference on bioelectrical impedance analysis (BIA) did not support the use of BIA under conditions that alter the normal relationship between the extracellular (ECW) and intracellular water (ICW) compartments. To extend applications of BIA to these populations, we investigated the accuracy and precision of seven previously published BIA models for the measurement of change in body water compartmentalization among individuals infused with lactated Ringer solution or administered a diuretic agent. Results were compared with dilution by using deuterium oxide and bromide combined with short-term changes of body weight. BIA, with use of proximal, tetrapolar electrodes, was measured from 5 to 500 kHz, including 50 kHz. Single-frequency, 50-kHz models did not accurately predict change in total body water, but the 50-kHz parallel model did accurately measure changes in ICW. The only model that accurately predicted change in ECW, ICW, and total body water was the 0/infinity-kHz parallel (Cole-Cole) multifrequency model. Use of the Hanai correction for mixing was less accurate. We conclude that the multifrequency Cole-Cole model is superior under conditions in which body water compartmentalization is altered from the normal state.

How much physical activity is needed to minimize weight gain in previously obese women?

Exercise is frequently identified as a predictor of weight maintenance after elective weight loss in retrospective studies of treatments for obesity. We conducted a prospective study to test whether physical activity measured soon after weight loss predicted weight maintenance and to determine how much physical activity was required to optimize maintenance. Thirty-two women [mean (+/- SD) age, 38 +/- 7 y; body mass index (in kg/m2), 24 +/- 3] were recruited through local advertising within 3 mo of reaching their target for weight loss (23 +/- 9 kg). Total energy expenditure (TEE) was measured by the doubly labeled water method. Postabsorptive resting metabolic rate (RMR) and postprandial RMR [expressed as thermic effect of a meal (TEM)] were measured by respiratory gas exchange. Women in the physically active group (ratio of TEE to RMR = 1.89 +/- 0.08) gained 2.5 +/- 3.1 kg during the 12 mo after reaching their target for weight loss, moderately active women (TEE:RMR = 1.64 +/- 0.05) gained 9.9 +/- 10.5 kg, and sedentary women (TEE:RMR = 1.44 +/- 0.08) gained 7.0 +/- 5.9 kg (P < 0.01). Retrospective analyses of weight regain as a function of energy expended in physical activity indicated a threshold for weight maintenance of 47 kJ x kg body wt(-1) x d(-1). This corresponds to an average of 80 min/d of moderate activity or 35 min/d of vigorous activity added to a sedentary lifestyle.

Use of bioelectrical impedance analysis measurements in the clinical management of patients undergoing dialysis

The use of bioelectrical impedance analysis (BIA) in patients with end-stage renal disease who are receiving dialysis provides researchers with two important applications: 1) a biological model in which the underlying assumptions of BIA can be tested, and 2) if valid, a tool that can be used to improve the clinical management of patients receiving dialysis. We review the rationale of and purpose for using BIA in the dialysis population, the physiologic changes that occur during dialysis that influence BIA measurements, and last, conclusions reached from the current scientific literature.

Clinical characteristics influencing bioelectrical impedance analysis measurements

Standardization of measurement conditions is essential for obtaining accurate, precise, and reproducible bioelectrical impedance analysis (BIA) data. Errors due to lack of measurement control are propagated in subsequent calculations of body composition and contribute to differences in predictive equations among investigators. Various individual and environmental factors have been shown to influence BIA. We review the factors that have been identified from the literature as being conditions requiring standardization both for healthy subjects and for those in a medical setting.

Effect of skin temperature on multifrequency bioelectrical impedance analysis

This study assessed the effects of changes in skin temperature on multifrequency bioimpedance analysis (MF-BIA) and on the prediction of body water compartments. Skin temperature (baseline 29.3 +/- 2.1 degrees C) of six healthy adults was raised over 50 min to 35.8 +/- 0.6 degrees C, followed by cooling for 20 min to 26.9 +/- 1.3 degrees C, by using an external heating and cooling blanket. MF-BIA was measured at both distal (conventional) and proximal electrode placements. Both distal and proximal impedance varied inversely with a change in skin temperature across all frequencies (5-500 kHz). The change in proximal impedance per degree centigrade change in skin surface temperature was approximately 60% of distal impedance. The change in measured impedance at 50 kHz erroneously increased predicted total body water (TBW) by 2.6 +/- 0.9 liters (P < 0.001) and underpredicted fat mass by 3.3 +/- 1.3 kg (P < 0.0001). Computer modeling of the MF-BIA data indicated changes in predicted water compartments with temperature modifications; however, the ratio of extracellular water (ECW) to TBW did not significantly change (P < 0.4). This change in impedance was not due to a change in the movement of water of the ECW compartment and thus probably represents a change in cutaneous impedance of the skin. Controlled ambient and skin temperatures should be included in the standardization of BIA measurements. The error in predicted TBW is < 1% within an ambient temperature range of 22.3 to 27.7 degrees C (72.1-81.9 degrees F).

Barriers to providing nutrition counseling by physicians: a survey of primary care practitioners

BACKGROUND

Previous surveys have shown that there is a disparity between physicians' beliefs about the importance of diet and nutrition in health maintenance and disease prevention and the actual delivery of nutrition counseling. The primary objective of this study was to assess the current attitudes, practice behavior, and barriers to the delivery of nutrition counseling by primary care physicians.

METHODS

A random-sample-mailed questionnaire was sent to 2,250 primary care physicians selected from the AMA masterfile from general practice, internal medicine, and pediatrics, representing self-employed, group, hospital, and HMO practices. Participants were stratified by age, gender, geographical region, and present employment. The main outcome measures were to determine time spent by physicians providing and percentage of patients receiving dietary counseling and to identify barriers to the delivery of nutrition counseling.

RESULTS

A 49% response rate (n = 1,103) was obtained. Results are presented for the 1,030 physicians (70% private practice) with complete data. Over two-thirds of physicians provide dietary counseling to 40% or less of patients and spend 5 or fewer min discussing dietary changes. Despite this pattern, nearly three-quarters of respondents feel that dietary counseling is important and is the responsibility of the physician. Ranking of perceived barriers to delivery of dietary counseling were lack of time, patient noncompliance, inadequate teaching materials, lack of counseling, training, lack of knowledge, inadequate reimbursement, and low physician confidence.

CONCLUSIONS

This survey suggests that multiple barriers exist that prevent the primary care practitioner from providing dietary counseling. A multifaceted approach will be needed to change physician counseling behavior.

Measurement of physical activity among black and white obese women

Several recent self-reported surveys have suggested that African-American women may engage in less leisure-time physical activity (PA) than whites. Objective measurements of PA have not been performed, however. Therefore, the purpose of this study was to compare the components of energy expenditure, including PA, between black and white obese women. Using the doubly labeled water method, total daily energy expenditure (TDEE), basal metabolic rate (BMR), thermic effect of a meal (TEM), and PA were measured in 14 black and 15 white moderately obese women over 2 weeks. No statistically significant differences were seen between the 2 groups in BMR, TEM or TDEE. Mean PA was significantly (p = 0.05) lower among black women compared to whites when expressed as MJ. d-1 (3.49 vs. 4.30) or kJ.kg-1.d-1 (37.6 vs. 47.7). Our study supports the survey differences seen in PA among black and white women.

Exercise enhances dietary compliance during moderate energy restriction in obese women

The effect of aerobic exercise on dietary compliance was assessed in 13 obese women (44 +/- 3% fat) during a 12-wk weight-reduction program (EX group). Seventeen obese women (45 +/- 5% fat) not engaged in aerobic exercise (NX group) served as control subjects. The reducing diets were designed to promote a weight loss of 1 kg/wk, with energy intakes individually prescribed (mean +/- SD: 4.9 +/- 0.6 MJ/d) to approximate 75% of each subject's measured basal metabolic rate. The EX group completed of three 45-min sessions/wk of supervised aerobic exercise at 65% of maximal oxygen consumption (VO2max). Daily energy intakes were calculated by summing changes in body stores, measured by total body water isotope dilution, and total daily energy expenditure, measured by doubly labeled water (DLW). Dietary compliance was assessed by comparing calculated intakes with prescribed intakes. Both the EX and NX groups reported consuming close to their prescribed daily intakes, with differences of -0.08 +/- 0.28 (EX group) and +0.03 +/- 0.57 (NX group) MJ/d, respectively. However, expenditure/balance data determined by the DLW method indicated that the EX subjects exhibited better dietary compliance than the NX subjects, with intakes exceeding those prescribed by only 0.7 +/- 1.5 compared with 2.3 +/- 1.6 MJ/d for the NX subjects (P = 0.01). Therefore, an additional benefit of aerobic exercise during energy restriction is enhanced dietary compliance, which has important implications for the treatment of moderate obesity.

Effects of aerobic exercise and dietary carbohydrate on energy expenditure and body composition during weight reduction in obese women

To test the benefits of aerobic exercise and dietary carbohydrate during reduced-energy feeding, 23 obese women (44 +/- 4% fat) were randomly assigned to either aerobic exercise (Ex) or no exercise (Nx), and to a low-fat (LF) or low-carbohydrate (LC) reducing diet (5.00 +/- 0.56 MJ/d) for 12 wk. Changes in body composition, postabsorptive resting metabolic rate (RMR), thermic effect of a meal (TEM), and total daily energy expenditure (TDEE) were measured by respiratory gas exchange and doubly labeled water. Significant effects of Ex included a greater loss of fat mass (Ex: -8.8 +/- 2.1 vs Nx: -6.1 +/- 2.3 kg, P = 0.008) and maintenance of TDEE (Ex: +0.07 +/- 1.23 vs Nx: -1.46 +/- 1.04 MJ/d, P = 0.004), due to a difference in physical activity (Ex: +0.75 +/- 1.06 vs Nx: -0.61 +/- 1.03 MJ/d, P = 0.006), which was not attributable solely to the Ex sessions. RMR in both groups decreased comparably (-0.54 MJ/d), and TEM (% of meal) did not change. Diet composition did not significantly influence body composition or energy expenditure changes, but a greater weight loss was observed after the LC than after the LF (-10.6 +/- 2.0 vs -8.1 +/- 3.0 kg, P = 0.037) diet. The addition of aerobic exercise to a low-energy diet was beneficial in the treatment of moderate obesity because of its favorable effects on body composition, physical activity, and TDEE.

Comparison of heart rate and physical activity recall with doubly labeled water in obese women

Comparison of heart rate and physical activity recall with doubly labeled water in obese women. Med. Sci. Sports Exerc., Vol. 27, No. 1, pp. 126-133, 1995. Accurate methods of estimating total daily energy expenditure (TDEE) that are inexpensive and differentiate activities of varying intensities are needed in obesity research. We compared minute-by-minute heart rate (HR) monitoring and the 7-d physical activity recall (PAR) questionnaire with doubly labeled water (DLW) for the measurement of TDEE and physical activity in 14 obese women (45% +/- 4% fat, mean +/- SD) before and during 12 wk of weight reduction. TDEE was measured over 2 wk by DLW. HR monitoring was conducted for 3 d, with individual VO2/HR calibrations applied to HR data above 3 METs. PAR revealed the amount of time spent in sleep, moderate, hard, and very hard activities during 1 wk, with time spent in light activities determined by difference. Mean TDEE values, expressed as the % difference from DLW, prior to weight loss were -5.2 +/- 10.8% by HR and 3.4 +/- 14.4 by PAR, and during the diet were + 0.9 +/- 14.1% by HR and + 0.9 +/- 14.7% by PAR. Individual variability was high for both HR (-24.0 to + 25.6%) and PAR (-27.4 to + 36.2%). Energy expended in physical activity prior to weight loss were 3.97 +/- 1.23 MJ.d-1 by DLW, 3.91 +/- 0.90 by HR, and 4.79 +/- 0.95 by PAR. During weight loss, physical activity values by DLW, HR, and PAR were 4.31 +/- 1.18, 4.84 +/- 2.22, and 4.64 +/- 1.06 MJ.d-1, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Relative dilution spaces of 2H- and 18O-labeled water in humans

The doubly labeled water method for measuring energy expenditure can be very sensitive to small differences in the ratio of the 2H to 18O isotope dilution spaces. Recently it has been suggested that the average ratio is higher than the 1.03 we previously recommended. We therefore combined the data from 99 recently studied subjects. Subjects (85 females and 14 males) were between the ages of 4 and 78 yr (mean = 34 yr) and between 10 and 52% (mean = 35%) fat. The average 2H-to-18O dilution space ratio was 1.034 +/- 0.014, which was very similar to the original assumption. As in recent reports, we did find that most of the variance (60%) was due to random analytic error and that there was no correlation between the dilution space ratio and age or body fat. However, in contrast to recent reports we found no evidence of a gender difference. Use of the constant dilution space ratio of 1.034 to recalculate CO2 product in published validation studies demonstrated improved accuracy, and thus the value of 1.034 is suggested for use in future studies.

Body weight and mortality

Over the years ideal or desirable weights have been associated with the lowest mortality and defined in a number of ways. The widely used height-weight tables of the Metropolitan Life Insurance Company, developed in the 1940s, have been supplanted in the last decade by new weight standards based on findings of several population-based studies that compared body weight to mortality. The Quetelet or body mass index (BMI), now used as the de facto criterion for defining a desirable weight index, indicates relative fatness and is only minimally correlated with height. However, the optimal BMI or weight for longevity remains to be defined for a number of methodological reasons. This article reviews the strength of the evidence for increased mortality in adults who are overweight or underweight based on standard BMI ranges and in those who reported a change in body weight. Epidemiological studies show that excess body weight is associated with increased mortality, depending on fat patterning, gender, and age. A similar increase is shown for subjects with body weight below the relative weight range, although here associated life-style factors are greater contributors. Preliminary data suggest that change in body weight may also be associated with increased mortality. Overall, carefully measured weight and height remain the most easily performed and useful determinants of nutritional status and predictors of mortality for the general population.

Errors in estimating peritoneal fluid by bioelectrical impedance analysis and total body electrical conductivity

Whole-body bioelectrical impedance analysis (BIA) and total body electrical conductivity (TOBEC) have been used to estimate body composition and generalized changes in total body water (TBW). The sensitivity of these methods to measure small, rapid, localized changes in body water has not been fully evaluated. We compared the prediction of TBW by whole-body and segmental BIA and TOBEC with deuterium oxide dilution (D2O) in 10 control subjects and 7 renal failure patients receiving continuous ambulatory peritoneal dialysis (CAPD) prior to and after dialysate infusion. Using D2O as the reference method, there was no significant mean residual error between TBW predicted by BIA and TOBEC in controls (-1.2 +/- 1.5 and -0.9 +/- 1.0 kg) and CAPD patients pre-infusion (-1.0 +/- 2.0 and 0.29 +/- 2.01 kg). After infusing 1.9 +/- 0.18 kg dialysate, the mean residual error between change in body weight and the three methods was -0.44 +/- 0.53 kg for D2O (p < 0.1), -1.7 +/- 0.25 kg for BIA (p < 0.0001), and 1.2 +/- 0.4 kg for TOBEC (p < 0.001). Segmental BIA detected a 7.6% reduction in trunkal resistance with no significant change across the limbs, consistent with abdominal fluid accumulation. It is concluded that whole-body BIA underpredicts and TOBEC overpredicts small changes in peritoneal fluids.

When your obese patient can't lose weight

"I can't lose weight" is a frequent refrain among obese patients. Even though a patient desires to lose extra pounds and apparently is complying with his or her physician's recommendations, the expected weight loss often does not occur. To achieve a more successful outcome in obese patients, the authors suggest that physicians become active rather than passive participants in the weight loss regimen.

Long-term compliance with a lipid-lowering diet

Compliance with a lipid-lowering diet was sustained in only 30% of patients following an initial three-month intervention. Additional strategies are required to support long-term adherence.

Is the impedance index (ht2/R) significant in predicting total body water?

We investigated the general utility of bioelectrical impedance analysis (BIA) and the implications of BIA theory in populations of various ages from infancy to adulthood by developing a single impedance equation. Four subject data sets representing 62 adults, 37 prepubertal children, 44 preschool children, and 32 premature low-birth-weight neonates were combined. Subjects were randomly divided into a development group (n = 116) and a cross-validation group (n = 59). The single best predictor of total body water (TBW) was height2/resistance (ht2/R), which explained 99% of the variation in TBW (SEE = 1.67 kg). The addition of weight reduced the SEE to 1.41 kg. A significant bias was only seen in the preschool children. These results were confirmed in the cross-validation group and the best prediction formula was TBW = 0.59 ht2/R + 0.065 wt + 0.04. We conclude that the impedance index (ht2/R) is a significant predictor of TBW and that there is some improvement in prediction of TBW by inclusion of a weight term.

Comparison of two bioelectrical impedance analysis models for total body water measurement in children

We compared two bioelectrical impedance analysis models, the right-sided tetrapolar method and an experimental cylindrical method, to total body water (TBW) determined by isotopic dilution in 37 prepubertal children aged 5-9 years, who were divided into development and cross-validation groups. Despite its theoretical advantage, no improvement in predicted TBW was seen with the experimental method. The best predictive equation, using the tetrapolar method, was TBW (kg) = 1.84 + 0.45 (height square/resistance) +0.11(weight); r2 = 0.98; SEE = 0.62 kg.

Should enteral nutrition be considered as primary therapy in acute Crohn's disease?

Clinical trials indicate that elemental enteral diets are equally as effective as corticosteroid treatment for acute Crohn's disease; however, a clear efficacy of polymeric formulas has yet to be demonstrated. Moreover, the mechanism of action of enteral nutrition remains uncertain, and further study is needed to define the precise role of specialized enteral formulas in the long-term management of this disease.

Bioelectrical impedance analysis: a review of principles and applications

Whole-body bioelectrical impedance analysis (BIA) is widely used by researchers and clinicians as a noninvasive and safe method to estimate body composition and body water volume in children and adults. Development of new approaches, such as segmental and multifrequency analyzers, should greatly expand the utility of this electrical technique. This article reviews the principles, underlying assumptions, clinical applications and future directions of the BIA method.

Nutrition training in graduate medical (residency) education: a survey of selected training programs

Because limited information exists about nutrition training of residents, we studied the teaching practices of nationally recognized nutrition programs. Two hundred thirty-eight nutrition educators and 787 residency-program directors identified 160 institutions with strong nutrition training. The 23 highest-ranked programs were surveyed and 7 were visited. The results showed that 1) clinically active physician-nutritionist role models are the key elements in teaching residents clinical nutrition; 2) multidisciplinary nutrition support teams are valuable learning resources unless they function primarily as technical support services; 3) nutrition elective rotations, although highly effective, are taken by a minority of residents; 4) the nutrition curriculum should include practical learning materials and conferences; and 5) a research environment is important to attract qualified physician-nutritionist role models. A major deficit is teaching nutritionally based approaches to disease prevention in the ambulatory setting. Finally, a shortage of nutrition-oriented physician role models is probably the major constraint in teaching nutrition to residents.

Orderly dieting and disordered eating: a case report

A moderately obese 49-year-old woman who was enrolled in a nutrition and weight control clinic quickly attained her target weight through an individualized program of balanced deficit diet, routine exercise, and weekly counseling. Weight loss continued until she was 15% below Metropolitan Relative Weight, when family members grew concerned that she had developed an eating disorder. Despite nutritional and behavioral counseling, she has rigorously maintained her exaggerated weight loss. This case report illustrates a potentially serious but often overlooked reason for careful monitoring of patients undergoing treatment for obesity. Health professionals involved in weight control programs should routinely assess patients for potential eating disorders.

Resting and total energy expenditure in patients with inflammatory bowel disease

Patients with inflammatory bowel disease often present with weight loss. Among possible causes, an elevated energy expenditure has frequently been suggested but is the least documented. In this study resting metabolic rate (RMR) and total daily energy expenditure (TDEE) were measured in 15 outpatients with inflammatory bowel diseases and in eight healthy control subjects. Measured RMR as a percentage of that predicted from fat-free mass was not significantly different for control subjects (102 +/- 9.8%, mean +/- SD) and patients (100 +/- 13.3%). TDEE, expressed as a multiple of RMR, was 1.70 +/- 0.31 for control subjects and 1.78 +/- 0.24 for patients. When patients were subgrouped as greater than or equal to 90% or less than 90% desirable body weight, a mean increase over RMR predicted from fat-free mass was seen in the underweight patients (106 +/- 9.3%) but not in normal-weight patients (99.0 +/- 15.6%). Mean TDEE/RMR values for the patient subgroups were 1.70 +/- 0.30 and 1.88 +/- 0.08, respectively. We conclude that stable outpatients with inflammatory bowel disease have only a minimal increase in energy needs.

Validation of bioelectrical-impedance analysis as a measurement of change in body composition in obesity

The bioelectrical-impedance-analysis (BIA) method accurately measures body composition in weight-stable subjects. This study validates the use of BIA to measure change in body composition. Twelve obese females underwent weight loss at a mean rate of 1.16 kg/wk. Body composition was measured by deuterium oxide dilution (D2O), BIA, and skinfold anthropometry (SFA) at baseline and at 5% decrements in weight. Highly significant correlations were obtained between D2O and BIA (r = 0.971) and between D2O and SFA (r = 0.932). Overall, BIA predicted change in fat-free mass with greater accuracy (to 0.4 kg) and precision (+/- 1.28 kg) than did anthropometry (to 0.8 kg and +/- 2.58 kg, respectively). We conclude that BIA is a useful clinical method for measuring change in body composition.

Implementing nutrition into the medical curriculum: a user's guide

The medical profession is facing the challenges of the 1990s with a shift to outpatient care and preventive services. Medical schools will need to respond to these forces by reevaluating their curricula and setting new objectives. Nutrition is an essential element in the process of curriculum change. The nutrition educator will be expected to take a leading role in integrating nutrition into the medical school curriculum. This report presents steps and strategies to initiate the process.

Priorities for nutrition content in a medical school curriculum: a national consensus of medical educators

The ASCN Committee on Medical/Dental School and Residency Nutrition Education conducted a series of activities to establish guidelines for nutrition core content in a medical school curriculum. These activities included mail surveys of medical-nutrition educators and a representative group of medical school curriculum administrators and a national consensus workshop of nutrition educators. Results indicated close agreement between the nutrition educators and curriculum administrators (r = 0.89, p less than 0.0001) on the importance ratings of 41 nutrition topics and on the number of hours of nutrition course work that medical schools should provide (44 vs 37 h, respectively, p = 0.14). There was consensus among the nutrition educators that 26 topics should be given priority ratings as essential for inclusion in medical course work. Further prioritization of these topics resulted in a listing of core content topics and subtopics to serve as a guide to administrators and educators for planning nutrition course work in a medical school curriculum.

Estimation of lean body mass by bioelectrical impedance analysis compared to skinfold anthropometry

Estimation of lean body mass (LBM) is an important procedure in nutritional assessment and the availability of a rapid, portable and reproducible method would be desirable for this purpose. At present, only bioelectrical impedance analysis (BIA) and skinfold anthropometry are applicable for clinical use. We compared the prediction of LBM by these two methods in 80 subjects stratified into four subgroups by body mass index (BMI): lean, normal, obese and super-obese. Highly significant correlation coefficients (r greater than 0.92, P less than 0.001) were seen for all subgroups with a mean difference between techniques LBManthro-LBMBIA/LBManthro X 100) of less than 1 kg or 1 per cent error. A greater s.d. and error was noted in the super-obese (BMI greater than or equal to 40.0). Fifteen subjects had measurements repeated after a mean weight loss of 10 per cent. Although mean difference between methods was not statistically significant, there was a large individual variation. It is concluded that there is an excellent agreement between the estimation of LBM by bioelectrical impedance and skinfold anthropometry in the weight-stable subject.

Endoscopic, radiographic, and clinical response to prolonged bowel rest and home parenteral nutrition in Crohn's disease

Total parenteral nutrition is widely used as a therapeutic measure in patients with severe, active Crohn's disease unresponsive to conventional medical management. We have reviewed our experience with 10 patients with nonfistulous Crohn's disease treated by home parenteral nutrition (HPN) and bowel rest (nothing-by-mouth) assessing the nutritional, radiologic, endoscopic, and clinical responses. After a mean of 4.1 months of treatment, all patients had a marked improvement in nutritional status and resolution of gastrointestinal symptoms; 90% reduced their corticosteroid dose. Eight of nine patients had endoscopic and/or radiographic evidence of mucosal healing. Although 60% of patients were able to avoid surgery and tolerate refeeding, all six patients continue to require steroids to control symptoms. Our study suggests that HPN and bowel rest is a useful therapeutic approach to selected patients with active Crohn's disease, which permits a reduction in corticosteroid dosage and partial healing of mucosal lesions in most. Further studies are required to determine which patients should receive HPN and its optimal duration.

Estimation of total body water by bioelectrical impedance analysis

Total body water (TBW) measured by bioelectrical impedance analysis (BIA) was directly compared with deuterium-isotope dilution in a total of 58 subjects. First, sex-specific and group equations were developed by multiple regression analysis in (10 each) obese and nonobese men and women. Height/resistive impedance was the most significant variable used to predict deuterium-dilution space (D2O-TBW) and, combined with weight, yielded R = 0.99 and SE of estimate = 1.75 L. Equations predicted D2O-TBW equally well for obese and nonobese subjects. Second, the equations were prospectively tested in a heterogeneous group of 6 males and 12 females. Sex-specific equations predicted D2O-TBW with good correlation coefficients (0.96 and 0.93), total error (2.34 and 2.89 L), and a small difference between mean predicted and measured D2O-TBW (-1.4 +/- 2.05 and -0.48 +/- 2.83 L). BIA predicts D2O-TBW more accurately than weight, height, and/or age. A larger population is required to validate the applicability of our equations.

Validation of doubly labeled water for measuring energy expenditure during parenteral nutrition

The doubly labeled water method was compared with intake-balance for measuring energy expenditure in five patients receiving total parenteral nutrition (TPN). Because parenteral solutions were isotopically different from local water, patients had to be placed on TPN at least 10 days before the metabolic period. Approximately 0.1 g 2H2O and 0.25 g H2(18)O per kg total body water were given orally. We collected saliva before, 3 h, and 4 h after the dose for measurement of total body water and urine before, 1 day, and 14 days after the dose for measurement of isotope eliminations. On day 14, total body weight was remeasured and change in body energy stores was calculated, assuming constant hydration. Intake was assessed from weights of TPN fluids plus dietary record for any oral intake. Energy expenditure from doubly labeled water (+/- SD) averaged 3 +/- 6% greater than intake-balance. Doubly labeled water method is a noninvasive, nonrestrictive method for measuring energy expenditure in patients receiving TPN.

Total parenteral nutrition-associated metabolic acidosis

To prevent acid-base disturbances, a patient receiving intravenous nutritional solutions must excrete the daily metabolic production of acid. These hydrogen ions are generated from external (infused) sources and internal metabolic processes. Patients with normal respiratory and renal organ function are capable of excreting these volatile and nonvolatile acids, respectively, and maintaining acid-base balance. However, increased renal or gastrointestinal loss of bicarbonate, diminished renal excretion of acid, or increased acid production may all result in a metabolic acidosis. This article reviews the mechanisms of hydrogen ion production associated with total parenteral nutrition and the variety of disease states leading to development of a metabolic acidosis.

Metabolic acidosis. Development in two patients receiving a potassium-sparing diuretic and total parenteral nutrition

Two patients developed a metabolic acidosis associated with a normal undetermined anion concentration while receiving a potassium-sparing diuretic and total parenteral nutrition. In both cases the metabolic acidosis resolved within one week after discontinuing administration of the diuretic. The use of potassium-sparing diuretics in a patient receiving total parenteral nutrition requires caution and continued monitoring for this potential drug-nutrient interaction.

Intense nutritional support in inflammatory bowel disease: a review

We have reviewed the value of intense nutritional support in inflammatory bowel disease (IBD), relying mostly on the limited uncontrolled studies that have been performed. In most circumstances, nutritional restitution and a short-term clinical remission are accomplished when this support is provided. In some patients, particularly those with Crohn's disease who undergo surgery, intense nutritional support probably decreases morbidity and mortality. Children with IBD can undergo linear growth rates with nutritional supplementation. There is a great need for additional controlled studies.