Mass-zero constrained molecular dynamics for electrode charges in simulations of electrochemical systems

Classical molecular dynamics simulations have recently become a standard tool for the study of electrochemical systems. State-of-the-art approaches represent the electrodes as perfect conductors, modeling their responses to the charge distribution of electrolytes via the so-called fluctuating charge model. These fluctuating charges are additional degrees of freedom that, in a Born-Oppenheimer spirit, adapt instantaneously to changes in the environment to keep each electrode at a constant potential. Here, we show that this model can be treated in the framework of constrained molecular dynamics, leading to a symplectic and time-reversible algorithm for the evolution of all the degrees of freedom of the system. The computational cost and the accuracy of the new method are similar to current alternative implementations of the model. The advantage lies in the accuracy and long term stability guaranteed by the formal properties of the algorithm and in the possibility to systematically introduce additional kinematic conditions of arbitrary number and form. We illustrate the performance of the constrained dynamics approach by enforcing the electroneutrality of the electrodes in a simple capacitor consisting of two graphite electrodes separated by a slab of liquid water.

Adherence to the Mediterranean Diet in children and adolescents: A systematic review

BACKGROUND AND AIM

A decreased adherence to the Mediterranean Diet (MD) may be related to a rise in chronic non-communicable diseases from childhood onward. The aim of this systematic review was to summarize the available literature regarding MD adherence in children and adolescents, and focusing, more specifically, on the association of MD adherence with demographic and anthropometric variables, body composition, lifestyle, and diet adequacy.

METHODS AND RESULTS

A search of scientific literature was carried out on PUBMED, SCOPUS, Clinical Trials Results, Google Scholar, and British Library Inside for studies published in the last 20 years. Fifty-eight papers were finally included according to the following criteria: MD adherence evaluated through a quantifying score or index, age 2-20 years, sample size >200 participants, observational or intervention studies regarding the general population. The KIDMED index was the most widely used scoring system. MD adherence widely varied within the Mediterranean countries for both children and adolescents, with also large differences among various European countries, while few data are available for non-Mediterranean countries. Most of the eligible studies showed that MD adherence was directly associated with physical activity (and possibly with diet adequacy) and inversely with sedentary behavior, while the results for gender, age, socioeconomic status and weight status were not consistent.

CONCLUSIONS

Further validation of MD indexes in terms of reproducibility and consistency with the MD is needed. At the same time, more prospective cohort and intervention studies may better elucidate the relationships of MD adherence with behavioral and health outcomes.

Protective role of the Mediterranean diet on several cardiovascular risk factors: evidence from Sicily, southern Italy

BACKGROUND AND AIMS

Epidemiological studies conducted in European countries demonstrated that the adoption of a Mediterranean diet protect against clustered risk factors but those evaluating such benefits specifically in southern Italy are scarce. Thus, the aim of this study was to assess the association between the adherence to the Mediterranean diet and cardiovascular risk factors obesity, diabetes, and hypertension.

METHODS AND RESULTS

A cross-sectional population-based survey including 3090 subjects was conducted in Sicily, southern Italy. Food intake was evaluated through a validated food frequency questionnaire and adherence to the dietary pattern was assessed using the MedDietScore. Linear and logistic regression models were performed to estimate odds ratios (ORs) and respective confidence intervals (CIs). After adjusting for confounding factors such as age and gender, participants in the highest tertile of the MedDietScore were less likely to be obese (OR 0.35, 95% CI: 0.24-0.51), hypertensive (OR 0.73, 95% CI: 0.55-0.97), and diabetic (OR 0.43, 95% CI: 0.24-0.77). Linear inverse relation between the MedDietScore and BMI (r(2) = 0.34, P < 0.001), waist circumference (r(2) = 0.17, P < 0.001), and waist-to-hip ratio (r(2) = 0.06, P < 0.001) was found.

CONCLUSION

Despite the prevalence rates of nutrition-related diseases are high in Sicily, greater adherence to the Mediterranean dietary pattern is still associated with a better health status.

Population based strategy for dietary salt intake reduction: Italian initiatives in the European framework

Excess dietary sodium chloride (salt) intake is etiologically related to hypertension and cardiovascular disease (CVD). Moderate reduction of salt intake reduces blood pressure (BP) and is expected to contribute to reduce the risk of CVD. Previous community-based trials to reduce BP by means of salt reduction were very successful. The initial positive results of national strategies of dietary salt intake reduction in several European countries, driven by the initiative of the World Health Organisation (WHO) and non-governmental organisations such as the World Action of Salt and Health (WASH), have paved the way for action in other European Union (EU) member states. In Italy, several initiatives aiming at reduction of salt intake at the population level have been recently undertaken. These initiatives include i) the evaluation of current dietary habits promoted by the Working Group for Dietary Salt Reduction in Italy (GIRCSI); ii) the chemical analysis of the bread salt content, a major source of sodium intake in Italy, and the agreement between the bakers' associations and the Ministry of Health for a gradual reduction of the bread salt content; iii) the implementation of educational campaigns to increase population awareness, iv) the involvement of the food catering system. In the immediate future, food reformulation must be extended to other food categories in collaboration with industry, foods' salt targets ought to be defined, the food labelling system must be improved and population salt awareness must be further increased through educational campaigns. The GIRCSI Working Group is committed to pursue these objectives.

Heart rate variability as a measure of autonomic nervous system function in anorexia nervosa

BACKGROUND AND HYPOTHESIS

Alteration in sympathovagal balance may be a mechanism of increased cardiovascular mortality and sudden death of patients with anorexia nervosa. This study was undertaken to characterize cardiac autonomic control in patients with anorexia nervosa by means of heart rate variability analysis.

METHODS

Heart period variability by 24-h Holter recording was evaluated in 13 young women with anorexia nervosa, 10 constitutionally thin women, and 10 women of normal weight.

RESULTS

High-frequency power, a measure of parasympathetic modulation of heart rate, and all-time domain measures of heart rate variability were higher in patients with anorexia nervosa than in thin women and in those of normal weight. Thin women showed lower values of total power and of most components of power spectrum.

CONCLUSIONS

Our data demonstrate an increased vagal tone in young women with anorexia nervosa. The marked increase in parasympathetic activity, not in response to an increase in sympathetic activity, could be detrimental and may contribute to the higher cardiovascular mortality of these patients.

Very low protein diet supplemented with ketoanalogs improves blood pressure control in chronic kidney disease

Blood pressure (BP) is hardly controlled in chronic kidney disease (CKD). We compared the effect of very low protein diet (VLPD) supplemented with ketoanalogs of essential amino acids (0.35 g/kg/day), low protein diet (LPD, 0.60 g/kg/day), and free diet (FD) on BP in patients with CKD stages 4 and 5. Vegetable proteins were higher in VLPD (66%) than in LPD (48%). LPD was prescribed to 110 consecutive patients; after run-in, they were invited to start VLPD. Thirty subjects accepted; 57 decided to continue LPD; 23 refused either diet (FD group). At baseline, protein intake (g/kg/day) was 0.79+/-0.09 in VLPD, 0.78+/-0.11 in LPD, and 1.11+/-0.18 in FD (P<0.0001). After 6 months, protein intake was lower in VLPD than LPD and FD (0.54+/-0.11, 0.78+/-0.10, and 1.04+/-0.21 g/kg/day, respectively; P<0.0001). BP diminished only in VLPD, from 143+/-19/84+/-10 to 128+/-16/78+/-7 mm Hg (P<0.0001), despite reduction of antihypertensive drugs (from 2.6+/-1.1 to 1.8+/-1.2; P<0.001). Urinary urea excretion directly correlated with urinary sodium excretion, which diminished in VLPD (from 181+/-32 to 131+/-36 mEq/day; P<0.001). At multiple regression analysis (R2=0.270, P<0.0001), BP results independently related to urinary sodium excretion (P=0.023) and VLPD prescription (P=0.003), but not to the level of protein intake. Thus, in moderate to advanced CKD, VLPD has an antihypertensive effect likely due to reduction of salt intake, type of proteins, and ketoanalogs supplementation, independent of actual protein intake.

Development of a tomato-based food for special medical purposes as therapy adjuvant for patients with HCV infection

OBJECTIVE

The present study aimed to develop a food for special medical purposes (FSMP) and to assess its efficacy as adjuvant therapy in patients with chronic hepatitis C virus (HCV).

DESIGN

Open randomized clinical trials with a tomato-based FSMP used as adjuvant treatment to the pharmacological therapy with pegilated interferon and ribavirin.

SUBJECTS

Eight healthy volunteers and 39 HCV patients.

INTERVENTIONS

For the bioavailability study, healthy subjects consumed 100 g/die FSMP for a week and their serum carotenoid profile at baseline, after the week of administration and 7 days later was determined. The same quantity of FSMP for 6 months by 20 of the 39 HCV patients was consumed in the clinical trial. Serum transaminase, haemoglobin (Hb) and hydroperoxide concentrations during the therapy were monitored in all patients.

RESULTS

FSMP consumption caused a fourfold increase of lycopene serum concentration in healthy subjects. A significant increase of carotenoids after 1 month of consumption also in patients with HCV was recorded. Transaminase and Hb serum levels, as well as therapeutic response, were not influenced by FSMP. The decrease in serum hydroperoxides was independent from FSMP consumption in long-term responder patients, whereas nonresponder (NR) patients of FSMP group showed higher reductions than NR patients of Control group.

CONCLUSIONS

The FSMP was effective in improving carotenoid status in healthy subjects. In HCV patients, it did not influence the therapeutic response, but it prevented carotenoid serum depletion and it was effective in improving the oxidative status during antiviral therapy in NR patients.

Bioavailability of carotenoids from spinach and tomatoes

BACKGROUND AND AIM

Few published studies have described the bioavailability of the different carotenoids in spinach. This was designed to evaluate the effects on plasma carotenoid concentrations of a daily consumption of spinach (rich in lutein and beta-carotene), alone or together with lycopene-rich tomato puree.

METHODS AND RESULTS

Nine healthy young women consumed a standard low-carotenoid diet during the pre-study phase, the spinach diet (standard diet plus 150 g spinach: 9 mg lutein, 4 mg beta-carotene) from day 0 to day 21, and then, after a wash-out period, the spinach-tomato diet (standard diet plus 150 g spinach and 25 g tomato puree: 9 mg lutein, 4.3 mg beta-carotene and 7 mg lycopene) from day 35 to day 56. The spinach and spinach-tomato supplements were consumed together with 10 g olive oil. Fasting blood samples were collected on day -7, and every week thereafter. Plasma carotenoid concentrations significantly decreased during the standard low-carotenoid diet. Lutein levels gradually increased after spinach consumption from 0.36+/-0.05 to 1.59+/-0.19 micromol/L (p<0.0001), decreased during the wash-out period from 1.59+/-0.19 to 0.62+/-0.07 micromol/L (p<0.001), and rose again after the intake of spinach-tomato puree from 0.62+/-0.07 to 1.55+/-0.17 micromol/L (p<0.0001). beta-carotene levels also increased during both dietary supplementation periods. Lycopene decreased during the spinach diet from 0.20+/-0.03 to 0.07+/-0.01 micromol/L (p<0.001) and increased during the spinach-tomato diet from 0.05+/-0.01 to 0.52+/-0.06 micromol/L (p<0.0001).

CONCLUSIONS

The results of this study confirm that a regular intake of selected vegetables leads to a progressive increase in plasma carotenoid concentrations. The addition of tomato puree to spinach does not decrease lutein plasma concentrations. Furthermore, baseline plasma levels of lutein and lycopene are important variables affecting the relative increase in their levels after supplementation: ie more depleted subjects are expected to have a greater percent rise in plasma carotenoid concentrations.

Nutrition and prevention of ischemic stroke: present knowledge, limitations and future perspectives

Stroke, particularly ischemic stroke, has a major impact on public health due to its high incidence, prevalence and rate of subsequent disability in Italy as in most industrialised countries. Apart from age, many modifiable factors, such as hypertension, smoking, diabetes, dyslipidemia, obesity, physical inactivity, alcohol abuse and hyperhomocysteinemia, have been recognised as playing a role in the pathogenesis of this disease. While appropriate pharmacological therapy has proven effective in the prevention of stroke in particular categories of patients, most of the above mentioned predisposing conditions are amenable to be affected by nutrition. Unequivocal demonstration of a protective or adverse role of single foods and nutrients against the risk of stroke has been however difficult to achieve due to confounding by biological variability, methodological inadequacies in the assessment of individual nutritional habits and difficulty to carry out long-term randomised controlled trials in the nutritional area. Notwithstanding, in several cases, causal relationships could be inferred from case-control and cohort studies in the presence of plausible and reproducible associations, evidence of dose-dependent effects and consistency in the results of different studies. The aim of this paper was to review present knowledge and highlight limitations and future perspectives about the role of nutrition in the prevention of ischemic stroke.

The prediction of single-frequency BIA variables from individual characteristics

To define whether reference values for bioimpedance analysis (BIA) can be predicted in healthy individuals, individual characteristics and BIA variables (resistance index=height(2)/parallel resistance and reactance index= height(2)/parallel reactance) were evaluated in non-obese healthy individuals: 863 men and 769 women with an age range 20-70 years and body mass index (BMI) 19.0-29.9 kg/m(2). The following predictive equations were obtained using multiple regression analysis:Resistance index (cm(2)/ohm)Males 21.06 + 0.087xage + 1.091xweight -1.801xBMI,Females 20.35 + 0.037xage + 0.878xweight - 1.343xBMIReactance index (cm(2)/ohm)Males 0.57 + 0.117xweight - 0.096xBMIFemales 1.42 + 0.078xweight - 0.075xBMIIn conclusion, reference BIA values seem to be reasonably predicted based on individual characteristics.

The prediction of basal metabolic rate in young adult, severely obese patients using single-frequency bioimpedance analysis

To evaluate whether bioimpedance analysis (BIA) is a useful tool for predicting basal metabolic rate (BMR), sex, age, height, weight, BMI, and single-frequency BIA variables (resistance index and phase angle) were assessed in 61 young adult non-diabetic obese patients (BMI >35 kg/m(2)). BMR was measured by indirect calorimetry. In both sexes BMR significantly correlated with weight, BMI, and resistance index. Using multiple regression analysis, the following prediction equations were derived: (1). considering individual characteristics: BMR (kcal/day)=780+11.4xweight (+221 for men); (2). including also BIA variables: BMR=- 96+8.4xresistance index+8.3xweight+82.5xphase angle. Thus, in young adult, severely obese individuals, BIA variables are significant predictors of BMR.

Comparison of bioelectrical impedance analysis and dual-energy X-ray absorptiometry for the assessment of appendicular body composition in anorexic women

OBJECTIVE

To establish the accuracy of bioelectrical impedance analysis (BIA) for the assessment of appendicular body composition in anorexic women.

DESIGN

Cross-sectional study.

SETTING

Outpatient University Clinic.

SUBJECTS

A total of 39 anorexic and 25 control women with a mean (s.d.) age of 21 (3) y.

METHODS

Total, arm and leg fat-free mass (FFM) were measured by dual-energy X-ray absorptiometry and predicted from total and segmental BIA at 50 kHz. The predictor variable was the resistance index (Rl), that is, the ratio of height (2) to body resistance for the whole body and the ratio of length(2)/limb resistance for the arm and leg.

RESULTS

Predictive equations developed on controls overestimated total, arm and leg FFM in anorexics (P<0.0001). Population-specific equations gave a satisfactory estimate of total and appendicular FFM in anorexics (P=NS) but had higher percent root mean square errors (RMSEs%) as compared to those developed on controls (8% vs 5% for whole body, 12% vs 10% for arm and 10% vs 8% for leg). The accuracy of the estimate of total and leg FFM in anorexics was improved by adding body weight (Wt) as a predictor with Rl (RMSE%=5% vs 8% and 7% vs 10%, respectively). However, the same accuracy was obtained using Wt alone, suggesting that in anorexics, BIA at 50 kHz is not superior to Wt for assessing total and leg FFM.

CONCLUSION

BIA shows some potential for the assessment of appendicular body composition in anorexic women. However, Wt is preferable to BIA at 50 kHz on practical grounds. Further studies should consider whether frequencies >50 kHz give better estimates of appendicular composition in anorexics as compared to Wt.

SPONSORSHIP

University of Napoli.

Comparison between different methods to assess the prevalence of obesity in a sample of Italian children

The aim of this study was to compare how different diagnostic criteria can influence the estimation of obesity in children. Five hundred and eighty-seven children from Southern Italy were evaluated for the presence of obesity according to six different methods: two using Ideal Body Weight, according to Tanner and the National Center for Health Statistics, and four using Body Mass Index, according to Rolland-Cachera, Must, Cole (International Obesity Task Force) and the Centers for Disease Control and Prevention. Large discrepancies were found between old and new methods in identifying childhood obesity with respect to absolute prevalence, differences between the sexes, and age-related trends. The use of different weight-height indices, the employment of different cut-off points, the large differences between the reference populations, and the different time periods of data collection explain differences between methods. This should be always taken into consideration when data from different epidemiological or clinical studies are compared.

Are the general equations to predict BMR applicable to patients with anorexia nervosa?

AIM

To determine whether the general equations to predict basal metabolic rate (BMR) can be reliably applied to female anorectics.

INDIVIDUALS AND METHODS

Two hundred and thirty-seven female patients with anorexia nervosa (AN) were divided into an adolescent group [n=43, 13-17 yrs, 39.3+/-5.0 kg, body mass index (BMI) (weight/height) 15.5+/-1.8 kg/m2] and a young-adult group (n=194, 18-40 yrs, 40.5+/-6.1 kg, BMI 15.6+/-1.9 kg/m2). BMR values determined by indirect calorimetry were compared with those predicted according to either the WHO/FAO/UNU or the Harris-Benedict general equations, or using the Schebendach correction formula (proposed for adjusting the Harris-Benedict estimates in anorectics).

RESULTS

Measured BMR was 3,658+/-665 kJ/day in the adolescent and 3,907+/-760 kJ/day in the young-adult patients. In the adolescent group, the differences between predicted and measured values were (mean+/-SD) 1,466 529 kJ/day (+44+/-21%) for WHO/FAO/UNU, 1,587+/-552 kJ/day (+47+/-23%) for the Harris-Benedict and -20+/-510 kJ/day for the Schebendach (+1+/-13%), while in the young-adult group the corresponding values were 696+/-570 kJ/day (+24+/-24%), 1,252+/-644 kJ/day (+37+/-27%) and -430+/-640 kJ/day (-9+/-16%). The bias was negatively associated with weight and BMI in both groups when using the WHO/FAO/UNU and Harris-Benedict equations, and with age in the young-adult group for the Harris-Benedict and Schebendach equations.

CONCLUSIONS

The WHO/FAO/UNU and Harris-Benedict equations greatly overestimate BMR in AN. Accurate estimation is to some extent dependent on individual characteristics such as age, weight or BMI. The Schebendach correction formula accurately predicts BMR in female adolescents, but not in young adult women with AN.

Body composition changes in patients with anorexia nervosa after complete weight recovery

OBJECTIVE

To assess body composition changes occurring in female anorectic patients after complete weight recovery.

DESIGN

Longitudinal study.

SUBJECTS

: Ten female patients with anorexia nervosa (age at baseline: 19.7+/-5.8 y) were studied both when undernourished (body mass index, BMI 14.8+/-1.3 kg/ m(2)) and after the achievement of a BMI >18.5 kg/m(2). The control group comprised 18 well-nourished women (age 20.1+/-4.4 y; BMI 19.0-23.0 kg/ m(2)).

INTERVENTIONS

Fat mass and fat-free mass were determined by dual-energy X-ray absorptiometry. Skinfold thicknesses and circumferences were also measured. Arm muscle area and arm fat area were calculated by standard formulas.

RESULTS

The undernourished patients had lower fat-free mass, fat mass, skinfold thicknesses and circumferences. After refeeding, fat mass represented 25-71% (mean 56%) of the mass regained, this percentage being directly related to the extent of weight gain. The increases in skinfolds and circumferences depended upon the site considered and were correlated to a various extent with those in weight or BMI. Skinfolds at biceps and abdominal sites and the waist-to-hip ratio remained significantly higher, whereas arm muscle circumference was significantly lower, in the refed group than in the control one.

CONCLUSION

The percentage of fat in the weight regained by refed female anorectic patients was directly related to the extent of body mass increase. Refed anorectic patients appear to preferentially regain fat in the abdominal and triceps regions. Abnormalities in skinfolds (at biceps and abdominal sites), arm muscle area and waist-to-hip ratio still persist in refed anorectic patients in comparison to control healthy controls.

Predictors of survival in terminal-cancer patients with irreversible bowel obstruction receiving home parenteral nutrition

Clinical, anthropometric, hematologic, and biochemical variables, evaluated immediately before starting nutritional treatment, were related to survival in 76 terminal-cancer patients with irreversible bowel obstruction receiving home parenteral nutrition. At baseline, abnormally low values were observed in the following percentages of patients: 40.8% for body mass index, 59.2% for serum albumin, 84.2% for hemoglobin, 48.7% for lymphocyte count, and 60% for serum cholesterol. Survival on home parenteral nutrition ranged between 6 and 301 d, with a median of 74 d. Hemoglobin, serum albumin and serum cholesterol were lower in patients with a survival of less than 3 mo. With regard to Karnofsky performance status, median survival times were 63 d for a score below or equal to 50 and 128 d for a score between 60 and 70. Albumin and a Karnofsky score above 50 (but not age, weight, body mass index, lymphocyte count, or cholesterol) emerged (with a positive sign) as predictors of survival. In conclusion, terminal-cancer patients with irreversible bowel obstruction are often malnourished, showing a high prevalence of anemia and hypoalbuminemia. Survival differs widely and can be predicted only to a limited extent from initial values of serum albumin and Karnofsky performance status.

Use and abuse of albumin: a survey of clinical records from an internal medicine ward

BACKGROUND AND AIMS

This study was to review albumin prescriptions and indications in 4122 patients hospitalized in internal medicine wards in the years 1996, 1998 and 1999, before and after the ad hoc regulations issued in 1997 by the Italian Ministry of Health.

METHODS

In 1996 (n=63), 1998 (n=59) and 1999 (n=55) 177 of these patients (4.3%) were given i.v. albumin.

RESULTS

161 (91%) of them had serum albumin values of <3.5 g/dl, while in only 36% were these values <2.5 g/dl.

CONCLUSION

In the majority of cases albumin was erroneously prescribed, often to enhance diuretic efficacy or in protein energy malnutrition. Its prescription has not been influenced by the new recommendations.

The prediction of basal metabolic rate in female patients with anorexia nervosa

OBJECTIVE

To evaluate in female patients with anorexia nervosa the accuracy of a specific predictive formula for basal metabolic rate (BMR) already proposed in the literature and to derive a new disease-specific equation with the same purpose.

DESIGN

Cross-sectional study.

SUBJECTS

One-hundred and twenty adolescent girls (<18 y) and young-adult women (18-30 y) with anorexia nervosa.

MEASUREMENTS

BMR was determined by indirect calorimetry or predicted according to the Schebendach formula, which was specifically derived for anorexia nervosa.

RESULTS

On average the Schebendach formula performed well in the adolescent group but not in the young-adult group. The range including 95% of the predicted-measured differences was in both cases wider than 2000 kJ/day. In the young-adult patients the accuracy of the prediction was also related to age and body mass index. Weight and age (but not height or body mass index) emerged as predictors of BMR in the sample as a whole, and only weight when the two age groups were considered separately, thus leading to three different equations. The intercepts of these regression lines were very close and not significantly different from zero while their standard error of estimate was 500-550 kJ/day.

CONCLUSION

The Schebendach formula is not very accurate in estimating the BMR of female anorectic patients. Moreover, in this group the relationship between BMR and weight was altered. The predictive formulas proposed by the present study have a reasonable prediction power.

Antioxidant activity and general fruit characteristics in different ecotypes of Corbarini small tomatoes

Sixteen ecotypes of Corbarini small tomatoes were studied. The antioxidant activity was evaluated with the DMPD (N, N-dimethyl-p-phenylenediamine) method in the water-soluble fraction (S-AA) and with the ABTS [2, 2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)] method in the water-insoluble fraction (I-AA). S-AA and I-AA were strongly related to each other, varying to a large extent between the ecotypes considered. They were also significantly correlated with fruit weight, total solids, and refractive index. The combination of the latter variables (by multiple regression analysis) accounted for 36% and 44% of the total variability of S-AA and I-AA, respectively. Moreover, when the ecotypes were subdivided according to their shape (round, pear-shaped, oval, and long), S-AA and I-AA were both significantly higher in round tomatoes and lower in the long ones. In conclusion, the antioxidant activity varies to a considerable extent between different ecotypes of Corbarini small tomatoes. These differences are related to shape and some other fruit characteristics.

Albumin synthesis is diminished in men consuming a predominantly vegetarian diet

Albumin synthesis was calculated in healthy male volunteers consuming diets differing in the relative contribution of protein from animal or vegetable sources. In one study (Study 1, n = 4) two isoenergetic and isonitrogenous diets were consumed for a period of 10 d each. One diet (diet A) was animal protein rich (74%), the other one (diet V) contained 67% of vegetable protein. Albumin synthesis rate was measured from L-[(2)H(5)]phenylalanine incorporation (43 mg/kg) at the end of each dietary period. Both albumin fractional synthesis rate (FSR) (5.7 +/- 0.6 vs. 6.7 +/- 0. 8%/d, P = 0.04) and absolute synthesis rate (ASR) (123 +/- 6 vs. 143 +/- 8 mg. kg(-1). d(-1), P = 0.05) were reduced after diet V. In a second study (Study 2, n = 8) a third dietary treatment was added (Diet VS). This was similar to diet V but supplemented with soy protein (18g/d). The results of study 2 confirmed that albumin synthesis was reduced after diet V (FSR: 5.9 +/- 0.3 vs. 6.7 +/- 0. 5%/d, P = 0.015; ASR: 126 +/- 7 vs. 146 +/- 9 mg. kg(-1). d(-1), P = 0.007), but it also showed that the drop could be prevented by adding supplemental protein to the predominantly vegetarian diet (Diet VS) (FSR: 6.4 +/- 0.3%/d, P = 0.08; ASR: 140 +/- 7 mg. kg(-1). d(-1), P = 0.03). Albumin synthesis appears to be modulated by changes in the proportion of animal vs. vegetable protein occurring in the diet. The mechanism might be related to differences in digestibility and consequently in net amino acid availability between diets.

Changes in bioimpedance analysis after stable refeeding of undernourished anorexic patients

OBJECTIVE

To evaluate bioimpedance analysis (BIA) parameters in patients with anorexia nervosa when undernourished and then after stable refeeding.

DESIGN

Follow-up study.

SUBJECTS

Thirteen patients with anorexia nervosa who were studied when undernourished (body weight (Wt): 36.9+/-5.6kg, body mass index (BMI): 14.8+/-1.8kg/m2) and after stable refeeding (Wt: 52.9+/-7.1kg, BMI: 21.2+/-2.3 kg/m2) compared to 25 well-nourished control women (Wt: 53.7+/-4.9 kg, BMI: 21.1+/-1.3 kg/m2).

MEASUREMENTS

Impedance and phase angle were determined for the whole body (13 patients) and separately for arms and legs (10 patients).

RESULTS

Bioimpedance index (height2/impedance) and phase angle were lower in the undernourished group. Whole-body impedance declined (median, min-max) by 45, 1-151 Ohm after refeeding; the variations of bioimpedance index (BI-Index) were weakly correlated (P < 0.10) with BMI changes. Limb phase angles increased with refeeding, but only changes in whole-body phase angle were correlated (P < 0.025) with the corresponding variations of Wt or BMI.

CONCLUSION

Whole-body phase angle increased after weight recovery of anorexic patients, suggesting the occurence of modifications in the extracellular-to-intracellular water ratio. These changes were proportional to the increase in BMI and Wt.

Fasting respiratory quotient as a predictor of weight changes in non-obese women

OBJECTIVE

To detect predictive variables of weight changes in non-obese women.

DESIGN

Three year follow-up study.

SUBJECTS

Fifty-eight women (age 40.0+/-12.8 y, height 159+/-7 cm, weight 62.5+/-9.6 kg and body mass index ((BMI) 24.7+/-3.7 kg/m2).

MEASUREMENTS

At baseline, basal metabolic rate (BMR) and respiratory quotient (RQ) by indirect calorimetry. Weight and BMI at baseline and after 3 y.

RESULTS

In both univariate and multivariate analyses, age and RQ at baseline were significant predictors (P<0.05) of subsequent changes in weight and BMI.

CONCLUSION

In non-obese women, RQ and age are independent predictors of subsequent weight changes.

Changes in the glycosylation pattern of circulating gonadotropins after acute administration of gonadotropin-releasing hormone in patients with anorexia nervosa

To study the involvement of gonadotropin-releasing hormone (GnRH) in glycosylation of circulating gonadotropin isoforms in anorexia nervosa (AN), 14 amenorrhoic patients with AN, 14 age-matched volunteers in early follicular phase, and five normal-weight re-fed patients with AN were investigated under baseline conditions and after acute administration of GnRH. Plasma gonadotropins were assayed using IRMA before and after concanavalin A affinity chromatography. Baseline plasma gonadotropin levels were lower for both AN and re-fed AN patients than in controls (P<0.005). The increase in FSH and LH after GnRH administration was lower than in controls for AN (P<0.005) and re-fed AN (P<0.005 and P<0.05 respectively) patients. Percentages of total gonadotropin not bound to concanavalin A (complex carbohydrate chains) under baseline conditions were higher in patients with AN than in controls (P<0.005) but decreased after GnRH administration (P<0.001). In re-fed AN patients, the percentage of unbound FSH was higher than in controls (P<0.05), and decreased after GnRH administration (P<0.001), whereas the percentages of unbound LH were not significantly different from controls either before or after GnRH administration. These data suggest that: (a) the acute administration of GnRH induces quantitative and qualitative changes in circulating gonadotropin isoforms in both normal controls and AN patients; (b) during recovery the LH response in re-fed AN patients is associated with a glycosylation pattern that is the same as that for controls.

Relations of left ventricular geometry and function to body composition in children with high casual blood pressure

To determine whether abnormal casual blood pressure (BP) is associated with left ventricular (LV) abnormalities in children, 190 6- to 11-year-old children (77 girls, 113 boys) were studied at a school site in Naples, Italy, by limited echocardiography and bioelectric impedance to calculate fat-free body mass (FFM). Single-visit BP measurements (defined as casual BP) were high (based on the Italian tables of BP) in 34 children (18%; 9 girls, 25 boys; 133+/-8/81+/-10 mm Hg) and obesity was present in 44 (23%; 15 girls, 29 boys). Sex- and age-independent risk of high casual BP value was 2.9-fold (odds ratio) greater in obese than in normal-weight children (95% confidence interval, 1.3 to 6.5; P<.01). LV mass (as both absolute value and normalized for height or FFM) was higher and relative wall thickness increased in children with high casual BP (all P<.01). Prevalence of LV hypertrophy was 21% among children with high casual BP (P<.004 versus 4.3% in normal group). Risk of LV hypertrophy was 5.5-fold higher in the presence of high casual BP (P<.004), whereas obesity, age, and sex did not have independent effects. Endocardial shortening was slightly higher in children with high casual BP (36.8+/-8.2%) than in children with normal BP (34.3+/-4.8%, P<.02), whereas midwall shortening was identical in the two groups (20%). Both endocardial shortening and midwall shortening were negatively related to end-systolic stress (r=-.62, SEE=3.8% and r=-.32, SEE=2.4% in normal children). Shortening as a percentage of predicted from wall stress was increased in children with high casual BP at the endocardial level (P<.001), whereas it was normal at the midwall. Therefore, (1) casual detection of high BP in school children is associated with LV geometric abnormalities similar to those found in adults with sustained hypertension (LV hypertrophy, concentric pattern); (2) similar to in adult hypertension, endocardial chamber function in children is supranormal; and (3) in contrast to findings in adults, midwall shortening is normal in children with high casual BP.

The prediction of total body water from bioelectrical impedance in patients with anorexia nervosa

Total body water (TBW) was measured by deuterium oxide (D2O) dilution and predicted from bioelectrical impedance (Z) in nineteen anorexic and twenty-seven control women. The equation of Kushner et al. (1992) based on the impedance index (ZI = height2/Z) gave biases of 0.9 (SD 2.5) and 0.8 (SD 2.5) litres in controls and patients respectively (NS, ANOVA). The ZI-based equation of Deurenberg et al. (1993) gave biases of 1.5 (SD 2.4) litres (NS) and 3.0 (SD 2.1) litres (P < 0.001) in controls and patients respectively. Despite the fact that weight was the most powerful predictor of TBW on the study sample (n 46, r2 0.90, P < 0.0001, SE of the estimate 1.6 litres, CV 5.7%), the formulas of Segal et al. (1991) and Kushner et al. (1992) based on the association of weight and ZI gave an inaccurate prediction of TBW in both control and anorexic subjects, with a bias ranging from -3.2 (SD 2.4) to 2.9 (SD 2.1) litres (P < or = 0.001). Population-specific formulas based on ZI (n 46) gave a more accurate prediction of TBW by bioelectrical impedance analysis on the study subjects, with biases of -0.1 (SD 1.8) and 0.5 (SD 1.7) litres in controls and patients respectively (NS). However, the individual bias was sometimes high. It is concluded that bioelectrical impedance analysis can be used to predict TBW in anorexic women at a population level, but the predictions are less good than those based on body weight alone.

[Evaluation of body composition in anorexia nervosa]

Bioimpedance analysis (BI) of body composition has been carried out in 116 women: 22 patients with anorexia nervosa (AN) and IMC between 16 and 18.5 kg/m2 (MPE-I: weight 45.3+/-3.1 kg; BMI 17.0+/-0.7 kg/m2); 39 AN patients with BMI< 16 kg/m2 (MPE-II: weight 37.2+/-3.8 kg; BMI 14.5+/-1.0 kg/ m2; 55 healthy women (control= CTR: weight 60.5+/-9.0 kg; BMI 22.8+/-3.1 kg/m2). BI was determined for the whole body and for body segments (arms, legs and trunk): phase angle (AF) of 50 kHz and impedance (Z) of 100, 50 and 5 kHz. Body water was estimated from Z to 50 kHz according to Kushner et al. (AJCN 1993). AF and Z100/Z5 (multifrequency BI) were considered as related to the ratio between extracellular water and intracellular water. Total body water was significantly different between the three groups: 26.5+/-2.9 L in the MPE-II group, 23.6+/-2.9 L in the MPE-I group; 30.3+/-3.7 L in the CTR women. In comparison with the CTR group whole-body AF and leg-AF was lower (p<0.01) in the MPE-II patients while both the MPE groups differed from the CTR group with respect to arm-AF. Multifrequency BI showed differences (p<0.01) between all the groups for the whole-body and segmental measures. Significant correlations for AF and Z100/Z5 vs BMI and % BF were apparent only in the MPE-II group. In conclusion, in the AN the marked modifications of BI parameters indicated a relative increase of extracellular water and were related to BMI and % BF in the very undernourished patients.

High prevalence of overweight in a children population living in Naples (Italy)

OBJECTIVE

The present study estimates the prevalence of obesity among ten-year old children living in Southern Italy and compares it with the prevalence of obesity among children living in other western countries.

METHODS

110 children attending the 4th grade of a randomly selected primary school in Naples were studies in the 1992. Eighty-eight per cent of the total school population was examined: 52 girls, 58 boys: mean age = 9.6 years (SEM = +/- 0.10). Each child underwent medical examination and anthropometric assessment. The percentile values for Body Mass Index (BMI = weight/height 2) and triceps skinfolds thickness (mm) were calculated and compared to that of children of the same age and sex living in other countries, chosen from comparable studies available in the literature.

RESULTS

Percentile values for triceps skinfolds thickness in Neapolitan children are similar to those reported in the other populations considered for comparison, however BMI values were different. Children in Naples have the highest BMI values at the 50th, 75th, 90th and 95th percentile. The prevalence of obesity among Neapolitan children was estimated using as a cut-off, the BMI value at the 90th percentile of each population considered for the comparison and calculating the rate ratio with 95% confidence interval (95% CI). The prevalence of obesity in Naples among girls, was 5.2 times (3.8-6.6 95% CI) as high as in France, 3.3 times (2.2-4.4) as high as in Holland, 1.7 times (0.9-2.5) as high as in USA, 2.5 times (1.7-3.4) as high as in Milan (Northern Italy); among boys it was 4.3 times (3.0-5.6) as high as in France, 4.0 times (2.7-5.2) as high as in Holland, 2.1 times (1.2-3.0) as high as in the USA, 2.5 times (1.7-3.4) as high as in Milan.

Relationship between hydration of lean body mass and visceral adipose tissue. A clinical study of women

OBJECT

To study the relationship between hydration of lean body mass and adipose tissue location.

DESIGN

Cross-sectional, clinical study of visceral adipose tissue area and total body water as a percentage of lean body mass.

PATIENTS

Seventy-two adult, overweight, women, 52 pre- and 20 post-menopausal (age: 18-72 years, body mass index: 26-52).

MEASUREMENTS

Total body water was obtained by electrical impedance measurement; visceral adipose tissue and lean body mass were obtained by computed tomography measurement of visceral adipose tissue area at the level of the 4th-5th lumbar vertebra.

RESULTS

Visceral adipose tissue was found, by multiple regression analysis, to be the only predictor of the hydration of the lean body mass. The other independent variables: age, menopausal status, body mass index, glucose and insulin both fasting and after glucose load were not able to significantly improve the predictive power.

CONCLUSION

Results of this study confirm the existence of a relationship between visceral adipose tissue content and hydration of the lean body mass.

Assessment of cardiac autonomic control by heart period variability in patients with early-onset familial obesity

For quantitative assessment of cardiac autonomic control, time and frequency domain measures of heart period variability were calculated by 24 h Holter recording in 10 young obese women with early-onset familial obesity and in 10 control subjects. Ultra low frequency and very low frequency power were lower in obese subjects than in controls (P < 0.05). High frequency power, a pure measure of vagal tone, was comparable between the two groups. However, low frequency power, which analysed over a 24 h Holter recording reflects parasympathetic more than sympathetic activity, was slightly lower in obese subjects than in controls (P = 0.06). Body mass index showed an inverse correlation with total power (r = -0.62; P < 0.05) and separately with ultra low (r = -0.59; P < 0.01), very low (r = -0.64; P < 0.005), low (r = -0.61; P < 0.005) and high frequency power (r = -0.53; P < 0.05). These results demonstrate a parasympathetic withdrawal increasing body weight. The reduction of ultra low frequency and very low frequency power, which are associated with sudden death, may help to explain the higher cardiovascular risk in obesity.

Altered glycosylation of pituitary gonadotropins in anorexia nervosa: an alternative explanation for amenorrhea

To investigate the relevance of glycoprotein polymorphism to gonadotropin bioactivity in vivo, plasma follicle-stimulating hormone (FSH) and luteinizing hormone (LH), 17 beta-estradiol (E2), testosterone and sex hormone binding globulin (SHBG) levels in 17 amenorrheic women affected with anorexia nervosa (14-29 years) and 10 age-matched normally cycling women were evaluated. Plasma FSH and LH levels were assayed using radioimmunoassay (RIA) and immunoradiometric assay (IRMA) methods, before and after concanavalin A-Sepharose (Con A) affinity chromatography. Significant RIA-IRMA differences in FSH and LH plasma values were present only in women with anorexia nervosa (p < 0.005). Moreover, in these patients both FSH and LH showed a reduced binding to the Con A, expressed as a percentage of unbound, suggesting altered glycosylation of these moieties. In conclusion, these findings hypothesize the involvement of glycosylation polymorphism in RIA-IRMA differences; support the usefulness of both RIA and IRMA methods in FSH and LH evaluation, before and after Con A chromatography; and suggest a new pathogenetic pathway to explain amenorrhea in anorexia nervosa.

Familial and environmental influences on body composition and body fat distribution in childhood in southern Italy

The aim of this paper was to evaluate the factors affecting body fat excess and distribution in prepubertal age. A cross-sectional survey was carried out on children attending the 4th grade of a primary school in Naples. Eighty-eight per cent of the total sample was examined: 52 girls, 58 boys; mean age = 9.6 yrs (s.e. +/- 0.10). Each child underwent a medical examination, anthropometric measurements and bio-impedance analysis of body composition. The parents were asked to fill in a questionnaire that included demographic data, family history, parent's weight and height, child's perinatal history and his or her involvement in sports activities. Data were analyzed by multiple linear regression. The results showed a direct correlation between parental BMI and children's anthropometric measurements: the children's BMI correlated with the fathers' (P = 0.02) and mothers' BMI (P = 0.027); the children's waist/hip ratio correlated with the fathers' BMI (P = 0.07); the children's subscapular skinfolds correlated with the father's (P = 0.07) and mothers' BMI (P = 0.02); the children's triceps skinfolds correlated with the fathers' BMI (P = 0.004). Among congenital factors, sex was shown to be correlated with the children's waist/hip ratio (P = 0.05) with a lower ratio in the female, indicating a sex influence on body fat distribution even in prepubertal age. The children's BMI correlated with their waist/hip ratio (P = 0.001). Children's systolic blood pressure showed a positive correlation with triceps (P = 0.04) and subscapular (P = 0.05) skinfolds thickness % FAT-PLI (P = 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac abnormalities in young women with anorexia nervosa

OBJECTIVE

To identify the characteristics of cardiac involvement in the self-induced starvation phase of anorexia nervosa.

METHODS

Doppler echocardiographic indices of left ventricular geometry, function, and filling were examined in 21 white women (mean (SD) 22 (5) years) with anorexia nervosa according to the DSMIII (Diagnostic and Statistical Manual of Mental Disorders) criteria, 19 women (23 (2) years) of normal weight, and 22 constitutionally thin women (21 (4) years) with body mass index < 20.

RESULTS

13 patients (62%) had abnormalities of mitral valve motion compared with one normal weight woman and two thin women (p < 0.001) v both control groups). Left ventricular chamber dimension and mass were significantly less in women with anorexia nervosa than in either the women of normal weight or the thin women, even after standardisation for body size or after controlling for blood pressure. There were no substantial changes in left ventricular shape. Midwall shortening as a percentage of the values predicted from end systolic stress was significantly lower in the starving patients than in women of normal weight: when endocardial shortening was used as the index this difference was overestimated. The cardiac index was also significantly reduced in anorexia nervosa because of a low stroke index and heart rate. The total peripheral resistance was significantly higher in starving patients than in both control groups. The left atrial dimension was significantly smaller in anorexia than in the women of normal weight and the thin women, independently of body size. The transmitral flow velocity E/A ratio was significantly higher in anorexia than in both the control groups because of the reduction of peak velocity A. When data from all three groups were pooled the flow velocity E/A ratio was inversely related to left atrial dimension (r = -0.43, p < 0.0001) and cardiac output (r = -0.64, p < 0.0001) independently of body size.

CONCLUSIONS

Anorexia nervosa caused demonstrable abnormalities of mitral valve motion and reduced left ventricular mass and filling associated with systolic dysfunction.

[Determinants of body fat in prepubertal age]

In order to evaluate the factors affecting body fat excess and distribution, we have studied children attending the 4th grade of a primary school randomly selected in Naples. 52 girls, 58 boys; mean age = 9.6 years (SE +/- 0.1) were examined. Among the familial factors assessed, a correlation between parental BMI and child's anthropometry was found. Among congenital factors, sex correlates with the children's waist/hip ratio ("t" = -2.07; p = 0.05). Moreover the girl's percent body fat was higher. These two findings suggest the expression of sexual characters in prepubertal age. Systolic blood pressure showed a positive correlation with children's percent body fat ("t" = 2.43; p = 0.016) and subscapular skinfold thickness ("t" = 1.19; p = 0.05), suggesting an influence of these factors on blood pressure level since this age. No correlation was found between children's BMI and weight at birth, family history of diabetes, hypertension or hyperlipidemia. Among environmental factors, only the mothers weight gain during pregnancy ("t" = -2.21; p = 0.03) and breast feeding ("t" = -2.07; p = 0.05) correlated with the children's BMI. The correlation between children's BMI and waist/hip ratio ("t" = 4.64; p = 0.0001), was not confirmed in children who exercise, suggesting a beneficial action of physical activity on body fat distribution. The identification in different populations of factors associated with childhood obesity is important for prevention planning.

Predicted and measured resting energy expenditure in healthy young women

Basal energy expenditure (BEE) was either measured by indirect calorimetry or predicted by different formulae in 104 young women: 74 lean and overweight subjects (normal weight, NWt) and 30 obese subjects. The predictive equations were based on weight alone (Owen, FAO-1, Schofield-1) or on weight and height (Harris-Benedict, Mifflin, Kleiber, and again FAO-2 and Schofield-2). With the exception of the Owen equation all the equations over-estimated measured BEE in both study groups. The ratio between measured and predicted value (% MP) varied between 102.3 (Owen) and 87.7 (Kleiber) in the NWt subjects and between 113.2 (Owen) and 89.3 (Schofield-1) in the obese subjects. The range including 95% of the predicted-measured differences (PMdiff) was larger than 1700 kJ/d in the NWt group and 2300 kJ/d in the obese group. In both study groups most of the equations showed a significant relationship between PMdiff and/or % MP with body weight and the magnitude of BEE. In conclusion, these equations are of little help in predicting BEE in a single subject and should be used with caution when assessing energy requirements in populations or groups of subjects.

The acute effect of dexfenfluramine on resting metabolic rate and postprandial thermogenesis in obese subjects: a double-blind placebo-controlled study

The effects of dexfenfluramine (dFE: 30 mg per os) on energy expenditure were evaluated in seven young obese male subjects (mean +/- s.d.: age 30.9 +/- 6.1 years; BMI 39.8 +/- 4.4 kg/m2). Each subject was submitted, on a double-blind protocol and by random order, to four tests in which dFE or placebo (Pla) were administered either in the fasting state or in combination with a mixed test meal. Energy expenditure was measured by indirect calorimetry for 60 min before (BMR) and from 90 to 330 min after dFE or Pla. In those cases where the protocol required it, a mixed test meal (5 MJ, 1200 kcal; percentage of protein, carbohydrate and fat: 15, 55, and 30 respectively) was eaten 120 min after dFE or Pla. In the fasting state resting metabolic rate increased after dFE (mean +/- s.d.: 0.49 +/- 0.20 kJ/min) but not after Pla (-0.04 +/- 0.16 kJ/min) in comparison to BMR, the difference between the two tests being highly significant (P < 0.01). Post-prandial thermogenesis (over 3h) was also significantly higher after dFE than after Pla (232 +/- 85 kJ vs. 181 +/- 73 kJ; P < 0.025). On the other hand, dFE did not affect respiratory quotient (RQ), either in the fasting state or in the fed state. These results show that in obese subjects dFE increases energy expenditure in the post-absorptive state, as well as after the ingestion of food.

Bioimpedance analysis and resting energy expenditure in undernourished and refed anorectic patients

Anthropometry, bioimpedance analysis (BIA) and resting energy expenditure (REE) were evaluated in young female patients affected by anorexia nervosa who were either severely malnourished (MnA) or already refed (RfA) and in a control group of healthy young women (WnC). Fat-free mass (FFM) and fat mass (FM), evaluated from skinfold thickness, were severely decreased in the MnA group while they were very similar in the RfA group and in the WnC group. With respect to BIA parameters, impedance (Z) was significantly higher in absolute terms in the MnA but lower than in the other groups when expressed as specific impedance, i.e. after normalization for both FFM and height. Phase angle significantly differed between the three groups, being significantly (P < 0.01) lower in the MnA (3.70 +/- 0.83 degrees) and the RfA (4.36 +/- 0.82) than in the WnC (5.17 +/- 0.40). REE was comparable in RfA subjects and WnC subjects, while it was sharply decreased (P < 0.01) in the MnA patients both in absolute value and after adjustment for body composition (FFM and FM) or body weight. This cross-sectional study shows that marked changes in BIA parameters occur in undernourished anorectic patients and also in the anorectic subjects who were previously very underweight but studied only after having already regained a normal body size. REE was deeply decreased in the undernourished anorectic women even when the differences in body composition or Wt were taken into account, indicating the occurrence of a significant adaptation of energy expenditure to chronic underfeeding.

Postprandial thermogenesis in leanness and anorexia nervosa

Resting energy expenditure (REE) and postprandial thermogenesis (PPT) after the ingestion of a mixed test meal (3.56 MJ, 850 kcal) were determined in 7 anorectic patients, 7 very lean women and 8 control women. REE is absolute value was sharply decreased in the anorectics, but did not significantly differ between the very lean and the control subjects. On the other hand, when adjusted for body weight, REE only tended (p = 0.18) to be lower in the anorectics in comparison to the control women. PPT was similar in the anorectics (187.2 +/- 24.6 kJ/4 h) and the controls (200.7 +/- 16.8 kJ/4 h), but lower in the lean subjects (137.5 +/- 20.0 kJ/4h: p less than 0.05) than in the other two groups. The present study shows that the thermic response to the ingestion of a mixed test meal was not decreased in undernourished anorectic patients whereas it was significantly reduced in very lean healthy women.

Postprandial thermogenesis in lean and obese subjects after meals supplemented with medium-chain and long-chain triglycerides

The thermic effect of medium-chain triglycerides (MCTs) was studied in six lean and six obese young males by evaluating postprandial thermogenesis (PPT) after the ingestion of mixed meals containing either 38 g long-chain triglycerides (LCTs) or 30 g MCTs plus 8 g LCTs. Postabsorptive resting metabolic rate (RMR) was higher (P less than 0.05) in the obese individuals than in the lean ones. PPT, evaluated as 6-h incremental areas above RMR, was greater (P less than 0.05) in both groups after meals containing MCTs. The thermic effect of MCTs was 119.7 +/- 33.9 and 144.7 +/- 48.8 kJ/6 h in the lean and the obese subjects, respectively. The postprandial response of glucose, insulin, and free fatty acids did not depend on the type of oil contained in the meal. Our study shows that PPT is enhanced in both lean and obese subjects when LCTs in a mixed meal are replaced with MCTs.

[Validity of 5 bioelectric impedance equations for the estimation of lean body mass in women]

Fat free mass (FFM) predicted by five bioelectrical impedance (BIA) available formulae (Segal et al., Lukaski et al., Kushner et al., Deurenberg et al., manufacturer's predictive equation) was compared with densitometrically-determined FFM (as a reference method) in two groups of young women with different anthropometric characteristics. In the farmers (very short and light individuals), none of the studied formulae was able to accurately predict FFM: this latter was overestimated in subjects with low and underestimated in those with high FFM. In the other group (INCAP employees), only values predicted by Lukaski formula were in perfect agreement with FFM, showing no bias depending on FFM changes. In conclusion, the available BIA formulae seem to be specific for population from which they were derived and could not be used on samples from other populations if not cross-validated.

[Basal metabolism and postprandial thermogenesis in anorexia nervosa and constitutional leanness]

Body composition and energy expenditure (basal metabolic rate--BMR--and postprandial thermogenesis--PPT) were evaluated in 11 anorectic patients, 16 very lean young women and 26 control female subjects. BMR in absolute terms was severely depressed in the anorectics when compared to the other two groups (p less than 0.01). After adjustment for fat free mass BMR was significantly higher in the lean subjects than the controls (p less than 0.05). PTT was studied for 240 minutes after the ingestion of a 3.56 MJ mixed meal (16% Prot, 50% CHO and 34% Fat) in 7 anorectics, 7 lean and 8 control women. PPT was similar in the anorectics and in the controls, but lower in the lean subjects (p less than 0.05) than in the other two groups. This study shows that a sharp decline in BMR occurs in severely undernourished anorectic patients who, however, have a normal PPT. On the other hand, very lean healthy women tend to have higher BMR but a decreased thermic response to a mixed test meal.