Total energy expenditure (H218O), physical activity level and milk output of lactating rural Bangladeshi tea workers and nontea workers.

OBJECTIVE: To assess the total daily energy expenditure (TDEE), milk output and physical activity level (PAL) of chronically malnourished lactating women using the doubly labelled water method (DLW). DESIGN: Prospective, longitudinal study designed to assess the extent of malnutrition and energetics of lactating tea workers and nontea workers. SETTING: North-east Bangladesh on women working and living in the same tea estates. SUBJECTS: Of an original cohort of 150 lactating women, 30 were selected to participate in this study when they were at about 12 months postpartum. One mother subsequently dropped out. INTERVENTIONS: On day 1 each women provided a urine sample, was administered a dose of DLW and 6 h later provided another sample. Further urine samples were collected for 21 subsequent days. In addition, every 5 days the mother provided a milk sample and at the same time her baby provided a urine sample. RESULTS: Mean (s.d.) BMI was 17.4 (1.63). Mean TDEE and PAL were significantly higher in workers than nonworkers (8.42 (1.38) and 6.83 (2.09) MJ/day, P = 0.02 and 1.92 (0.34) and 1.59 (0.44), P = 0.03, respectively). Mean milk output was similar in the two groups (672 (180) ml and 749 (189) ml in workers and nonworkers, respectively). CONCLUSIONS: Based on international BMI cutoffs, 79% of mothers were suffering from some degree of chronic energy deficiency. A total of 35% of workers and 17% of nonworkers were engaged in strenuous physical activity. The mean milk output of both workers and nonworkers was not different and was high especially as most of the mothers were about 12 months postpartum. No relationship was found between menses return and any of the variables studied. SPONSORSHIP: World Health Organization, Nestle Foundation, UNICEF.

Body fat measurement in Indian men: comparison of three methods based on a two-compartment model.

UNLABELLED: Obesity is a major risk factor for diabetes and related disorders. The current classification of obesity is based on body mass index (BMI, kg/m(2)), which is a surrogate for the total body fat. Since the relationship between BMI and body fat varies in different populations, an independent validation of the BMI-body fat relationship in the population of interest is desirable. OBJECTIVES: (1) To study the validity of field methods of measuring body fat (multiple skinfolds and bioimpedance) against a criterion method (deuterium dilution) and (2) To compare the prevalence of obesity (WHO 2000 criteria for BMI) with adiposity (body fat >25%) in middle-aged Indian men in rural and urban Pune. DESIGN: Community-based multistage stratified random sampling of middle-aged men from rural and urban Pune for study of body composition and cardiovascular risk. A third of these men, selected to represent wide BMI distribution, were studied for body fat measurements by specific methods. SUBJECTS: A total of 141 healthy men, approximately similar number from rural, urban slums and middle class from Pune. They were 39.3 (+/-6.2) y old and had a BMI of 21.9 (+/-3.7) kg/m(2). MEASUREMENTS: Anthropometry (height, weight and multiple skinfold thicknesses) by trained observers using standardised technique to calculate body fat by Durnin and Womersley's equation. Total body water and body fat by bioelectrical impedance analysis (BIA) and deuterium oxide dilution (D(2)O). RESULTS: Mean total body fat was 14.3 kg (23.0%) by anthropometry, 16.5 kg (26.0%) by BIA and 15.3 kg (24.6%) by D(2)O method. Although there was a good correlation between fat estimation by three methods (r= approximately 0.9, P<0.001 all), compared to D(2)O method anthropometry underestimated body fat by 1.0 kg and BIA overestimated fat by 1.2 kg (P<0.001 both). Using the standard cut-point of 25% body fat for 'adiposity' 29.5% rural, 46.0% slum and 75.0% middle class men were adipose. These proportions were considerably higher than the number of men who were 'preobese' (BMI> or =25-29.9 kg/m(2), 9.0% rural, 22.0% urban slums and 27.0% urban middle class) and 'obese' (BMI >30 kg/m(2), 4.0% urban slums, none in rural and urban middle class). CONCLUSION: We recommend that future studies assessing risk for chronic diseases in Indians should measure adiposity by anthropometry (multiple skinfolds) or BIA (calibrated for Indians) rather than relying only on BMI cut-points.

A long-term study on vector abundance & seasonal prevalence in relation to the occurrence of Japanese encephalitis in Gorakhpur district, Uttar Pradesh.

BACKGROUND & OBJECTIVES: Japanese encephalitis (JE) virus is an important cause of viral encephalitis in Gorakhpur district, UP. The area has been experiencing outbreaks of JE since 1978. No in-depth longitudinal studies have been carried out on the mosquito species, particularly JE vectors prevailing in the area. Entomological studies were carried out in the district in order to determine the species composition, relative abundance and seasonal prevalence of mosquitoes in relation to the incidence of JE. METHODS: Three JE affected villages were selected as study sites. Weekly visits were made to each village and mosquito collections were made in and around the pig enclosures and cattle sheds with the help of mouth aspirators, aided by flash lights at dusk. RESULTS: The overall mosquito population showed a bimodal pattern with short and tall peaks during March and September respectively. Based on the elevated density and infection with JE virus, Culex tritaeniorhynchus has been considered responsible for causing epidemics in the area. Cx. pseudovishnui, Cx. whitmorei, Cx. gelidus, Cx. epidesmus, Anopheles subpictus, An. peditaeniatus and Mansonia uniformis are suspected to have played some role in the epidemiology of JE in the region. JE cases were reported between August and November with the peak in October when the vectors population, particularly Cx. tritaeniorhynchus was on the decline. INTERPRETATION & CONCLUSION: The results of the study indicate that Cx. tritaeniorhynchus, the most likely vector of JE together with other known vector species remained more active during the period of paddy cultivation. Integrated antilarval measures before the beginning of paddy irrigation may check the breeding of JE vectors in the paddy fields. It may prove beneficial in reducing the vector population during the JE transmission season.

Total energy expenditure & physical activity level in chronically energy deficient Indian males measured by the doubly labelled water technique.

Total energy expenditure (TEE) and basal metabolic rate (BMR) in the free-living state were measured in healthy south Indians, by the doubly labelled water (DLW) method. From these measurements, estimates of physical activity level (PAL) could be calculated. A total of 18 subjects were studied in 3 groups of 6 subjects each: Group I (urban controls), Group II (urban slum, chronically undernourished) and Group III (rural). The urban slum recruits were chronically energy deficient (CED), and had a low BMI (average 17.0 kg/m2), while the rural subjects had an average BMI of 18.1 kg/m2. The TEE measured by the doubly labelled water technique was 11.2, 7.1 and 12.2 MJ/day for Groups I, II and III respectively. The TEE was significantly lower in the urban CED group as obtained by the one way ANOVA. The estimates of TEE by the DLW technique were compared with estimates made by whole body calorimetry, in the urban groups of subjects. The TEE obtained by calorimetry was 10.3 +/- 1.6 and 7.3 +/- 0.2 MJ/day in Groups I and II respectively. There were no significant differences between the TEE measured by the two methods, in both the groups. The two methods also correlated well, and the mean difference between the methods, in both groups was -0.5 +/- 1.1 MJ/day, which was about 6 per cent of the value of TEE measured by the DLW method. The calculated PAL (by using TEE measured by DLW/BMR) was 1.79, 1.54 and 1.90 for Groups I, II and III respectively. The results showed that the activity of chronically energy deficient subjects, in urban slums, was reduced, and that this may be their method of conserving energy to maintain a stable body weight. Rural males had a high activity level, even though they had a low BMI.

Adaptation to low energy intakes: the responses and limits to low intakes in infants, children and adults.

Reduction in energy intake below the acceptable level of requirement for an individual results in a series of physiological and behavioural responses, which are considered as an adaptation to the low energy intake. This ability of the human body to adapt to a lowering of the energy intake is without doubt beneficial to the survival of the individual. However, what is more controversial is the view held by some that the body can metabolically adapt in a beneficial manner to a lowered intake and consequently that the requirements for energy are variable given the same body size and composition and physical activity levels. Much of this confusion is the result of considerable evidence from studies conducted in well-nourished adults who, for experimental or other reasons, have lowered their intakes and consequently demonstrated an apparently enhanced metabolic efficiency resulting from changes in metabolic rates which are disproportionate to the changes in body weight. Similar increases in metabolic efficiency are not readily seen in individuals who on long-term marginal intakes, probably from childhood, have developed into short-statured, low-body-weight adults with a different body composition. It would thus appear that the generally used indicator of metabolic efficiency in humans, that is a reduced oxygen consumption per unit fat free mass, is fraught with problems since it does not account for variations in contributions from sub-compartments of the fat free mass which include those with high metabolism at rest such as brain and viscera and those with low metabolism at rest such as muscle mass. Metabolic rate per unit fat free mass thus, does not reflect true variations in metabolic efficiency and is due largely to variations in body composition. This finding combined with the evidence that behavioural adaptation in habitual physical activity patterns which occurs on energy restriction is not necessarily beneficial to the individual raises doubts about the role of adaptation to low intakes in determining one's requirement for energy. The evidence is overwhelming that both in children and adults, changes in body size and composition as well as in levels of habitual physical activity may be the most important consequences of a lowered energy intake and cannot be assumed to be a part of a beneficial adaptation that influences energy requirements.

No evidence for an ethnic influence on basal metabolism: an examination of data from India and Australia.

A lower BMR of Indians, when compared with Westerners matched for age, sex and either surface area or body weight, has often been reported in the literature and has been interpreted to reflect an ethnic influence on BMR. To determine the contribution of body composition to these observed differences in BMR, we analysed the data on ninety-six Indians and eighty-one Caucasian Australians of both sexes, aged 18-30 years, studied in Bangalore, India and Melbourne, Australia. Absolute BMR and BMR adjusted for body weight were significantly lower in Indians when compared with Australians of the corresponding sex. However, BMR adjusted for fat-free mass (FFM) in men, and BMR adjusted for FFM and fat mass (FM) in women, were not significantly different between the two groups. Stepwise regression of FFM, FM, sex (0 = women; 1 = men) and ethnicity (0 = Indian; 1 = Australian) on BMR, resulted in the following relationship for the combined data on all subjects: BMR = 88.7 x FFM (kg) + 1713 (n 177; r 0.92; r2 0.85; SEE 425 kJ). The Indian equations of Hayter & Henry (1994), based on body weight, resulted in a significant bias (measured-predicted BMR) of 318 (SE 54) kJ/d in Indian men and -409 (SE 70) kJ/d in Indian women. The equation of Cunningham (1991), based on FFM, accurately predicted the BMR of Indian men, Indian women and Australian men. The small but significant bias of 185 (SE 61) kJ/d in Australian women, may be explained by the significant contribution of FM to BMR in this group. The present study does not provide any evidence for an ethnic influence on basal metabolism. The results strongly support the use of FFM, rather than body weight, for the prediction of BMR in population groups of varying body size and composition. This would allow an accurate estimation of BMR and hence energy requirements in population groups worldwide.

Whole body protein metabolism in human pulmonary tuberculosis and undernutrition: evidence for anabolic block in tuberculosis.

1. Differing patterns of protein metabolism are seen in wasting due to undernutrition and wasting due to chronic infection. 2. We investigated whole body energy and protein metabolism in nine subjects with pulmonary tuberculosis, six undernourished subjects (body mass index < 18.5 kg/m2) and seven control subjects from an Indian population. Fasting subjects were infused with L-[1-13C]leucine (2.3 mumol.h-1.kg-1) for 8 h, 4 h fasted then 4 h fed. Leucine kinetics were derived from 13C-enrichment of leucine and alpha-ketoisocaproic acid in plasma and CO2 in breath. 3. Undernourished subjects, but not tuberculosis subjects, had higher rates of whole body protein turnover per unit lean body mass than controls [163.1 +/- 9.4 and 148.6 +/- 14.6 mumol compared with 142.8 +/- 14.7 mumol leucine/h per kg, based on alpha-ketoisocaproic acid enrichment (P = 0.039)]. 4. In response to feeding, protein oxidation increased in all groups. Tuberculosis subjects had the highest fed rates of oxidation (47.0 +/- 10.5 compared with 37.1 +/- 5.4 mumol.h-1.kg-1 in controls), resulting in a less positive net protein balance in the fed phase (controls, 39.7 +/- 6.2; undernourished subjects, 29.2 +/- 10.6; tuberculosis subjects, 24.5 +/- 9.3; P = 0.010). Thus fed-phase tuberculosis subjects oxidized a greater proportion of leucine flux (33.2%) than either of the other groups (controls, 24.0%; undernourished subjects, 24.0%; P = 0.017). 5. Tuberculosis did not increase fasting whole body protein turnover but impaired the anabolic response to feeding compared with control and undernourished subjects. Such 'anabolic block' may contribute to wasting in tuberculosis and may represent the mechanism by which some inflammatory states remain refractory to nutrition support.

Metabolic responses to repeated infusions of identical doses of norepinephrine in chronically energy deficient human subjects.

The physiological effects of three 30 min infusions of identical doses of norepinephrine (0.15 microgram/kg FFM/min) separated by 60 min intervals were assessed in well nourished (WN; n = 6) and chronically energy deficient (CED; n = 6) subjects. Each subject also underwent control, vehicle infusions with 0.9 per cent saline on a separate day. Oxygen consumption (VO2) was significantly higher during the third infusion of NE as compared to the first in both groups. This increment in VO2 occurred despite similar plasma peak NE levels in both infusions. Increments in plasma glucose and free fatty acids were also similar during the first and third infusions. The study demonstrates that thermogenic potentiation which we had earlier demonstrated in WN subjects, occurs in CED subjects as well. Thermogenic potentiation is not associated with altered plasma NE kinetics or mobilisation of substrates.

Validation of expedient methods for measuring body composition in Indian adults.

The body composition of 99 men and 89 women from south India was estimated using hydrodensitometry, bioelectrical impedance and skinfold thickness. Comparisons of the hydrodensitometry (reference method) and skinfold methods showed that there were no significant differences between the methods, for estimates of fat free mass (FFM) and per cent fat. The mean difference between the estimates FFM (bias), from skinfold measurement and hydrodensitometry was small for both groups (+0.16 +/- 1.09 kg in men and +0.67 +/- 0.9 kg in women). The same trend was observed in per cent fat estimates (-0.37 +/- 2.04 in men and -1.49 +/- 2.28 in women), showing that the skinfold method can be used as an accurate and expedient method to determine body composition. The bioelectrical impedance method obtained a significantly lower FFM and higher body fat than the reference (hydrodensitometry) method. This could have been due to the use of an inappropriate equation derived from Western population studies. Hence, a new predictive equation, for the measurement of FFM by the bioelectrical impedance method was derived for this population, using the variables of height2/impedance and FFM measured by underwater weighing. The new equation for the bioelectrical impedance method then gave values of body composition which compared well (0.26 +/- 2.32 kg) in men and (0.36 +/- 2.49 kg) in women with the hydrodensitometry method.

Diet induced thermogenesis with oral & intravenous feeding in chronically undernourished human subjects.

The parasympathetic nervous system (PNS) has been shown to be important in the mediation of diet induced thermogenesis (DIT). Chronically energy deficient (CED) subjects have a high resting parasympathetic tone, which could lead to a greater than expected DIT. DIT was studied in chronically energy deficient adult men and healthy age-matched volunteers (6 controls, 7 CED subjects) with an isocaloric (600 kcal) meal given by the oral and intravenous (i.v.) routes on two consecutive days, on a crossover basis. The resting metabolic rate (RMR) and the DIT were measured over 6 h, along with cardiovascular, biochemical and anthropometric parameters. Anthropometrically (height, weight, fat free mass, body mass index, mid upper arm circumference and sum of skinfolds), the CED group differed significantly from the well-nourished control group. There were no significant differences between the two groups in the basal state for metabolic (RMR, oxygen consumption, respiratory quotient), cardiovascular [blood pressure (BP), heart rate, cardiac output], and biochemical (plasma glucose, insulin and norepinephrine) parameters. The CED group had a significantly higher DIT response for both meal types when compared to the controls, when expressed as an absolute value and as a percentage response. However, the response was not significant when corrected for the meal size and body weight. There were also no significant differences between the two meal types in each group for the metabolic, cardiovascular and biochemical parameters during the DIT period, although, in general, the oral meal gave a larger DIT response compared to the i.v. meal. Both groups predominantly oxidised fat during the fasted stage and switched to carbohydrate oxidation when fed. It appears that, the previously demonstrated higher tone in the PNS, does not make a significant contribution to the thermic response of a meal in these subjects.

Prediction of total body water in Indian men from anthropometry and bioelectrical impedance using deuterium dilution as reference.

Total body water (TBW) obtained by deuterium dilution (TBWD) in 45 adult Indian males of low body mass index was compared with values obtained from bioelectrical impedance (TBWImp) and two anthropometry-based prediction equations. Bioelectrical impedance significantly underestimated TBW when compared with deuterium dilution, by 2.75 SD 2.86 kg. Comparisons of the anthropometry-based prediction equations demonstrated that TBW was overestimated by 0.87 SD 2.49 kg, and 2.47 SD 2.57 kg, respectively. Since all parameters in the bioelectrical impedance method were standardized, the difference in the values could have been because of the equation used. Therefore, a fresh equation for the measurement of TBW by the bioelectrical impedance method was derived using the variables of height2/impedance and weight. New prediction equations for TBW were also derived based on anthropometric variables of weight and height. Body weight has the greatest influence in the prediction equations for TBW, and the equation derived was TBW (kg) = 0.533 x body weight (kg) + 3.77, SEE = 2.4 kg. Using height2/impedance gave the relationship: TBW (kg) = 0.568 body weight-0.04 height2/impedance + 4.35, SEE = 1.9 kg.

Measurement of total energy expenditure by the doubly labelled water technique in free living Indians in Bangalore city.

Doubly labelled (2H2(18)O) water was used to determine the daily total energy expenditure (TEE) in the free living state of 6 adult, healthy, weight stable, male volunteers over a period of 21 days. The body weights of the subjects ranged from 42.3-70.4 kg. Isotope pool sizes and elimination rates were calculated from 18O and 2H enrichments in basal and daily (21 days) post dose urine samples using the multipoint slope intercept method after corrections for isotope fractionation. The physical activity level (PAL) of the subjects was also measured during the experiment as the ratio of measured TEE to measured basal metabolic rate (BMR). Simultaneous prediction of the total energy expenditure was also carried out by combining the measurements of BMR by indirect calorimetry, and daily physical activity level by 7 day recall. TEE calculated by the isotopic technique was 9.35 +/- 2.00 MJ/day, with an inter individual variation of 21.4 per cent. The measured BMRs in the subjects along with PALs obtained by recall, gave a total daily energy expenditure of 8.66 +/- 2.20 MJ/day with an inter individual variation of 25.4 per cent. The average BMR was 5.59 +/- 0.99 MJ/day and the average PAL (by recall) was 1.54 +/- 0.12. The inter individual variation of the BMR was 17.7 per cent and that of the recalled PAL was 7.9 per cent; the latter increased to 12.2 per cent when the PAL was calculated from the ratio of the measured TEE to the BMR. There was no significant differences between the methods (isotopic and predicted by BMR), although, the TEE obtained by the isotopic method was higher, by about 0.7 MJ/day, or 7.9 per cent, than the TEE predicted by BMR.

Thermal, cardiovascular & thermogenic responses to mild cold exposure in chronically energy deficient human subjects.

Thirteen young, male adults were investigated for thermal, cardiovascular and metabolic responses to truncal cooling for 40 min. The subjects were divided into two groups [well nourished controls (WN) and chronically energy deficient (CED)] on the basis of anthropometry and socio-economic status. The CED group had significantly greater reductions in peripheral forearm blood flow and surface finger tip temperatures on exposure to cold when compared to the well nourished controls. The CED group also showed a significant rise in oxygen consumption (3.4%), while no thermogenic response was observed in the WN controls. There was no fall in deep body temperature in either group. The study suggests that chronically energy deficient subjects thermoregulate appropriately on exposure to mild cold. The deficiency in insulative body fat is made up for by evoking greater peripheral vasoconstrictor responses as well as thermogenic mechanisms. The study suggests that on exposure to cold, thermoregulation takes precedence over energy conservation in chronically energy deficient subjects.

Maximal voluntary contraction as a functional indicator of adult chronic undernutrition.

Maximal voluntary contraction (MVC) using a handgrip dynamometer was assessed in seventy-two young adult males. The subjects were divided into two groups on the basis of a BMI of 18.5 kg/m2. The subjects with a BMI < 18.5 kg/m2 (n 38) were further divided into an underweight (UW; n 20) group and a chronically energy-deficient (CED; n 18) group. The CED subjects had significantly lower MVC (30.1, SD 5.9 kg) than either the well-nourished controls (BMI > 18.5 kg/m2: 39.8, SD 5.8 kg) or the underweight group (37.6, SD 4.9 kg). The differences between the CED and UW groups persisted even after the MVC were corrected for forearm muscle area and stature. The results suggest that MVC may be a useful functional indicator of nutritional status particularly in differentiating subjects with chronic undernutrition from individuals who are underweight and not undernourished but have similar BMI.