[Nutrition is not visible in medical educations].
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Education, Medical↗
Biomedical subjects
E Forsum
Publications and source records attributed to E Forsum.
Changes in adipose tissue volume and distribution during reproduction in Swedish women as assessed by magnetic resonance imaging.
Adipose tissue volume (ATV; total, subcutaneous, and nonsubcutaneous) was assessed by magnetic resonance imaging in the whole body and in six body compartments of 15 healthy Swedish women before pregnancy and 5-10 d, and 2, 6, and 12 mo postpartum. ATV increased by 5.43 +/- 4.72 L (mean +/- SD) during pregnancy and decreased by 3.18 +/- 4.61 L during the first 6 mo postpartum. The women had more ATV (2.86 +/- 2.32 L) 12 mo after delivery than before pregnancy. Of the ATV gained during pregnancy, 76% was placed subcutaneously and the decrease postpartum was due to a loss of subcutaneous ATV. During pregnancy, 68% of the increased ATV was placed in the trunk and 16% in the thighs. Postpartum fat was mobilized more completely from the thighs than from the trunk. For all variables studied variations between women were large. The results also show that women with a high weight gain during pregnancy retain lean tissue in their bodies.
Adipose Tissue↗
Body composition and fat distribution during the first 2 weeks of gestation in ad lib.-fed and energy-restricted rats.
Knowledge about changes in body composition during gestation is of interest when estimating energy requirements during pregnancy, and relevant since reproduction is often surprisingly well maintained in malnourished females. Due to difficulties in conducting such studies in humans, studies in rats are of interest. Therefore, maternal retention of fat and fat-free weight was estimated in rats during the first 2 weeks of gestation and during a corresponding time period in virgin controls. Groups fed ad lib. or 70% of ad lib. intake during the 4 weeks preceding conception and during gestation were studied. Retention was estimated by comparing pregnant and virgin rats with rats killed at the time of conception. Body fat was analysed chemically and fat-free weight was body weight minus body fat. Each rat was divided into twelve to fourteen parts and the fat content of each part was analysed. Pregnant ad lib.-fed rats retained more fat and fat-free weight than did virgin ad lib.-fed controls. In the energy-restricted group the pregnant rats retained more fat-free weight while virgin rats retained slightly more fat than did pregnant rats. The difference between pregnant and virgin rats with respect to the amount of fat in the different body parts was small in both feeding groups. Thus, the statement that fat stored at specific sites in the maternal body represents an important source of energy for use during lactation was not supported. The findings suggest that pregnancy stimulates growth of the maternal body and that chronic moderate energy restriction curtails this growth.
Adipose Tissue↗
Total body fat and its distribution during human reproduction as assessed by magnetic resonance imaging.
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Adipose Tissue↗
Adipose tissue distribution as assessed by magnetic resonance imaging and total body fat by magnetic resonance imaging, underwater weighing, and body-water dilution in healthy women.
A method for estimating total body fat (TBF) and the amount and distribution of adipose tissue in humans by using magnetic resonance imaging (MRI) is described. Thirty transaxial images of subjects were taken by a nuclear magnetic imager (0.02 T). Adipose tissue volume was calculated from adipose tissue area in each image and from the distances between images. The CV when estimating total volume of body adipose tissue was 1.5%. TBF of healthy Swedish women was estimated by the MRI method (n = 25), by underwater weighing (UWW) (n = 20), and by body-water dilution (BWD) (n = 23). When assessed by MRI and BWD, women contained 1.4 +/- 2.9% less and 4.7 +/- 4.0% more TBF, respectively, than when assessed by UWW. On average, 74.2% of total adipose tissue volume was situated subcutaneously. Subcutaneous fat:fat-free body weight and nonsubcutaneous fat:fat-free body weight were both significantly correlated with percent TBF but the women stored excess fat subcutaneously rather than nonsubcutaneously.
Adipose Tissue↗
Estimation of total body fat and subcutaneous adipose tissue in full-term infants less than 3 months old.
Both fetal and neonatal nutrition may influence the body fat content of infants. Epidemiologic field studies would be facilitated by a simple method of measuring total body fat (TBF). The accuracy of a method, based on skinfold measurements, of estimating TBF was evaluated in 22 infants by comparing the results with those obtained by the body water dilution technique. Because the accuracy was poor, a modification was evaluated in 14 of the infants. The measurements were used to calculate the amounts of subcutaneous and nonsubcutaneous body fat. Estimates of the thickness of subcutaneous adipose tissue made with calipers and ultrasonography were compared with each other and with those obtained with Futrex 5000, a device based on the principle of near-infrared interactance. The composition of the adipose tissue in biopsy specimen from 38 infants was analyzed and contained a mean of 0.66 g of fat/cm3. Results obtained by Futrex 5000 correlated with subcutaneous adipose tissue thickness only when the latter was thin. Estimates of adipose tissue thickness by calipers were significantly higher than estimates by ultrasonography at the forearm, thigh, and calf, whereas the opposite was found at the triceps, biceps, umbilicus, and nipple. The amount of nonsubcutaneous fat, in relation to body weight minus subcutaneous fat, increased with age and was higher in girls than in boys. Skinfolds were poor predictors of TBF. However, it may be possible to predict TBF from anthropometric measurements if appropriate knowledge about the growth and development of adipose tissue in infancy are available.
Adipose Tissue↗
Total energy expenditure of healthy Swedish women during pregnancy and lactation.
Total energy expenditure (TEE) was estimated in healthy Swedish women by the doubly labeled water method in a longitudinal study during pregnancy and lactation. Measurements were made before pregnancy (A); in gestational weeks 16-18 (B), 30 (C), and 36 (D); as well as 2 (F) and 6 (G) mo after delivery. When the results were interpreted, earlier published data regarding resting metabolic rate (RMR), energy intake, and energy in breast milk were also considered. TEE (MJ/d) and TEE/RMR were 10.5 +/- 2.2 (mean +/- SD) and 1.87 +/- 0.42 (n = 28), 9.6 +/- 2.8 and 1.65 +/- 0.67 (n = 22), 12.5 +/- 3.4 and 1.82 +/- 0.45 (n = 22), 12.2 +/- 4.1 and 1.66 +/- 0.52 (n = 19), 10.6 +/- 2.0 and 1.82 +/- 0.41 (n = 23), and 10.8 +/- 2.7 and 1.79 +/- 0.42 (n = 23) at A, B, C, D, F, and G, respectively. The results indicated that physical activity tended to be decreased during early pregnancy. Taking changes in body energy stores into consideration, it was estimated that subjects recorded 86% and 77% of their energy intakes at A and F respectively.
Adipose Tissue↗
Energy restriction and the partitioning of energy among the costs of reproduction in rats in relation to growth of the progeny.
Compared with well-nourished controls, progeny of energy-restricted females are smaller and grow less well. The mechanisms behind these effects are frequently studied in rats but interpretation of such studies requires knowledge about the partitioning of dietary energy among the costs of reproduction and maternal needs. Energy partitioning was studied in rats fed ad libitum or 70% of ad libitum intake from 24-34 d before conception until d 14 of lactation and in virginal controls. Body composition was estimated for adult rats on d 1 of gestation, for adult rats and litters on d 1, 9 and 14 of lactation and for virginal controls after 65 d of dietary treatment. Milk production and composition were also studied. Dams in the two groups retained similar amounts of energy during pregnancy. Mobilized body energy corresponded to only 6 and 12% of the energy in milk for ad libitum-fed and restricted rats, respectively. Adult energy-restricted rats were smaller than their ad libitum-fed counterparts and thus needed less energy for maintenance. During lactation, energy-restricted rats used less energy per unit body size than ad libitum-fed rats. Pups of restricted dams were not only smaller, they also utilized milk energy less efficiently than did pups of well-fed dams.
Aging↗
Composition of faeces from human subjects consuming diets based on conventional foods containing different kinds and amounts of dietary fibre.
The stool-bulking effect of dietary fibre (DF) is well-documented and believed to be important in the postulated beneficial effect of DF on human health. The aim of the present study was to investigate the digestibility of DF in relation to its stool-bulking properties and to study possible mechanisms for this effect. Four diets, based on conventional foods only, were studied in balance experiments on human subjects. Diet A contained DF mainly from whole-grain cereals while diets B1 and B2 contained DF mainly from pulses, vegetables and fruit. Diet C was a low-fibre diet. Faeces was fractionated into four fractions, each enriched in one of the following three components: undigested DF (fractions 1 + 2), faecal bacteria (fraction 3) and soluble components (fraction 4). The digestibility of DF in diets A, B1 and B2 was 0.62, 0.88 and 0.90 respectively. Subjects consuming diet A excreted slightly more fraction 3 than subjects consuming the other diets. Thus, the statement that DF of high digestibility stimulates microbial growth in the gut was not supported. The water-holding capacity of fraction 1 was studied in vitro and was found to be low. It is suggested that undigested soluble DF is important in the stool-bulking properties of DF.
Adult↗
Estimation of body fat in healthy Swedish women during pregnancy and lactation.
Reliable estimates of changes in body fat are important in studies of energy requirements during human reproduction. It is not known if current methods for the estimation of total body fat (TBF) are adequate for this purpose. In this paper earlier reported data from 29 women are used to show how methodology affects estimates of changes in TBF during reproduction. Skinfold thicknesses are also reported and equations relating these measurements to TBF were developed and used to demonstrate how well the skinfold technique could estimate such changes. No correlation was found between changes in body weight and body fat during early pregnancy or between the maternal changes in body weight and body fat over the complete pregnancy. These findings are tentatively explained by changes in the degree of hydration of the body.
Adipose Tissue↗
Resting metabolic rate and body composition of healthy Swedish women during pregnancy.
Body weight, resting metabolic rate (RMR), total body potassium (TBK), and total body water were measured and total body fat (TBF) was calculated in a longitudinal study of 22 pregnant, healthy Swedish women. Measurements were made before pregnancy, at gestational weeks 16-18, 30, and 36, and 5-10 d and 6 mo postpartum. RMR increased more during pregnancy than previous estimates on well-nourished women showed and the increase was significantly correlated with the birth weight of the baby. TBK decreased during the first part of pregnancy; measurements at weeks 16-18 and 30 were significantly lower than the prepregnancy value and changes in TBK and RMR were significantly correlated. TBF gain during pregnancy was 5.8 +/- 4.0 kg and 60% was already gained by gestational weeks 16-18. Gain in fat was not correlated with birth weight.
Adipose Tissue↗
Energy metabolism, body composition, and milk production in healthy Swedish women during lactation.
Variables of relevance to energy requirements during reproduction were studied in 23 healthy lactating Swedish women. Body composition and resting metabolic rate (RMR) were studied before pregnancy and three times postpartum. Energy intake was studied before pregnancy and, together with breast-milk production, 2 mo postpartum. The women gained 5.8 +/- 4.2 kg fat during pregnancy and their average fat content was unchanged during the first 2 mo of lactation whereas a slight loss (1.7 +/- 4.2 kg) occurred during the following 4 mo. RMR increased slightly during lactation in spite of a decrease in fat-free body weight 2 and 6 mo postpartum. Energy intake increased during lactation (280 +/- 440 kcal/d). The women produced 740 +/- 150 g breast milk/d containing 0.64 +/- 0.08 kcal/g. The results indicate that current estimates of energy needs during lactation may be too high.
Adipose Tissue↗
Metabolizable energy in humans in two diets containing different sources of dietary fiber. Calculations and analysis.
The metabolizable energy (ME) of two high fiber diets, providing between 33 and 74 g dietary fiber (DF) per day, was calculated by application of Atwater's general factors (4, 9 and 4 kcal/g protein, fat and carbohydrate, respectively), Merrill and Watt's specific factors, and the British approach in which ME from carbohydrates is calculated by multiplication of the monosaccharide equivalent by 3.75 kcal/g. These factors were applied to the intakes of fat, protein and carbohydrate of 20 human subjects in two balance experiments. ME estimated by Merrill and Watt's factors agreed better with ME estimated in the balance experiment than did ME calculated by Atwater's factors or by the British approach. It was calculated that the DF in diet A, derived mainly from cereals, contributed 2.5 +/- 1.4 kcal/g to ME of the diet. The corresponding figure for DF in diet B, derived mainly from beans, vegetables and fruits, was 3.1 +/- 1.2 kcal/g. It was concluded that Merrill & Watt's factors represent the best system in current use for calculation of ME in DF-rich diets.
Adult↗
Growth, body composition and breast milk intake of Swedish infants during early life.
The growth and breast milk intake of 22 healthy completely breast fed Swedish infants (9 girls, 13 boys) during the first 10 wk of life are reported and were found to be similar to those of other healthy breast fed populations of infants. Also the body composition (body fat and lean body tissue) was estimated by an anthropometric method at the age of about 10 and 65 days. It was found that the breast milk intake correlated significantly with weight and fat gain but not with gain in lean body tissue or with gain in length. These findings suggest that energy rather than protein intake limited growth in this group of infants. Also the results confirm the fact that the capacity for fat retention is high during early life and show that the size of fat stores is related to breast milk intake.
Body Composition↗
Energy maintenance cost during pregnancy in healthy Swedish women.
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Adolescent↗
Casein content of human milk.
Three methods for estimating the casein content of human milk were tested; isoelectric precipitation with washing and correction for co-precipitating proteins, sedimentation by ultracentrifugation, and indirect analysis (ie analyzing for the content of the major whey proteins and subtracting these from the total protein content). Gel electrophoresis and amino acid analysis were used to confirm some of the results. The casein content (mg/ml) of mature human milk (n = 9) was 2.33 +/- 1.69 by isoelectric precipitation, 1.80 +/- 0.48 by sedimentation and 2.96 +/- 1.08 by the indirect approach. A probable partition of nitrogen in breast milk would be casein N: whey protein N: non-protein N of 20:50:30; ie the correct ratio of casein nitrogen: whey nitrogen is approximately 20:80. Analysis of trace elements and minerals demonstrates that of total Ca 10%, Mg 5%, Zn 28%, Cu 17%, and Fe 27% is bound to casein when prepared by ultracentrifugation while isoelectric precipitation causes a redistribution of some of these elements. Since the protein ratio of human milk is considered a guideline when manufacturing infant formulas, these findings should be considered with regard to infant nutrition.
Amino Acids↗
Effect of reduced energy intake versus increased physical activity on the outcome of nitrogen balance experiments in man.
The effects of energy deficiency created by a reduced energy intake versus an increased physical activity on urinary nitrogen excretion, nitrogen balance and the biological value of the dietary protein (0.57 g/kg/day from a mixed diet) are reported. Two experiments, 21 and 27 days respectively, designed to even out possible effects of time on nitrogen balance, were conducted on 12 young adult men and women. During energy deficiency, urinary nitrogen increased while nitrogen balance and biological value decreased. No significant differences between the two kinds of energy deficiency were found but the effect on the parameters studied tended to be less pronounced the longer the subjects had been on the experimental diets.
Adult↗
Calculation and determination of metabolizable energy in mixed diets to humans.
Several approaches are currently in use for calculating metabolizable energy of mixed diets from the foods and nutrients they contain. This study compares the metabolizable energy content of six low fiber and one high fiber diet as calculated by conventional procedures (ie, using Atwater's general factors, Merrill and Watts specific factors, and the British procedure where the monosaccharide equivalent of available carbohydrates is multiplied by 3.75 kcal/g) with values for metabolizable energy measured in balance experiments on human subjects. For the low fiber diets, the conventional procedures for calculation of metabolizable energy showed an average deviation between calculated and measured values of up to about 6% of the value obtained in balance experiments. For the high fiber diet Merrill and Watts specific factors and Atwater's general factors were superior to the British approach for calculation of metabolizable energy. Fecal energy content in relation to intake of undigestible energy is discussed.
Adult↗