The aim of this work was to evaluate whether oxytocin administered in male rats subcutaneously early in life in the absence or presence of food restriction during pregnancy has life-long effects on the α₂-agonist binding sites in the nucleus of the solitarii tract (NTS), in the hypothalamus and the amygdala, as evaluated by quantitative receptor autoradiography. Maternal food restriction alone increased the affinity of the α₂-agonist [³H]UK14.304 binding sites exclusively in the NTS. In offspring from ad libitum fed dams, oxytocin treatment significantly increased the density of α₂-agonist binding sites in the NTS and in the hypothalamus. The K_d value of the α₂-agonist binding sites in the hypothalamus of these rats, but not in the other regions studied, was also significantly increased. In offspring from food-restricted dams, oxytocin treatment produced a significant increase of the B_max values in the hypothalamus and the amygdala and the K_d value of the α₂-agonist binding sites in the NTS of these rats also was selectively and significantly increased. These results suggest that a postnatal, oxytocin-induced increase of regional α₂-adrenoceptor function can be seen in adulthood by a persistent, regionally selective increase in the density of central α₂-adrenoceptor agonist binding sites, in the absence of an affinity change in the NTS. Such a regional increase of α₂-adrenoceptor signalling in adulthood may contribute to the anti-stress action of postnatal oxytocin. By contrast, after prenatal stress, the potential increase in α₂-adrenoceptor signalling takes place via selective increases of density with no changes of affinity of the α₂-agonist binding sites in the hypothalamus and the amygdala.

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The publication of the Department of Health White Paper "The Health of the Nation" (1992) and "Our Healthier Nation" (1998) gave emphasis to the importance of nutritional health of the nation at all ages. It is clear that the achievement of specific targets for pregnancy and infancy as set out in the White Paper will involve the training of all health care professionals in nutrition education. This book responds to the challenge and focuses on good nutrition for and during pregnancy, in low birth weight infants, and during infancy. It has a strong public health emphasis, dealing with health prevention issues for the Nation s younger population. The text is written as a scientific reference book for those seeking to apply science in the support of a successful pregnancy and in the prevention of nutritional problems during foetal and early post natal life. The importance of optimal nutrition during these periods of life is emphasised by the overwhelming evidence that nutritional problems in early embryonic life may cause congenital malformations and during late foetal life and early post natal life may set the molecular programme for later disease development.

Infant birth weight has increased recently, representing an obstetric and potentially a public health problem since high birth weight involves a risk of obesity later in life. Maternal nutritional status is important for fetal growth and therefore relationships between maternal body weight and composition v. birth weight and infant subcutaneous adipose tissue were investigated in twenty-three healthy women and their newborn infants using multiple and simple linear regression analysis. Furthermore, using previously published data for nineteen infants, it was demonstrated that an anthropometric method could provide useful estimates of the amount of subcutaneous adipose tissue. Birth weight was correlated with the maternal content of total body fat (TBF) both before pregnancy and in gestational week 32 and, together with gestational age at birth, TBF (%) before pregnancy explained 45% of the variation in birth weight. This figure was not increased when gestational gains in weight or TBF were added to the model. Furthermore, in infants, birth weight correlated with the amount of their subcutaneous adipose tissue. Together maternal TBF (%) and amount of subcutaneous adipose tissue in infants explained 61–63% of the variation in birth weight while the amount of infant subcutaneous adipose tissue alone explained only 55%. The maternal TBF content is likely to be important for the recent increase in birth weight. This factor probably causes a general augmentation in fetal growth rather than a specific stimulation of adipose tissue growth.

Blood IGF-I concentrations are persistently elevated throughout pregnancy in humans and guinea pigs and may regulate substrate partitioning between mother and conceptus. In the guinea pig, liver and adipose tissue have recently been suggested to contribute to the increased levels of circulating IGF-I in mid-pregnancy, but whether this persists in late pregnancy in undernutrition is not known. Therefore the effect of pregnancy and undernutrition on circulating IGF-I and hepatic expression of IGF-I in late gestation in the guinea pig was examined. Female guinea pigs (Cavia porcellus) were fed ad libitum throughout pregnancy or 70% of ad libitum intake for 28 days prior to and throughout pregnancy (term is 69 d). Non-pregnant animals were maintained for 88 days on the same diets. Plasma IGF-I was measured by RIA after molecular sieving chromatography at low pH. Abundances of IGF-I and ß-actin mRNA in maternal liver were quantified by digoxigenin-ELISA after RT PCR. Late pregnancy increased both the concentration of IGF-I protein (p < 0.001) in plasma and the relative abundance of liver IGF-I mRNA (p < 0.001) in ad libitum fed, but not in feed restricted pregnant guinea pigs. The concentration of IGF-I protein in plasma correlated positively with the relative abundance of IGF-I mRNA in liver overall (p < 0.002), suggesting the liver as a major source of endocrine IGF-I in late pregnant guinea pigs. This study demonstrates that hepatic expression of IGF-I remains elevated during late pregnancy in the well fed guinea pig, which is in contrast to that observed in other non-human species. © 2005 Elsevier Ltd. All rights reserved.

Current recommendations propose that an entire pregnancy requires an additional amount of energy from the diet equivalent to 335 000 kJ. This figure is mainly based on increases in the basal metabolic rate (BMR) and retention of total body fat (TBF). The BMR response to pregnancy varies considerably among women, but the factors responsible for this variability are unknown. TBF can be calculated from total body water (TBW) and the hydration factor (HF), using the so-called two-component model. However, the validity of this model during pregnancy has been questioned. Furthermore, current recommendations propose that energy needs during pregnancy may be partly offset by reductions in physical activity, but this statement is supported by little experimental evidence. The aims of this thesis were: to evaluate if the physical activity level (PAL) can be estimated by means of heart rate recording, accelerometry, and a questionnaire in women planning pregnancy; to assess the effect of pregnancy on energy expenditure due to physical activity, on activity pattern and on the biological variability of HF; to evaluate the use of bioimpedance spectroscopy (BIS) for assessing TBW during pregnancy; and to identifY factors explaining the variability of the BMR response to pregnancy.

Healthy women were studied before pregnancy (n=38), and in gestational weeks 8, 14, 20, 32, 35 and 2 weeks post partum (n=23). Total energy expenditure (TEE), BMR, TEE/BMR, activity pattern, body composition, circulatory variables and serum levels of thyroid hormones and insulin growth factor-I (IGF-1) were measured. Foetal weight in gestational week 31 and infant birth weight were assessed.

All estimates of PAL were imprecise and too low in women planning pregnancy. There was little change in TEE/BMR in gestational week 14, but it was significantly reduced in gestational week 32. However, activity pattern was largely unaffected by pregnancy. The biological variability of HF was 2%, 3% and 1.7% or less of average HF before pregnancy and in gestational weeks 14 and 32, respectively. BIS underestimated TBW during pregnancy. In gestational week 14, the increase in BMR correlated significantly with the increase in body weight and with TBF (%)before pregnancy. Together these variables explained about 40% of the variability in the BMR response. In gestational week 32, the increase in BMR correlated significantly with changes in body weight, TBF, fat-free mass, IGF-I, cardiac output and free triiodothyronine. At this stage of gestation the increase in body weight in combination with foetal weight or with the increased levels of IGF-I in serum explained about 60% of the variability of the increased BMR.

In conclusion: I) Heart rate recording, accelerometry and the questionnaire produced inappropriate PAL estimates. 2) In women maintaining their pre-pregnant activity pattern the increase in BMR represents the major component of the increased energy expenditure during pregnancy. 3) The two-component model for assessing TBF is appropriate in late gestation, while its precision may be impaired in early pregnancy. 4) BIS in its present form is not appropriate for assessing TBW during pregnancy. 5) Nutritional factors are important regarding the variability in the BMR response to pregnancy.

Human pregnancy is associated with increased requirements for dietary energy and this increase may be partly offset by reductions in physical activity during gestation. Studies in well-nourished women have shown that the physical activity level (PAL), obtained as the total energy expenditure (TEE) divided by the BMR, decreases in late pregnancy. However, it is not known if this decrease is really caused by reductions in physical activity or if it is the result of decreases in energy expenditure/BMR (the so-called metabolic equivalent, MET) for many activities in late pregnancy. In the present study activity pattern, TEE and BMR were assessed in twenty-three healthy Swedish women before pregnancy as well as in gestational weeks 14 and 32. Activity pattern was assessed using a questionnaire and heart rate recording. TEE was assessed using the doubly labelled water method and BMR was measured by means of indirect calorimetry. When compared to the pre-pregnant value, there was little change in the PAL in gestational week 14 but it was significantly reduced in gestational week 32. Results obtained by means of the questionnaire and by heart rate recording showed that the activity pattern was largely unaffected by pregnancy. The findings support the following conclusion: in a population of well-nourished women where the activity pattern is maintained during pregnancy, the increase in BMR represents approximately the main part of the pregnancy-induced increase in TEE, at least until gestational week 32.

Bioimpedance spectroscopy (BIS) is a technique of interest in the study of human pregnancy because it can assess extracellular (ECW), intracellular (ICW), and total body water (TBW) as ECW plus ICW. The technique requires appropriate resistivity coefficients and has not been sufficiently evaluated during the reproductive cycle. Therefore, in a methodological study, we estimated ECW, ICW, and TBW, by means of BIS, and compared the results with the corresponding estimates obtained by using reference methods. Furthermore, results obtained by means of population-specific resistivity coefficients were compared with results obtained by means of general resistivity coefficients. These comparisons were made before pregnancy, in gestational weeks 14 and 32, as well as 2 wk postpartum in 21 healthy women. The reference methods were isotope and bromide dilution. Average ICW, ECW, and TBW, estimated by means of BIS, were in agreement with reference data before pregnancy, in gestational week 14, and postpartum. The corresponding comparison in gestational week 32 showed good agreement for ICW, whereas estimates by means of BIS were significantly (P < 0.001) lower than the corresponding reference values for ECW and TBW. Thus the BIS technique, which was based on a model developed for the nonpregnant body, estimated increases in ICW accurately, whereas increases in ECW and TBW tended to be underestimated. Estimates obtained by using population-specific and general resistivity coefficients were very similar. In conclusion, the results indicated that BIS is potentially useful for studies during pregnancy but that further work is needed before it can be generally applied in such studies.

Background: Knowledge of the biological variability of the hydration factor (HF), ie, the ratio between total body water and fat-free mass, is important when calculating total body fat by means of the commonly used two-component model, which is based on estimates of body weight and total body water. The effect of pregnancy on the biological variability of HF, and consequently on the precision of the two-component model, is unknown.

Objective: Our goal was to assess the effect of pregnancy on HF and its biological variability.

Design: HF was assessed in 33 women planning pregnancy and in 17 of these women during gestational weeks 14 and 32 and 2 wk postpartum. HF was calculated by using estimates of body weight, total body water obtained by means of deuterium dilution, and body volume measured by using underwater weighing.

Results: In the 17 women who became pregnant, HF was 0.718 ± 0.023, 0.723 ± 0.031, 0.747 ± 0.017, and 0.734 ± 0.020 before pregnancy, in gestational week 14, in gestational week 32, and 2 wk postpartum, respectively. The biological variability represented ≈2% of average HF in the nonpregnant state. The corresponding figure was >3% in gestational week 14 but ≤1.7% in gestational week 32.

Conclusion: The two-component model for assessing body fat is as appropriate during late gestation as it is in the nonpregnant state, although its precision may be impaired when applied during the first part of pregnancy.

Simple methods were developed and evaluated to assess total energy expenditure in 24 healthy, Swedish women planning pregnancy. Total energy expenditure was measured by the doubly-labeled water method (reference method) and three simple methods: heart rate recording, movement registration by an accelerometer, and a questionnaire. Mean total energy expenditure obtained by the four methods varied between 2,530 kcal per 24 hours (10,570 kJ/24 hours) and 2,730 kcal per 24 hours (11,420 kJ/24 hours). No significant difference between the results obtained by the different methods was found. The mean difference between the simple method and the reference method was for the questionnaire 204 +/- 508 kcal per 24 hours (853 +/- 2,124 kJ/24 hours), for the heart rate recorder 58 +/- 338 kcal per 24 hours (241 +/- 1,416 kJ/24 hours) and for the accelerometer 6 +/- 325 kcal per 24 hours (25 +/- 1,360 kJ/24 hours). The heart rate recorder and the questionnaire overestimated high and underestimated low energy expenditures. The accelerometer and the heart rate recorder were able to assess mean total energy expenditure of groups. No systematic bias was found when the accelerometer was used.

According to the report of the World Health Organization (1985), total energy expenditure (TEE) in human subjects can be calculated as BMR × physical activity level (PAL). However, other reports have pointed out limitations in the suggested procedure related to the % body fat of the subjects. The purpose of the present study was to evaluate the World Health Organization (1985) procedure in thirty-four healthy women with BMI 18-39 kg/m². BMR and TEE were measured using indirect calorimetry (BMR_meas) and the doubly-labelled water method (TEE_ref) respectively. When assessed using the doubly-labelled water and skinfold-thickness methods, the women had 34 (SD 8) and 33 (SD 6) % body fat respectively. On the basis of guidelines provided by the World Health Organization (1985), 1.64 was selected to represent the average PAL of the women. Furthermore, PAL was also assessed by means of an accelerometer (PAL_acc), heart-rate recordings (PAL_HR) and a questionnaire (PAL_q). These estimates were: PAL_acc 1.71 (SD 0.17), PAL_HR 1.76 (SD 0.24), PAL_q 1.86 (SD 0.27). These values were lower than TEE_ref/BMR_ref, which was 1.98 (SD 0.21). BMR assessed using equations recommended by the World Health Organization (1985) (BMR_predicted) overestimated BMR by 594 (SD 431) kj/24 h. However, when TEE was calculated as BMR_predicted × PAL_acc, BMR_predicted × PAL_HR and BMR_predicted × PAL_q respectively, average results were in agreement with TEE_ref. Furthermore, TEE values based on BMR_predicted and PAL_acc, PAL_HR, PAL_q as well as on PAL = 1.64, minus TEE_ref, were significantly correlated with body fatness. When the same PAL value (1.64) was used for all subjects, this correlation was particularly strong. Thus, the World Health Organization (1985) procedure may give TEE results that are biased with respect to the body fatness of subjects.

Background: The total energy cost of pregnancy is largely due to an elevated basal metabolic rate (BMR). Large variations in the BMR response to pregnancy have been reported, but the factors associated with this variability are incompletely known.

Objective: The objective was to identify factors associated with variability in the BMR response to pregnancy.

Design: In 22 healthy women, BMR, body weight (BW), total body fat (TBF), fat-free mass (FFM), circulatory variables, serum concentrations of insulin-like growth factor I (IGF-I), and thyroid hormones were measured before pregnancy and in gestational weeks 14 and 32. BMR and BW were also measured in gestational weeks 8, 20, and 35. Fetal weight was estimated in gestational week 31.

Results: In gestational week 14, the increase in BMR correlated significantly with the corresponding increase in BW and with the prepregnancy percentage of TBF. Together these variables explained ≈40% of the variability in the BMR response. In gestational week 32, the increase in BMR correlated significantly with the corresponding changes in BW, TBF, FFM, IGF-I, cardiac output, and free triiodothyronine. The increase in BW in combination with fetal weight or with the elevated concentration of IGF-I in serum explained ≈60% of the variability in the increase in BMR.

Conclusions: Weight gain and the prepregnancy percentage of TBF—ie, factors related to the maternal nutritional situation—are important factors with regard to the variability in the BMR response to pregnancy. Thus, it is important to consider the nutritional situation before and during gestation when assessing pregnancy energy requirements.

Adequate fetal growth is of importance for health in adulthood. Maternal nutritional status has been suggested to be one major factor influencing fetal development. The nature of how the mother's nutritional status and her metabolic, endocrine and physiological adaptations to pregnancy interact and how these interactions affect fetal growth is unclear. The insulin-like growth factor (IOF)-system has been suggested to be one mediator between maternal nutritional status and fetal growth. Impaired fetal growth may have life-long effects, but little is known about the possibilities to ameliorate intrauterine perturbations postnatally. Oxytocin, an anti-stress hormone, was used as a model to study such possibilities.

The aims were: to measure serum levels of IGF-I, IGF-II, IGF-binding protein (IGFBP)-1, IGFBP-3 and protease activity against IOFBP-3 in healthy women before, during and after pregnancy; to study the relationships regarding maternal body weight and composition before and during pregnancy versus components of the maternal IGF-system in serum in healthy women; to study the relationships regarding components of the maternal IGF-system in serum versus infant birth weight; to measure the expression of mRNA for IGF-I and IGF-II in different tissues in guinea pigs and to study how these expressions are altered by gestation and food restriction; to study long-term effects of maternal food restriction during gestation on health related variables in adult rat offspring; to study long-term effects of early postnatal treatment of oxytocin in the adult rat offspring.

Healthy women were studied before pregnancy, in weeks 8, 14, 20, 32, 35 of pregnancy and 2 weeks postpartum. Body weight, body composition and serum levels of IGF-I, IGF-II, IGFBP-1, IGFBP-3 and protease activity against IOFBP-3 were measured. Infant body weight and length at birth were obtained from hospital records. The amounts of mRNA for IGF-I and IGF-II in the liver, adipose tissues, muscles, spleen, uterus and placenta were measured in virginal and pregnant guinea pigs, being either ad libitum fed or food restricted. Rat dams were either ad libitum fed or food restricted during gestation. Their offspring received oxytocin or NaCI at day 1-14 of age. Blood pressure, plasma levels of corticosterone, IGF-1, IGFBP-1, and reproductive performance were measured in the adult offspring.

All of the studied components of the IGF-system in serum underwent changes during pregnancy. The levels of IGF-1 were reduced in early pregnancy compared to before conception. The lower the body weight or the less amount of body fat before pregnancy, the larger the decrease in IGF-I in early pregnancy. The combination of body weight before pregnancy and the serum level of IGF-I in early pregnancy explained as much as 47 % of the variation in birth weight, indicating that the higher the maternal body weight before pregnancy and the lower the level of IGF-I in early pregnancy, the heavier the infant. From week 20 of pregnancy, maternal levels of IGFBP-I were negatively correlated to birth weight. In late pregnancy, the abundance of IGFBP-I and protease activity in serum together explained 35% of the variation in birth weight, indicating that the lower the IGFBP-I and the higher the protease activity, the higher the birth weight. In guinea pigs, mRNA for IGF-I was expressed in high amounts in adipose tissue and liver, whereas mRNA for IGF-II were highly expressed in placenta and liver. The expression of IGF-I was in general unaffected by food restriction, but doubled during gestation, whereas the expression of IGF-II in the placenta was decreased by food restriction and increased in the liver by gestation. Maternal food restriction during gestation caused increased levels of corticosterone, IGF-I and IGFBP-I, but no elevation in blood pressure, in adult offspring. Early postnatal oxytocin treatment decreased blood pressure and corticosterone, whereas the influence on reproductive performance was dependent on the nutritional status of their dams and the current nutritional experience in adulthood.

In conclusion, this thesis confirms that the IGF-system may be one factor mediating the effects of maternal nutritional status on fetal growth. It also supports the suggestion that IGFBP-I in maternal serum may be used as a marker of infant birth weight. Adipose tissue was shown to produce high amounts of IGF-I, indicating endocrine functions during gestation. Postnatal oxytocin treatment ameliorated some of the adverse effects in adult offspring, induced by maternal food restriction.

Low birth weight due to maternal malnutrition is associated with increased risk of developing diseases in adulthood, for example, cardiovascular disease. Postnatal oxytocin treatment has previously been shown to have positive effects on blood pressure and corticosterone levels in adult offspring from malnourished dams. The aims of this study were to investigate if maternal food restriction during gestation alters plasma levels of insulin-like growth factor I (IGF-I), IGF binding protein 1 (IGFBP-1), glucose, and insulin in adult male rat offspring, and if postnatal oxytocin treatment has any effect on those changes. Adult offspring from food-restricted mothers had increased levels of IGF-I and IGFBP-1 compared with ad libitum–fed offspring. Postnatal oxytocin treatment had no effect on the IGF system in adulthood. In conclusion, maternal malnutrition during gestation altered the IGF system in adult rat offspring.

Objectives: To investigate the following relationships: 1) maternal body weight and composition versus insulin-like growth factor (IGF)-I and IGF binding protein (IGFBP)-1 in maternal serum before and during pregnancy, and 2) IGF-I and IGFBP-1 in maternal serum during pregnancy versus infant birth weight, body composition and ponderal index.

Study design: Serum was collected from 23 healthy women before pregnancy, and in weeks 14, 32 and 35 of pregnancy. On these occasions maternal body weight and composition were assessed. Weight, length and body composition of the newborn were measured. Linear and multiple linear regression analyses were applied.

Results: Women with the lowest body weight and body fat content had the largest decreases in IGF-I in early pregnancy. During pregnancy maternal fat-free body weight was positively related to IGF-I, whereas body fat was inversely related to IGFBP-1. Maternal body weight before pregnancy and IGF-I in week 14 of gestation explained 47 % of the variation in birth weight.

Conclusion: The maternal IGF-system may be a mediator of the effect of maternal nutritional status on fetal growth.

The maternal insulin-like growth factor (IGF)-system is considered to influence fetal growth. In this longitudinal study of 23 healthy women we aimed 1) to assess maternal serum levels of IGF-I, IGF-II, IGF binding protein (IGFBP)-1, IGFBP-3 and protease activity against IGFBP-3 before, during and after pregnancy, and 2) to relate these levels in early and late pregnancy to fetal and birth weight. Serum was collected before pregnancy, in weeks 8, 14, 20, 32 and 35 of pregnancy and 2 weeks postpartum. IGF-I, IGF-II, IGFBP-1, and IGFBP-3 were analyzed with radioimmuno/radiometric assays and protease activity with Western blot. Fetal weight was measured by means of ultrasound (week 31 of pregnancy) and birth weight was recorded. IGF-I was initially decreased during pregnancy, compared to before conception. This early decrease was not correlated with fetal or birth weight. In late pregnancy, IGF-I and protease activity were positively related to fetal weight, whereas from week 20 of pregnancy IGFBP-1 showed an inverse association with birth weight. We suggest that in healthy pregnant women there is a fine-tuned balance within the maternal IGF-system, with components With either promoting or restricting influences on fetal growth. The results indicate that maternal IGFBP-1 cguld be used from mid-pregnancy as a marker for birth weight.

The insulin-like growth factor (IGF) system is subjected to pregnancy-associated changes in the circulation and is suggested to be of importance for partitioning of nutrients between the mother and the foetus. Interestingly, maternal undernutrition alters the pregnancy-associated changes, with possible adverse consequences for the mother and the foetus. However, it is not known how malnutrition and pregnancy alter the expression of mRNA for IGFs locally in different tIssues. The aims of this study were to investigate where IGF-I and IGF-II are expressed in guinea pigs and how this expression is altered during food restriction and pregnancy. Ad libitum-fed and food-restricted (fed 70% of the ad libitum-fed intake four weeks before pregnancy and throughout the study) guinea pigs were mated. On day 40 of pregnancy and on the corresponding day for virginal females the animals were killed. mRNA for IGF-I and IGF-II was analysed in various organs/tIssues by solution hybridisation. mRNA for IGF-I was expressed in high amounts in uterus, liver and adipose tIssues. The expression was not affected by food restriction, but was increased in liver and adipose tIssue and decreased in uterus by pregnancy. mRNA for IGF-II was expressed in high amounts in the placenta and liver. In the placenta the expression was decreased by food restriction. Pregnancy increased the levels of mRNA for IGF-II in the liver. Food-restricted dams had smaller foetuses and placentas. In conclusion, this study indicates an important role for the adipose tIssue during gestation, not only as an energy store but also as an endocrine tIssue expressing IGF-I. The decreased expression of IGF-II in the placenta due to food restriction is suggested to have adverse effects on placental structure and function.

Repeated oxytocin administration to adult rats causes a long-term decrease of plasma levels of corticosterone and blood pressure and stimulates growth and fat retention. Maternal undernutrition increases blood pressure and plasma corticosterone in adult offspring. We hypothesized that oxytocin treatment early in life would alleviate adverse effects of intrauterine food restriction. Male pups from ad libitum-fed and food-restricted (fed 60% of ad libitum intake) dams were injected with oxytocin or saline in days 1–14 after birth. At 4 mo, blood pressure, plasma levels of corticosterone, and adiposity were assessed. Oxytocin treatment decreased blood pressure independently of nutrition, whereas the increased plasma levels of corticosterone were lowered to normal levels in food-restricted offspring. Blood pressure and adiposity were not affected by in utero food restriction, whereas birth and adult weight were. In conclusion, postnatal events may alleviate adverse effects caused by in utero food restriction. In contrast to more severe food restriction, a moderate general food restriction during gestation had no effect on blood pressure in the offspring.

Aim: To evaluate a method based on measurements of skinfold thickness (SFT) in infants under four months of age.

Methods: Adipose tissue volume was assessed by means of magnetic resonance imaging and total body fat (TBF) by means of a method based on skinfold measurements previously developed for children under two years of age (TBF-SFT). Estimates of TBF obtained by means of body water dilution (TBF-BWD) represented reference values. The subjects were 45 fullterm infants, 4-131 days old, and eight premature infants born in gestational weeks 30-33 and studied at a postnatal age of 63 ± 10 days.

Results: In fullterm infants TBF-SFT and TBF-BWD were 23.3 ± 3.4 and 21.8 ± 7.0 %, respectively, and the difference between the two methods was non-significant. However TBF-SFT minus TBF-BWD (%, y) was significantly con-elated (p<0.0001) with the average TBF-SFT and TBF-BWD (%, x), showing that the skinfold method overstimated TBF in lean infants while it underestimated TBF in infants with a high body fat content. In fullterm infants adipose tissue (AT) contained 0.68 ± 0.14 g fat/ml. Significant correlations were found between the AT fat content (g/ml, y) and TBF-BWD (%, x) (p<0.0001 ), as well as between the AT fat content (g/ml, x) and TBF-SFT minus TBF-BWD (%, y) (p<0.0001). In premature infants TBF-SFT (%), TBF-BWD (%) and the AT fat content were similar to the corresponding figures for nine fullterm newborns.

Conclusion: In fullterm infants the skinfold method produced biased estimates of TBF, which to a large extent can be explained by a variation in the AT fat content. However, the method has the potential to provide meaningful results in groups of infants with similar AT fat content.

Aim: To assess total energy expenditure (TEE) and body composition, i.e. total body water (TBW) and adipose tissue volume (ATV), at term age in 8 healthy preterm infants, born between gestational weeks 30 and 33, and in 9 healthy full-term newborns.

Methods: Total and subcutaneous ATVs were assessed using magnetic resonance imaging, while TEE and TBW were estimated using doubly labelled water.

Results: Total ATV was 272 ±21 and 261 ± 56 ml/kg body weight, while subcutaneous ATV was 88.9 ± 1.6 and 89.7 ± 2.0% of total ATV for preterm and full-term infants, respectively. The corresponding figures for TBW (as percentage of body weight) were 67.4 ± 2.5 and 68.1 ± 4.1, respectively. A significant correlation between ATV/kg body weight and body weight was found for full-term (p < 0.0001) but not for preterm infants. TEE for preterm infants was 315 ± 20 kJ/kg body weight/24 h, which was significantly higher (p < 0.05) than TEE for full-term infants (254 ± 45 kJ/kg body weight/24 h). At the time of investigation preterm infants weighed significantly (p < 0.05) less (540 g) than full-term infants. After the time of investigation, weight gains of preterm and full-term infants were 38 ± 12 and 24 ± 14 g/24 h, respectively.

Conclusion: When compared to full-term newborns, predominantly breastfed healthy preterm infants at term postconceptional age were significantly smaller, had a similar average proportion of body fat and showed catch-up growth. Their higher TEE/kg body weight can be explained by a higher growth rate and possibly also by higher physical activity.

Information about body fatness is important during nutritional assessment of infants, but current methods to estimate body composition in vivo are often not applicable in infants. Therefore, a new method based on magnetic resonance imaging (MRI) was developed. This method, which can assess the volume and distribution of adipose tissue (AT) as well as total body fat, was applied in 11 healthy full-term infants. Their total body water was also estimated using the isotope dilution technique. Adipose tissue volume (ATV) was calculated from AT area in 16 images of the body taken by an MRI scanner (1.5 tesla). AT area was assessed using a computer program in which AT criteria was defined by the observer. ATV of the infants was therefore evaluated once by three observers and twice by a fourth observer. The different observers estimated total, s.c., and non-s.c. ATV with a precision that varied between 1.9 and 7.2%, 2.0 and 4.8%, and 4.2 and 40.7%, respectively. Variations during AT area calculations accounted for a large part of the imprecision when assessing total and s.c. ATV. The linear relationship between percent total body water and total ATV in relation to body weight was significant in all evaluations. Although average total ATV varied when estimated by the four observers, there was, within each evaluation, a fairly constant order between infants with respect to their ATV. It is concluded that the MRI procedure represents a useful possibility to assess body fatness in infants.

Oxytocin treatment may permanently alter endocrine axes resulting in anti-stress and anabolic effects. However, the nutritional status influences the effects of oxytocin. The specific aims of this study were to investigate the effects of postnatal oxytocin treatment on reproductive performance in adult life, by studying maternal weight gain, adiposity, plasma levels of IGF-I as well as fetal and placental weights in the following groups of animals: (1) Ad libitum fed dams coming from ad libitum fed mothers. (2) Ad libitum fed dams coming from food-restricted mothers. (3) Food-restricted dams coming from ad libitum fed mothers. (4) Food-restricted dams coming from food-restricted mothers. Oxytocin treatment postnatally had long-term effects and increased adiposity in pregnant dams and stimulated placental and fetal growth relative to saline-treated dams. However, if the dams themselves had been exposed to food restriction during fetal life, the effect of postnatal oxytocin treatment changed. The oxytocin-treated mothers were still fatter but had smaller fetuses. In conclusion, postnatal oxytocin treatment influences reproductive performance in later life but is dependent on the mother’s previous and current nutritional experience.

Background: Nutrition during early life is of fundamental importance for optimal health during childhood as well as later in life. The prevalence and the severity of obesity in children and adults are presently increasing at alarming rates world wide, which is of great concern as obesity is associated with increased morbidity. Available systematic information regarding body composition development during childhood is presently very limited and there is a need for accurate methods for determining body fatness in young children. The doubly labelled water (DLW)-method is non-invasive and measures total body water (TB W) and total energy expenditure (TEE) of humans during true free-living conditions. Estimates of TB W can be used to assess body fatness. Previous studies in young children below 3 years of age have shown low values for TEE, indicating that current recommendations for dietary energy intake are too high. However, in most of these studies the children were below 6 months of age, and no Swedish studies cover the age range 7-36 months of age.

Subjects & Methods: TEE and TBW were measured by means of the DLW-method in healthy Swedish children at 9 (n=30) or 14 (n=29) months of age. Total body fat (TBF) was calculated from TBW and body weight using the body water dilution (BWD)-method. When expressed in percent of body weight, these estimates (% TBF-BWD) represented reference values for body fatness. Body fatness was also measured using the skin fold thickness technique (% TBF-SFT) and body mass index (BM I). The children were ranked and grouped into five groups with increasing levels of body fatness using %TBF-BWD, %TBF-SFT and BMI, respectively.

Results: TEE was 323 ± 38, 322 ± 29, 313 ± 23 and 331 ± 28 kJ/kg/d for 9-month-old girls and boys and 14-month-old girls and boys, respectively. BMI, %TBF-SFT and %TBF-BWD for all children were 17.5 ± 1.6, 27.8 ± 3.7% and 29.1 ± 4.4%, respectively. %TBF-BWD minus %TBF-SFT was = 1.35 ± 4.06% (n=59). By measuring %TBF-SFT or BMI, about 35% of the children could be classified in the correct group with respect to body fatness. Serious misclassification was more common for %TBF-SFT (29%) than for BMI (17%). There was a significant inverse linear relationship between PAL and %TBF-BWD (r = -0.81, P<0.00l, n=59).

Conclusions: The requirements for dietary energy of a group of Swedish children, 9 and 14 months of age, were 15-20% lower than indicated by current recommendations. In the group of children studied, BMI as well as the skinfold technique were poor tools for classification of body fatness. The skinfold technique produced inaccurate and imprecise estimates of body fatness. It can be speculated that the relationship between PAL and %TBF-BWD indicates that children with a high percent body fat are more likely to be in a state of positive energy balance, which would favour fat retention, possibly establishing a vicious cycle early in life leading to further accumulation of fat in the body.

Objectives: To measure total energy expenditure (TEE) and total body water (TBW) in healthy Swedish children 9 or 14 months of age. To compare their TEE with current recommendations for energy intake. To define their body composition and relate this to energy expenditure.

Design: Children were investigated at 9 or 14 months. The following variables were measured: TEE and TBW (by the doubly labelled water method), weight and length. Total body fat (TBF), sleeping metabolic rate, activity energy expenditure and physical activity level (PAL) were calculated.

Subjects: Thirty infants 9 months of age and 29 children 14 months of age.

Results: TEE was 32338, 32229, 31323 and 33128 kJ/kg/day in 9-month-old girls, 9-month-old boys, 14-month-old girls and 14-month-old boys, respectively. At 9 months of age girls and boys contained 29.64.8 and 29.74.5% TBF, respectively. At 14 months the corresponding figures were 29.14.3 and 28.24.3%. There was a significant negative relationship between PAL and %TBF (r=-0.81, P<0.001, n=59).

Conclusions: Measured TEE plus calculated energy cost of growth confirm previous estimates that the physiological energy requirements of children 9 and 14 months of age are 15–20% lower than current recommendations for energy intake. One possible interpretation of the relationship between PAL and %TBF is that children with a high TBF content are less physically active than children with less TBF. However, this relationship needs further studies.

Objective: To compare body fatness estimated using a skinfold technique and body mass index (BMI) with body fatness estimated using the body water dilution method in healthy Swedish children 9 or 14 months of age.

Methods: Total body fat (TBF) was calculated from total body water, estimated using the doubly labelled water method, and body weight. When expressed in per cent of body weight, these estimates (%TBF-BWD) represented reference values for body fatness. Body fatness was also calculated from skinfold thickness (%TBF-SFT) and as BMI. The children were ranked and grouped into five groups with an increasing level of body fatness using BMI, %TBF-SFT and %TBF-BWD, respectively.

Subjects: A total of 30 infants 9 months of age and 29 children 14 months of age.

Results: On average, the children (n=59) had a BMI=17.51.6 kg/m² and contained 27.83.7 %TBF-SFT and 29.14.4 %TBF-BWD. %TBF-BWD minus %TBF-SFT was=1.354.06%. By measuring %TBF-SFT or BMI, about 35% of the children could be classified in the correct group with respect to body fatness. Serious misclassification (ie two or more groups too high or too low) was, however, more common for %TBF-SFT (29%) than for BMI (17%).

Conclusions: The capacity of BMI to place children in the correct body fatness group was poor although not quite as poor as the corresponding capacity of the skinfold technique. The latter method produced inaccurate and imprecise estimates of body fatness.