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Background: More information is needed on the efficacy of carotenoids from plant foods in improving vitamin A status. Objective: We aimed to quantify the efficacy of provitamin A-rich vegetables and fruit in improving vitamin A status. Design: Breastfeeding women in 9 rural communes in Vietnam were randomly allocated to 1 of 4 groups: the vegetable group (n = 73), which ingested 5.6 mg/3-carotene/d from green leafy vegetables; the fruit group (n = 69), which ingested 4.8 mg /3-carotene/d from orange or yellow fruit; the retinol-rich group (n = 70), which ingested 610 [micro]g retinol/d from animal foods and 0.6 mg [beta]-carotene/d; and the control group (n = 68), which ingested 0.4 mg [beta]-carotene/d. Meals of groups 1,2, and 4 contained Results: Mean (95% CI) changes in serum retinol concentrations of the vegetable, fruit, retinol-rich, and control groups were 0.09 (0.03, 0.16), 0.13 (0.07, 0.19), 0.25 (0.17, 0.33), and 0.00 (-0.06, 0.06) [micro]mol/L, respectively. Mean (95% CI) changes in breast-milk retinol concentrations were 0.15 (0.04, 0.27), 0.15 (0.02, 0.28), 0.48 (0.32, 0.64), and -0.06 (-0.21, 0.09) [micro]mol/L, respectively. According to these findings, the equivalent of 1 [micro]g retinol would be 12 [micro]g [beta]-carotene (95% CI: 8, 22 [micro]g) for fruit and 28 [micro]g [beta]-carotene (17, 84 [micro]g) for green leafy vegetables. Thus, apparent mean vitamin A activity of carotenoids in fruit and in leafy vegetables was 50% (95% CI: 27%, 75%) and 21% (7%, 35%), respectively, of that assumed. Conclusion: The bioavailability of carotenoids from vegetables and fruit is less than previously assumed. KEY WORDS Bioavailability, vitamin A, Vietnam, breastfeeding women, carotenoids, food-based approaches

Background: Oral iodized poppy seed oil is an appropriate measure for controlling iodine deficiency in areas where iodized salt is not yet available. However, a more effective and cheaper iodized oil preparation is needed. Objective: The aim of this study was to compare the efficacy of iodized peanut oil with that of iodized poppy seed oil. Design: Schoolchildren aged 8-10 y were supplemented with a single oral dose of iodized peanut oil (P200, P400, or P800 mg I), iodized poppy seed oil (PS400 mg I), or peanut oil (placebo). The concentration of urinary iodine (UI) was measured at 0, 4, 12, 25, and 50 wk, whereas thyroid volume and serum thyrotropin and free thyroxine concentrations were measured at 0, 25, and 50 wk. Results: UI was higher in all treatment groups than in the placebo group, except at baseline. UI in the P200 group was not significantly different from that in the PS400 group at all times of measurement. In a comparison of preparations supplying 400 mg I conducted by using a mathematical model, iodine retention from the peanut oil preparation was 3 times that from the poppy seed oil, and the protection period for peanut oil was twice as long as that for the poppy seed oil (P < 0.001 for both). The reduction in thyroid volume was greater in the treatment groups than in the placebo group (P < 0.001). No significant differences in serum hormone concentrations were observed between groups before or after treatment. Conclusion: Iodized peanut oil is more efficacious in controlling iodine deficiency than is iodized poppy seed oil containing the same amount of iodine. KEY WORDS Iodized oil, peanut oil, poppy seed oil, efficacy, iodine, deficiency, schoolchildren, Indonesia

Oral supplementation with iodized oil for correction of iodine deficiency in a population has advantages over intramuscular injection but the duration of effect is shorter. The relation of intestinal parasite treatment and efficacy of oral iodized oil was examined in an intervention study in 8-10-y-old schoolchildren in Malawi. Severely iodine-deficient schoolchildren with a single parasitic infestation of Ascaris lumbricoides (n = 44), hookworm (n = 42), or Entamoeba histolytica (n = 24) were randomly allocated to receive or not receive treatment before taking a 1-mL oral supplement (490 mg I) of iodized ethyl esters from poppy seed oil. The urinary iodine concentration was measured at various time points after supplementation to define the time intervals before urinary iodine concentrations returned to 0.40 [Mu]mol/L, indicating moderate iodine deficiency. Treatment with metronidazole for E. histolytica increased the protection period from 2.0 to 2 1.0 wk (P[is less than]0.05). For all untreated children together, the duration of effect was 9.2 wk shorter (P[is less than].001) than that for their treated peers (16.8 wk). We conclude that intestinal parasitic infestations reduce the efficacy of oral supplementation with iodized ethyl esters by interfering with absorption.

We studied the nutrition information seeking behavior of primary care physicians (PCPs) and also PCPs' implementation of different strategies of nutrition guidance of patients. This was done by means of a questionnaire mailed to a nationwide random sample of 1000 PCPs in the Netherlands. The net response rate was 64%. The two most important nutrition information sources for PCPs were a dietitian (72% of respondents) and the literature (34% of respondents). Eighty-five percent of PCPs reported that they were actively involved in seeking nutrition information. For nutrition education of patients, PCPs gave personal information to patients, referred patients to a dietitian, and made publications available in the surgery. As preferred methods of obtaining nutrition information themselves, PCPs listed scientific journals, postgraduate nutrition education, congresses and study days, and publications. Determinants of nutrition information seeking behavior of PCPs as well as their implementation of different strategies of patient nutrition education were identified and discussed. PCPs were familiar with the body mass index, which is encouraging because treatment of overweight and obesity starts with a valid assessment. The findings in this study lead to a prudent positive conclusion about PCPs and nutrition information in practice. From this study and others it can be concluded that there are growing opportunities, challenges, and tools for PCPs to become more actively involved in nutrition guidance of patients.

To clarify the role of the primary care physician (PCP) in providing nutrition information to the public, we investigated in a random sample of Dutch consumers their referral to 11 nutrition information sources, including the PCP, their perceived expertise of these sources. their interest in nutrition information, and their nutritional attitudes and beliefs. Factor analysis over these 11 sources of nutrition information resulted in two factors: noncommercial sources (a = 0.70) and commercial sources ([Alpha] = 0.78). Respondents' referral to and perceived expertise on a five-point scale of noncommercial sources was higher than for commercial sources [respectively. 54% compared with 21%, P [is less than] 0.0001. and 3.9 [+ or -] 0.6 compared with 2.7 [+ or -] 0.6 (x [+ or -] SD), P [is less than] 0.01]. The individual Spearman correlation coefficient between referral scores and perceived expertise was [Rho] = 0.35 [+ or -] 0.36 (x [+ or -] SD). For most sources, referral to that source was dependent on a higher interest in information about a healthy diet and on perceived expertise of the source. There were three leading noncommercial sources: the PCP. the dietitian, and the Netherlands Food and Nutrition Education Bureau (FNEB). Careful analysis revealed that because of their high referral scores, high perceived expertise, and reach to nearly all segments of the population, PCPs are in a unique position compared with dietitians and the FNEB.

Iodine excretion in urine after oral dosing with iodized oil is influenced by various factors involved in the retention and elimination of iodine by the body. In a study comparing different treatments of severely iodine-deficient schoolchildren from Malawi, a hyperbolic function was found to describe changes in urinary iodine concentration over time more adequately than a simple exponential function. Compared with oil A, comprising ethyl esters of iodized fatty acids, the retention and elimination of iodine from oil B, comprising triacylglycerol esters of iodized fatty acids, were significantly greater. The mean duration of effectiveness of oral iodized oil, based on urinary iodine concentrations >0.40 [mu]mol/L, was estimated to be 13.7, 9.9, and 52.5 wk for a single dose of iodized oil A (490 mg I), a split dose of iodized oil A (2 x 245 mg L), and a single dose of iodized oil B (675 mg I), respectively. Dividing the dose of oil A into two equal amounts given on consecutive days did not improve its efficacy.

To investigate the relationship between age and energy expenditure, resting metabolic rate (RMR) and diet-induced thermogenesis (DIT; for 180 min after a 1.3-MJ meal) were measured by indirect calorimetry in 56 young and 103 elderly subjects. In addition, the influence of body composition, body-fat distribution, and physical activity level on this relationship was studied. RMR was significantly lower in elderly (3.98 [+ or -] 0.46 and 3.33 [+ or -] 0.39 kJ/min for men and women, respectively) than in young (5.29 [+ or -] 0.53 and 4.08 [+ or -] 0.33 kJ/min for men and women, respectively) subjects, which persisted after adjustment for body composition. DIT was significantly lower in older than in younger men (126 [+ or -] 27 vs 154 [+ or -] 34 kJ/180 min) but not in women (111 [+ or -] 26 vs 115 [+ or -] 25 kJ/180 min). The difference in men disappeared after adjustment for body composition. No clear relation between physical activity level and RMR or DIT was observed. These results demonstrate a relationship of age per se with RMR but not with DIT. Am J Clin Nutr 1995;61:772-8.

Basal metabolic rate (BMR), thermic effect of a meal (TEM), anthropometry, and dietary intakes were measured in 18 control subjects; 18 pregnant women at 12, 24, and 34 wk gestation; and in 17 of these women at 12 and 24 wk postpartum, to uncover any metabolic economy associated with either pregnancy or lactation. Results indicated that the BMR and TEM were not associated with any energy saving either during pregnancy or lactation. Mean weight gain from 12 wk gestation to term was 11.4 [+ or -] 3.7 kg; mean birth weight of the infants was 3.06 [+ or -] 0.41 kg. Estimated gain in adipose tissue and fat mass were 3.1 [+ or -] 3.6 and 2.5 [+ or -] 2.9 kg, respectively. Energy cost of pregnancy was estimated to be 303 [+ or -] 171 MJ. The cumulative increase in energy intake over the last two trimesters of pregnancy was 290 [+ or -] 280 MJ, meeting a large part of the total estimated cost of pregnancy. Weight gained by infants who were exclusively breast-fed from birth to 12 wk of age was used as a proxy indicator of adequate lactational performance. The extra energy required during lactation appeared to have been met largely by increases in energy intake, rather than by any metabolic economy or increase in fat mobilization. Am J Clin Nutr 1995;61:501-13

This study was performed on 34 female farmers in northern Benin during 2 consecutive years. Body composition, energy intake, energy expenditure, resting metabolic rate (RMR), and energy cost of cycling on a bicycle were measured in three periods per year. Energy intake showed seasonal fluctuations of [nearly equal to] 1.7 MJ/d in 1990 and 0.6 Mj/d in 1991. Body weight fluctuated between periods, with the lowest weight in preharvest periods. Observed changes in body weight were 2.6 [+ or -] 2.3 and 0.9 [+ or -] 1.7 kg in 1990 and 1991, respectively. The same pattern was observed in both fat mass and fat-free mass. RMR, energy cost of cycling, and delta work efficiency did not show any seasonal changes. It is concluded that metabolic adaptation, as a response to a seasonal food shortage up to 15% of average daily intake, will not occur. Am J Clin Nutr 1995;61;466-72

The resting metabolic rate (RMR) and thermic effect of a standard test meal (TEM) were measured twice each during the follicular and luteal phases (confirmed by plasma concentrations of progesterone and estradiol) of a single menstrual cycle, and once during the follicular phase of the following menstrual cycle, by using indirect calorimetry, in 13 well-nourished Indian women. There was a significant increase in the TEM (P < 0.05) (6.72 [+ or -] 1.57% vs 7.96 [+ or -] 1.48% of the energy content of the test meal for follicular and luteal phases, respectively) of 18.5% during the luteal phase of the menstrual cycle but no significant difference in the RMR or postmeal total energy output (PMTEO). Dietary energy and macronutrient intakes in all subjects in both phases of the menstrual cycle were also similar. The RMR and the PMTEO were also similar when measured in the follicular phase of consecutive menstrual cycles.

Eighty iron-deficient, nonpregnant female workers were randomly assigned to ferrous sulphate (60 or 120 mg Fe/d) or placebo treatment for 12 wk. Energy expenditure was estimated during 3 d by heart rate (HR) recording. Production efficiency (PE) was calculated as the ratio of productivity to energy expenditure. In the iron-treated group mean hemoglobin (Hb) increased from 114 to 127 g/L (P < 0.001), mean serum ferritin increased from 9.7 to 30.0 [mu]g/L (P < 0.001), and mean free erythrocyte protoporphyrin decreased from 1.01 to 0.49 [mu]mol/L (P < 0.001). Mean HR at work decreased from 95.5 to 91.1 beats/min (P < 0.001), which was inversely correlated with the change in Hb (r = 0.60, P < 0.001). PE increased significantly in the iron-treated group (P < 0.001) and its change paralleled the change in Hb (r = 0.58, P < 0.001). The results show that iron supplementation enabled these women to do the same work at a lower energy cost. Am J Clin Nutr 1994;59:908-13.

To investigate changes in energy metabolism during pregnancy complete 8-d energy balances were measured before pregnancy and at 12,23, and 34 wk gestation in 12 healthy Dutch women. While for each individual woman experimental diets were kept constant throughout the study with average intakes of 8.76 [+ or -] 0.92 MJ/d (before pregnancy), 8.72 [+ or -] 1.08 MJ/ d (week 12), 8.85 [+ or -] 0.93 MJ/d (week 23), and 8.72 [+ or -] 1.12 MJ/ d (week 34), neither the digestibility nor the metabolizability of the supplied diets showed significant changes from before pregnancy (92.8% and 88.6% respectively) throughout pregnancy (92.7% and 88.2%, respectively). Twenty-four-hour energy expenditure (24-h EE) increased significantly from 8.63 [+ or -] 0.80 MJ/ d (before pregnancy) to 8.73 [ + or -] 1.15, 9.08 [+ or -] 1.08, and 9.94 [+ or -] 0.94 MJ/d in weeks 12, 23, and 34 of gestation, to the extent predictable from changes in resting metabolic rate so that in an experimental setting with physical activity and energy intake standardized there seems little scope for other adaptive mechanisms.

Energy metabolism was measured in 24 women before pregnancy and during lactation (2 mo postpartum). Resting metabolic rate (RMR) increased by 0.17 [+ or -] 0.38 kJ/min and postprandial metabolic rate (PPMR) showed a similar increase (0.17 [+ or -] 0.45 kJ/min). Thus, the thermic effect of the meal (PPMR minus RMR) was not affected by lactation. Between subjects, the lactation-induced increase in RMR appeared to positively related to body weight. During lactation gross metabolic rates during cycling (CMR) were slightly reduced and net metabolic rates during cycling (CMR minus RMR) tended to decrease by 0.6 kJ/min at all workloads; however, the decrease was statistically significant only at the lowest workload. Changes in metabolic rate during the recovery period after exercise were not significant, but resembled changes in RMR rather than changes in CMR. We conclude that no major changes in metabolic efficiency occurred during lactation.

Magnetic resonance imaging was used to study the effect of a single weight cycle on three fat depots: the visceral and subcutaneous abdominal depots and the subcutaneous depot at the trochanter level. Obese subjects (17 men, 15 women) were examined before and after weight-loss intervention and 67 wk after intervention. They lost 12.9 [+ or -] 3.3 ([bar][chi] [+ or -] SD) kg body wt during intervention and regained 11.9 [+ or -] 5.1 kg during follow-up. Weight regain did not result in greater body fatness than before weight loss (initial fat mass: 34.3 [+ or -] 6.1 kg, final fat mass: 32.8 [+ or -] 7.7 kg; P = 0.047). There was no indication of a preferential deposition of visceral fat after weight regain (initial visceral fat area: 120 [+ or -] 41 [cm.sup.2], final visceral fat area: 110 [+ or -] 48 [cm.sup.2] P = 0.087). On the contrary, there was a slight tendency to accumulate subcutaneous fat at the expense of visceral fat. It is concluded that weight loss followed by weight regain neither leads to a greater body fatness nor to a larger amount of visceral fat compared with before weight loss. Am J Clin Nutr 1993;58:853-7.

The prediction of energy expenditure (EE) from minute-by-minute heart rate (HR) recording was evaluated in 40 female workers, with emphasis on the inter- and intraindividual variation of this method. The results show that the relationship between EE and HR varied greatly between and within subjects. The inter- and intraindividual CVs were 14-18% and 11-20%, respectively. The poor limits of agreement in EE (mean difference +/- 2 SD) between group and individual calibration curves indicate that estimated EE from group curves is inferior to estimated EE from individual curves. Therefore, it is concluded that to have the best estimates of individual EE, only individual calibration curves should be used. At different occasions these curves should be generated again. Because the limits of agreement in EE between individual curves based on 18 and 9 different activities were wide (-2399 to 1817 kJ/16 h), it is preferable to have a wide range of different activities in the individual calibration procedure.

A cross-sectional study of the prevalence of iron and vitamin A deficiency in normal pregnant women in West Java, Indonesia, was carried out. Of the 318 women studied, 49.4% were anemic and, according to multiple criteria, 43.5% had iron-deficiency anemia, 22.3% had iron-deficient erythropoiesis, and 6.6% had iron depletion. Serum retinol values revealed that 2.5% of the pregnant women were vitamin A deficient and 31% had marginal vitamin A status. The relative dose-response test carried out on 45 women showed that 4 (8.9%) had deficient vitamin A liver stores. After gestational stage, parity, and subdistrict were adjusted for, serum retinol concentrations were significantly positively associated (P < 0.01) with hemoglobin concentrations, hematocrit, and serum iron concentrations. The suboptimal vitamin A status associated with nutritional-deficiency anemia suggests that pregnant women in the area should be supplemented not only with iron but also with vitamin A. This proposal should be tested in an intervention study. Am J Clin Nutr 1992;56:988-93.

Between 6 and 30 wk postpartum, body weight and body-fat mass of 40 healthy, rural, lactating Filipino women decreased by 1.5 (P < 0.05) and 0.7 kg (P < 0.05), respectively. Energy intake decreased slightly (NS) from 8.84 [+ or -] 2.05 MJ/d (2113 [+ or -] 489 kcal/d; [X Bar] [+ or -] SD) at 6 wk to 8.67 [+ or -] 2.37 MJ/d (2073 [+ or -] 566 kcal/d) at 30 wk. Basal metabolic rate (BMR) remained unchanged throughout lactation, and physical-activity level increased significantly (P < 0.05) from 1.61 [+ or -] 0.17 X BMR at 6 wk to 1.97 [+ or -] 0.18 X BMR at 30 wk. Energy intakes at 6 and 30 wk of lactation were 1.02 and 0.77 MJ/d (244 and 185 kcal/d) higher (P < 0.05), respectively, than in early pregnancy. At ages 1-6 mo, mean weights and lengths of mainly breast-fed infants had Z scores between 0 and - 1. By using the growth patterns of the breast-fed infants as proxy indicators for adequacy of lactational performance, this study suggests that present recommended energy intakes for lactation are too high for healthy Filipino women who show adequate lactational performance. Am J Clin Nutr 1992;56:874-80.

Body composition of 24 rural Beninese women was assessed in a pre- and a postharvest season by using skinfold-thickness measurements, bioelectrical-impedance analysis (BIA), and deuterium oxide ([D.sub.2]O) dilution. Fat mass assessed by [D.sub.2]O dilution was 12.3 [+ or -] 3.3 kg; by skinfold-thickness measurements, 13.8 [+ or -] 3.3 kg; and by BIA, 14.1 [+ or -] 2.9 kg. Fat mass assessed by [D.sub.2]O was significantly lower (P < 0.05) than fat mass assessed by the other two methods. Body weight in the postharvest season was 0.8 [+ or -] 1.6 kg higher (P < 0.05) than during the preharvest season. All three methods demonstrated that there were no significant changes in fat mass but that fat-free mass increased significantly (P < 0.05) from pre- to postharvest season. Am J Clin Nutr 1992;55:321-5. KEY WORDS Body composition, seasonality, rural African women, skinfold thickness, impedance, deuterium dilution

The energy cost of lactation, which consists of energy needed to produce the breast milk and energy content of the milk itself, has been estimated at 700 calories per day over the first six months after birth. But the additional energy requirements of lactation are often not met by well-nourished women, that is, they do not increase their food intake by this amount. It has been suggested that the energy cost of lactation may have been overestimated. In addition, breakdown of the mother's fat stores or reduced daily energy expenditure for activity can compensate for an increase in energy needs due to lactation. Energy expenditure can be reduced by lower physical activity and more efficient energy metabolism. The ability of well-nourished Dutch women to cope with the energy stress of lactation was assessed. Energy balance was evaluated by measuring food intake, body weight, body fat mass, levels of physical activity, basal metabolic rate, and breast milk production. In addition, the growth of the breast-fed infant was assessed to determine the adequacy of lactation. The energy intake of 40 lactating women at nine weeks after delivery was higher than that of 16 nonlactating women. Lactation required 650 calories per day, and lactating women tended to compensate for these extra energy needs by: eating more; using fat stores as an energy source; and reducing energy expenditure. These findings show how well-nourished women can meet the energy demands of lactation, and that current recommendations of energy requirements during breast-feeding are overestimated. (Consumer Summary produced by Reliance Medical Information, Inc.)

Much research has been done to estimate the number of extra calories women need during pregnancy. It has been difficult to obtain accurate estimates because there are many interacting factors involved in a pregnant woman's energy needs, including her activity level, her energy stores before pregnancy, and the weight gained during pregnancy. The latest recommendation of the Food and Agriculture Organization/World Health Organization/United Nations University (FAO/WHO/UNU) is an additional 285 calories per day, averaged over the course of the pregnancy. This amount should support the needs of women who begin pregnancy marginally underweight or undernourished and who do not reduce their physical activity during pregnancy. For healthy, well-nourished women who do reduce their activity, an average increase of 200 calories per day is recommended; the 85 calories subtracted primarily represents the savings for decreased physical activity. However, studies of women in both developing and developed countries have found that they generally increase energy consumption by less than the recommended amounts. This has led to the supposition that the amount of energy saved by reducing activity during pregnancy may be greater than previously thought. In this study, 25 sedentary Dutch women were assessed throughout pregnancy and the first year after the baby's birth; their activities, weight, and basal metabolic rate (energy used to maintain basic body functions while at rest) were measured. The assessment done at one year postpartum represented the nonpregnant, nonlactating state. It was found that compared with this time point, energy used for physical activity was reduced by an average of 70 calories/day during pregnancy and 50 calories/day in the first six months postpartum. Thus in these healthy, sedentary women, the amount of energy saved by reducing activity during pregnancy and lactation was modest, and was actually less than the 85 calories/day estimated by the FAO/WHO/UNU. Therefore, the amount of calories saved by decreasing physical activity does not explain why women in some studies have consumed less than the recommended increase in dietary energy for pregnancy. (Consumer Summary produced by Reliance Medical Information, Inc.)

Research studies have clearly demonstrated that the amount of energy (calories) burned by the body decreases while on a low-calorie diet. There are several reasons for this: the amount of lean (muscle) tissue decreases, so less energy is needed to maintain its function; less food is consumed so the heat production that follows a meal is lower; less energy is expended to move the body because it weighs less; and metabolic adaptation may also occur. This last phenomenon was explored to determine whether metabolic adaptation, specifically a slowed metabolism, occurs during and then continues after a period of calorie restriction and weight loss. If the metabolic rate remains slowed after dieting, this could explain the tendency to easily regain the weight lost, a complaint of many dieters. A group of 13 overweight women was studied before and after eight weeks of dieting. Most the women were again evaluated one month and one year after the dieting period ended. The evaluations consisted of measuring their energy expenditure over 24 hours and monitoring their spontaneous physical activity. Each subject was individually evaluated in a respiration chamber, a sealed room in which the person's use of oxygen and production of carbon dioxide can be measured; these values are indicative of the energy burned. Results showed that the women lost an average of 20 pounds and kept the weight off throughout the follow-up period. During the entire study, no changes in energy requirement (based on body weight) or metabolic efficiency were noted. Spontaneous activity decreased while dieting and then increased afterwards. These findings support other studies, which have reported that no metabolic adaptations occur during, or persist after, short-term dieting. The possibility remains that individuals deprived of adequate calories throughout their lives adapt to this situation with a slowed metabolic rate. (Consumer Summary produced by Reliance Medical Information, Inc.)

Rickets in children is caused primarily by vitamin D deficiency, which limits calcium absorption and leads to bone deformities. Rickets is being reported more frequently in Western countries, particularly in families that follow the macrobiotic or other alternative diets. Caucasian infants born in 1985 in the Netherlands who were put on a macrobiotic diet by their parents were evaluated for vitamin D levels and rickets. The macrobiotic diet allowed unpolished rice, high-fiber vegetables, nuts, seeds, fruits and very rarely, fish. Meats and dairy products were avoided. Twenty-eight percent of 53 macrobiotic infants aged 10 to 20 months had physical symptoms of rickets during late summer and fall. Of the original group, 25 were examined again in early spring, at which time 55 percent had physical symptoms of rickets. Blood vitamin D was lower at this time, probably because sunlight enhances vitamin D levels and children get less sun exposure during the winter. This study strongly confirms the theory that the macrobiotic diet can be damaging to bone development in young children. This is because the diet is low in calcium and vitamin D and high in fiber; fiber reduces calcium absorption. While the study was being conducted, most macrobiotic teachers and parents following the diet were not open to providing either dairy products or vitamin D supplements to the children. The researchers proposed inclusion of fatty fish, and this was accepted and recommended by Michio Kushi, the leader of the macrobiotic philosophy. But fish alone will not provide enough vitamin D and calcium for children, so the researchers also suggested allowing one serving per day of dairy products. This idea is gaining support among followers of the macrobiotic diet. Reduction of fiber would also be beneficial; this can be done by sieving cereals and vegetables for a longer time and using less whole grain foods. (Consumer Summary produced by Reliance Medical Information, Inc.)

The amount of energy expended while performing various activities has been measured in pregnant women. Because they must move a heavier body as pregnancy progresses, it was expected that they would burn more calories than nonpregnant women. But it was found that the energy expenditure of pregnant women was the same, or even lower, than that of nonpregnant women. This was explained by the tendency of pregnant women to move at a slower pace to compensate for the extra work of moving a heavier body. But researchers wondered whether energy expenditure would be higher in pregnancy if the woman was not able to reduce her pace. The energy expenditure of 39 healthy Dutch women was measured while walking at a fixed pace on a treadmill during and after pregnancy; they were not allowed to move more slowly as they gained weight during the later months of pregnancy. Fifteen of these women had been evaluated before pregnancy as well. Treadmill metabolic rate (energy expenditure, TMR) was higher in late pregnancy (36 weeks) than at 24 weeks gestation or 9 weeks postpartum. But it was considered remarkable that the TMR was constant throughout the first two trimesters of pregnancy and was also the same as before and after pregnancy, even though by the end of the second trimester the women had gained more than 13 pounds on average. The results clearly demonstrate that throughout most of pregnancy, energy expenditure during treadmill exercise is not directly dependent on body weight. The caloric cost of treadmill walking was actually two percent lower on average during pregnancy than before or after pregnancy; this was due to increased energy efficiency during pregnancy. The practical application of this information is that during the first and second trimester of pregnancy women who engage in substantial amounts of weight-bearing exercise do not need any more calories to support exercise than do nonpregnant women. A given activity at a set pace appears to use up the same amount of calories in a pregnant woman as in a nonpregnant woman. (Consumer Summary produced by Reliance Medical Information, Inc.)

Previous studies have reported that during fasting or prolonged dieting, the metabolic rate of individuals decreases by 6 to 30 percent. In subjects who lost weight, the amount of energy burned per day also dropped by 10 to 15 percent. A slimming diet has been used in the Netherlands were the dieter alternates between eating only bread and water on one day and eating normally the next day. Some believe this alternating approach is more effective in promoting weight loss than a continuous low-calorie diet because of metabolic rate effects. Twenty-seven overweight women participated in a study that compared the alternating pattern with continuous calorie restriction. The subjects followed three different reducing diets: a diet that alternated daily between bread and water and a weight maintenance regimen; a diet that continuously supplied 50 percent of weight maintenance needs; and a diet that alternated daily between 50 percent and 100 percent of weight maintenance needs. These different regimens were compared based on their effect on metabolic rate; this was obtained by measuring the amount of energy subjects expended while sleeping and energy expended over 24 hours. Alteration between low and maintenance caloric intake did not result in a decline of metabolic rate. After eight weeks of dieting with various combinations of regimens, subjects had a 7 to 13 percent reduction in sleeping energy expenditure and a 12 to 16 percent reduction in 24-hour energy expenditure. Subjects also spontaneously reduced their physical activity while dieting. The decline in energy expenditure was attributed to loss of body weight, reduced physical activity, and reduction in energy burned while digesting lesser amounts of food. (Consumer Summary produced by Reliance Medical Information, Inc.)