Intakes of retinol and carotenoids and its determining factors in the Red River Delta population of northern Vietnam.

OBJECTIVE: To describe the household intakes of retinol and carotenoids and social economic factors determining their intakes. SUBJECTS: Data on a total of 1001 households (771 in rural areas and 230 in urban areas) were used in the analyses. Interviewed person was household food preparer. RESULTS: Mean (s.d.) intake of carotenoids was 4178 (3154) microg/capita/day in rural and 4208 (3408) microg/capita/day in urban areas and intake of retinol was 101 (275) microg/capita/day in rural and 201 (470) microg/capita/day in urban areas. Multivariate analyses show that the subjects in households with four or more members consume about 700 microg carotenoids less compared to households with less than three members. Households with a higher expenditure (fourth quartile) consumed about 100 microg retinol/day more than those with a lower expenditure (first quartile). CONCLUSION: Carotenoids from plant food sources is the main source of vitamin A intake of the population and its main determinants are household expenditure and size of household. Food fortification and dietary diversification with special emphasis on promotion of consumption of animal foods should be key strategies for overcoming vitamin A deficiency in Vietnam.

A critical evaluation of heart rate monitoring to assess energy expenditure in individuals.

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.

Changes in fat-free mass during weight loss measured by bioelectrical impedance and by densitometry.

A group of 13 apparently healthy, premenopausal obese women (134-196% ideal weight) volunteered in a weight reduction study for 8 wk on a 4200 kJ (1000 kcal) diet. Before and after the weight reduction period body composition was measured by densitometry and by the bioelectrical impedance method. Changes in fat mass and fat-free mass were calculated. Mean weight loss was 10.0 +/- 2.8 kg and loss of fat-free mass was measured to be 2.3 +/- 1.7 kg (23%) by densitometry and 0.6 +/- 1.9 kg (6%) by impedance measurements. The underestimation of the change in fat-free mass measured by the impedance method could be due to losses of water bound to glycogen after the weight-reduction period. For this reason the impedance method may be not applicable in studies in which changes in glycogen stores can be expected.

Resting metabolic rate and diet-induced thermogenesis in young and elderly subjects: relationship with body composition, fat distribution, and physical activity level.

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 +/- 0.46 and 3.33 +/- 0.39 kJ/min for men and women, respectively) than in young (5.29 +/- 0.53 and 4.08 +/- 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 +/- 27 vs 154 +/- 34 kJ/180 min) but not in women (111 +/- 26 vs 115 +/- 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.

Dependence of the effects of dietary cholesterol and experimental conditions on serum lipids in man. I. Effects of dietary cholesterol in a linoleic acid-rich diet.

In this experiment the effect of dietary cholesterol in a linoleic acid-rich diet on serum cholesterol was tested. In a cross-over design 41 young healthy students received a linoleic acid-rich diet for 4 weeks at two levels of dietary cholesterol. The diet contained 14 to 15 energy% linoleic acid. The high cholesterol diet was obtained by adding two egg yolks a day to the rations. Supplementation of the linoleic acid-rich diet with the egg yolk cholesterol caused a significant rise of serum cholesterol of about 11 mg/100 ml (0.29 mmole/liter). The dietary cholesterol did not influence serum triglyceride levels. The influence on serum cholesterol was much less than expected, based on several predictive formulas. It is concluded that the presence of a high content of linoleic acid in the diet reduces the effect of dietary cholesterol on serum cholesterol if the cholesterol is provided as egg yolk.

A mathematical relationship between the fatty acid composition of the diet and that of the adipose tissue in man.

Based on literature data, the hypothesis is advanced that in human subjects a direct mathematical relationship exists between the average fatty acid composition of the habitual diet and that of the lipid stores of subcutaneous adipose tissue. Since the half-life of adipose tissue fatty acids in man is in the order of 600 days, the fatty acid pattern of depot fat provides a qualitative measure of the fat intake over a period of 2 to 3 years. It is concluded that in long-term experimental and epidemiological nutritional surveys the adipose tissue fatty acid pattern of the subjects is a useful index of the average composition of their habitual dietary fat.

Resting metabolic rate and work efficiency of rural Beninese women: a 2-y longitudinal study.

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 approximately 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 +/- 2.3 and 0.9 +/- 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.

Effect of a weight cycle on visceral fat accumulation.

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 +/- 3.3 (mean +/- SD) kg body wt during intervention and regained 11.9 +/- 5.1 kg during follow-up. Weight regain did not result in greater body fatness than before weight loss (initial fat mass: 34.3 +/- 6.1 kg, final fat mass: 32.8 +/- 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 +/- 41 cm2, final visceral fat area: 110 +/- 48 cm2; 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.

Energy requirements and energy expenditure of lean and overweight women, measured by indirect calorimetry.

To estimate the energy requirement of lean and overweight women, 29 lean (body weight, 59 +/- 1 kg; means +/- SEM) and 18 overweight (94 +/- 5 kg) women consumed a weight-maintenance diet for 8 d. The final 80 h were spent in a whole-body indirect calorimeter. Actual metabolizable energy intake (ME) was measured by analyzing food, feces, and urine. Mean ME was 8.88 +/- 0.13 MJ/d (2123 +/- 30 kcal/d) (lean) and 10.12 +/- 0.29 MJ/d (2419 +/- 70 kcal/d) (overweight). Mean 24-h energy expenditure (24hEE) of the lean (8.58 +/- 0.13 MJ or 2052 +/- 32 kcal) was lower than that of the overweight (10.70 +/- 0.45 MJ or 2558 +/- 108 kcal; p less than 0.001) women. Energy balance was close to zero in both groups. Therefore, 24hEE was used as an estimation of energy requirement. Multiple-regression analysis showed body weight to be the best single predictor of 24hEE. Our data may be useful for prediction of energy requirements of women (aged 20-50 yr) in normal life.

Relative and biomarker-based validity of a food-frequency questionnaire estimating intake of fats and cholesterol.

The relative validity of a 104-item food-frequency method to assess intakes of fats and cholesterol was tested against the dietary history of 191 men and women. Pearson correlation coefficients ranged from 0.38 for linoleic acid (% of energy) to 0.83 for energy intake, with 0.78 and 0.75 for the intakes of total fat and saturated fatty acids, respectively. Mean intakes were overestimated by the food-frequency questionnaire relative to the dietary history by 5% for energy and monounsaturated fatty acids (% of energy) and up to 30% for linoleic acid intake. Linoleic acid concentrations in erythrocytes and adipose tissue were used as biomarkers of intake. The correlation of the linoleic acid intake according to the food-frequency questionnaire with linoleic acid in erythrocytes and adipose tissue was 0.44 and 0.28, respectively, and the dietary history gave similar values. The food-frequency questionnaire gives results similar to those from the dietary history and is thus considered appropriate for classifying subjects according to their fat intake.

Energy intake, energy expenditure, and body composition of poor rural Philippine women throughout the first 6 mo of lactation.

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 +/- 2.05 MJ/d (2113 +/- 489 kcal/d; mean +/- SD) at 6 wk to 8.67 +/- 2.37 MJ/d (2073 +/- 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 +/- 0.17 x BMR at 6 wk to 1.97 +/- 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.

Body composition of rural Beninese women in different seasons assessed by skinfold thickness and bioelectrical-impedance measurements and by a deuterium oxide dilution technique.

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 (D2O) dilution. Fat mass assessed by D2O dilution was 12.3 +/- 3.3 kg; by skinfold-thickness measurements, 13.8 +/- 3.3 kg; and by BIA, 14.1 +/- 2.9 kg. Fat mass assessed by D2O was significantly lower (P less than 0.05) than fat mass assessed by the other two methods. Body weight in the postharvest season was 0.8 +/- 1.6 kg higher (P less than 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 less than 0.05) from pre- to postharvest season.

Effects of casein versus soy protein diets on serum cholesterol and lipoproteins in young healthy volunteers.

The effects of casein and soy protein on serum cholesterol levels and lipoprotein composition were studied in 69 healthy volunteers (18 to 28 yr of age) under strict dietary control. Subjects were fed for 6 wk on diets containing 13% of energy as protein, 38% as fat (P/S ratio = 0.6) and about 380 mg cholesterol per day. Of the protein in the diets 65% consisted of casein or soy protein or a 2:1 mixture of casein and soy protein. After a control period of 10 days during which all the subjects received the casein-soy diet, 20 subjects continued on this diet for the next 4 wk as a base-line control, 25 subjects switched to the casein diet, and the remaining 24 subjects switched to the soy diet. Both food records and chemical analysis of double portions revealed that the diets were completely identical except for the type of protein. Average serum cholesterol levels at the end of the control period were 152 +/- 27 mg/dl (3.93 +/- 0.69 mmol/l) and 153 +/- 23 mg/dl (3.95 +/- 0.60 mmol/l) (mean +/- SD) for the casein and soy group, respectively. At the end of the test period the levels were 149 +/- 24 and 150 +/- 23 mg/dl, respectively; thus there was no significant change on either diet. On the casein diet there was no change in the low-density lipoprotein cholesterol concentration, and only a slight, nonsignificant increase in the high-density lipoprotein cholesterol concentration. On the soy diet, however, there was a significant decline in low-density lipoprotein-cholesterol (-6.6 mg/dl; -0.17 mmol/l) and a significant increase in high-density lipoprotein-cholesterol (+5.8 mg/dl; +0.15 mmol/l). The decline in low-density lipoprotein cholesterol in the soy group was significantly different from the small change in the casein group, but the difference in increase in high-density lipoprotein cholesterol in the soy and the casein group was only weakly significant. This suggest that soy protein could have a slight beneficial effect on the distribution of cholesterol over the various lipoprotein fractions, even at constant total cholesterol concentration.

Dependence of the effects of dietary cholesterol and experimental conditions on serum lipids in man. III. The effect on serum cholesterol of removal of eggs from the diet of free-living habitually egg-eating people.

Forty-four healthy free living volunteers were used to study the effect of the removal of eggs from a habitual egg-rich diet. The subjects, recruited by advertising, normally consumed at least 1 egg per day. During the 3-week experimental period they were not allowed to eat any eggs or products containing large amounts of eggs, except cakes and tarts. Elimination of eggs from a habitual egg-rich diet did result in a small but significant decrease in serum cholesterol levels in all subjects. No correlation could be demonstrated between changes in serum cholesterol levels and the age of the subjects and between changes in serum cholesterol levels and the numbers of eggs eaten per week before the experimental period. A significant negative correlation was found between changes in serum cholesterol levels and the Quételet index for obesity and between changes in serum cholesterol levels and the serum cholesterol levels before the experimental period. The results indicate that a very variable response is present in a human population toward dietary cholesterol. More research seems to be necessary to describe and select the population of hyperresponders, the subjects who are more sensitive to changes in dietary cholesterol, and the hyporesponders. The results moreover indicate that effects of dietary changes in a free-living population are much smaller than can be accomplished in populations under controlled conditions.

Effect of intestinal parasite treatment on the efficacy of oral iodized oil for correcting iodine deficiency in schoolchildren.

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 mumol/L, indicating moderate iodine deficiency. Treatment with metronidazole for E. histolytica increased the protection period from 2.0 to 21.0 wk (P < 0.05). For all untreated children together, the duration of effect was 9.2 wk shorter (P < 0.001) 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.

Influence of diets containing casein, soy isolate, and soy concentrate on serum cholesterol and lipoproteins in middle-aged volunteers.

Fifty-seven healthy volunteers (mean age 46 yr) were fed for 45 days on diets containing 16% of energy as protein, 35% as fat (polyunsaturated/saturated fat ratio = 0.5) and about 375 mg cholesterol/day. Of the protein in the diets 60% was provided as caseinate, as soy protein isolate, or as soy protein concentrate. After a control period of 17 days during which all the subjects received the casein diet, 17 subjects continued on this diet for the next 28 days (test period), 20 subjects switched to the soy isolate diet, and the remaining 20 subjects switched to the soy concentrate diet. Serum cholesterol levels at the end of the control period were 207 +/- 36, 205 +/- 40, and 199 +/- 35 mg/dl (mean +/- SD) for the casein, isolate, and concentrate groups, respectively. Mean changes over the test period were -2 +/- 10, -8 +/- 12, and +1 +/- 10 mg/dl, respectively. Compared with the casein diet, the isolate diet caused a small, nonsignificant decline in both serum total cholesterol and low-density lipoprotein cholesterol (-6.5 mg/dl) and an increase in high-density lipoprotein cholesterol (+5.8 mg/dl) (p less than 0.05). These effects may have been more obvious if there had been no differences between groups in weight loss. No correlation was found between the response and the initial cholesterol level. No differences in lipoprotein composition were found between the casein and soy concentrate groups. Our data suggest that soy protein preparations do not have dramatic effects on the serum total cholesterol concentration in healthy subjects. However, pure soy protein might have some beneficial effect on the distribution of cholesterol over the lipoproteins. The lack of effect of the less refined soy protein concentrate suggests that the dietary fiber and other nonprotein components of soy concentrate do not have, at least in the short-term, a favorable effect on serum cholesterol and lipoproteins in healthy adults.

Blood pressure and diet in normotensive volunteers: absence of an effect of dietary fiber, protein, or fat.

In the course of four controlled experiments on the effect of specific dietary components on cardiovascular risk factors, the effects on blood pressure of various sources of dietary fiber, of type and amount of dietary fat, and of animal versus plant were measured in young normotensive volunteers. In each of the four experiments a group of 50 to 75 healthy student volunteers received a control diet for 11/2 to 21/2 wk. They were then randomized into subgroups which received various test diets for periods ranging from 4 to 12 wk. In each experimental one group received the control diet throughout the whole experimental period. Diets differed between groups in one dietary component only. All foodstuffs were weighed out individually according to each person's energy needs. Body weights and Na intake were controlled. Initial blood pressures were about 120 mm Hg systolic and 70 mm Hg diastolic. Both systolic and diastolic blood pressure decreased during the test period in all four experiments on almost every diet, including the control diets, by about 0 to 5 mm Hg. However, changes in blood pressure over the test period were never significantly different between the test groups and the control groups. Thus, none of the investigated dietary factors had a demonstrable effect on blood pressure in young normotensive persons.

Orange fruit is more effective than are dark-green, leafy vegetables in increasing serum concentrations of retinol and beta-carotene in schoolchildren in Indonesia.

The objectives of this study were to quantify the effectiveness of dietary retinol sources, orange fruit, and dark-green, leafy vegetables in improving vitamin A status, and to test whether orange fruit is a better source of vitamin A and carotenoids than are leafy vegetables. Anemic schoolchildren aged 7-11 y (n = 238) in West Java, Indonesia, were randomly allocated to 1 of 4 groups to consume 2 complete meals/d, 6 d/wk, for 9 wk: 1) 556 retinol equivalents (RE)/d from retinol-rich food (n = 48); 2) 509 RE/d from fruit (n = 49); 3) 684 RE/d from dark-green, leafy vegetables and carrots (n = 45); and 4) 44 RE/d from low-retinol, low-carotene food (n = 46). Mean changes in serum retinol concentrations of the retinol-rich, fruit, vegetable, and low-retinol, low-carotene groups were 0.23 (95% CI: 0.18, 0.28), 0.12 (0.06, 0.18), 0.07 (0.03,0.11), and 0.00 (-0.06, 0.05) micromol/L, respectively. Mean changes in serum beta-carotene concentrations in the vegetable and fruit groups were 0.14 (0.12, 0.17) and 0.52 (0.43, 0.60) micromol/L, respectively. Until now, it has been assumed that 6 microg dietary beta-carotene is equivalent to 1 RE. On the basis of this study, however, the equivalent of 1 RE would be 12 microg beta-carotene (95% CI: 6 microg, 29 microg) for fruit and 26 microg beta-carotene (95% CI: 13 microg, 76 microg) for leafy vegetables and carrots. Thus, the apparent mean vitamin A activity of carotenoids in fruit and in leafy vegetables and carrots was 50% (95% CI: 21%, 100%) and 23% (95% CI: 8%, 46%) of that assumed, respectively. This has important implications for choosing strategies for controlling vitamin A deficiency. Research should be directed toward ways of improving bioavailability and bioconversion of dietary carotenoids, focusing on factors such as intestinal parasites, absorption inhibitors, and food matrixes.

Diurnal variation in postabsorptive resting metabolic rate and diet-induced thermogenesis.

Postabsorptive resting metabolic rate (RMR) and diet-induced thermogenesis (DIT) were repeatedly assessed on different days in 10 young men of normal weight on mornings and afternoons. No significant diurnal variation was found in RMR, DIT, total postprandial substrate oxidation, and overall postprandial nutrient balances. The pattern of postprandial substrate oxidation indicated an increased glucose oxidation in the first hour after ingestion of a meal on morning tests compared with afternoon tests. This was probably related to differences in the degree of the postabsorptive state, ie, 12-14 h on morning tests and 6-7 h on afternoon tests.

A critical appraisal of goiter assessment and the ratio of urinary iodine to creatinine for evaluating iodine status.

Iodine status can be evaluated by goiter assessment and measurement of urinary iodine concentration in either 24-h urine collections or in casual samples. It is often impossible to make 24-h collections. Therefore, iodine concentration in casual samples is often expressed in terms of urinary creatinine, assuming creatinine excretion to be constant between and within individuals. In this study large inter- and intraindividual variations were observed in the creatinine content of casual samples ranging from 0.6 to 9.87 mmol/L. Further, the urinary iodine-creatinine ratio correlated significantly with the creatinine concentration; Spearman's rank-order correlation coefficient, rs = 0.39 (P < 0.001). If creatinine is a suitable index to correct for variations in iodine excretion, no correlation would be expected. We conclude that the iodine-creatinine ratio in casual urine samples is an unsuitable indicator for evaluating iodine status in areas where large inter- and intraindividual variations in urinary creatinine excretion exist.