Modifications of circadian cortisol rhythm by cyclic and continuous total enteral nutrition

To clarify the relationship between the pattern of diet intake and the circadian adrenocortical rhythm, we measured plasma cortisol levels at 4-h intervals over a 24-h period in 18 patients who were in the vegetative state and had been receiving total enteral nutrition (TEN) for 4 weeks. One group of 6 patients was given a liquid diet intraduodenally and continuously throughout a day (continuous TEN), whereas the two other groups received their daily enteral feeding during a restricted time of day, either in the daytime from 0800 h to 2000 h (diurnal TEN, 6 patients) or in the nighttime from 2000 h to 0800 h (nocturnal TEN, 6 patients). In patients with diurnal TEN, there was a clear cortisol rhythm with a peak of 0800 h, whose pattern was quite similar to the well-established cortisol rhythm in normal subjects. Patients with nocturnal TEN also showed a cortisol rhythm, but the peak appeared at 1600 h. There was no appreciable difference in the amplitude of the rhythm between the two groups. Patients with continuous TEN did not show any consistent circadian cortisol rhythms. Plasma levels of glucose, insulin, and free fatty acids also showed circadian fluctuations corresponding to the pattern of diet infusion in the groups with diurnal and nocturnal TEN, and remained almost constant throughout a day in the group with continuous TEN. We conclude from these results that the timing of diet intake may have a synchronizing effect on the circadian cortisol rhythm in man, as it does in laboratory animals.     

Circadian rhythm and stress in the elderly: a study using salivary cortisol levels as an indicator

Biological response to stress was studied in the healthy elderly by fluctuations of their circadian rhythms using salivary cortisol levels as an indicator. Social activities per se may not be stressors, but may serve as a "eustress" to the elderly when they are in good health because their rhythm is maintained. Concerning the occupations of the subjects, the rhythms of elderly watchmen showed no disturbance when they slept for three hours between 23:00 and 2:00. However, those who were unable to sleep showed disturbed rhythms. We concluded that disturbance of a rhythm that has been established on the basis of being active during the day time and sleeping at night could be a stressor to the elderly rather than stress due to working as a guard.     

Short-term orlistat treatment does not affect mineral balance and bone turnover in obese men

Orlistat is a gastrointestinal lipase inhibitor that is used to reduce dietary fat absorption and to enhance weight loss in subjects consuming a hypocaloric diet. To assess whether orlistat has an effect on the metabolism of six minerals, a 21-d, double-blind, randomized, parallel-group, placebo-controlled mineral balance study was conducted in obese (body mass index > 30 kg/m(2)) men. Subjects consumed a hypocaloric diet with a constant daily mineral content and received daily oral treatment with orlistat (120 mg three times daily) (n = 14) or placebo (three times daily) (n = 14) for 21 d. After a 14-d equilibration period, calcium, phosphorus, magnesium, iron, copper and zinc balances were assessed for d 15-21. In addition, the effect of diet and orlistat treatment on bone metabolism was estimated from measurement of biomarkers of bone formation and bone resorption. Serum and urine electrolytes were also measured at baseline and at the end of treatment. Orlistat inhibited fat absorption by approximately 33% (P < 0.05). There were no significant differences in mineral apparent absorption, urinary mineral loss or mineral balance between the orlistat and placebo groups. Markers of bone turnover and serum and urine electrolytes did not differ between the orlistat and placebo groups. Orlistat was well tolerated; adverse events were of mild or moderate intensity, and the majority of these events were unrelated or remotely related to study treatment. In obese men consuming a hypocaloric diet, the administration of orlistat had no significant effect on the balance of six selected minerals. In addition, biomarkers of bone turnover, as well as serum and urine electrolytes, were not affected by orlistat treatment.     

Effects of cyclic and continuous total enteral nutrition on 24-h rhythms of body temperature and urinary excretions.

To clarify the relationship between the pattern of diet intake and circadian rhythm in man, we measured body temperature and urinary excretions at 4-h intervals over a 24-h period in 18 patients who were in vegetative states and had been receiving total enteral nutrition (TEN) for at least 4 weeks. One group of patients was given a liquid diet intraduodenally and continuously throughout a day (continuous TEN), whereas the two other groups received their daily enteral feeding during a restricted time of day, either in the daytime from 0800 h to 2000 h (diurnal TEN) or in the nighttime from 2000 h to 0800 h (nocturnal TEN). In the diurnal TEN group, there was a clear body temperature rhythm with a peak at 2000 h, whose pattern was similar to the well-established body temperature rhythm in normal subjects. The nocturnal TEN group also showed a temperature rhythm, but the peak appeared at 0400 h. The continuous TEN group did not show any consistent body temperature rhythms. These effects of the schedule of TEN were quite similar to those on the circadian cortisol rhythm reported previously (J. Nutr. Sci. Vitaminol., 35, 639-647, 1989). In contrast to the body temperature rhythm, the rhythm of urinary excretions of water, sodium and potassium was little influenced by the schedule of TEN, showing a normal pattern with more excretions during the daytime in every group. Essentially the same effects were confirmed in a patient who received the three schedules of TEN in rotation for 5 weeks of each schedule.(ABSTRACT TRUNCATED AT 250 WORDS)     

Salivary cortisol for monitoring circadian rhythm variation in adrenal activity during shiftwork

Summary To examine the validity of salivary cortisol for monitoring circadian rhythm variation in adrenal activity during shiftwork, saliva and blood samples were collected at 4-h intervals in experimental short-term shifts, i.e., day (work 0830–1600 h; sleep 0030–0800 h), evening (work 1630–2400 h; sleep 0430–1200 h), and night (work 0030–0800 h; sleep 1230–2000 h) shifts over 2 days. Cortisol levels, determined by radioimmunoassay, and the circadian profiles of saliva and sera were compared. The salivary cortisol showed relatively low levels, the 2-day mean value being 3.1%–3.3% that of serum total cortisol through all shifts. Significant differences in the serum to saliva cortisol ratios were noted among shifts and subjects. When expressed as a relative percentage of a 2-day mean value, however, salivary cortisol paralleled the modified circadian profiles of serum total cortisol of the evening and night shifts, with no significant time lag and no difference in magnitude. The cosinor analysis supported this finding. Thus, salivary cortisol appears to be an excellent measure for monitoring circadian rhythm variation in adrenal activity in healthy individuals during shiftwork.     

Consequences of modified fasting in obese pediatric and adolescent patients II. Metabolic effects of glucose compared to fat non-protein calories

We examined the effect of hypocaloric protein and fat compared to protein and carbohydrate-containing diets on 8 obese inpatients 154–226% of ideal body weight. When the carbohydrate-containing diet followed the fat-containing diet, weight loss slowed and nitrogen balance improved from ?0.4±0.5 g/day to 3.9±0.8 g/day during the first week of the carbohydrate-containing diet (p<0.5). By week 3 of the carbohydrate-containing diet, weight loss and nitrogen balance were not different from that seen during the third week of a fat-containing diet, despite persistence of significantly higher serum insulin and T₃ and lower β-hydroxybutyrate concentrations on the carbohydratecontaining diet. Although metabolic differences exist between isocaloric high and low carbohydrate-containing weight reduction diets, equivalent weight loss and nitrogen balance can be anticipated by the third week of therapy.     

Changes in the excretion of corticosteroids and catecholamines in tractor-drivers

Summary An investigation was carried out to study the effect of mechanized agricultural work on the excretion of some corticosteroids and catecholamines in tractor-drivers during a seasonal field work. Group 1 (15 subjects) was examined three times: in the morning hours before starting work and at two intervals during the first and second half of the working day. In group two (11 subjects) the characteristics of the circadian rhythm for 24 h were investigated in urine collected at six intervals.The results from both studies disclose a considerable increase of the total 17-ketosteroids, total 17-oxycorticosteroids, free 11-oxycortico steroids, noradrenaline and adrenaline excretion levels which indicates overactivity of the hypothalamic-pituitary-adrenal and sympathetic nervous systems. The circadian rhythms of the examined parameters are characterized by an increasing of the mesors and a lowering of the amplitudes of the rhythmic variations. No significant changes of corticosteroids and catecholamines are established. Considerable interindividual differences in the course of excretion of the studied indices as well as the lack of marked circadian rhythm in about 50% of the subjects are found.     

Urinary catecholamines and salivary cortisol on workdays and days off in relation to job strain among female health care providers

OBJECTIVES: This study examined the effects of psychosocial job strain on the excretion of neuroendocrine stress hormones (adrenaline, noradrenaline, and cortisol) on workdays and days off. METHODS: Japanese female health care providers (N=16) filled out Karasek's job content questionnaire and had their neuroendocrine excretions (ie, urinary catecholamines and salivary cortisol) measured on a day off and on two workdays (one day shift and one night shift). After control for age and job experience as covariates, a repeated-measures analysis of variance was carried out. RESULTS: Noradrenaline excretion was significantly greater over time in the high-strain group than in the low-strain group, and that of the high-demand group was significantly greater over time than that of the low-demand group. Adrenaline excretion did not significantly differ between the groups. The group with high supervisory support had significantly higher adrenaline excretion than the group with low supervisory support. The concentration of salivary cortisol on a dayshift was significantly lower, but marginally, in the high-strain group than in the low-strain group. CONCLUSIONS: Psychosocial job strain is associated with greater noradrenaline excretion over time. This finding suggests unwinding sympathetic nervous activity. The low cortisol levels of the high-strain group may indicate circadian rhythm disturbance induced by job strain. Supervisory relationships may have a particular influence for the studied occupation because the participants had more administrative contact with supervisors than support at the worksite; therefore, supervisory support may increase adrenaline excretion.     

Seadragon VI: a 7-day dry saturation dive at 31 ATA. IV. Circadian analysis of body temperature and renal functions

Circadian rhythms of body temperature and daytime rhythms of urine flow and urinary excretion of electrolytes were investigated in 4 male subjects before, during, and after a 7-d stay in a dry heliox 31 ATA environment. The chamber temperature was maintained at about 28 degrees C during pre- and postdive 1 ATA periods and was raised to 31.5 degrees C at 31 ATA. The circadian rhythm of the rectal temperature, as analyzed by the cosinor fitting method, showed the same mesor (the mean level of fluctuation) and the amplitude at 31 and 1 ATA. However, a reversible phase shift was noted at 31 ATA in which the acrophase shifted to 1435 h at 31 ATA from 1540 h (predive) or 1610 h (postdive) at 1 ATA. This shift was attributed to an early rise of rectal temperature during night at 31 ATA. A similar phase shift was observed at 31 ATA for the skin temperature of the forehead, a region not covered by clothing or blanket. The daytime rhythms of urinary excretion of water, Na, Cl, urea, and total osmotic substances were similar, with the acrophase at 1300-1500 h at both 1 and 31 ATA. On the other hand, the daytime rhythm for urinary excretion of K, which was similar to the above at 1 ATA, disappeared at 31 ATA. The urinary excretion of endogenous creatinine remained constant during both daytime and nighttime at both 1 and 31 ATA. These results suggest that exposure to 31 ATA may alter the underlying pattern of circadian or daytime rhythms for thermoregulatory and certain renal functions.     

Occasional physical inactivity combined with a high-fat diet may be important in the development and maintenance of obesity in human subjects

BACKGROUND: A better understanding of the environmental factors that contribute to obesity is imperative if any therapeutic effect on the increasing prevalence of overweight and obesity in the United States is to be achieved. OBJECTIVE: This study examined the effect of the interaction of diet composition and physical inactivity on energy and fat balances. DESIGN: Thirty-five normal-weight and obese subjects were randomly assigned to either a 15-d isoenergetic high-carbohydrate (HC) or high-fat (HF) diet according to a crossover design. During the first 14 d, body weight and physical activity were maintained. On day 15, subjects spent 23 h in a whole-room indirect calorimeter and were fed a diet similar to that consumed during the previous 7 d while remaining physically inactive. RESULTS: Energy intakes required to maintain body weight stability during the first 14 d were similar between diets. Normal-weight and obese subjects consuming both diets had a positive energy balance on the sedentary day (day 15), suggesting that subjects were less active in the calorimeter. There was no significant effect of diet composition on total energy balance and total protein-energy balance on day 15; however, carbohydrate balance was more positive with the HC (2497.8 +/- 301.2 kJ) than with the HF (1159 +/- 301.2 kJ) diet (P = 0.0032). Most importantly, fat balance was more positive with the HF (1790.8 +/- 510.4 kJ) than with the HC (-62.8 +/- 510.4 kJ) diet (P = 0.0011). CONCLUSION: Chronic consumption of a high-carbohydrate diet could provide some protection against body fat accumulation in persons with a pattern of physical activity that includes frequent sedentary days.     

Hypocaloric enteral tube feeding in critically ill obese patients

OBJECTIVE: We respectively compared the nutritional and clinical efficacies of eucaloric and hypocaloric enteral feedings in 40 critically ill, obese patients admitted to the trauma or surgical intensive care unit. METHODS: Adult patients, 18 to 69 years old, with weights greater than 125% of ideal body weight, normal renal and hepatic functions, and who received at least 7 d of enteral tube feeding were studied. Patients were stratified according to feeding group: eucaloric feeding (>or=20 kcal/kg of adjusted weight per day; n = 12) or hypocaloric feeding (<20 kcal/kg of adjusted weight per day; n = 28). The goal protein intake for both groups was approximately 2 g/kg of ideal body weight per day. Clinical events and nutrition data were recorded for 4 wk. RESULTS: Patients were similar according to sex, age, weight, body mass index, Second Acute Physiology and Chronic Health Evaluation score, Trauma score, and Injury Severity Score. The hypocaloric feeding group received significantly fewer calories than the eucaloric group (P相似文献   

Material hardship alters the diurnal rhythm of salivary cortisol

BACKGROUND: In the quest for biological mechanisms underlying socioeconomic differences in health outcomes, attention has turned to the role of the hypothalamic-pituitary-adrenocortical axis. As there is some evidence that both acute and chronic stress raise cortisol levels, and material hardship is a stressor, we examined the relationship of chronic material hardship with salivary cortisol levels over the day. METHODS: The data are from a survey of a sample of poor women aged 18-54. Up to four repeated measures of salivary cortisol levels were obtained from 188 women in this sample and modelled as a diurnal profile. Self-reports of a variety of sources of material hardship over the preceding year were combined into a single scale. Specific dimensions of the subjects' cortisol profiles were compared across levels of material hardship. RESULTS: Salivary cortisol varied over the day, and by level of reported material hardship. Upon awakening, salivary cortisol levels were comparable across hardship levels. But soon after waking, women at low levels of hardship experienced both a significantly sharper morning surge and subsequently a sharper decline in salivary cortisol (16.0 and 29.5 nmol/l/h) than women with high hardship levels (5.9 and 24.3 nmol/l/h). These differences in cortisol diurnal pattern tended to be related in a dose-response way to levels of material hardship. CONCLUSIONS: Material hardship among poor women is associated with changes in the diurnal rhythms of cortisol, particularly in the waking response, which is blunted in women with high levels of hardship.     

Circadian rhythms of seven heavy metals in plasma, erythrocytes and urine in men: observation in metal workers

To elucidate circadian rhythms (variation within a day) of 7 toxic or essential metals in plasma and erythrocytes in relation to the rhythms in urine in men, 19 male metal foundry workers were examined; they were exposed to lead (Pb), zinc (Zn) and copper (Cu) occupationally but separated from the exposure during the study. Circadian rhythms were found for plasma concentration of Pb, cadmium (Cd), Zn, Cu and chromium (Cr) in the workers. Circadian rhythms were also found for Pb, inorganic mercury (Hg), Zn and Cr in erythrocytes and for all metals except Zn in urine. Both the plasma and urinary levels of Pb, Cd, Cu and Cr together with urinary excretion of Mn and creatinine tended to decrease during night hours; both the erythrocyte and urinary levels of Hg together with both the plasma and erythrocyte levels of Zn tended to increase during morning hours. The results of profile analysis suggested that the circadian rhythm of Pb in urine was affected more strongly by its plasma and erythrocyte rhythms than by the rhythm of creatinine in urine, i.e. the rhythm of glomerular filtration; the urinary rhythms of Cd, Cr, and Mn were affected more by the creatinine rhythm; and the urinary rhythm of Cu was affected by both its plasma and creatinine rhythms. On the other hand, the urinary rhythm of Hg was assumed to be independent of the creatinine rhythm and be affected by its erythrocyte rhythm. The present study suggested that different biological limit values might be needed for different hours of the day especially for shift workers who are exposed to various heavy metals. Instead, further studies should be conducted to find the adjustment methods by which no circadian rhythms are discerned.     

Protein-induced hypercalciuria: a longer term study.

Urine calcium excretion is known to be directly correlated with the level of dietary protein intake. In this experiment we examined the persistence of the hypercalciuria induced by the consumption of high protein diets, and the mechanism of the calciuric response. In a 95-day metabolic study, each of six adult male subjects received formula diets supplying 12 g nitrogen or 36 g nitrogen, and approximately 1400 mg calcium per day. Urine calcium increased rapidly and significantly from an average of 191 mg/day on the 12 g nitrogen diet to 277 mg/day on the 36 g nitrogen diet. There was no significant difference in the apparent absorption of calcium, so that overall calcium balance was -37 mg/day on the 12 g nitrogen diet, and significantly lower at -137 mg/day in subjects consuming the high protein diet. Levels of urinary hydroxyproline, serum insulin, and parathyroid hormone were not significantly increased by high intakes of protein. A decrease in the fractional reabsorption of calcium by the kidney seems to be the most likely cause of the protein-induced hypercalciuria. The consumption of high calcium diets is unlikely to prevent the negative calcium balance and probable bone loss induced by the consumption of high protein diets.     

Nitrate and nitrogen balances in men

Nitrate is a nitrogen-containing compound that is not detected by the traditional Kjeldahl method of nitrogen analysis. Nitrate balance studies were done in order to determine if nitrate production in the human body contributes to the irrationally positive nitrogen balances that have been reported in healthy adults. Seven healthy young men, confined to a metabolic unit, received five diets for 9 days each: a mixed foods diet, a fiber-free egg formula diet, and egg formula with California small white beans, lima beans, and wheat bran added. Nitrate-nitrogen intake with the mixed foods diet was 75 mg/day and nonnitrate nitrogen intake was 19 g/day; crude Kjeldahl nitrogen balance (intake--(urinary + fecal)) was 0.64 +/- 1.23 g/day. Nitrate-nitrogen excretion exceeded intake by 0.10 +/- 0.05 g/day. With the four other diets, nitrate-nitrogen intake was almost nil (about 2 mg/day) and nonnitrate nitrogen intake was 95 mg/kg body weight; crude Kjeldahl nitrogen balances ranged from -0.63 +/- 0.73 to 0.02 +/- 0.45 g N/day. With these four diets, feces contained about 80 mg nitrate-nitrogen/day and urine contained about 8 mg. Saliva obtained before lunch had about 1 ppm nitrate-nitrogen with the formula diets and 5 ppm with the mixed foods diet. Net synthesis of nitrate is quite variable but appears to be of the order of 100 mg nitrate-nitrogen/day. Although the excess nitrate excretion increased total nitrogen excretion by less than 5%, it could account for as much as 10 to 20% of unexplained positive nitrogen balances previously reported in well-controlled studies.     

Consumption of whole-grain cereals during weight loss: effects on dietary quality, dietary fiber, magnesium, vitamin B-6, and obesity

OBJECTIVE: While various weight-management approaches produce weight loss, they may differ in dietary quality. We monitored changes in nutrient intakes in overweight and obese subjects on three different weight-management programs. DESIGN: Randomized clinical trial (pilot study) with two 12-week phases: phase 1, weekly counseling; phase 2, monitoring only. SUBJECTS/SETTING: One hundred eighty nonsmoking, sedentary overweight and obese adults began this outpatient study; 134 (body mass index [calculated as kg/m(2)]=30.9+/-2.4; age=42.3+/-1.2 years) were used in analyses. INTERVENTION: Twenty-four weeks of exercise only (control group), hypocaloric diet plus exercise, or hypocaloric diet with fiber-rich whole-grain cereals plus exercise. MAIN OUTCOME MEASURES: At weeks 0, 12, and 24, diet quality was assessed by 3-day food records and body weight was measured. STATISTICAL ANALYSES PERFORMED: Three-way analysis of variance with repeated measures. RESULTS: The hypocaloric diet with fiber-rich whole-grain cereals plus exercise decreased energy intake more than exercise only (P=0.032). By week 12, the hypocaloric diet with fiber-rich whole-grain cereals plus exercise and the hypocaloric diet plus exercise decreased total fat more than exercise only, which was sustained in the hypocaloric diet with fiber-rich whole-grain cereals plus exercise at 24 weeks (P<0.001). At weeks 12 and 24, the hypocaloric diet with fiber-rich whole-grain cereals plus exercise reduced saturated fat intake more than exercise only. The hypocaloric diet with fiber-rich whole-grain cereals plus exercise increased total fiber, insoluble fiber (both P<0.001), magnesium (P=0.004), and vitamin B-6 (P=0.002) intakes more than the hypocaloric diet plus exercise and exercise only. Calcium and vitamin E intakes were inadequate in all groups. Weight loss was similar in the hypocaloric diet with fiber-rich whole-grain cereals plus exercise and the hypocaloric diet plus exercise. CONCLUSIONS: Weight-reduction strategies may be associated with reduced intake of micronutrients, such as calcium and vitamin E. However, a hypocaloric diet with fiber-rich whole-grain cereal is effective for improving or maintaining other aspects of dietary quality during weight loss.     

Nitrogen and energy balance in septic and injured intensive care patients: response to parenteral nutrition

We studied energy and nitrogen balance in 50 intensive care patients with sepsis (n = 18) or multiple trauma (n = 32). Most patients were mechanically ventilated during the study. Within 72h of admission the patients were randomised to receive one of 5 infusion regimens for 48h (group n = 9-11). The control group received hypocaloric glucose, two groups received 1.5g/kg/day of amino-acids, either with hypocaloric glucose on both days or with energy adjusted to pre-nutrition REE on the second day. The fourth group received 0.6g/kg/day of amino-acids and energy at REE, and the fifth group a high nitrogen (18g/day) regimen with a stepwise increase in energy intake from day 1 to day 2. Baseline REE was 118 +/- 18.9% of predicted. No significant differences in REE were observed between the diagnostic groups, treatments or measurements performed during mechanical or spontaneous ventilation. Nitrogen balance in the control group was -250.3 +/- 83.3 mg/kg on day 1 and 218.6 +/- 95.3 mg/kg on day 2. Nitrogen balance remained negative in all groups throughout the study (range of group means-218.6 to -48.5 mg/kg/day). Increasing energy intake equal to prenutrition REE at an amino-acid dosage of 1.5g/kg/day decreased the negative nitrogen balance by 66%. Further increase in energy balance had only a marginal effect on nitrogen balance.     

Long-term validation of 1 g of protein per kilogram body weight from a predominantly vegetable mixed diet to meet the requirements of young adult males

Eight healthy young men participated in a 90-d metabolic balance study designed to assess the adequacy of 1 g of protein (N X 6.25) per kilogram body weight per day provided by a predominantly vegetable diet. The mean gross energy intake of the subjects was 49 kcal/(kg X d). The individuals received the experimental diet for eleven 8-d experimental periods. Three isoenergetic, isonitrogenous meals were served at 0800, 1200 and 1900. Anthropometric measurements and biochemical determinations in blood were made at the beginning of the study and afterwards at regular 15-d intervals. Body weight was measured daily. The mean overall weight change for the group was -0.8 kg. The mean daily urinary nitrogen output decreased from an initial value of 134.6 mg/(kg X d) to a final figure of 115.1 mg/(kg X d) (P less than 0.01), while the daily fecal N decreased from 31.5 to 26.3 mg/(kg X d) (P less than 0.05). Mean cumulative nitrogen balances were slightly positive for seven out of the eight individuals with an overall mean nitrogen balance value of +6.7 mg N/(kg X d). Biochemical and hematological values showed no significant changes throughout the study, except for a decrease in serum cholesterol. It is concluded that the "Chilean" mixed diet fed at the level of 1 g of protein per kilogram body weight per day with sufficient energy meets the long-term protein-energy needs of healthy young men, thus supporting the 1984 FAO/WHO/UNU safe recommended daily protein allowance of 0.75 g of reference protein, with a correction for the lower digestibility of vegetable sources.     

Studies on fatigue and shift work in nurses]

Effects of shift work on physiological parameters and autonomic nervous-adrenal system were studied on six hospital nurses. Their body temperature, heart rate, blood pressure, fluctuation in ECG R-R intervals, serum catecholamines and cortisol, and subjective fatigue ratings before and after day, evening and night shift were determined. Furthermore, mean heart rates, walk steps, estimated energy expenditure, and urinary catecholamine excretion were determined three times for eight hours each during each shift work day. The following results were obtained: 1) No significant changes were detected in the physiological parameters before and after each shift work, except for elevation in plasma adrenaline level after night shift. 2) Heart rate, blood pressure and subjective fatigue rating tended to be higher, though not significantly, at the beginning of night shift, when compared with the data obtained on the some time of day, i.e., at the end of evening shift. 3) On the other hand, the plasma cortisol level tended to be suppressed after night shift, suggesting that even one night shift work may change the circadian rhythm of plasma cortisol. 4) Statistical analyses showed that in contrast to day and evening shift, in night shift there was no significant positive correlation between eight-hour walk steps, and eight-hour mean heart rate and urinary adrenaline excretion, suggesting an altered circadian rhythm in heart rate and urinary adrenaline excretion and also a possible additional psychological load in night shift. These results suggest that even one night shift work could modulate the autonomic nervous-adrenal activity of hospital nurses, compared with day or evening shift, and indicate that it is necessary to lengthen the time interval before and after night shift work.     

Changes in folate status in overweight/obese women following two different weight control programmes based on an increased consumption of vegetables or fortified breakfast cereals

The modification of folate status was analysed in a group of sixty-seven overweight/obese women of childbearing age (20-35 years). Subjects were randomly assigned to one of two slightly hypocaloric diets: diet V (increased consumption of vegetables) or diet C (increased consumption of breakfast cereals). Dietetic, anthropometric and biochemical data were collected at the start of the study and again at 2 and 6 weeks. At 6 weeks a weight loss of 2.0 (sd 1.3) kg was achieved in V subjects and of 2.8 (sd 1.4) kg in C subjects (P < 0.05). At the start of the study, 64.2 % of all subjects had a folate intake of < 67 % of the recommended intake; this fell to just 3 % (7.14 % of V subjects and 0 % of C subjects) by week 6. Significant increases were only seen in C subjects in serum folate concentrations (both at 2 and 6 weeks), accompanied by a significant reduction in serum homocysteine (at week 6). Some 62.1 % of all subjects had serum folate concentrations of > or = 13.6 nmol/l (associated with a very low risk of neural tube defects) at the start of the study, while 87.0 % (85.2 % of V subjects and 88.9 % of C subjects) had concentrations of > or = 13.6 nmol/l at 6 weeks (P < 0.01). Increasing the relative consumption of vegetables/cereals in the context of a slightly hypocaloric diet may therefore be a good way to lose body weight. Breakfast cereals may be of special help with respect to folate status and serum homocysteine levels in overweight/obese young women following energy restriction diets.