Lack of association between changes in plasma leptin concentration and in food intake during the menstrual cycle

BACKGROUND: Changes in plasma leptin concentration and food intake occur during the menstrual cycle; because leptin regulates food intake, one could hypothesize that changes in plasma leptin concentration and in food intake are associated throughout the menstrual cycle. However, no data have ever been provided to support such a relationship. The aim of our study was to investigate, during the different phases of the menstrual cycle, (a) the changes in plasma leptin concentration and, if such changes were demonstrated, (b) the potential relationship between the changes in plasma leptin concentration and food intake. DESIGN: The study was designed as an observational study. The plasma leptin concentration was determined in 16 healthy, young women during different phases of the menstrual cycle. At the same time, the basal metabolic rate (BMR), respiratory quotient (RQ) and food intake (FI) were also determined. RESULTS: The plasma leptin concentration increased throughout the menstrual cycle (P < 0.01 for trend) and was significantly correlated with plasma progesterone concentration (r = 0.55, P < 0.007, for follicular phase, r = 0.58, P < 0.02, for the periovulatory period and r = 0.57, P < 0.02, for the luteal phase). No significant differences in BMR and fasting RQ throughout the different phases of the menstrual cycle were found. In contrast, FI significantly declined in the periovulatory phase. No significant correlations between BMR, RQ and FI values and fasting plasma leptin concentration at all menstrual phases were found. CONCLUSION: Changes in plasma leptin concentration and in food intake were found at different phases of the menstrual cycle. Nevertheless, no correlation among those parameters at any phase of the menstrual cycle was observed.     

Glucagon-like peptide-1: a potent regulator of food intake in humans

Background/Aims—Studiesin animals suggest a physiological role for glucagon-likepeptide-1-(7-36)-amide (GLP-1) in regulating satiety. The role ofGLP-1 in regulating food intake in man has, however, not been investigated.
Subjects—Sixteen healthy male subjects were examined in adouble blind placebo controlled fashion.
Methods—The effect ofgraded intravenous doses (0,0.375, 0.75, and 1.5 pmol/kg/min) ofsynthetic human GLP-1 on food intake and feelings of hunger and satietywas tested in healthy volunteers.
Results—Graded GLP-1infusions resulted in a dose dependent reduction in food intake(maximal inhibition 35%, p<0.001 vcontrol) and a similar reduction in calorie intake (32%; p<0.001). Fluid ingestion was also reduced by GLP-1 (18% reduction, p<0.01). Noovert side effects were produced by GLP-1, but subjects experienced less hunger and early fullness in the period before a meal during GLP-1infusion at the highest dose (p<0.05).
Conclusions—Intravenousinfusions of GLP-1 decrease spontaneous food intake even atphysiological plasma concentrations, implying an important role forGLP-1 in the regulation of the early satiety response in humans.

Keywords:glucagon-like peptide-1; satiety; food intake; hunger and fullness score

     

Dietary intakes and nutrient status of vegetarian preschool children from a British national survey

Background Dietary intakes and nutrient status were compared in meat‐eaters and non‐meat‐eaters from the National Diet and Nutrition Survey of children aged 1.5–4.5 years. Methods Children (n = 1351) were categorized as ‘omnivores’ or ‘vegetarians’, according to whether they consumed meat or meat products during a 4‐day dietary record. Blood samples were also obtained for analysis of haematological and biochemical nutrient status. Results Three per cent of children were ‘vegetarian’. They consumed higher proportions of milk and milk products, although this was significant only in older children (P = 0.007), owing to high consumption by the high proportion of Asian children. In vegetarians, energy intakes tended to be lower in both age groups. Percentage energy from protein and fat were lower, while that from carbohydrate was higher compared with omnivores. Cholesterol intakes were lower, significantly so for younger children (P < 0.001). Intakes of micronutrients were either higher (vitamins C and E, potassium) or lower (niacin and sodium) in younger vegetarians compared with omnivores. Energy‐adjusted intakes of iron and zinc did not differ significantly from those of omnivores, although both intakes were low in many children (6–20% < LRNI), particularly in the younger group. Haematological and biochemical nutrient status indices showed few differences. Serum ferritin was lower in vegetarians, significantly so in younger children (P = 0.002). Antioxidant vitamin (A, C and E) status tended to be higher in vegetarians, while vitamin B₁₂ intakes and status were more than adequate. Apart from poorer vitamin D intake and status in older Asian vegetarians, very few ethnic differences were observed. Conclusions Nutrient intakes and status were generally adequate in preschool children who did not eat meat. Although serum ferritin levels were inferior (particularly in vegetarians under 3 years old), the lower intakes of fat, cholesterol and sodium, and higher antioxidant vitamin intakes and status indices were potentially beneficial. Given a balanced diet, adequate nutrient intakes and status can be maintained without consuming meat.     

炊具、温度、时间、食物种类对煎炸植物油卫生质量的影响

以羰基价,酸价为指标,采用正交设计研究炊具,温度、时间、食物种类对煎炸过程中花生油及调和油卫生质量的影响。结果表明温度、时间、炊具对煎炸植同的羰基价均有显著性影响,当前温度达２５０℃,时间达５ｈ时,温度与时间存在协同作用。食物、温度、炊具对煎炸植同酸价影响有显著性。     

Estimates of the theoretical maximum daily intake of erythorbic acid, gallates, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) in Italy: a stepwise approach

The three recent EU directives which fixed maximum permitted levels (MPL) for food additives for all member states also include the general obligation to establish national systems for monitoring the intake of these substances in order to evaluate their use safety. In this work, we considered additives with primary antioxidant technological function for which an acceptable daily intake (ADI) was established by the Scientific Committee for Food (SCF): gallates, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and erythorbic acid. The potential intake of these additives in Italy was estimated by means of a hierarchical approach using, step by step, more refined methods. The likelihood of the current ADI to be exceeded was very low for erythorbic acid, BHA and gallates. On the other hand, the theoretical maximum daily intake (TMDI) of BHT was above the current ADI. The three food categories found to be main potential sources of BHT were “pastry, cake and biscuits”, “chewing gums” and “vegetables oils and margarine”; they overall contributed 74% of the TMDI. Actual use of BHT in these food categories is discussed, together with other aspects such as losses of this substance in the technological process and percentage of ingestion in the case of chewing gums.     

Effect of salt intake on jejunal dopamine,Na+,K+‐ATPase activity and electrolyte transport

The present study addresses the question of the relevance of salt intake on jejunal dopamine, Na⁺,K⁺‐ATPase activity and electrolyte transport. Low salt, but not high salt, intake for 2 weeks increased dopamine levels in the jejunal mucosa accompanied by a marked decrease in L ‐3,4‐dihydroxyphenylalanine tissue levels. By contrast, in rats fasted for 72 h the effect of refeeding for 24 h with a low salt diet failed to change dopamine tissue levels, although it significantly increased those of L ‐3,4‐dihydroxyphenylalanine. By contrast, high salt intake markedly increased the tissue levels of both dopamine and L ‐3,4‐dihydroxyphenylalanine, without changes in dopamine/ L ‐3,4‐dihydroxyphenylalanine tissue ratios. Tissue levels of both L ‐3,4‐dihydroxyphenylalanine and dopamine in control conditions (normal salt intake for 2 weeks) were markedly higher (P < 0.05) than in rats submitted to 72 h fasting plus 24 h refeeding. The effect of fasting for 72 h followed by 24 h refeeding was a marked decrease in jejunal Na⁺,K⁺‐ATPase activity, particularly evident for rats fed a normal salt and high salt diets during the refeeding period. Basal short circuit current was similar in rats fed a normal salt diet for 2 weeks and 24 h, and the type of diet failed to alter basal short circuit current after refeeding with normal, low and high salt diets. On the other hand, the effect of prolonged low salt intake was a marked decrease in jejunal Na⁺,K⁺‐ATPase activity and basal short circuit current, whereas high salt intake failed to alter enzyme activity and basal short circuit current. In rats fed for 2 weeks a high salt diet ouabain was found to be more potent in reducing jejunal short circuit current than in rats fed normal and low salt diets. The effect of furosemide was more marked in rats fed for 2 weeks high and low salt diets than in animals receiving a normal salt intake. Dopamine (up to 1 μmol L^–1) was found not to alter Na⁺,K⁺‐ATPase and basal short circuit current in jejunal epithelial sheets, in rats fed with normal, low and high salt diets for 2 weeks and 24 h.     

体外循环对肺内分流量的影响及其原因探讨

目的 为了研究体外循环对肺内分流量（简称Ｑｓ／Ｑｔ）的影响及其原因。方法 在吸纯氧下测定体外循环前及结束后２０’、２ｈ、４ｈ、８ｈ的肺内分流量。结果 在体外循环结束后２０分钟、２ｈ、４ｈ时肺内分流均增加（Ｐ〈０．０５）,８ｈ开始恢复。结论体外循环可引起肺内分流量增加,其原因存在着解剖分流的增加,也可能同时存在肺泡萎陷。     

钠摄入量对充血性心衰大鼠血浆及心肌Ang Ⅱ、Ald和ANP水平的影响

观察严格限钠或适量补钠对充血性心衰(CHF)大鼠血钠及血浆和心肌组织中血管紧张素Ⅱ(AngⅡ)、醛固酮(Ald)和心钠素(ANP)水平的影响。结果表明：限钠使血钠进一步降低(P＜ 0.05), 血浆AngⅡ、Ald、ANP水平进一步升高(均 P＜ 0.01),尿钠、尿量显著减少,心衰加重;补钠则使血钠恢复正常,血浆AngⅡ和Ald降至正常,ANP仍保持较高水平,尿钠、尿量显著增加,心衰缓解。提示：充血性心衰时,适当补钠可促使RAAS与ANPS两大激素系统之间的活性恢复平衡、促进排钠利尿、心衰缓解。     

口服琼脂加蓝光治疗降低新生儿血清胆红素水平的效果观察

目的 比较口服琼脂加蓝光治疗和单纯蓝光治疗降低新生儿血清胆红素水平的效果。方法 110例新生儿黄疸患儿分成观察组和对照组,观察组采用口服琼脂500mg/(kg·次),q6h加蓝光治疗,对照组采用常规蓝光治疗,8h/d。比较两组患儿总胆红素(TBIL)、直接胆红素(DBIL)、间接胆红素(IBIL)水平的变化。结果 观察组治疗后血清TBIL下降幅度大于对照组,差异有显著意义(P<0.002),IBIL下降幅度大于对照组,差异有显著意义(P<0.01),但DBIL下降幅度差异无显著意义(P>0.05)。结论 口服琼脂加蓝光治疗降低新生儿血清胆红素水平效果优于对照组,具有安全、经济、方便、有效的优点,可推广应用。     

经济收入对成人膳食结构和营养摄入影响的动态研究

目的 :动态研究经济收入对成人膳食结构和营养摄入的影响。方法 :1 997年对湖南省长沙市和沅陵县成人的经济收入水平、膳食结构和营养摄入进行调查并与 1 991年的调查结果对比分析。结果 :随着经济收入的提高 ,两地居民谷类食物摄入量下降 ,动物性食物摄入量上升 ;蛋白质、脂肪等营养素均随经济收入水平的提高而摄入增加 (P<0 .0 5 ) ;在高、中收入人群碳水化合物热能比低于 6 0 % ,脂肪热能比超过 30 %。结论 :城乡居民膳食结构随着经济增长而处于转型过程中 ,存在地区之间食物构成的不平衡性和营养摄入不平衡现象 ,应及时采取有效措施