首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 10 毫秒
1.
Accumulation in chick livers of 9-cis versus all-trans beta-carotene   总被引:1,自引:0,他引:1  
Previous results indicated that beta-carotene, as present within the unicellular alga Dunaliella, accumulated in the liver of chicks to a much higher degree than did synthetic all-trans beta-carotene. Because the Dunaliella beta-carotene is composed of an approximately equal mixture of two stereoisomers, 9-cis and all-trans, we tested whether a similar mixture of purified beta-carotene isomers would yield comparable results. Indeed, analysis of liver following 2 wk of feeding show a 10-fold higher accumulation of beta-carotene in the chicks fed a mixture of purified 9-cis and all-trans beta-carotene as compared with those fed only all-trans beta-carotene. The ratio of 9-cis to all-trans beta-carotene in the liver was about three times higher than that present in the beta-carotene fed to the chicks. Retinol and retinyl esters accumulated to a similar degree in the livers of chicks given all treatments.  相似文献   

2.
This article critically reviews the behavioral and biological associations of dietary restraint. Behaviorally, dietary restraint manifests itself in the form of less variety in the diet and reduced energy intake. As practiced by some, dietary restraint may create biological and psychological feelings of deprivation that lead to greater reactivity to food cues, cravings, counterregulation, disinhibition, periodic overeating, and weight gain. Biologically, it is often associated with unhealthy changes in body composition, hormonal changes, reduced bone density, menstrual disturbances, and lower resting energy expenditure. Caution is indicated in the promotion of dietary restraint as a general principle for managing weight.  相似文献   

3.
4.
5.
Weight loss after bariatric surgery decreases the earlier expansion of the adventitial vasa vasorum (VV), a biomarker of early atheromatous disease. However, no data are available regarding weight loss achieved by very low calorie ketogenic diets (VLCKD) on VV and lipid-based atherogenic indices. A randomized clinical trial was performed to examine changes in adventitial VV density in 20 patients with moderate obesity who underwent a 6-month very low calorie ketogenic diet (VLCKD, 600–800 kcal/day), and 10 participants with hypocaloric diet based on the Mediterranean Diet (MedDiet, estimated reduction of 500 kcal on the usual intake). Contrast-enhanced carotid ultrasound was used to assess the VV. Body composition analysis was also used. The atherogenic index of plasma (log (triglycerides to high-density lipoprotein cholesterol ratio)) and the triglyceride-glucose index were calculated. Serum concentrations of soluble intercellular adhesion molecule 1 (sICAM-1), and soluble vascular cell adhesion molecule 1 (sVCAM-1) were measured. The impact of weight on quality of life-lite (IWQOL-Lite) questionnaire was administered. Participants of intervention groups displayed a similar VV values. Significant improvements of BMI (−5.3 [−6.9 to −3.6] kg/m2, p < 0.001), total body fat (−7.0 [−10.7 to −3.3] %, p = 0.003), and IWQOL-Lite score (−41.4 [−75.2 to −7.6], p = 0.027) were observed in VLCKD group in comparison with MedDiet group. Although after a 6-months follow-up period VV density (mean, right and left sides) did not change significantly in any group, participants in the VLCKD exhibited a significantly decrease both in their atherogenic index of plasma and serum concentration of sICAM-1. A 6-month intervention with VLCKD do not impact in the density of the adventitial VV in subjects with moderate obesity, but induces significant changes in markers of endothelial dysfunction and CV risk.  相似文献   

6.
The effectiveness of beta-carotene (betaC) as a vitamin A (VA) precursor may be influenced by the proportions of cis isomers of betaC consumed in the diet. Although the metabolic fates of cis isomers of betaC are poorly understood, their retinol equivalency has been assigned a value 50% that of all-trans (at) betaC. A dose-response design was used to estimate the relative VA value (VAV) of atbetaC, 9-cis (9c) betaC and 13-cis (13c) betaC in gerbils using total liver retinol as a measure of VAV. Ten groups of gerbils received a daily dose of oil with or without betaC isomer by gavage for 7 d. Nine groups (n = 5) were divided equally among the three betaC dosing treatments with each isomer provided at 141, 275 and 418 nmol/d. Total liver VA (171-259 nmol) in gerbils administered atbetaC was higher than total liver betaC (25-53 nmol). Stores of VA and betaC in livers from gerbils administered atbetaC were higher than stores of VA and betaC in livers from those given 9cbetaC or 13cbetaC. The relative VAV of cis betaC isomers was estimated by comparing slopes of dose-response lines of all three betaC isomers using atbetaC as a reference. Total liver VA and betaC increased linearly (P < 0.05) with increasing betaC intake in gerbils gavaged with all three betaC isomer oils. The relative VAV of 9cbetaC was less (38%) and 13cbetaC was more (62%) than the assigned value of 50% that of atbetaC. Thus, the proportions of cis isomers of betaC contained in a food could negatively affect the vitamin A value of the diet.  相似文献   

7.
OBJECTIVE: This study examined the factors associated with the diagnostic outcome of obese individuals with and without binge eating disorder (BED) 1 year after completing a very low calorie diet (VLCD) program. METHOD: Participants included 63 individuals with BED, 36 individuals with subthreshold BED, and 29 individuals with no binge eating symptoms. Diagnoses before and after VLCD were obtained using the Structured Clinical Interview for DSM-IV (SCID) interviews. The severity of psychiatric symptoms were assessed using various rating scales. RESULTS: Fifty-six percent (n = 36) of the participants who met criteria for BED at baseline did not meet diagnostic criteria 1 year later. None of the baseline factors were statistically associated with outcome. DISCUSSION: Although the main hypothesis was not supported, absence of a BED diagnosis at 12-month follow-up after a VLCD diet appears to be associated with less weight gain at 1-year follow-up regardless of baseline diagnosis.  相似文献   

8.
Self-reported weight and height: implications for obesity research   总被引:1,自引:0,他引:1  
BACKGROUND: Self-reported weight and height are under- and over-reported, respectively, in epidemiologic studies. This tendency, which may adversely affect study operations, has not been evaluated among subjects being enrolled into a weight-loss program. METHODS: Self-reported weight, height, and body mass index (BMI) were compared to measured values in 97 overweight or obese (BMI>27.3) women being enrolled into a randomized, controlled trial of two behavioral interventions for weight loss. The effects of demographic factors, baseline weight, baseline height, and baseline BMI on weight and height reporting were assessed. RESULTS: There was a significant difference between measured and reported weight (mean difference=-3.75 lb, p=0.0001) and height (mean difference=+0.35 in., p=0.0007). The mean difference between measured and reported BMI was -1.14 kg/m(2) (p=0.0001). Unemployed, retired, or disabled women were more likely to under-report their BMI than employed women (p=0.001). Six percent of subjects who were initially considered eligible for the study on the basis of the self-report were eventually excluded from the study because they did not meet the inclusion criterion for BMI. CONCLUSIONS: Obese women who seek weight-loss assistance tend to under-report their weight and over-report their height, suggesting that self-reported data are likely to be inaccurate. Misreporting is apparently influenced by employment and disability and has the potential to complicate recruitment of subjects for research studies.  相似文献   

9.
A low-calorie diet (LCD) is an effective strategy to lose weight and improve cardiometabolic risk factors, however, sexual dimorphism may be present. This study aims to investigate sexual dimorphism in cardiometabolic risk factors following weight loss and after weight maintenance. 782 overweight/obese participants (65% women) of the DiOGenes trial followed an 8-week LCD (~800 kcal/day), with a 6-months follow-up weight maintenance period on ad libitum diets varying in protein content and glycemic index. Men lost more body weight during the LCD period (−12.8 ± 3.9 vs. −10.1 ± 2.8 kg, respectively, p < 0.001), but regained more weight during the follow-up period than women (1.5 ± 5.4 vs. −0.5 ± 5.5 kg, respectively, p < 0.001). Even though beneficial LCD-induced changes in cardiometabolic risk factors were found for both sexes, improvements in HOMA-IR, muscle and hepatic insulin sensitivity, triacylglycerol, HDL−, LDL− and total cholesterol, diastolic blood pressure, cholesterol esters, sphingomyelins and adiponectin were more pronounced in men than women (std. ß range: 0.073–0.144, all q < 0.05), after adjustment for weight change. During follow-up, women demonstrated a lower rebound in HDL-cholesterol, triacylglycerol and diacylglycerol (std. ß range: 0.114–0.164, all q < 0.05), independent of changes in body weight. Overall, we demonstrated sexual dimorphism in LCD-induced changes in body weight and cardiometabolic risk profile, which may be attributed to differences in body fat distribution and metabolic status.  相似文献   

10.
11.
The role of formula very low‐energy diets (VLEDs, <800 kcal/day) and low‐energy diets (LEDs, 800–1200 kcal/day) within clinical practice has regained attention over the last few years. Formula diets can achieve clinically significant weight reduction in the short‐term (3–5 months) and new evidence demonstrates that long‐term weight loss maintenance (up to 4 years) is achievable. Weight reductions of between 10% and 15% bodyweight have been reported, which is associated with clinically meaningful health outcomes in a number of obesity‐related co‐morbidities including type 2 diabetes (T2D), obstructive sleep apnoea and osteoarthritis. Recent evidence indicates that using a formula LED with a weight loss maintenance programme can help people with overweight or obesity and T2D achieve remission. Despite this, few healthcare professionals in the UK routinely use LEDs. Concerns about adherence, risk of precipitating eating disorders, safety, cost and long‐term efficacy may, in part, contribute to their under use. To help inform healthcare professionals on the use of formula diets within clinical practice, this review examines the current evidence for the use of VLEDs and LEDs for weight loss and weight loss maintenance, and in the treatment of obesity‐related co‐morbidities, including T2D, osteoarthritis, psoriasis, obstructive sleep apnoea and secondary coronary prevention, with a particular focus on T2D remission.  相似文献   

12.
We evaluated the relationship between fetal growth in preterm babies using the head circumference (HC)/chest circumference (CC) ratio and other anthropometric parameters at birth and at school age. Data were collected from 187 very low birth weight (VLBW) children born at less than 30 weeks of gestational age (GA) at birth and at 6 years. We assessed the correlation between the HC/CC ratio and body weight (BW), body length (BL), and HC z-scores at birth, and BW, body height (BH), and body mass index (BMI) z-scores at 6 years. Multiple regression analysis showed that BW z-score, BL z-score, and HC z-score at birth were significantly associated with HC/CC at birth. The BMI z-score at 6 years was also significantly associated with HC/CC at birth. The HC/CC ratio at birth is a reliable parameter for evaluating fetal growth restriction and a possible predictor of physical growth in VLBW children.  相似文献   

13.
Objective: To compare relative weight, weight loss efforts and nutrient intakes among similarly health-conscious vegetarian, past vegetarian and nonvegetarian premenopausal women.

Methods: Demographic data, lifestyle practices and weight loss efforts (by questionnaire), body mass index (BMI;kg/m2) and dietary intake (via multiple-pass 24-hour diet recall) were compared in a convenience sample of 90 current vegetarians, 35 past vegetarians and 68 nonvegetarians.

Results: Age (31.9 ± 8.8), educational attainment, smoking status, alcohol use, physical activity and perceived health status were similar among the three groups of women. BMI did not differ by dietary pattern and averaged 23.7 ± 4.7 for all women combined. Participants had intentionally lost ≥ 10 pounds a mean of 2.1 times, and 39% of women perceived themselves to be overweight; again, no differences were observed among dietary groups. Dietary intakes of vegetarians and current nonvegetarians were consistent with current recommendations for macronutrient composition (<30% fat, <10% saturates). Compared to current nonvegetarians, current vegetarians had lower intakes of protein, saturated fat, cholesterol, niacin, vitamins B12 and D, and higher fiber and magnesium intakes. Vegetarians’ mean vitamin B12 and D intakes were well below recommendations.

Conclusions: Relative weight and weight loss efforts do not differ by dietary pattern among similarly health-conscious vegetarian and nonvegetarian women. The only differences in nutrient intake with potential health implications were vitamins D and B12.  相似文献   

14.

Background

The decision to lose weight among adolescents is complex and is guided by a number of body‐related factors. This study examined the extent of agreement between actual weight, measured as body mass index, and self‐perceived weight and assessed their relative importance in weight loss behaviour among Lebanese adolescents.

Methods

Data on 278 adolescents aged 13–17 years were drawn from the nationwide Nutrition and Non‐Communicable Disease Risk Factor Survey (Lebanon, 2009). Binary multivariable logistic regressions were conducted to test associations with “effort to lose weight” as the outcome variable, controlling for a number of potential confounders.

Results

Close to 36% reported trying to lose weight. Around 21% and 13% were overweight and obese, respectively, and 40% and 10% perceived their weight as slightly high and very high, respectively. Inaccurate perceivers, those underestimating or overestimating their weight, constituted 39%, with overall percent agreement between actual and self‐perceived weight being 60.8% (kappa statistic = 0.319, 95% CI [0.242, 0.396]). About a third of the overweight adolescents (30.5%) and more than half of the obese (56.8%) underestimated their weight. In the multivariable analysis, self‐perceived weight was statistically significant and a stronger predictor of weight loss effort than body mass index (adjusted odds ratios = 14.42 and 6.42 for slightly high and very high perceived weight, respectively, compared to odds ratios = 1.47 and 2.31 for overweight and obese adolescents, respectively).

Conclusion

Health professionals need to consider self‐perceived weight in conjunction with actual weight in their pursuit of weight management goals and in planning prevention programmes that guide weight loss behaviours for adolescents.  相似文献   

15.
Obesity in women of reproductive age is common. Emerging evidence suggests that maternal obesity not only increases the risk of adverse pregnancy outcomes but also has an enduring impact on the metabolic health of the offspring. Given this, management of obesity prior to pregnancy is critically important. Almost all international guidelines suggest that women with obesity should aim to achieve weight loss prior to pregnancy. However, current pre-conception weight loss therapies are sub-optimal. Lifestyle modification typically results in modest weight loss. This may assist fertility but does not alter pregnancy outcomes. Bariatric surgery results in substantial weight loss, which improves pregnancy outcomes for the mother but may be harmful to the offspring. Alternative approaches to the management of obesity in women planning pregnancy are needed. Very low energy diets (VLEDs) have been proposed as a possible tool to assist women with obesity achieve weight loss prior to conception. While VLEDs can induce substantial and rapid weight loss, there are concerns about the impact of rapid weight loss on maternal nutrition prior to pregnancy and about inadvertent exposure of the early fetus to ketosis. The purpose of this review is to examine the existing literature regarding the safety and efficacy of a preconception VLED program as a tool to achieve substantial weight loss in women with obesity.  相似文献   

16.
This study analyzes the impact of local mandatory calorie labeling laws implemented by New York jurisdictions on body weight. The analysis indicates that on average the point‐of‐purchase provision of calorie information on chain restaurant menus reduced body mass index (BMI) by 1.5% and lowered the risk of obesity by 12%. Quantile regression results indicate that calorie labeling has similar impacts across the BMI distribution. An analysis of heterogeneity suggests that calorie labeling has a larger impact on the body weight of lower income individuals, especially lower income minorities. The estimated impacts of calorie labeling on physical activity, smoking, and the consumption of alcoholic beverages, fruits, and vegetables are small in magnitude, which suggests that other margins of adjustment drive the body‐weight impacts estimated here. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

17.
目的探讨极低出生体重儿贫血的发生时间及影响因素,为临床诊治提供参考依据。方法收集2012年1月-2013年12月本院收治的147例极低出生体重儿(very low birth weight infants,VLBWI)的临床资料数据,根据贫血发生时间分为4组,对每组患儿相关临床资料进行分析。结果 147例VLBWI临床诊断贫血的平均日龄为(12.26±7.95)d,其中早期贫血发生者44例(29.9%),晚期贫血发生者103例(70.1%)。4组VLBWI分别在新生儿期累积采血量、累积输血量、基础血红蛋白及基础平均红细胞压积方面差异有高度统计学意义(P0.01);同时各组患儿在胎盘早剥、宫内窘迫、新生儿颅内出血等围产因素的比较差异有统计学意义(P0.05)。多因素Logistic回归分析,早期医源性失血及基础血红蛋白与贫血早期发生的关系更为密切。结论贫血是VLBWI生后常见并发症。早期医源性失血及基础Hb水平是导致贫血早发的高危因素,多种围生期因素可影响贫血发生时间,目前输血治疗仍是治疗VLBWI贫血的常规甚至是首选方法。  相似文献   

18.
9-cis beta-Carotene was extracted from a commercial extract of the algae Dunaliella salina (Betatene), and its actions on proliferation and gene expression were examined in murine 10T1/2 cells and human HaCaT keratinocytes. The 9-cis isomer was less active than all-trans beta-carotene in reducing proliferation and in upregulating expression of connexin 43 in 10T1/2 cells. However, it had comparable ability to suppress carcinogen-induced neoplastic transformation. When tested in HaCaT cells in organotypic culture, it was less active in inducing connexin 43 expression and suppressing expression of keratin K1. In this assay the all-trans isomer was highly active at 10(-6) M, whereas 10(-5) M 9-cis beta-carotene was required to produce a comparable effect. Only small reductions in expression of the basal keratin 5 were seen. All-trans and 9-cis retinoic acids, potential metabolites of beta-carotene isomers, were studied in the same systems. In contrast to the carotenoids, the 9-cis isomer of retinoic acid was approximately 10-fold more active in suppressing neoplastic transformation and inducing connexin 43 expression in both cell types than the all-trans isomer. The retinoic acid isomers were about equipotent in suppressing K1 expression. Cellular levels of 9-cis beta-carotene were approximately 3.5-fold lower than levels of all-trans beta-carotene, suggesting that part, but not all, of this decreased activity of the 9-cis isomer was due to decreased cell uptake. Thus 9-cis beta-carotene is consistently less active than the all-trans isomer; that 9-cis retinoic acid is, in general, much more potent than the all-trans isomer suggests little or no conversion from the carotenoid to the retinoid under these culture conditions.  相似文献   

19.
This study was performed to determine (1) the normal serum response to a single oral dose of beta-carotene (BC), (2) the effect of meal timing and serum response to meal lipids on serum BC, (3) the effect of administered BC on other serum carotenoids and retinoids, and (4) the relationship of body composition to serum BC response. Subjects consumed one BC dose with a liquid 500 kcal BC-free diet; fasting and hourly venous blood was collected for 8 hours and again at 24 hours. A second liquid BC-free meal was consumed 4 hours post-dosing; this midday meal was omitted in some subjects. Serum BC levels rose and peaked initially at 5 hours, but continued to be absorbed in most subjects, remaining significantly elevated at 24 hours as compared to baseline values (p less than 0.001), independent of BC dose. The area under the BC absorption curve (8-hr AUC) increased linearly with BC dose and correlated positively with peak serum triglycerides (TG) after a meal (n = 26 tests, r = 0.56, p less than 0.003). Omission of the midday meal significantly delayed the initial BC peak to 7 hours (p less than 0.0004). Serum levels of retinol, alpha-carotene, cryptoxanthin, lycopene, and lutein remained unchanged. Serum retinyl esters did not rise in all subjects following BC intake; when it did, retinyl esters rose and peaked concomitantly with BC, but declined within 8 hours. There was no correlation between the initial serum BC, peak BC, 24-hr BC, 8-hr AUC, or peak serum TG and the percentage of body fat. We conclude that: (1) the timing of the serum response to oral BC is independent of dose, (2) the serum BC response is greater in those with a greater serum triglyceride response to meal lipids, (3) BC at the doses given does not alter the levels of other serum carotenoids, and (4) there is no correlation between the serum BC parameters measured and adiposity.  相似文献   

20.
Objective: To compare the use of meal replacements or medication during weight maintenance subsequent to weight loss using a very low-energy diet (VLED) in overweight or obese adults.

Design: Participants followed a liquid VLED of 2177 kJ for 12 weeks followed by 4 weeks of re-orientation to solid foods. Participants were randomized at week 16 to receive either meal replacements or Orlistat both combined with a structured meal plan containing an energy value calculated to maintain weight loss.

Subjects: Sixty-four women (age = 49.9 ± 10 y, weight = 101.6 ± 17.1 kg, height = 164.9 ± 6.0 cm, BMI = 36.7 ± 5.4 kg/m2) and 28 men (age = 53.7 ± 9.6 y, weight = 121.8 ± 16.0 kg, height = 178.7 ± 5.6 cm, BMI = 37.8 ± 4.9 kg/m2) completed a 1 year weight management program. Behavioral weight management clinics included topics on lifestyle, physical activity (PA), and nutrition. Participants met for 90 min weekly for 26 weeks, and then biweekly for the remaining 26 weeks.

Outcomes: Minutes of PA, fruits and vegetables (FV), and pedometer steps were recorded on a daily basis and reported at each group meeting. Body weight was obtained at each group meeting.

Results: During VLED, the MR group decreased body weight by 22.8 ± 6.1 kg and the Orlistat group decreased body weight by 22.3 ± 6.1 kg. During weight maintenance, there was no significant group by time interaction for body weight, PA, FV consumption, or pedometer steps. At week 16, the meal replacement group had a body weight of 85.4 ± 14.3 kg that increased to 88.1 ± 16.5 kg at 52 weeks (p < 0.05). At week 16, the Orlistat group had a body weight of 85.7 ± 17.9 kg that increased to 88.5 ± 20.3 kg at 52 weeks (p < 0.05).

Conclusions: Subsequent to weight loss from a VLED, meal replacements and Orlistat treatments were both effective in maintaining weight significantly below baseline levels over a 52 week period of time. Meal replacements may be a viable alternative strategy to medications for weight maintenance.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号