Insulin action, regional fat, and myocyte lipid: altered relationships with increased adiposity

OBJECTIVE: Abdominal fat and myocyte triglyceride levels relate negatively to insulin sensitivity, but their interrelationships are inadequately characterized in the overweight. Using recent methods for measuring intramyocyte triglyceride, these relationships were studied in men with a broad range of adiposity. RESEARCH METHODS AND PROCEDURES: Myocyte triglyceride content ((1)H-magnetic resonance spectroscopy of soleus and tibialis anterior muscles and biochemical assessment of vastus lateralis biopsies), regional fat distribution (DXA and abdominal magnetic resonance imaging), serum lipids, insulin action (euglycemic hyperinsulinemic clamp), and substrate oxidation rates (indirect calorimetry) were measured in 39 nondiabetic men (35.1 +/- 7.8 years) with a broad range of adiposity (BMI 28.6 +/- 4.1 kg/m(2), range 20.1 to 37.6 kg/m(2)). RESULTS: Relationships between insulin-stimulated glucose disposal and regional body fat depots appeared more appropriately described by nonlinear than linear models. When the group was subdivided using median total body fat as the cut-point, insulin-stimulated glucose disposal correlated negatively to all regional body fat measures (all p < or = 0.004), serum triglycerides and free fatty acids (p < 0.02), and both soleus intramyocellular lipid (p = 0.003) and vastus lateralis triglyceride (p = 0.04) in the normal/less overweight group. In contrast, only visceral abdominal fat showed significant negative correlation with insulin-stimulated glucose disposal in more overweight men (r = -0.576, p = 0.01), some of whom surprisingly had lower than expected myocyte lipid levels. These findings persisted when the group was subdivided using different cut-points or measures of adiposity. DISCUSSION: Interrelationships among body fat depots, myocyte triglyceride, serum lipids, and insulin action are generally absent with increased adiposity. However, visceral abdominal fat, which corresponds less closely to total adiposity, remains an important predictor of insulin resistance in men with both normal and increased adiposity.     

Pistachio nut consumption and serum lipid levels

OBJECTIVE: Clinical and epidemiological studies have reported the beneficial effects of tree nuts and peanuts on serum lipid levels. We studied the effects of consuming 15% of the daily caloric intake in the form of pistachio nuts on the lipid profiles of free-living human subjects with primary, moderate hypercholesterolemia (serum cholesterol greater than 210 mg/dL). METHODS: design: Randomized crossover trial. setting: Outpatient dietary counseling and blood analysis. subjects: 15 subjects with moderate hypercholesterolemia. intervention: Fours weeks of dietary modification with 15% caloric intake from pistachio nuts. Measures of Outcome: Endpoints were serum lipid levels of total cholesterol, HDL-C, LDL-C, VLDL-C, triglycerides and apolipoproteins A-1 and B-100. BMI, blood pressure, and nutrient intake (total energy, fat, protein, and fiber) were also measured at baseline, during, and after dietary intervention. RESULTS: No statistically significant differences were observed for total energy or percent of energy from protein, carbohydrate or fat. On the pistachio nut diet, a statistically significant decrease was seen for percent energy from saturated fat (mean difference, -2.7%; 95% CI, -5.4% to -0.08%; p = 0.04). On the pistachio nut diet, statistically significant increases were seen for percent energy from polyunsaturated fat (mean difference, 6.5%; 95% CI, 4.2% to 8.9%; p<.0001) and fiber intake (mean difference, 15 g; 95% CI, 8.4 g to 22 g; p = 0.0003). On the pistachio diet, statistically significant reductions were seen in TC/HDL-C (mean difference, -0.38; 95% CI, -0.57 to -0.19; p = 0.001), LDL-C/HDL-C (mean difference, -0.40; 95% CI, -0.66 to -0.15; p = 0.004), B-100/A-1 (mean difference, -0.11; 95% CI, -0.19 to -0.03; p = 0.009) and a statistically significant increase was seen in HDL-C (mean difference, 2.3; 95% CI, 0.48 to 4.0; p = 0.02). No statistically significant differences were seen for total cholesterol, triglycerides, LDL-C, VLDL-C, apolipoprotein A-1 or apolipoprotein B-100. No changes were observed in BMI or blood pressure. CONCLUSION: A diet consisting of 15% of calories as pistachio nuts (about 2-3 ounces per day) over a four week period can favorably improve some lipid profiles in subjects with moderate hypercholesterolemia and may reduce risk of coronary disease.     

Dietary fat intake and plasma lipid levels in adolescents.

The relationship between dietary fat intake and fasting plasma lipid levels was assessed in 35 female and 19 male adolescents recruited from two local education authority schools in Norwich, UK. Dietary intakes were assessed using a 7-day weighed dietary record method, coupled with the collection of duplicate diets. Fat and energy intakes calculated using food composition tables were compared with values obtained by direct analysis of duplicate diets. Fasting plasma lipid levels (total, HDL and LDL cholesterol and triglycerides) were measured and compared with total dietary lipids and fatty acid intakes. The average proportion of energy consumed as fat was higher than is currently considered desirable but lower than previous studies have reported for adults. Mean serum total cholesterol values were 4.2 (SEM 0.1) mmol for females and 4.5 (SEM 0.2) mmol for males; this difference was not statistically significant. In male subjects the dietary fatty acid profiles were significantly correlated with several parameters of plasma lipid status which are thought to be risk factors for coronary heart disease, and in particular with the ratio of total:HDL cholesterol.     

Association of lifestyle with serum lipid levels: a study of middle-aged Japanese men

Cross-sectional associations between lifestyle and serum lipid levels were examined in 1591 Japanese male office workers aged 35 to 59 years in Osaka, Japan. From multiple linear regression analyses, significant correlates with low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and Log triglyceride levels and the ratio of LDL cholesterol to HDL cholesterol were, in the order of relative importance: BMI, alcohol intake (negative) and age for LDL cholesterol level; BMI (negative), cigarette smoking (negative), alcohol intake, consideration for nutritional balance, hours of brisk walking, hours of walking at an ordinary pace and physical exercise for HDL cholesterol level; BMI, cigarette smoking, consideration for nutritional balance (negative), hours of work (negative), alcohol intake and coffee drinking (negative) for Log triglyceride level; and BMI, alcohol intake (negative), cigarette smoking, consideration for nutritional balance (negative), age, hours of brisk walking (negative) and the frequency of snack intake between meals for the ratio of LDL cholesterol to HDL cholesterol. Our data suggest that obesity, cigarette smoking and snack intake between meals are atherogenic whereas alcohol consumption, consideration for nutritional balance and walking long hours, especially at a brisk pace, are anti-atherogenic in middle-aged Japanese men.     

Association between chronic periodontitis and serum lipid levels

Regarding the high prevalence of hyperlipidaemia, which is one of the major risk factors of cardiovascular disease, and uncertain reports about the relation between periodontal disease and serum lipid profile, this study was conducted to assess this relation. The historical cohort study was conducted on 52 cases including 26 persons with chronic periodontitis as case group, and 26 healthy subjects as control group. Both groups had the same age and weight ranges, sex, and diet, without any periodontal treatment history in the past six months, underling systemic disease such as diabetes, anti-hyperlipidemic drugs or active tobacco smoking history. Low Density Lipoprotein (LDL), High Density Lipoprotein (HDL), Triglyceride (TG) and Total Cholesterol (CHOL) were measured by direct enzymatic assay. TG level was 128.4 +/- 71.1 mg/dl in control group and 165.2 +/- 83.7 in case group indicating a significantly higher level in case group (P<0.05). In control group, 30.8 percent and in case group, 61.5 percent had abnormal serum cholesterol levels, which presents a significantly higher level in case group (P<0.03). Other serum level indices did not show any significant difference. Although it seems that patients with chronic periodontal disease are more susceptible to hyperlipidemia, it is doubtful that the former causes an increase in serum lipid levels, so we suggest studying the effects of treating chronic periodontitis on serum lipid level.     

体脂分布特征与血脂关系及其预测血脂异常的观察

目的 研究体脂分布特征与血脂关系及其预测血脂异常的价值.方法 采用整群抽样方法抽取北京市郊区居民有效样本784名,测量其身高、体重、腰围(WC)、臀围、身体成分与高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)、总胆固醇(TC)、三酰甘油(TG),并计算体重指数(BMI)与腰臀比(WHR).结果 年龄调整偏相关分析显示WC与HDL-C(r=-0.310)、LDL-C(r =0.204),WHR与TC (r=0.151)、TG (r=0.271)的相关性最好.BMI、WC、WHR、躯干脂肪质量(TFM)分组分析显示WC、WHR、TFM能敏感地反应人体血脂水平的变化;BMI、WC、WHR、TFM能敏感地反应低HDL、高TG及血脂异常的风险.ROC曲线分析显示WC、WHR、BMI、TFM预测血脂异常风险的ROC曲线皆在参考线上方,且男女受试者WHR (0.684、0.630)、WC (0.667、0.616)、TFM(0.661、0.604)的ROC曲线下面积有大于BMI (0.629、0.597)的趋势,但差异均无统计学意义(P＞0.05).结论 体脂分布特征指标如WHR、WC、TFM与BMI相比,在预测血脂异常风险中的应用价值更高;以Youden指数最大值为判定依据预测血脂异常风险,男性理想界值点BMI为24 kg/m2,WHR为0.91,WC为85 cm,TFM为7.5 kg;女性BMI为25 kg/m2,WHR为0.91,WC为87 cm,TFM为9.Skg.由于样本量较少,有待进一步扩大范围的研究.     

Effects of soybean beta-conglycinin on body fat ratio and serum lipid levels in healthy volunteers of female university students

The changes in body fat ratio and serum lipids induced by the ingestion of beta-conglycinin were examined in 41 healthy female university student volunteers. The trend of change in body fat ratio following the ingestion of beta-conglycinin differed between students with a baseline body fat ratio over 25% and those less than 25%. In the former group, the ingestion of beta-conglycinin suppressed the increase in body fat ratio. Moreover the six subjects who had a high total cholesterol level (5.72 mmol/L or higher) tended to have reduced levels of serum triglyceride, free fatty acid, total cholesterol and lipoprotein (a) after the ingestion of beta-conglycinin, although those levels did not change significantly. The number of subjects was only six, therefore it was inferred that significant changes were not observed. Thus, ingestion of soybean beta-conglycinin suppressed the increase in body fat ratio in individuals with a high baseline body fat ratio and reduced relatively high serum levels of lipids. Those results suggest that if soybean beta-conglycinin is ingested continuously (5 g daily), it will be effective in keeping body fat ratio and serum lipid levels normal and eliminating excessive lipids from the body.     

Sources of variability of human plasma apolipoprotein A-IV levels and relationships with lipid metabolism

Plasma apolipoprotein (apo) A-IV concentration was determined by immunoelectrophoretic assay (EIA) in 119 nuclear families. No significant effect of concomitants such as age, weight, height, body mass index, tobacco, and alcohol consumption was observed on apo A-IV levels in men and in boys. In women, contraceptive use and hormonal status affected apo A-IV levels. In girls, only age influenced the quantitative phenotype. After adjusting by specific concomitants significant correlations were observed between apo A-IV levels and triglycerides, apolipoprotein A-I and apo B levels, suggesting a role of apolipoprotein A-IV in the hepatic lipid metabolism. Intrafamilial correlations were estimated to investigate the plausibility of a common family factor. The results obtained in this study showed a significant correlation between family members with the exception of mother-daughter pairs. Using a variance components model, the contribution of genetic and environmental factors was then investigated. Different statistical models were used and two major hypotheses were statistically acceptable: the first hypothesis supports that shared and specific environmental factors explain 35 and 65%, respectively, of the total adjusted plasma apo A-IV variation. The fraction of apo A-IV variability attributable to genetic factors was null. The second hypothesis supports that the fraction of variability attributable to apo A-IV genetic variation is 67% and the common spouse environmental factors are responsible for 33% of the total variability and no specific environmental effect was found. Among the two hypotheses, taking account of the metabolism function, we support the first one without excluding gene- environment interactions which could mask the genetic influence. © 1994 Wiley-Liss, Inc.     

Relationship between tocopherols and serum lipid levels in children with beta-thalassemia major

Serum tocopherol levels were found to be below normal (less than 0.5 mg/100 ml) in nine (50%) of 18 children with beta-thalassemia major receiving inadequate treatment with blood transfusions. The mean tocopherol levels were significantly lower in the children with beta-thalassemia (0.57 mg/100/ml +/- 0.20) than in the controls (1.08 mg/100 ml +/- 0.24). Serum total lipid levels were found to be low in children with beta-thalassemia. The difference between the mean total lipid level in the beta-thalassemic patients (365 mg/100 ml +/- 75) as compared to that of the controls (581 mg/100 ml +/- 94) was highly significant (P less than 0.01). The ratio of serum tocopherol to 1 g total lipids was lower in children with beta-thalassemia (1.41 mg/100 ml +/- 0.43) than in the controls (1.88 mg/100 ml +/- 0.46) and the difference was significant. Yet, only three out of the 18 children with beta-thalassemia showed a ratio of less than 0.8 mg/100 ml tocopherol per 1 g total lipid which may be considered indicative of tocopherol deficiency.     

减体质量饮食对血脂影响的研究进展

减体质量能降低糖尿病、心脏病、高血压和某些癌症等发生的可能性.减体质量方法有外科手术、饮食治疗和运动疗法等.减体质量饮食主要分为低脂肪饮食、低糖类饮食和高蛋白质饮食.不同减体质量饮食模式对脂代谢的影响各异.以下就减体质量饮食对血脂的影响进行综述.     

Community exposure to perfluorooctanoate: relationships between serum levels and certain health parameters

OBJECTIVE: The objective of this study was to determine whether certain biomarkers of toxicity and/or a past diagnosis of liver or thyroid disease were associated with serum perfluorooctanoate concentrations (PFOA) in a community with longstanding environmental exposure to PFOA. METHODS: Serum (PFOA), hematologic and biochemical biomarkers, and a questionnaire were administered to 371 residents selected by stratified random sampling and a lottery among volunteers. Median PFOA was 354 ng/mL (interquartile range, 181-571 ng/mL). RESULTS: No significant positive relationships between serum (PFOA) and liver or renal function tests, cholesterol, thyroid-stimulating hormone, or with red cell indices, white cell, or platelet counts. Mean serum (PFOA) was not increased in those with a history of liver or thyroid disease. CONCLUSIONS: No toxicity from PFOA was demonstrated using the measured end points; other end points need to be addressed.     

Effects of various combinations of omega 3 and omega 6 polyunsaturated fats with saturated fat on serum lipid levels and eicosanoid production in rats

The effects of varying the ratio of polyunsaturated/saturated fatty acids (P/S) and omega 3/omega 6 polyunsaturated fatty acids (PUFA) of dietary fats on lipid metabolism were studied in rats using safflower oil (SFO), linseed oil (LSO), palm oil (PLO), and a 1:1 combination of these oils. The hypocholesterolemic and hypotriglyceridemic effects depended on the P/S ratio of dietary fats, LSO (omega 3 PUFA) being more effective than SFO (omega 6 PUFA). A similar pattern of the response was observed on liver cholesterol and triglyceride. The liver cholesterol-lowering effect of LSO, but not SFO, remained even when they were combined with PLO. The activity of liver delta 6-desaturase tended to be higher while that of liver phospholipase A2 was significantly lower in the LSO group than in the SFO or PLO groups. The aortic PGI2 production and the production by platelets of thromboxane A2 were significantly low in rats fed LSO accompanying a distinct reduction of arachidonate in tissue phospholipids. The depressing effect of LSO disappeared when it was combined with SFO but not with PLO. There were no significant differences in enzyme activities and eicosanoid production between SFO and PLO in spite of a large difference in their P/S ratio. Thus, lipid parameters examined were complicatedly regulated by the ratios of omega 3/omega 6 as well as P/S, suggesting an existence of an appropriate ratio for these variables.     

Emplotting children's lives: developmental delay vs. disability

While it is increasingly possible to envision "perfect" babies, it is not always the case that reproduction actually proceeds according to individual will; for example, there has been no recent reduction in rates of childhood disability. Nevertheless, in most studies of new reproductive technologies, the birth of those children whom few would actively choose-"defective" or disabled infants-is presented only in hypothetical terms. This paper argues for expanding the domain of reproduction to include research on the parenting of children with disabilities. Based on a qualitative research project carried out at a hospital-based newborn follow-up program that serves as an evaluation site determining eligibility for early intervention services for infants and young children with disabilities, this paper focuses on a particular part of women's experience of acquiring new knowledge about personhood and disability, that is, on the period of time when a woman has recently had confirmed that reproduction has, in her case, gone awry. Disability in many cultures, including the United States, diminishes personhood. I suggest that American mothers' narratives, by utilizing the concept of developmental delay, can assert personhood, or rather, the potential for its future attainment; in doing so, they justify ongoing nurturance of a disabled child in spite of negative attitudes about disability. A particular case of one mother's emplotment of her child's life within a story of developmental delay, in competition with the physician's story of disability, is analyzed. The paper concludes with reflections on how stories of developmental delay told by mothers just encountering a diagnosis of disability may differ from the stories told by those who have experienced mothering a disabled child over time, and on the implications of these differences for the cultural construction of personhood in the United States.