代谢综合征患者血清磷脂脂肪酸构成及其与胰岛素抵抗的关系研究

目的 研究代谢综合征患者血清磷脂脂肪酸构成及其与胰岛素抵抗的关系.方法 采集87例代谢综合征患者和102名健康者血样,采用色谱/质谱联合分析其血清磷脂脂肪酸构成,用胰岛素抵抗指数( homeostasis model assessment-insulin resistance,HOMA-IR)评价调查对象胰岛素抵抗.结果 代谢综合征组饱和脂肪酸(saturated fatty acid,SFA)、n-6/n-3多不饱和脂肪酸(n-6/n-3 polyunsaturated fatty acid,n-6/n-3 PUFA)比值较健康对照组升高(均有P＜0.001),PUFA/SFA比值较健康对照组降低(P＜0.001).相关性分析显示HOMA-IR与n-6/n-3 PUFA呈正相关,与n-3 PUFA呈负相关.结论 代谢综合征患者存在血清磷脂脂肪酸构成改变现象,SFA增高而PUFA降低,而且n-3 PUFA与胰岛素抵抗呈负相关.提示代谢综合征患者应减少SFA摄入,注意补充n-3 PUFA.     

An Investigation into the Association between DNA Damage and Dietary Fatty Acid in Men with Prostate Cancer

Prostate cancer is a growing problem in New Zealand and worldwide, as populations adopt a Western style dietary pattern. In particular, dietary fat is believed to be associated with oxidative stress, which in turn may be associated with cancer risk and development. In addition, DNA damage is associated with the risk of various cancers, and is regarded as an ideal biomarker for the assessment of the influence of foods on cancer. In the study presented here, 20 men with prostate cancer adhered to a modified Mediterranean style diet for three months. Dietary records, blood fatty acid levels, prostate specific antigen, C-reactive protein and DNA damage were assessed pre- and post-intervention. DNA damage was inversely correlated with dietary adherence (p = 0.013) and whole blood monounsaturated fatty acids (p = 0.009) and oleic acid (p = 0.020). DNA damage was positively correlated with the intake of dairy products (p = 0.043), red meat (p = 0.007) and whole blood omega-6 polyunsaturated fatty acids (p = 0.015). Both the source and type of dietary fat changed significantly over the course of the dietary intervention. Levels of DNA damage were correlated with various dietary fat sources and types of dietary fat.     

N-3 fatty acids reduced trans fatty acids retention and increased docosahexaenoic acid levels in the brain

Introduction: The levels of docosahexaenoic acid (DHA, 22:6n-3) and arachidonic acid (AA, 20:4n-6) are critical for the normal structure and function of the brain. Trans fatty acids (TFA) and the source of the dietary fatty acids (FA) interfere with long-chain polyunsaturated fatty acids (LC-PUFA) biosynthesis.

Objectives: The aim of this study was to investigate the effect of TFA supplementation in diets containing different proportions of n-9, n-6, and n-3 FA on the brain FA profile, including the retention of TFA, LC-PUFA levels, and n-6/n-3 PUFA ratios. These parameters were also investigated in the liver, considering that LC-PUFA are mainly bioconverted from their dietary precursors in this tissue and transported by serum to the brain. Also, stearoyl-CoA desaturase-1 (SCD1) and sterol regulatory element-binding protein-1c (SREBP-1c) gene expressions were evaluated.

Methods: Male CF1 mice were fed (16 weeks) diets containing different oils (olive, corn, and rapeseed) with distinct proportions of n-9, n-6, and n-3 FA (55.2/17.2/0.7, 32.0/51.3/0.9, and 61.1/18.4/8.6), respectively, substituted or not with 0.75% of TFA. FA composition of the brain, liver, and serum was assessed by gas chromatography.

Results: TFA were incorporated into, and therefore retained in the brain, liver, and serum. However, the magnitude of retention was dependent on the tissue and type of isomer. In the brain, total TFA retention was lower than 1% in all diets.

Discussion: Dietary n-3 PUFA decreased TFA retention and increased DHA accretion in the brain. The results underscore the importance of the type of dietary FA on the retention of TFA in the brain and also on the changes of the FA profile.     

Development of insulin resistance and its relation to diet in the obese child

The incidence rate of obesity in youth has continued to increase worldwide and about 30% of obese children display insulin resistance (IR) and other metabolic abnormalities. The present study reviews the mechanisms for development of IR in the obese child and possible links between IR and dietary factors in childhood and adolescence. Although increased concentrations of plasma free fatty acids (FFA) and their counter part at intracellular level, long-chain acyl-coenzyme A (LC acyl-CoA), have been related to the early onset of IR in childhood obesity, a new endocrine paradigm states that adipose tissue secretes a wide variety of hormones and cytokines that regulate lipid energy metabolism. These hormonal changes precede any changes in metabolites such as FFA and glucose and appear to be associated with early IR in childhood. Excessive caloric intake increases IR in children; opposite, substantial reduction of overweight achieved by a hypocaloric diet decreases it. Elevated consumption of animal protein, particularly in early life, as well as diets rich in saturated, trans, and n-6 polyunsaturated fatty acids, and diets with a high carbohydrate to fat ratio, besides a high glycaemic and low-fiber diet also appear to exacerbate adiposity and IR.     

Dietary intake of medium- and long-chain triacylglycerols ameliorates insulin resistance in rats fed a high-fat diet

Objective

Excessive accumulation of visceral fat is strongly associated with insulin resistance. The present investigation examined the effects of dietary intake of medium- and long-chain triacylglycerols (MLCTs), which have been shown to induce significantly lower visceral fat accumulation in rats and humans, on high-fat diet-induced obesity and insulin resistance in rats. These effects were then compared with those observed in long-chain triacylglycerol (LCT)-fed rats.

Methods

After an 8-wk feeding of a high-fat diet, which induced severe whole-body insulin resistance, male Sprague-Dawley rats were fed a standard diet containing LCTs or MLCTs for 6 wk. After the dietary treatment, an oral glucose tolerance test was performed.

Results

Although body weight and total intra-abdominal fat mass did not differ between the two groups, mesenteric fat weight in the MLCT-fed group was significantly lower than that in the LCT group (P < 0.05). The increase in plasma insulin concentrations, but not in glucose, after glucose administration (area under the curve) was significantly smaller in the MLCT group than in the LCT group (P < 0.01) and was significantly associated with mesenteric fat weight (P < 0.05). MLCT-fed rats had significantly higher plasma adiponectin concentrations compared with LCT rats (P < 0.05). Adiponectin concentrations were negatively correlated with the area under the curve for plasma insulin (P < 0.05) and tended to be inversely related to mesenteric fat weight (P = 0.08).

Conclusion

These results suggest that dietary intake of MLCTs may improve insulin resistance in rats fed a high-fat diet, at least in part through increased adiponectin concentrations caused by a lower mesenteric fat mass.     

Essential fatty acid-rich diets protect against striatal oxidative damage induced by quinolinic acid in rats

Essential fatty acids have an important effect on oxidative stress-related diseases. The Huntington's disease (HD) is a hereditary neurologic disorder in which oxidative stress caused by free radicals is an important damage mechanism. The HD experimental model induced by quinolinic acid (QUIN) has been widely used to evaluate therapeutic effects of antioxidant compounds. The aim of this study was to test whether the fatty acid content in olive- or fish-oil-rich diet prevents against QUIN-related oxidative damage in rats. Rats were fed during 20 days with an olive- or a fish-oil-rich diet (15% w/w). Posterior to diet period, rats were striatally microinjected with QUIN (240?nmol/µl) or saline solution. Then, we evaluated the neurological damage, oxidative status, and gamma isoform of the peroxisome proliferator-activated receptor (PPARγ) expression. Results showed that fatty acid-rich diet, mainly by fish oil, reduced circling behavior, prevented the fall in GABA levels, increased PPARγ expression, and prevented oxidative damage in striatal tissue. In addition none of the enriched diets exerted changes neither on triglycerides or cholesterol blood levels, nor or hepatic function. This study suggests that olive- and fish-oil-rich diets exert neuroprotective effects.     

Association between Mediterranean diet adherence and dyslipidaemia in a cohort of adults living in the Mediterranean area

The aim of the present study was to determine the association between Mediterranean diet adherence and dyslipidaemia in a cohort of adults living in the Mediterranean area. The cross-sectional study comprised a total sample of 2044 men and women, aged >18?years old from southern Italy. The Mediterranean diet adherence was assessed using a validated score (MEDI-LITE score). Clinical data were investigated and anthropometric examinations were collected using standardised methods. Among included individuals, 18.4% had dyslipidaemia. The percentage of females with dyslipidaemia was higher than males (21.2% vs. 14.6%). Higher adherence to Mediterranean diet was inversely associated with dyslipidaemia (OR: 0.56, 95% Cl: 0.36, 0.86). Similar association was observed in men, but not in women. On the contrary, a positive association was found between dyslipidaemia and current smoking and higher occupational status. Our results support the potential effectiveness of this diet in the prevention of dyslipidaemia and justify future intervention studies.     

Effects of Mediterranean Diet or Low-Fat Diet on Blood Fatty Acids in Patients with Coronary Heart Disease. A Randomized Intervention Study

The Mediterranean diet (MD) prevents cardiovascular disease by different putative mechanisms, including modifications in the blood fatty acid (FA) profile. Polytherapy for secondary cardiovascular prevention might mask the effect of MD on the FA profile. This study was aimed to assess whether MD, in comparison with a low-fat diet (LFD), favorably modifies the blood FA profile in patients with coronary heart disease (CHD) on polytherapy. One hundred and twenty patients with a recent history of coronary stenting, randomized to MD or to LFD, completed 3 months of this open-label dietary intervention study. Diet Mediterranean-ness was evaluated using the Mediterranean Diet Adherence Screener (MeDAS) score. Both diets significantly reduced saturated FA (p < 0.01). Putative favorable changes in total n-3 FA (p = 0.03) and eicosapentaenoic acid plus docosahexaenoic acid (EPA + DHA; p = 0.04) were significantly larger with MD than with LFD. At 3 months, in the whole cohort, the MeDAS score correlated inversely with palmitic acid (R = −0.21, p = 0.02), and with palmitoleic acid (R = −0.32, p = 0.007), and positively with total n-3 FA (R = 0.19, p = 0.03), EPA (R = 0.28, p = 0.002), and EPA + DHA (R = 0.21, p = 0.02). In CHD patients on polytherapy, both MD and LFD shift FA blood composition towards a healthier profile, with a more favorable effect of MD on omega−3 levels.     

Association between Physical Activity and Non-Alcoholic Fatty Liver Disease in Adults with Metabolic Syndrome: The FLIPAN Study

Background: A lifestyle with regular PA (physical activity) and Mediterranean diet has benefits on NAFLD (non-alcoholic fatty liver disease) and MetS (metabolic syndrome). Objectives: To assess the association between physical activity and NAFLD in adults with MetS. Design: Cross-sectional study in 155 participants (40–60 years old) from Balearic Islands and Navarra (Spain) with diagnosis of NAFLD and MetS, and BMI (body mass index) between 27 and 40 Kg/m². Methods: PA level was categorized into two groups according to weekly METs (metabolic equivalents of tasks). PA was assessed using a validated Minnesota questionnaire and accelerometers. MetS parameters were assessed by blood collection analysis and NAFLD by abdominal MRI (magnetic resonance imaging). Results: Participants with high PA showed more energy expenditure and expended more calories than ingested (−143.9 Kcal/day; p < 0.001). PA was a risk factor for AST (aspartate aminotransferase) (adjusted OR: 7.26; 95% CI: 1.79–29.40) and a protective factor for ALT (alanine aminotransferase) (adjusted OR: 0.24; 95% CI: 0.12–0.48), GGT (gamma-glutamyl transferase) (adjusted OR: 0.52; 95% CI: 0.29–0.94) and IFC-NMR (intrahepatic fat content by nuclear magnetic resonance) (adjusted OR: 0.26; 95% CI: 0.12–0.56) when sociodemographic confounders were considered. Conclusions: NAFLD patients with high PA showed more positive relationship on MetS parameters and liver profile (ALT, GGT, IFC-NMR) than subjects with low PA, but not for AST. Difference between calories ingested and expended influenced this relationship.     

肥胖儿童血清维生素D、甲状旁腺素及胰岛素抵抗水平分析

目的:分析肥胖儿童血清VD、PTH及胰岛素抵抗水平,探讨肥胖与上述指标的关系。方法:在健康体检时,利用体重指数(BMI),以中国肥胖工作组制定的标准进行筛查,将研究对象分为肥胖组与对照组,采集空腹静脉血分别测定25(OH)D、1,25(OH)2D、PTH、血钙、磷和碱性磷酸酶(AP),测定FINS和FPG计算HOMA-IR,测定身高、体重计算BMI。结果:肥胖组VD缺乏率明显高于对照组。与对照组相比,肥胖儿童的BMI、PTH和HOMA-IR明显升高,VD水平明显降低(P0.05)。BMI与血清VD呈明显负相关,与PTH和HOMA-IR呈明显正相关。PTH与25(OH)D呈明显负相关,与HOMA-IR呈明显正相关;25(OH)D与HOMA-IR呈明显负相关。结论:肥胖儿童血清VD水平降低,PTH增高,胰岛素抵抗增强。肥胖与VD、PTH和HOMA-IR相关,PTH、25(OH)D与HOMA-IR分别相关。     

Inverse association between coffee drinking and serum uric acid concentrations in middle-aged Japanese males

Consumption of caffeine-rich beverages, which have diuretic properties, may decrease serum uric acid concentrations. We examined cross-sectionally the relationship of coffee and green tea consumption to serum uric acid concentrations in 2240 male self-defence officials who received a pre-retirement health examination at four hospitals of the Self-Defence Forces between 1993 and 1994. The mean levels of coffee and green tea consumption were 2.3 and 3.1 cups/d respectively. There was a clear inverse relationship between coffee consumption and serum uric acid concentration. When adjusted for hospital only, those consuming less than one cup of coffee daily had a mean serum uric acid concentration of 60 mg/l, while that of those drinking five or more cups of coffee daily was 56 mg/l (P < 0.0001). No such relationship was observed for green tea, another major dietary source of caffeine in Japan. The relationship between coffee consumption and serum uric acid concentration was independent of age, rank in the Self-Defence Forces, BMI, systolic blood pressure, serum creatinine, serum total cholesterol and serum HDL-cholesterol concentrations, smoking status, alcohol use, beer consumption and intake of dairy products. These findings suggest that coffee drinking may be associated with lower concentrations of serum uric acid, and further studies are needed to confirm the association.     

Association between Mediterranean Diet and Fatty Liver in Women with Overweight and Obesity

Obesity is a risk factor for NAFLD. However, not all people with obesity have an excessive intrahepatic fat content. Adherence to a high-quality dietary pattern may also promote liver health in obesity. A cross-sectional study of 2967 women with overweight and obesity was carried out to assess the association between a Mediterranean diet and fatty liver. All women underwent clinical examination, anthropometric measurements, blood sampling, ultrasound measurements of abdominal visceral and subcutaneous fat, and assessment of adherence to the Mediterranean diet using the 14-item MEDAS questionnaire. Fatty liver index (FLI), NAFLD fatty liver steatosis (NAFLD-FLS) and hepatic steatosis index (HSI) were calculated. In women with obesity, the MEDAS score was inversely associated with FLI (β = −0.60, 95% CI: −1.04, −0.16, p = 0.008), NAFLD-FLS (β = −0.092, 95% CI: −0.134, −0.049, p < 0.001) and HSI (β = −0.17, 95% CI: −0.30, −0.04, p = 0.011). Stronger associations were observed in premenopausal women with obesity. Mediterranean diet was inversely associated with NAFLD-FLS in women with overweight, independently of menopausal status. In conclusion, Mediterranean diet is associated with a better liver status in women with overweight and obesity. This may have a public health impact and be useful in drafting nutritional guidelines for NAFLD.     

哈萨克族代谢综合征与游离脂肪酸及胰岛素抵抗关系

目的 探讨游离脂肪酸(FFA)、胰岛素抵抗(IR)与新疆哈萨克族代谢综合征(MS)关系。方法 在哈萨克族人群现况调查中,随机抽取MS患者195例和健康者120人进行病例对照研究;检测糖代谢相关指标,采用比色法测定FFA浓度,采用放射免疫法测定空腹胰岛素(FINS)浓度,计算胰岛素抵抗指数(HOMA_IR)。结果 MS病例组男性FFA为(0.57±0.22)mmol/L,女性为(0.65±0.24)mmol/L,对照组男性为(0.46±0.22)mmol/L,女性为(0.52±0.17)mmol/L;MS病例组男性HOMA_IR为(5.17±4.89),女性为(3.75±3.37),对照组男性为(1.62±1.29),女性为(2.20±1.53);2组男、女性FFA、HOMA-IR差异均有统计学意义(均P<0.01);随着FFA浓度与HOMA_IR的增加,MS患者比例增加;多因素logistic回归分析显示,FFA浓度为0.55 mmol/L～、0.69 mmol/L～,对MS的影响分别OR=4.374(95%CI=1.271～15.046)和OR=4.208(95%CI=1.068～16.586);HOMA_IR为3.96～时,对MS的影响OR=8.552(95%CI=2.064～35.428);FFA、HOMA_IR与MS各组分的相关均有统计学意义(P<0.05);调整年龄、性别、HOMA_IR等影响后,FFA只与腰围、舒张压相关(P<0.05)。结论 胰岛素抵抗可能是新疆哈萨克族人群中MS重要的独立危险因素,而FFA可能不是一个独立危险因子,它可能通过其他机制影响机体产生胰岛素抵抗,从而导致MS及其各组分的发生和发展。     

Effect of substituting saturated with monounsaturated fatty acids on serum visfatin levels and insulin resistance in overweight women: A randomized cross-over clinical trial

Objective: This study aimed to determine the effects of a monounsaturated fatty acids (MUFA)-rich diet on serum visfatin, interleukin-6 and insulin levels among overweight women. Design: In this randomized cross-over clinical trial, 17 premenopausal overweight women were included. Participants were randomly assigned to consume either a hypocaloric, saturated fatty acids (SFA)-rich diet (16% SFA and 8% MUFA) or a hypocaloric, MUFA-rich diet (16% MUFA and 8% SFA) for 12 weeks crossing over after a 2-week washout period. Percentages of energy from other macronutrients were similar between the two diets. Biochemical and anthropometric assessments were done at the first and at the end of each period. Statistical analyses were done using paired t-test. In all statistical analysis, p < 0.05 was considered as significant. Results: The participant's mean body mass index was 27.6 kg/m². Mean percentages of MUFA intake were 13% during MUFA-rich diet and 7% during SFA-rich diet. The corresponding values for SFA intake were 8.5% and 14%, respectively. We failed to find any significant differences between two intervention diets in terms of their effect on the serum levels of IL-6, visfatin and insulin. However, serum visfatin and IL-6 levels increased during the SFA-rich diet (0.4 ± 0.4 ng/ml and 0.19 ± 0.3 pg/ml, respectively) and decreased during the MUFA-rich diet ( ? 0.7 ± 0.5 ng/ml and ? 0.17 ± 0.3 pg/ml, respectively). In spite of a slight reduction in both periods, changes in serum insulin levels did not reach significant levels comparing the two periods. Conclusions: Our findings did not support any significant effect of a MUFA-rich intake on serum IL-6 and insulin levels as compared with a SFA-rich diet; however, it has the potential to favourably affect serum visfatin levels.     

Perturbation of phospholipid and triacylglycerol fatty acid positional location in the heart of rats depleted of n-3 long-chain polyunsaturates

Rats depleted of long-chain polyunsaturated n-3 fatty acids (n-3–D) display several features of the metabolic syndrome, including obesity, liver steatosis, insulin resistance, hypertension, and cardiac hypertrophy. In this study, the heart phospholipid (PL) and triacylglycerol (TG) fatty acid content and pattern were compared between female control rats (C) and n-3–D rats. The sole n-3 fatty acids found in n-3–D rats, C22:5(n-3) and C22:6(n-3), were 10 to 20 times lower than in C. The total fatty acid content of PL was lower in n-3–D rats than C. No ectopic TG accumulation was found in n-3–D rats. In both PL and TG, the C16:0/C16:1(n-7) and C18:0/C18:1(n-9) ratios suggested increased Δ9-desaturase activity in n-3–D rats. The PL C18:2(n-6)/C20:4(n-6) and C20:4(n-6)/C22:4(n-6) ratios were also lower in n-3–D rats than C. Prior intravenous injection of a medium-chain TG:fish oil emulsion to n-3–D rats 60 to 120 minutes before killing augmented the PL content in C22:5(n-3) and C22:6(n-3), minimized the age-related decrease in the PL C18:1(n-9) relative content, and increased the TG C22:4(n-6) content. The alteration of cardiac function in n-3–D rats and its improvement after injection of medium-chain TG:fish oil emulsion coincides with parallel changes in heart lipid fatty acid content and pattern.     

脂肪肝患者A-FABP与胰岛素抵抗关系

目的探讨非酒精性脂肪肝病(NAFLD)患者血清脂肪细胞型脂肪酸结合蛋白(A-FABP)与胰岛素抵抗(IR)的关系。方法选择NAFLD患者119例,正常对照120人,测量身高、体重、腰围、臀围、体质指数及腰臀比,检测血清中总胆固醇、甘油三酯、高密度脂蛋白胆固醇、空腹血糖、空腹胰岛素抵抗指数及脂肪细胞型脂肪酸结合蛋白,并进行对比分析。结果NAFLD组血清A-FABP水平(13.45±5.06),明显高于对照组(9.14±5.00)μg/L(P0.01);且血清A-FABP水平与体质指数(BMI)、腰围(WC)、腰臀比(WHR)、收缩压(SBP)、舒张压(DBP)、甘油三酯(TG)、空腹胰岛素(FINS)、空腹血糖(FPG)及胰岛素抵抗指数(HOMA-IR)呈正相关(r依次分别为0.560,0.538,0.384,0.426,0.341,0.302,0.345,0.256,0.359,P均0.01),而与HDL-C呈负相关(r=-0.337,P0.001)。结论NAFLD患者存在胰岛素抵抗,且血清A-FABP水平与胰岛素抵抗密切相关。