Lower Triacylglycerol Concentrations Research Articles

Blood Lipid Components and SREBP-1 Gene Expression in Broiler Chickens Fed Different Dietary Lipid Sources

Background: Liver plays an important role in energy homeostasis. Intense liver diseases are accompanied with lower concentrations of n-3 and n-6 poly unsaturated fatty acids (PUFA). It has been found that n-3 PUFA play importantly protective roles in the liver. There was limited information about the effects of lipid sources on serum lipid components and liver sterol regulatory element binding-1 (SREBP-1) gene expression. Therefore, the aim of this study was to evaluate and compare the effects of fish oil, corn oil, olive oil and tallow, respectively, as dietary sources of n-3, n-6, n-9 and saturated fatty acid on serum lipid compound and liver SREBP-1 gene expression in broiler chicks.Materials, Methods & Results: In a completely randomized design, 240 one-day-old broiler chicks were allocated to five dietary treatments, four replicates and 12 chicks per each. Dietary treatments included of: control (diet without lipid supplementation) and diet supplemented with fish oil as a n-3 fatty acid source, corn oil as a n-6 fatty acid source, olive oil as a n-9 fatty acid source and tallow as a saturated fatty acid which were added to diets at 1.5, 3 and 4% in the starter, grower and finisher, respectively. At days 28 and 42 of age, liver tissue was dissected out and samples were placed in liquid nitrogen, also blood samples were collected. The SREBP-1 mRNA expression in liver tissue was quantitated using RT-PCR. Broilers fed diets containing fish oil, corn oil and olive oil as unsaturated fatty acid sources had lower concentrations of triacylglycerol than those fed other diets. Also, diets containing fish oil and tallow showed the lowest low density lipoprotein (LDL) levels at day 28 of age. Diets containing corn oil and olive oil showed higher levels of cholesterol and high density lipoprotein (HDL) than other diets but, these differences were not significant at days 28 and 42 of age (P ≥ 0.05). In both sampling periods, the chickens fed diets containing tallow expressed higher (P < 0.05) SREBP-1 gene as compared to those fed other dietary lipids. Broilers fed diet containing corn oil had higher (P < 0.05) SREBP-1 gene expression than those fed diet containing fish oil and olive oil.Discussion: Serum lipids were affected by dietary fat source. Lower concentration of serum triacylglycerols was found in broilers fed fish oil and corn oil diets as dietary n-3 and n-6 fatty acid sources. It was shown that dietary PUFA, especially n-6 and n-3 fatty acids could reduce hepatic fatty acid and triacylglycerol synthesis. Broilers fed corn oil diet showed elevated LDL levels respect with those fed fish oil or tallow at day 28 of age. The results showed that dietary polyunsaturated fatty acids and saturated fatty acids substantially affected on SREBP-1 gene expression at days 28 and 42 of age. The birds fed fish oil as n-3 PUFA source expressed lower SREBP-1 gene compared with other groups at day 28 of age. Longer chain length, high number of double bonds, and the presence of the first double bond gives these fatty acids distinct and unique properties that separate them and their metabolic products from the more common n-6 and n-9 fatty acids. The finding of this study indicated lipogenic effects of tallow and then corn oil. The results confirmed that each of dietary lipid sources had different effect on serum lipid components. It was also found that SREBP-1 gene expression is age-dependent and it increased as age of broilers increased.

Effects of a plant product consisting of green tea and curcuma extract on milk production and the expression of hepatic genes involved in endoplasmic stress response and inflammation in dairy cows

During the periparturient phase, cows are typically in an inflammation-like condition, and it has been proposed that inflammation associated with the induction of stress of the endoplasmic reticulum (ER) in the liver contributes to the development of fatty liver syndrome and ketosis. In the present study, the hypothesis that supplementation of dairy cows with a plant product consisting of green tea (95%) and curcuma extract (5%) rich in polyphenols attenuates inflammation and ER stress in the liver during early lactation was investigated. Twenty-seven cows were assigned to two groups, either a control group (n = 14) or a treatment group (n = 13). Both groups of cows received a total mixed ration, and the ration of the treatment group was supplemented with 0.175 g of the plant product per kg dry matter from week 3 prepartum to week 9 postpartum. Dry matter intake and energy balance during week 2 to week 9 postpartum were not different between the two groups. However, cows supplemented with the plant product had a greater amount of energy-corrected milk during week 2 to week 9 postpartum and lower concentrations of triacylglycerols and cholesterol in the liver in week 1 and week 3 postpartum than cows of the control group (p < 0.05). Cows supplemented with the plant product showed a trend towards a reduced mRNA concentration of haptoglobin (p < 0.10), while relative mRNA concentrations of eight genes of the unfolded protein response considered in the liver were not different between the two groups of cows. Relative hepatic mRNA concentration of fibroblast growth factor, a stress hormone induced by various stress conditions, was reduced at week 1 and week 3 postpartum in cows supplemented with the plant product (p < 0.05). Overall, the data of this study suggest that – although there were only minor effects on the occurrence of ER stress and inflammation – a supplementation of polyphenols might be useful to improve milk yield and prevent fatty liver syndrome in dairy cows.

Slower Rate of Fat Absorption at Dinner versus Lunch is Associated with Lower Concentrations of Triacylglycerols (TG) the Following Morning

High postprandial TG are a risk factor for cardiovascular disease (CVD) and little is known about the impact of successive meals on the circadian TG pattern. Here, we measured the rate of fat absorption during two sequential meals to determine how lipid processing after dinner contributes to fasting TG concentrations the next morning. Non-diabetic adults (n=6, BMI 20-49, fasting TG 50-198 mg/dL) were fed a low-fat breakfast, followed by a lunch and dinner of identical composition (35% fat, 46% carbohydrates and 18% protein). Stable isotopes were added to lunch (d31-tripalmitin) and dinner (13C4-tripalmitin) to measure the kinetics of dietary fat absorption in TRL-TG by GC/MS. Blood samples were taken intermittently throughout the day and through the next morning. For insulin and glucose, the AUCs were not significantly different between the two meals. However, the rate of fat absorption was 1.9-fold higher after lunch than dinner (0.27±0.03 vs 0.14±0.04 mmol/L/h, respectively; P=0.04). Interestingly, faster dinner absorption rates were strongly correlated with higher 5h incremental contributions of dinner fat to TRL-TG (r2=0.996; P=0.0001). These data suggest that faster absorption contributes to poor tolerance to dietary fat. Further, faster absorption correlated with subsequently higher fasting TG (r2=0.975; P=0.0002). In summary, isotopic labelling of successive meals allows for the identification of diurnal control of TG metabolism. These data provide a mechanism to explain why therapies that lower evening meal TG absorption rates, such as increased fiber content or reduced fat content of meals, may reduce CVD risk.

Decreased Concentrations of the Lipoprotein Lipase Inhibitor Angiopoietin-Like Protein 4 and Increased Serum Triacylglycerol Are Associated With Increased Neonatal Fat Mass in Pregnant Women With Gestational Diabetes Mellitus

Angiopoietin-like protein 4 (ANGPTL4) is an extracellular inhibitor of lipoprotein lipase (LPL) activity. No studies have been done in pregnancy in which hypertriglyceridemia and tissue-specific changes in LPL activity are present. The objective of the study was to determine the relationship between neonatal fat mass (FM) and concentrations of ANGPTL4 and triacylglycerols (TAG) in maternal and cord serum of pregnant women with gestational diabetes mellitus (GDM) compared with controls. Maternal blood samples (control, n = 90, and GDM, n= 80) and umbilical cord blood were drawn before and after vaginal delivery, respectively. Control and GDM subjects were grouped separately into 3 subgroups, according to neonatal FM: 0-25th percentiles, 25th-75th percentiles, and 75th-100th percentiles. Glucose, insulin, TAG, nonesterified fatty acids (NEFAs), and ANGPTL4 were determined in maternal and neonatal serum. Age and pregestational body mass index did not differ between GDM and control women in any subgroups. Maternal serum of GDM pregnant women who delivered the newborn with the highest FM showed the highest concentrations of TAG and NEFAs and lowest concentration of ANGPTL4, despite glucose and insulin concentrations being independent of changes in neonatal FM. However, cord serum of neonates of GDM patients with the highest FM showed higher concentrations of insulin and lower concentrations of TAG than those with lower neonatal FM but no significant differences in NEFAs or ANGPTL4 concentrations. In well-controlled GDM pregnancies, decreased maternal ANGPTL4 concentrations and a gradient of TAG toward the fetus are related with higher neonatal FM. However, in GDM fetuses with the highest FM, the potential effect of ANGPTL4 inhibiting adipose tissue LPL activity could be overcome by their hyperinsulinemia.

“Leaner and less fit” children have a better cardiometabolic profile than their “heavier and more fit” peers: The Healthy Growth Study

Background and aimsTo examine differences in cardiometabolic risk factors between children of different BMI and fitness levels. Methods and resultsFrom a representative sample of 1222 boys and 1188 girls, aged 9–13 years, anthropometric, body composition, physical activity, cardiorespiratory fitness, biochemical and blood pressure data was collected. The prevalence of overweight and obesity was 29.9% and 11.8% respectively. In both genders, plasma HDL cholesterol concentration was higher in the ‘leaner and less fit’ group (lowest quartile of BMI and lowest quartile of fitness) compared to the ‘heavier and more fit’ (highest quartile of BMI and highest quartile of fitness) and intermediate (all other children) groups (p < 0.05). Furthermore, the ‘leaner and less fit’ groups in both genders had lower triacylglycerol concentration, total-to-HDL cholesterol ratio, HOMA-IR, insulin and systolic blood pressure levels compared to the ‘heavier and more fit’ and/or intermediate groups. Similar trends were observed for hypertension in boys and insulin resistance for both genders. Finally, the effect size of being ‘leaner and less fit’ on serum levels of cardiometabolic risk indices was mainly small to medium (i.e. Cohen's d 0.2–0.5). ConclusionLeaner and less fit boys and girls had better cardiometabolic risk profiles than their heavier and more fit peers, probably suggesting a higher importance of leanness over fitness in children from a cardiometabolic health benefit perspective.

Historical temperature variability affects coral response to heat stress.

Coral bleaching is the breakdown of symbiosis between coral animal hosts and their dinoflagellate algae symbionts in response to environmental stress. On large spatial scales, heat stress is the most common factor causing bleaching, which is predicted to increase in frequency and severity as the climate warms. There is evidence that the temperature threshold at which bleaching occurs varies with local environmental conditions and background climate conditions. We investigated the influence of past temperature variability on coral susceptibility to bleaching, using the natural gradient in peak temperature variability in the Gilbert Islands, Republic of Kiribati. The spatial pattern in skeletal growth rates and partial mortality scars found in massive Porites sp. across the central and northern islands suggests that corals subject to larger year-to-year fluctuations in maximum ocean temperature were more resistant to a 2004 warm-water event. In addition, a subsequent 2009 warm event had a disproportionately larger impact on those corals from the island with lower historical heat stress, as indicated by lower concentrations of triacylglycerol, a lipid utilized for energy, as well as thinner tissue in those corals. This study indicates that coral reefs in locations with more frequent warm events may be more resilient to future warming, and protection measures may be more effective in these regions.

The Effect of Rat Strain, Diet Composition and Feeding Period on the Development of a Nutritional Model of Non-Alcoholic Fatty Liver Disease in Rats

Non-alcoholic fatty liver disease (NAFLD) is an important cause of liver-related morbidity and mortality. The aim of this work was to establish and characterize a nutritional model of NAFLD in rats. Wistar or Sprague-Dawley male rats were fed ad libitum a standard diet (ST-1, 10 % kcal fat), a medium-fat gelled diet (MFGD, 35 % kcal fat) and a high-fat gelled diet (HFGD, 71 % kcal fat) for 3 or 6 weeks. We examined the serum biochemistry, the hepatic malondialdehyde, reduced glutathione (GSH) and cytokine concentration, the respiration of liver mitochondria, the expression of uncoupling protein-2 (UCP-2) mRNA in the liver and histopathological samples. Feeding with MFGD and HFGD in Wistar rats or HFGD in Sprague-Dawley rats induced small-droplet or mixed steatosis without focal inflammation or necrosis. Compared to the standard diet, there were no significant differences in serum biochemical parameters, except lower concentrations of triacylglycerols in HFGD and MFGD groups. Liver GSH was decreased in rats fed HFGD for 3 weeks in comparison with ST-1. Higher hepatic malondialdehyde was found in both strains of rats fed HFGD for 6 weeks and in Sprague-Dawley groups using MFGD or HFGD for 3 weeks vs. the standard diet. Expression of UCP-2 mRNA was increased in Wistar rats fed MFGD and HFGD for 6 weeks and in Sprague-Dawley rats using HFGD for 6 weeks compared to ST-1. The present study showed that male Wistar and Sprague-Dawley rats fed by HFGD developed comparable simple steatosis without signs of progression to non-alcoholic steatohepatitis under our experimental conditions.

Improvements in Coronary Heart Disease Risk Indicators by Alternate‐Day Fasting Involve Adipose Tissue Modulations

The ability of alternate-day fasting (ADF) to modulate adipocyte parameters in a way that is protective against coronary heart disease (CHD) has yet to be tested. Accordingly, we examined the effects of ADF on adipokine profile, body composition, and CHD risk indicators in obese adults. Sixteen obese subjects (12 women/4 men) participated in a 10-week trial with three consecutive dietary intervention phases: (i) 2-week baseline control phase, (ii) 4-week ADF controlled feeding phase, and (iii) 4-week ADF self-selected feeding phase. After 8 weeks of treatment, body weight and waist circumference were reduced (P < 0.05) by 5.7 ± 0.9 kg, and 4.0 ± 0.9 cm, respectively. Fat mass decreased (P < 0.05) by 5.4 ± 0.8 kg, whereas fat-free mass did not change. Plasma adiponectin was augmented (P < 0.05) by 30% from baseline. Leptin and resistin concentrations were reduced (P < 0.05) by 21 and 23%, respectively, post treatment. Low-density lipoprotein cholesterol (LDL-C) and triacylglycerol concentrations were 25% and 32% lower (P < 0.05), respectively, after 8 weeks of ADF. High-density lipoprotein cholesterol (HDL-C), C-reactive protein, and homocysteine concentrations did not change. Decreases in LDL-C were related to increased adiponectin (r = -0.61, P = 0.01) and reduced waist circumference (r = 0.39, P = 0.04). Lower triacylglycerol concentrations were associated with augmented adiponectin (r = -0.39, P = 0.04) and reduced leptin concentrations (r = 0.45, P = 0.03) post-treatment. These findings suggest that adipose tissue parameters may play an important role in mediating the cardioprotective effects of ADF in obese humans.

Blood concentrations of individual long-chain n–3 fatty acids and risk of nonfatal myocardial infarction

BackgroundWhereas dietary intake of long-chain n−3 fatty acids has been associated with risk of nonfatal myocardial infarction (MI), few studies have examined the relation for blood concentrations. ObjectiveWe aimed to investigate the effect of long-chain n−3 fatty acids in blood on the risk of nonfatal MI. DesignBaseline blood samples were collected from 32 826 participants of the Nurses' Health Study in 1989–1990, among whom 146 incident cases of nonfatal MI were ascertained during 6 y of follow-up and matched with 288 controls. ResultsAfter multivariate adjustment, the relative risks (95% CI) comparing the highest with the lowest quartiles in plasma were 0.23 (0.09, 0.55; P for trend = 0.001) for eicosapentaenoic acid (EPA), 0.40 (0.20, 0.82; P for trend = 0.004) for docosapentaenoic acid (DPA), and 0.46 (0.18, 1.16; P for trend = 0.07) for docosahexaenoic acid (DHA). The associations for these fatty acids in erythrocytes were generally weaker and nonsignificant. In contrast to EPA and DHA, blood concentrations of DPA were not correlated with dietary consumption of n−3 fatty acids. Higher plasma concentrations of EPA, DPA, and DHA were associated with higher plasma concentrations of HDL cholesterol and lower concentrations of triacylglycerol and inflammatory markers. ConclusionsHigher plasma concentrations of EPA and DPA are associated with a lower risk of nonfatal MI among women. These findings may partly reflect dietary consumption but, particularly for DPA, may indicate important risk differences based on metabolism of long-chain n−3 fatty acids.

Modeling of the kinetic for the acidolysis of different triacylglycerols and caprylic acid catalyzed by Lipozyme IM immobilized in packed bed reactor

This work proposes a lumped kinetic model for the acidolysis of a triacylglycerol (TAG) and an odd free fatty acid (FFA) in a non-aqueous medium, catalyzed by a 1,3 specific lipase immobilized on a solid support. This model is based on the mechanism of the acidolysis reaction by considering the following hypothesis: (1) only the fatty acids in positions 1 and 3 of TAG are exchanged and these two positions in the glycerol backbone are equivalent and (2) the only intermediate of appreciable lifespan in which the enzyme participates is the acyl-enzyme complex. The kinetic equation obtained for the rate of incorporation of an odd fatty acid to TAG has been applied to the results obtained in the acidolysis of three oils (commercial triolein, cod liver oil (CLO) and a commercial oil enriched in eicosapentaenoic acid (EPA), EPAX 4510TG) with caprylic acid (CA), catalyzed by the immobilized lipase Lipozyme IM contained in a packed bed reactor (PBR). The acidolysis has been carried out by recirculating the reaction mixture through the PBR until the reaction equilibrium was reached. In these conditions it has been proved that the PBR behaves as a perfect mixed dispersion reactor and the experimental results obtained at low TAG concentrations ( < 100 mol / m 3 ) have been acceptably fitted to the kinetic expression obtained from the proposed model, with only two fitting parameters. However, for TAG concentrations higher than 100 mol / m 3 , an appreciable reduction of the reaction rate was observed. This result was due to the decrease of the effective diffusivity of reactants within the pores of the support where the lipase is immobilized, since the viscosity of the reaction mixture increases appreciably when the reactant concentration also does. When this phenomenon is included in the developed kinetic model, the experimental results obtained at high TAG concentrations could also be explained, even in absence of the organic solvent ( n -hexane). It is observed that the influence of diffusion into the pores increases with the degree of CA incorporation to TAG, which was due to the increase of TAG and native fatty acid concentrations in the particle pores, which determines a continuous decrease in the effective diffusivity of CA.

Effect of proteins from beef, pork, and turkey meat on plasma and liver lipids of rats compared with casein and soy protein

Objective We assessed the effect of dietary proteins isolated from beef, pork, and turkey meat on concentrations of cholesterol and triacylglycerols in plasma, lipoproteins, and liver and the composition of the microsomal membrane (fatty acids, phosphatidylcholine/phosphatidylethanolamine ratio) compared with that of casein and soy protein in rats. Methods Five groups of 12 rats each were fed semisynthetic diets for 20 d that contained 200 g/kg of proteins isolated from beef, pork, or turkey meat or, as controls, casein or soy protein. Results Rats fed beef, pork, or turkey proteins did not differ in cholesterol concentrations of plasma, lipoproteins, and liver and in composition of microsomal membrane from rats fed the casein diet. All groups fed a protein from an animal source had higher very low-density lipoprotein (VLDL) and liver cholesterol concentrations than did rats fed soy protein. However, rats fed pork protein had lower concentrations of triacylglycerols in liver, plasma, and VLDL and lower mRNA concentrations of sterol regulatory element binding protein-1 and glucose-6-phosphate dehydrogenase than did rats fed casein. However, concentrations of plasma and VLDL triacylglycerols in rats fed pork protein were not as low as those observed in rats fed soy protein. Conclusion Proteins isolated from beef, pork, or turkey meat do not differ from casein in their effects on cholesterol metabolism. Pork protein decreases plasma triacylglycerol concentrations compared with casein but not compared with soy protein. The triacylglycerol-lowering effect of pork protein compared with casein is suggested to be caused by decreased hepatic fatty acid synthesis.

Lifestyle modifies obesity-associated risk of cardiovascular disease in a genetically homogeneous population

The association between obesity and cardiovascular disease risk differs across populations. Whether such differences in obesity-related risk factors exist within population groups of the same genetic origin but with differences in lifestyle remains to be determined. The aim was to analyze whether obesity was associated with the same degree of metabolic disturbances in 2 groups of genetically homogeneous Inuit who were exposed to considerable differences in lifestyle. We studied obesity and cardiovascular disease risk factors in a cross-sectional population survey of 2311 Inuit living in Denmark (n = 995) or Greenland (n = 1316). The participants received an oral-glucose-tolerance test. Blood tests were supplemented by structured interviews and anthropometric and blood pressure measurements. The trend in the association between obesity and metabolic effects was not significantly different in the Inuit populations, but the values of several risk factors were significantly different. At any given level of obesity, Inuit residents in Greenland had lower blood pressure and lower concentrations of triacylglycerol and postchallenge plasma glucose and insulin than did the Inuit migrants in Denmark. The trend in the association with obesity categories was different only for HDL cholesterol, with higher concentrations observed in women Inuit migrants in Denmark than in women Inuit residents in Greenland. The health risk associated with obesity clearly varies within groups of Inuit living in Greenland and Inuit migrants living in Denmark. The findings indicate that lifestyle factors modify the cardiovascular disease risk associated with obesity.

Effect of a high-carbohydrate vs a high– cis-monounsaturated fat diet on lipid and lipoproteins in individuals with and without type 2 diabetes

It is not known whether the extent of the improvement in lipids and lipoproteins on a high– cis-monounsaturated (high-mono) diet compared with a high-carbohydrate (high-carb) diet is different in patients with type 2 diabetes mellitus (T2DM) and nondiabetic subjects. The aim of this study is to compare the effect of a high-mono and a high-carb diet on lipids and lipoproteins in patients with T2DM and nondiabetic subjects. Ten healthy nondiabetic men, 8 men with T2DM on dietary therapy alone, and 10 men with T2DM requiring insulin therapy were fed an isoenergic high-carb diet (60% energy as carbohydrate and 25% as fat) and a high-mono diet (50% energy as fat and 35% as carbohydrate) for 2 to 4 weeks in a randomized, crossover fashion. Dietary fiber, simple carbohydrates, and cholesterol were held constant across diets. The lipid and lipoprotein responses to these diets were compared in nondiabetic and T2DM subjects by repeated measures analysis of variance model. Patients with T2DM had 2.2 to 2.3 times greater reductions in plasma triacylglycerol, very low-density lipoprotein (VLDL) cholesterol, and total cholesterol/high-density lipoprotein cholesterol ratio (TC/HDLC) on the high-mono diet compared with the high-carb diet than the nondiabetic subjects ( P = .02-.04). The reductions in triacylglycerol and VLDL cholesterol were 2.7 times greater ( P = .009-.02) in T2DM subjects with high plasma triacylglycerol concentrations (>2.26 mmol/L) but only 1.4 to 2.0 times greater ( P = .16-.52) in T2DM patients with low triacylglycerol concentrations (<2.26 mmol/L) compared with nondiabetic subjects who all had low triacylglycerol concentrations (<2.26 mmol/L). Patients with T2DM experienced greater decreases in plasma triacylglycerol, VLDL cholesterol, and TC/HDLC on a high-mono diet compared with a high-carb diet than nondiabetic subjects. The extents of the improvements were likely related to plasma triacylglycerol concentrations in patients with T2DM.

Dietary Conjugated Linoleic Acids Lower the Triacylglycerol Concentration in the Milk of Lactating Rats and Impair the Growth and Increase the Mortality of their Suckling Pups

Recent studies showed that conjugated linoleic acids (CLA) lower triacylglycerol concentrations in the milk of lactating animals. This study was performed to determine the reasons for this phenomenon; we also investigated whether there is a relation between altered lipid metabolism in the liver and the reduction in milk triacylglycerols in rats fed CLA. Two groups of female rats were fed diets containing 0 [sunflower oil (SFO) group] or 14.7 g/kg diet of a CLA mixture (CLA group) at the expense of sunflower oil during growth, pregnancy, and lactation. CLA-fed rats had 49 and 80% lower mRNA concentration and activity of fatty acid synthase, respectively, a 51% lower mRNA concentration of lipoprotein lipase (LPL) in their mammary glands at d 17 of lactation, and a 46% lower milk fat content than SFO rats (P < 0.05). Although CLA rats had lower concentrations of triacylglycerols in the liver than SFO rats (20.8 +/- 2.6 vs. 62.6 +/- 27.7 micromol/g, P < 0.05), concentrations of triglycerides in plasma, which are the substrates of LPL, did not differ between the groups. Moreover, the number of pups per litter, litter weights, and pup weights at d 17 of lactation were 41, 35, and 22% lower, respectively, in the CLA group than in the SFO group. In conclusion, the present study suggests that dietary CLA reduces triacylglycerol concentrations in the milk via reduced de novo fatty acid synthesis in the mammary gland and an impaired uptake of fatty acids from lipoproteins into the mammary gland. This might be the reason for reduced growth rates and an increased mortality of suckling pups.

Effects of a long-term vegetarian diet on biomarkers of antioxidant status and cardiovascular disease risk

Objective We compared plasma biomarkers of antioxidant status, oxidative stress, inflammation, and risk for coronary heart disease in long-term vegetarians and age- and sex-matched omnivores. Methods Thirty vegetarians (mean age ± standard deviation: 44.2 ± 9.0 y) were recruited. The subjects had been vegetarian for 5 to 55 y (21.8 ± 12.2 y). The control group comprised 30 adults selected by age-stratified sampling from a community health project (mean age: 44.0 ± 9.2 y). Fasting plasma total antioxidant status (ferric-reducing antioxidant power), ascorbic acid (AA), α-tocopherol (total and lipid standardized), malondialdehyde, total cholesterol, triacylglycerol, uric acid (UA), and high-sensitivity C-reactive protein (hsCRP) were measured. Results Plasma AA was significantly higher in the vegetarians than in the omnivores (90.5 ± 21.0 and 61.8 ± 17.0 μM; P < 0.001). The vegetarians had lower concentrations of triacylglycerol, UA, and hsCRP. Plasma total and lipid-standardized α-tocopherol concentrations were also lower in the vegetarians: 22.0 ± 5.9 and 27.0 ± 7.9 μM versus 3.76 ± 0.57 and 4.23 ± 0.58 μM per millimoles per liter of total cholesterol plus triacylglycerol, respectively. There was a significant inverse correlation between AA and UA ( r = −0.343, P < 0.01; n = 60) and between AA and hsCRP ( r = −0.306, P < 0.05; n = 55). Plasma ferric-reducing antioxidant power and malondialdehyde did not differ significantly between groups; however, the contribution of AA to the total antioxidant capacity of plasma was approximately 50% greater in the vegetarians. Conclusions A long-term vegetarian diet is associated with markedly higher fasting plasma AA concentrations and lower concentrations of TAG, UA, and hsCRP. Long-term vegetarians have a better antioxidant status and coronary heart disease risk profile than do apparently healthy omnivores. Plasma AA may act a useful marker of overall health status.

Effects of weight loss on changes in insulin sensitivity and lipid concentrations in premenopausal African American and white women , ,

Few studies have tested the hypothesis that changes in disease risk factors are more closely associated with changes in visceral fat than with changes in other adipose tissue depots, particularly in subjects with different ethnic or racial backgrounds. We describe changes in triacylglycerol, total cholesterol, HDL cholesterol, LDL cholesterol, insulin sensitivity (S(i)), visceral fat, and subcutaneous abdominal adipose tissue (SAAT) with weight loss in premenopausal, overweight [body mass index (in kg/m(2)): 27-30], African American (n = 19) and white (n = 18) women. Assessments were performed before and after diet-induced weight loss to a BMI < 25. Body composition and body fat distribution were assessed with dual-energy X-ray absorptiometry and computed tomography, respectively; S(i) was assessed with an intravenous-glucose-tolerance test and minimal modeling. White women lost significantly more visceral fat and less SAAT than did African American women despite similar weight losses (approximately 13 kg). Mixed-model analysis indicated significant effects of time (ie, weight loss) on S(i), triacylglycerol, HDL cholesterol, and LDL cholesterol and of race on triacylglycerol. Time x race interaction terms were not significant. After adjustment for either total body or visceral fat, time was not related to any outcome variable; however, race remained significantly related to triacylglycerol. With weight loss, moderately overweight African American and white women experienced significant improvements in S(i) and lipids. The beneficial effects of weight loss did not differ with race and could not be attributed to a specific body fat depot. Lower triacylglycerol concentrations among African American women are independent of both obesity status and body fat distribution.

Effect of a 28-d treatment with L-796568, a novel β3-adrenergic receptor agonist, on energy expenditure and body composition in obese men

Stimulation of energy expenditure (EE) with selective thermogenic beta-adrenergic agonists may be a promising approach for treating obesity. We analyzed the effects of the highly selective human beta(3)-adrenergic agonist L-796568 on 24-h EE, substrate oxidation, and body composition in obese, weight-stable men. In this 2-center, double-blind, randomized, parallel-group study, we measured 24-h EE before and after 28 d of treatment with L-796568 (375 mg/d) or placebo during weight maintenance (ie, without dietary intervention) in nondiabetic, nonsmoking men aged 25-49 y with body mass index (in kg/m(2)) of 28-35 (n = 10 subjects per treatment group). The mean change in 24-h EE from before to after treatment did not differ significantly between groups (92 +/- 586 and 86 +/- 512 kJ/24 h for the L-796568 and placebo groups, respectively). The change in 24-h nonprotein respiratory quotient from before to after treatment did not differ significantly between groups (0.009 +/- 0.021 and 0.009 +/- 0.029, respectively). No changes in glucose tolerance were observed, but triacylglycerol concentrations decreased significantly with L-796568 treatment compared with placebo (-0.76 +/- 0.76 and 0.42 +/- 0.31 mmol/L, respectively; P < 0.002). Overall, treatment-related changes in body composition were not observed, but higher plasma L-796568 concentrations in the L-796568 group were associated with greater decreases in fat mass (r = -0.69, P < 0.03). Treatment with L-796568 for 28 d had no major lipolytic or thermogenic effect but it lowered triacylglycerol concentrations. This lack of chronic effect on energy balance is likely explained by insufficient recruitment of beta(3)-responsive tissues in humans, down-regulation of the beta(3)-adrenergic receptor-mediated effects with chronic dosing, or both.

Plasma fatty acids, triacylglycerol and cholesterol of the tuatara (Sphenodon punctatus punctatus) from islands differing in the presence of rats and the abundance of seabirds

AbstractNorthern tuatara Sphenodon punctatus punctatus survive on about 26 islands off the north‐east coast of the North Island, New Zealand. These rare, lizard‐like reptiles include seabirds in their diet. The presence of the Pacific rat Rattus exulans on some islands has been implicated in the decline of tuatara populations through predation and competition for food. Pacific rats and tuatara eat similar dietary items, including seabirds. Seabirds have high levels of the long chain n‐3 polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The potential contribution of seabirds to the diet of tuatara was investigated by measuring the composition of plasma fatty acids and the concentrations of triacylglycerol and cholesterol of adult tuatara from Green Island (rat‐free, numerous seabirds) and Coppermine Island (rat‐inhabited, relatively few seabirds). The composition of plasma fatty acids differed between islands and sexes. Specifically, tuatara from rat‐free Green Island had higher levels of the long chain PUFAs arachidonic acid, EPA and DHA compared to tuatara on rat‐inhabited Coppermine Island, and males had significantly higher levels of DHA than females on both islands. Concentrations of plasma triacylglycerol and cholesterol were higher in tuatara from Green Island than Coppermine Island. Males had higher cholesterol but lower triacylglycerol concentrations than females. Differences in fatty acid composition and lipid concentrations between groups of tuatara imply differences in diet. Tuatara on the rat‐free island evidently had a higher intake of n‐3 PUFAs compared with tuatara on the rat‐inhabited island. This is probably due to higher seabird consumption, or perhaps to the presence of other dietary items containing EPA and DHA. High concentrations of plasma triacylglycerol and cholesterol may be the result of a high intake of insect larvae. We recommend the direct investigation of the diets of northern tuatara and the consequences of differences in the composition of plasma fatty acids for reproduction.

Coronary heart disease risk factors in middle-aged former top-level athletes.

A cross-sectional study was conducted to determine the impact of previous athleticism on coronary heart disease (CHD) risk factors in 168 middle-aged men and 147 middle-aged women in Estonia. Participants were divided into four groups: physically active ex-athletes (AA), sedentary ex-athletes (SA), recreational exercisers (RE), and non-exercisers (NE). The Sharkey's questionnaire was applied to determine the CHD risk factors, health habits, medical, safety, personal, psychological and women's risk factors scores. Anthropometric characteristics, resting systolic and diastolic blood pressure values (SBP, DBP), and physical working capacity (PWC170) were measured. Concentrations of total cholesterol (CHOL), high-density lipoprotein cholesterol (HDL-C), triacylglycerols (TG), and glucose were determined. Low-density lipoprotein cholesterol (LDL-C) and HDL-C/CHOL ratio were computed. From the questionnaire results, significant differences in CHD risk scores in both sex groups in favour of AA and RE were found. DBP in men was significantly higher in SA, and SBP in women was significantly higher in NE in comparison with other groups. PWC170 and PWC170/kg was highest in AA and lowest in NE in both sex groups. There were no significant differences for blood biochemical parameters between women's groups. In men, AA had a lower CHOL level in comparison with SA and NE, and lower concentrations of TG and LDL-C than other groups. AA and RE had a higher HDL-C concentration and HDL-C/CHOL ratio in comparison with the other groups. In conclusion, differences in CHD risk factors were related to current physical activity, and were more expressed in men than in women.

Effects of shrimp consumption on plasma lipoproteins

Shrimp is very low in total fat, yet it has a high cholesterol content. Although shrimp is a popular food in the American diet, many people avoid it because of its high cholesterol content. The objective of this study was to test the effect of the addition of cholesterol from shrimp to a low-fat baseline diet as well as to compare the effect of an equal amount of dietary cholesterol derived from shrimp or egg on the plasma lipoprotein pattern of normolipidemic subjects. In a randomized crossover trial, a diet containing 300 g shrimp/d, which supplied 590 mg dietary cholesterol/d, significantly increased low-density-lipoprotein (LDL) cholesterol by 7.1% (P = 0.014) and high-density-lipoprotein (HDL) cholesterol by 12.1% (P = 0.0001) when compared with a baseline diet matched for fat content but containing only 107 mg cholesterol/d. However, because the percentage increase in LDL cholesterol was less than for HDL cholesterol, the shrimp diet did not worsen the ratio of total cholesterol to HDL cholesterol or the ratio of LDL to HDL cholesterol. Moreover, shrimp consumption decreased triacylglycerol (triglyceride) concentrations by 13% (P = 0.004). The diet containing two large eggs per day with 581 mg dietary cholesterol/d also raised LDL- and HDL-cholesterol concentrations compared with baseline, but the percentage increase in LDL cholesterol (10.2%, P = 0.0001) was more than for HDL cholesterol (7.6%, P = 0.004) and there was a trend toward worse lipoprotein ratios. In a comparison of the two high-cholesterol diets, the shrimp diet produced significantly lower ratios of total to HDL cholesterol and lower ratios of LDL to HDL cholesterol than the egg diet as well as lower triacylglycerol concentrations. We conclude that moderate shrimp consumption in normolipidemic subjects will not adversely affect the overall lipoprotein profile and can be included in "heart healthy" nutritional guidelines.