Effects of short-term detraining on postprandial metabolism, endothelial function, and inflammation in endurance-trained men: dissociation between changes in triglyceride metabolism and endothelial function. j.gill@bio.gla.ac.uk

Comparison of the Reductions in LDL-C and Non-HDL-C Induced by the Red Yeast Rice Extract Xuezhikang Between Fasting and Non-fasting States in Patients With Coronary Heart Disease

Background: Xuezhikang, an extract of red yeast rice, effectively lowers fasting blood lipid levels. However, the influence of Xuezhikang on the non-fasting levels of low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol (non-HDL-C) has not been explored in Chinese patients with coronary heart disease (CHD).

Methods: Fifty CHD patients were enrolled and randomly divided into two groups (n = 25 each) to receive 1,200 mg/d of Xuezhikang or a placebo for 6 weeks as routine therapy. Blood lipids were repeatedly measured before and after 6 weeks of treatment at 0, 2, 4, and 6 h after a standard breakfast containing 800 kcal and 50 g of fat.

Results: The serum LDL-C levels significantly decreased, from a fasting level of 3.88 mmol/L to non-fasting levels of 2.99, 2.83, and 3.23 mmol/L at 2, 4, and 6 h, respectively, after breakfast (P < 0.05). The serum non-HDL-C level mildly increased from a fasting level of 4.29 mmol/L to non-fasting levels of 4.32, 4.38, and 4.34 mmol/L at 2, 4, and 6 h post-prandially, respectively, and the difference reached statistical significance only at 4 and 6 h after breakfast (P < 0.05). After 6 weeks of Xuezhikang treatment, the patients had significantly lower fasting and non-fasting serum levels of LDL-C and non-HDL-C (P < 0.05) than at pretreatment. The LDL-C levels were reduced by 27.8, 28.1, 26.2, and 25.3% at 0, 2, 4, and 6 h, respectively, and the non-HDL-C levels were reduced by 27.6, 28.7, 29.0, and 28.0% at 0, 2, 4, and 6 h, respectively, after breakfast. No significant difference was found in the percent reductions in the LDL-C and non-HDL-C levels among the four different time-points.

Conclusions: Six weeks of Xuezhikang treatment significantly decreased LDL-C and non-HDL-C levels, with similar percent reductions in fasting and non-fasting states in CHD patients, indicating that the percent change in non-fasting LDL-C or non-HDL-C could replace that in the fasting state for evaluation the efficacy of cholesterol control in CHD patients who are unwilling or unable to fast.

The chronic effect of physical activity on postprandial triglycerides in postmenopausal women: A randomized controlled study

Objective

This study examined the chronic effect of increased physical activity on postprandial triglycerides in older women.

Methods

Twenty-six women, aged 72 ± 5 years (mean ± SD), participated in this study. Participants in the physical activity group (n = 11) were asked to increase their activities above their usual lifestyle levels for 12 weeks. Participants in the control group (n = 15) maintained their usual lifestyle for 12 weeks. All participants rested and consumed a standardized breakfast after a 24-h period of physical activity avoidance at baseline, 4 weeks, and 12 weeks. Blood samples were collected in the fasted state (0 h) and at 2, 4, and 6 h after breakfast.

Results

The average increased time spent in self-selected activities per day was 1.1 ± 19.3 min over the 12 weeks compared with the baseline in the physical activity group. There was no difference in the postprandial time-averaged triglyceride area under the curve at baseline (1.59 ± 0.81 vs. 1.39 ± 0.67 mmol/L, p = 0.515) or over the 12-week intervention (1.78 ± 1.00 vs. 1.31 ± 0.67 mmol/L, p = 0.212) between the physical activity and control groups.

Conclusion

Postprandial triglyceride concentrations were not reduced after performing self-selected activities under free-living conditions in older women when these responses were determined 24 h after the last physical activity bout. (Trial registration ID: UMIN000037420).

The relationship between dietary patterns and lipoprotein-associated phospholipase A2 levels in adults with cardiovascular risk factors: Tehran Lipid and Glucose Study

Background:

Pathogenesis of cardiovascular diseases (CVDs) may be indicated by lipoprotein-associated phospholipase A2 (Lp-PLA2), serving as an inflammatory biomarker. However, the general dietary predictors of Lp-PLA2 have not been investigated so far. The aim of the present study is to investigate the relationship between the serum levels of Lp-PLA2 and dietary patterns in adults with cardiovascular risk factors.

Materials and Methods:

Dietary patterns extracted using factor analysis and serum levels of Lp-PAL2 in 470 adults aged 40–70 years who participated in the 5^th phase of the Tehran Lipid and Glucose Study (2011–2014) were determined. Associations between the dietary patterns and serum levels of Lp-PAL2 considering some confounder factors were evaluated.

Results:

The results showed that Western and semi-Mediterranean dietary patterns had significant effects on changes in Lp-PLA2 levels in univariate analyses. In multivariate analyses, after adjusting for age, sex, total cholesterol, low-density lipoprotein cholesterol, body mass index and physical activity, energy intake, hormone therapy for women, and taking blood lipid-lowering drugs as potential confounders, the Western dietary pattern remained a significant factor influencing the Lp-PLA2 level (β value: 1.65, 95% confidence interval: 1.12, 1.89; P < 0.05). Moreover, after adjustment for the mentioned confounder factors, the effect of the semi-Mediterranean dietary pattern on Lp-PLA2 disappeared.

Conclusion:

It can be concluded that the Western dietary pattern is associated with higher Lp-PLA2 levels. We recommend that adults eat less carbonated drinks, fast foods, salty snacks, mayonnaise, and organ meat to counteract increased serum Lp-PLA2 levels, which are directly associated with vascular inflammation and CVDs.

Retired Elite Athletes' Physical Activity, Physiological, and Psychosocial Outcomes During Single- and Double-Player Exergaming

McDonough, DJ, Pope, ZC, Zeng, N, Lee, JE, and Gao, Z. Retired elite athletes' physical activity, physiological, and psychosocial outcomes during single- and double-player exergaming. J Strength Cond Res 33(12): 3220-3225, 2019-Elite athletes (i.e., athletes who play sport professionally) are a population who commonly exceed recommended physical activity (PA) guidelines and have higher health statuses compared with the general population. However, elite athletes transitioning into retirement often become physically inactive given they no longer require long hours of training and competition, and their physiological and psychosocial health suffers as a result. Therefore, this study's purpose was to examine differences in retired elite athletes' acute PA, physiological, and psychosocial outcomes during single- and double-player exergaming. Twenty retired Olympic athletes (18 females; (Equation is included in full-text article.)= 27.3 ± 4.3 years) participated in 2 separate 20-minute exergaming sessions (a): Xbox 360 Reflex Ridge single player and (b) Xbox 360 Reflex Ridge double player. Subjects' situational interest, enjoyment, and self-efficacy were examined using validated questionnaires; rating of perceived exertion (RPE) using the modified Borg RPE scale; and moderate-to-vigorous PA, steps, and energy expenditure tracked using ActiGraph GT3X+ accelerometers. Repeated-measures analysis of variances revealed no significant differences for any outcome between the 2 exercise sessions except for RPE (F (1, 38) = 4.6; p < 0.05; η = 0.11), which was higher in the single-player session compared with the double-player session (10.3 ± 2.3; 8.7 ± 1.6, respectively). Observations indicated double-player exergaming to be perceived as less intense than single-player exergaming despite similar PA and physiological outcomes, suggesting retired elite athletes may better adhere to exergaming in a double-player mode.

Bioavailability of orange juice (poly)phenols: the impact of short-term cessation of training by male endurance athletes

Background: Physical exercise has been reported to increase the bioavailability of citrus flavanones.Objective: We investigated the bioavailability of orange juice (OJ) (poly)phenols in endurance-trained males before and after cessation of training for 7 d.Design: Ten fit, endurance-trained males, with a mean ± SD maximal oxygen consumption of 58.2 ± 5.3 mL · kg^-1 · min^-1, followed a low (poly)phenol diet for 2 d before drinking 500 mL of OJ containing 398 μmol of (poly)phenols, of which 330 μmol was flavanones. After the volunteers stopped training for 7 d the feeding study was repeated. Urine samples were collected 12 h pre- and 24 h post-OJ consumption. Bioavailability was assessed by the quantitative analysis of urinary flavanone metabolites and (poly)phenol catabolites with the use of high-pressure liquid chromatography-high resolution mass spectrometry.Results: During training, 0-24-h urinary excretion of flavanone metabolites, mainly hesperetin-3'-O-glucuronide, hesperetin-3'-sulfate, naringenin-4'-O-glucuronide, naringenin-7-O-glucuronide, was equivalent to 4.2% of OJ flavanone intake. This increased significantly to 5.2% when OJ was consumed after the volunteers stopped training for 7 d. Overall, this trend, although not significant, was also observed with OJ-derived colonic catabolites, which, after supplementation in the trained state, were excreted in amounts equivalent to 51% of intake compared with 59% after cessation of training. However, urinary excretion of 3 colonic catabolites of bacterial origin, most notably, 3-(3'-hydroxy-4'-methoxyphenyl)hydracrylic acid, did increase significantly when OJ was consumed postcessation compared with precessation of training. Data were also obtained on interindividual variations in flavanone bioavailability.Conclusions: A 7-d cessation of endurance training enhanced, rather than reduced, the bioavailability of OJ flavanones. The biological significance of these differences and whether they extend to the bioavailability of other dietary (poly)phenols remain to be determined. Hesperetin-3'-O-glucuronide and the colonic microbiota-derived catabolite 3-(3'-hydroxy-4'-methoxyphenyl)hydracrylic acid are key biomarkers of the consumption of hesperetin-O-glycoside-containing OJ and other citrus products. This trial was registered at clinicaltrials.gov as NCT02627547.

Magnitude and Timing of the Postprandial Inflammatory Response to a High-Fat Meal in Healthy Adults: A Systematic Review

Research findings over the past several decades have shown that inflammation is a prominent feature of many chronic diseases, with poor diet being one likely inflammatory stimulus. Specifically, a single high-fat meal (HFM) has been suggested to increase inflammation, although there is currently no consensus with regard to the specific changes in many of the proinflammatory markers that are frequently assessed after an HFM. The aim of this systematic review was to objectively describe the postprandial timing and magnitude of changes in 5 common inflammatory markers: interleukin (IL) 6, C-reactive protein (CRP), tumor necrosis factor (TNF) α, IL-1β, and IL-8. Ten relevant databases were searched, yielding 494 results, of which 47 articles met the pre-established inclusion criteria: 1) healthy men and women aged 18-60 y, 2) consuming a single HFM (≥30% fat, ≥500 kcal), and 3) assessing relevant inflammatory markers postmeal for ≥2 h. The only marker found to consistently change in the postprandial period was IL-6: on average, from a baseline of ∼1.4 pg/mL, it peaked at ∼2.9 pg/mL ∼6 h post-HFM (an average relative change of ∼100%). CRP, TNF-α, IL-1β, and IL-8 did not change significantly in 79% (23 of 29), 68% (19 of 28), 67% (2 of 3), and 75% (3 of 4) of included studies, respectively. We conclude that there is strong evidence that CRP and TNF-α are not responsive at the usual time scale observed in postprandial studies in healthy humans younger than age 60 y. However, future research should further investigate the role of IL-6 in the postprandial period, because it routinely increases even in healthy participants. We assert that the findings of this systematic review on markers of inflammation in the postprandial period will considerably aid in informing future research and advancing clinical knowledge.

Postprandial lipemic and inflammatory responses to high-fat meals: a review of the roles of acute and chronic exercise

Postprandial lipemia is an independent risk factor for development of cardiovascular disease. Postprandial inflammation following the prolonged elevation of triglycerides occurring subsequent to ingestion of high-fat meals, provides a likely explanation for increased disease risk. Substantial evidence has shown that acute exercise is an effective modality for attenuation of postprandial lipemia following a high-fat meal. However, much of the evidence pertaining to exercise intensity, duration, and overall energy expenditure for reducing postprandial lipemia is inconsistent. The effects of these different exercise variables on postprandial inflammation is largely unknown. Long-term, frequent exercise, however, appears to effectively reduce systemic inflammation, especially in at-risk or diseased individuals. With regard to an acute postprandial response, without a recent bout of exercise, high levels of chronic exercise do not appear to reduce postprandial lipemia. This review summarizes the current literature on postprandial and inflammatory responses to high-fat meals, and the roles that both acute and chronic exercise play. This review may be valuable for health professionals who wish to provide evidence-based, pragmatic advice for reducing postprandial lipemia and cardiovascular disease risk for their patients. A brief review of proposed mechanisms explaining how high-fat meals may result in pro-inflammatory and pro-atherosclerotic environments is also included.

Eight-Week Training Cessation Suppresses Physiological Stress but Rapidly Impairs Health Metabolic Profiles and Aerobic Capacity in Elite Taekwondo Athletes

Changes in an athlete’s physiological and health metabolic profiles after detraining have not been studied in elite Taekwondo (TKD) athletes. To enable a better understanding of these physiological changes to training cessation, this study examined the effects of 8-weeks detraining on the aerobic capacity, body composition, inflammatory status and health metabolic profile in elite TKD athletes. Sixteen elite TKD athletes (age: 21.0 ± 0.8 yrs, BMI: 22.4 ± 3.9 kg/m²; Mean ± SD; 11 males and 5 females) participated in this study. Physical activity level assessment using computerized physical activity logs was performed during the competitive preparation season (i.e. one-week before national competition) and at two week intervals throughout the detraining period. Participant aerobic capacity, body fat, and blood biomarkers were measured before and after detraining, and the blood biomarker analyses included leukocyte subpopulations, blood glucose, insulin, dehydroepiandrosterone-sulfate (DHEA-S), and cortisol. Eight-week detraining increased DHEA-S/cortisol ratio (+57.3%, p = 0.004), increased insulin/cortisol ratio (+59.9%, p = 0.004), reduced aerobic power (–2.43%, p = 0.043), increased body fat accumulation (body fat%: +21.3%, p < 0.001), decreased muscle mass (muscle mass%: –4.04%, p < 0.001), and elevated HOMA-IR (the biomarker of systemic insulin resistance; +34.2%, p = 0.006). The neutrophil-to-lymphocyte ratio (NLR), a systemic inflammatory index, increased by 48.2% (p = 0.005). The change in aerobic capacity was correlated with the increased fat mass (r = –0.429, p = 0.049) but not with muscle loss. An increase in the NLR was correlated to the changes in HOMA-IR (r = 0.44, p = 0.044) and aerobic capacity (r = –0.439, p = 0.045). We demonstrate that 8-week detraining suppresses physiological stress but rapidly results in declines in athletic performance and health metabolic profiles, including reduced aerobic capacity, increased body fat, muscle loss, insulin resistance development and elevated systemic inflammatory status in these young elite TKD athletes. The inflammation state was positively associated with insulin resistance development, fat mass, WHR (the index for central fat accumulation), and the decline in VO₂max.

Postprandial Inflammatory Responses and Free Fatty Acids in Plasma of Adults Who Consumed a Moderately High-Fat Breakfast with and without Blueberry Powder in a Randomized Placebo-Controlled Trial

BACKGROUND

Saturated fatty acids (FAs) released from triglyceride-rich lipoproteins (TGRLs) activate Toll-like receptor 2 (TLR-2) and induce the expression of proinflammatory cytokines in monocytes. Certain plant polyphenols inhibit TLR-mediated signaling pathways.

OBJECTIVE

We determined whether plasma free FAs (FFAs) after a moderately high-fat (MHF, 40% kcal from fat) breakfast modulate the inflammatory status of postprandial blood, and whether blueberry intake suppresses FFA-induced inflammatory responses in healthy humans.

METHODS

Twenty-three volunteers with a mean ± SEM age and body mass index (in kg/m(2)) of 30 ± 3 y and 21.9 ± 0.4, respectively, consumed an MHF breakfast with either a placebo powder or 2 or 4 servings of blueberry powder in a randomized crossover design. The placebo powder was provided on the first test day and the blueberry powder doses were randomized with a 2-wk washout period. Plasma concentrations of lipids, glucose, and cytokines were determined. To determine whether FFAs derived from TGRL stimulate monocyte activation, and whether this is inhibited by blueberry intake, whole blood was treated with lipoprotein lipase (LPL).

RESULTS

The median concentrations of FFAs and cytokines [tumor necrosis factor-α, interleukin (IL)-6 and IL-8] in postprandial plasma (3.5 h) decreased compared with fasting plasma regardless of the blueberry intake (P < 0.001 for FFAs and P < 0.05 for cytokines). However, concentrations of FFAs and cytokines including IL-1β increased in LPL-treated whole blood compared with untreated blood samples from participants who consumed the placebo powder. Blueberry intake suppressed IL-1β and IL-6 production in LPL-treated postprandial blood compared with the placebo control when fasting changes were used as a covariate.

CONCLUSIONS

The plasma FFA concentration may be an important determinant affecting inflammatory cytokine production in blood. Supplementation with blueberry powder did not affect plasma FFA and cytokine concentrations; however, it attenuated the cytokine production induced by ex vivo treatment of whole blood with LPL. This trial was registered at clinicaltrials.gov as NCT01594008.

The effect of moderate intensity exercise in the postprandial period on the inflammatory response to a high-fat meal: an experimental study

Background

Consuming a high-fat meal (HFM) may lead to postprandial lipemia (PPL) and inflammation. Postprandial exercise has been shown to effectively attenuate PPL. However, little is known about the impact of postprandial exercise on systemic inflammation and whether PPL and inflammation are associated. The purpose of this study was to determine whether moderate intensity exercise performed 60 min following a true-to-life HFM would attenuate PPL and inflammation.

Methods

Thirty-nine young adults (18–40 year) with no known metabolic disease were randomized to either a control group (CON) who remained sedentary during the postprandial period or an exercise (EX) group who walked at 60 % VO_2peak to expend ≈ 5 kcal/kgbw one-hour following the HFM. Participants consumed a HFM of 10 kcal/kgbw and blood draws were performed immediately before, 2 h and 4 h post-HFM.

Results

At baseline, there were no differences between EX and CON groups for any metabolic or inflammatory markers (p > 0.05). Postprandial triglycerides (TRG) increased from baseline to 4 h in the EX and CON groups (p < 0.001), with no differences between groups (p = 0.871). High density lipoprotein cholesterol (HDL-C) decreased in both groups across time (p < 0.001) with no differences between groups (p = 0.137). Interleukin-6 (IL-6) was significant as a quadratic function over time (p = 0.005), decreasing from baseline to 2 h then increasing and returning to baseline at 4 h in all participants with no difference between groups (p = 0.276). Tumor necrosis factor-alpha (TNF-α) was not different from baseline to 4 h between groups (p > 0.05). There was an increase in soluble vascular adhesion molecule (sVCAM-1) from baseline to 4 h (p = 0.027) for all participants along with a group x time interaction (p = 0.020). Changes in TRG were associated with changes in interleukin-10 (IL-10) from 0 to 2 h (p = 0.007), but were not associated with changes in any other inflammatory marker in the postprandial period (p > 0.05).

Conclusions

Despite significant increases in PPL following a HFM, moderate intensity exercise in the postprandial period did not mitigate the PPL nor the inflammatory response to the HFM. These results indicate that in populations with low metabolic risk, PPL and inflammation following a HFM may not be directly related.

Influence of aerobic training and detraining on serum BDNF, insulin resistance, and metabolic risk factors in middle-aged men diagnosed with metabolic syndrome

OBJECTIVE

To study the influence of aerobic exercise training on brain-derived neurotrophic factor (BDNF), insulin resistance, and lipid profile in middle-aged men diagnosed with metabolic syndrome (MetS).

DESIGN

This is an experimental repeated measure study.

SETTING

Subjects participated in aerobic training programs (18 sessions of 25-40 minutes per session) in Guilan University gymnasium and court.

PARTICIPANTS

A total of 21 middle-aged men (50-65 years old) diagnosed with MetS participated.

INTERVENTIONS

We randomly divided 21 middle-aged men with MetS into exercise and control groups. The exercise group followed an aerobic training program (18 sessions, 3/wk) at 50% to 60% of V[Combining Dot Above]O2 peak (25-40 minutes per session) and 6 weeks of detraining. Blood samples were collected at baseline, end of the training, and detraining.

MAIN OUTCOME MEASURES

High BDNF level in patients with MetS and its reduction after chronic aerobic exercise.

RESULTS

Aerobic training significantly decreased all the metabolic risk factors, including overall MetS z score, insulin resistance, and lipid profile (P < 0.05). After the detraining period, plasma triglyceride, high-density lipoprotein, and also overall MetS z score remained unchanged (P < 0.05); however, serum BDNF, which was decreased by aerobic training (P = 0.013), restored to the baseline at the end of the detraining (P = 0.018).

CONCLUSIONS

Improved metabolic risk factors along with decreased serum BDNF in response to aerobic training and the opposite direction during the detraining emphasize the importance of physical activity in the treatment of MetS and prevention of related diseases.

Effect of repeated sprints on postprandial endothelial function and triacylglycerol concentrations in adolescent boys

This study investigated whether repeated, very short duration sprints influenced endothelial function (indicated by flow-mediated dilation) and triacylglycerol concentrations following the ingestion of high-fat meals in adolescent boys. Nine adolescent boys completed two, 2-day main trials (control and exercise), in a counter-balanced, cross-over design. Participants were inactive on day 1 of the control trial but completed 40 × 6 s maximal cycle sprints on day 1 of the exercise trial. On day 2, capillary blood samples were collected and flow-mediated dilation measured prior to, and following, ingestion of a high-fat breakfast and lunch. Fasting flow-mediated dilation and plasma triacylglycerol concentration were similar in the control and exercise trial (P > 0.05). In the control trial, flow-mediated dilation was reduced by 20% and 27% following the high-fat breakfast and lunch; following exercise these reductions were negated (main effect trial, P < 0.05; interaction effect trial × time, P < 0.05). The total area under the plasma triacylglycerol concentration versus time curve was 13% lower on day 2 in the exercise trial compared to the control trial (8.65 (0.97) vs. 9.92 (1.16) mmol · l(-1) · 6.5 h, P < 0.05). These results demonstrate that repeated 6 s maximal cycle sprints can have beneficial effects on postprandial endothelial function and triacylglycerol concentrations in adolescent boys.

Effect of a mixed meal on plasma lipids, insulin resistance and systemic inflammation in non-obese Indian adults with normal glucose tolerance and treatment naïve type-2 diabetes

AIM

Asian Indians are believed to have a lower capacity to clear a glucose load even during normoglycemia. High post meal glucose levels have been linked to postprandial dyslipidemia and generation of proinflammatory cytokines. Since humans spend most of their time in the postprandial state, the present study aims to evaluate the relationship of insulin resistance (IR) in the basal state with dyslipidemia and systemic inflammation (hs-CRP, IL-6 and TNF-a), in the fasting state, 2h and 4h after a mixed meal, in Indian adults with normal glucose tolerance, and new onset type-2 diabetes.

METHODS

Forty-eight people with type 2 diabetes and 32 individuals with normoglycemia, 30-70 years age, not on medications, underwent blood sampling after overnight (12h) fast and 2 and 4h after a mixed meal (carbohydrates, proteins and fat content 79.1%, 7.7% and 13.2%, respectively).

RESULTS

Triglyceride (TG), TG/HDL-C (high density lipoprotein), HDL-C/LDL-C (low density lipoprotein) ratios, IR parameters, and inflammatory markers were significantly higher among patients with diabetes. There was a fall in total cholesterol (TC), HDL-C and LDL-C at 2 and 4h after the meal in both groups. Compared with fasting, 4-h postprandial TC, TG and HDL-C were significantly better positively correlated with IR in normal individuals. Postprandial hs-CRP was not significantly different to fasting in both groups. Postprandial IL-6 and TNF-α were significantly lower in both groups.

CONCLUSION

Consumption of a carbohydrate rich meal is associated with a rise in TG and fall in TC, HDL-C, LDL-C, IL-6 and TNF-α among normal individuals and people with type 2 diabetes.

The Postprandial Effects of a Moderately High-Fat Meal on Lipid Profiles and Vascular Inflammation in Alzheimer's Disease Patients: A Pilot Study

Objective

Alzheimer’s disease (AD) is a neurodegenerative disease of aging with unknown causative factors. Accumulating evidence suggests that inflammation and neurovascular dysfunction play important roles in AD. The postprandial period following a moderately high-fat meal is associated with vascular inflammation in young, healthy individuals; however, this relationship has not been investigated in Alzheimer’s patients despite their exaggerated inflammatory state.

Methods

Patients with AD and age-matched control subjects were recruited through the UC Davis Alzheimer’s Disease Center. All subjects consumed a moderately high-fat breakfast meal. Fasting and postprandial blood samples were collected for lipid, lipoprotein, and oxylipin analyses, as well as assays for cytokine levels and monocyte activation.

Results

The plasma lipid analyses revealed similar levels of triglycerides and esterified oxylipins between groups, but there was an interaction between postprandial non-esterified fatty acid (NEFA) levels and body mass index in the AD group compared to the control subjects. The AD group also had increased behenic acid and decreased linoleic and oleic acids in the postprandial period; however, these were not significantly different. Inflammatory assays revealed elevated fasting levels of interleukin (IL)-10 and IL-12 p70, but no change in monocyte activation in the AD group.

Conclusion

The postprandial period following a moderately high-fat meal is not associated with an exaggerated inflammatory state in Alzheimer’s patients, and basal esterified oxylipin profiles do not indicate elevated oxidative stress. However, the baseline inflammatory state during fasting in AD patients includes elevated levels of plasma IL-10 and IL-12 p70, which may indicate a balance between immune responses mediated by these interleukins.

Effects of the n-6/n-3 polyunsaturated fatty acids ratio on postprandial metabolism in hypertriacylglycerolemia patients

Background

Atherosclerosis is a postprandial phenomenon. The balanced n-6/n-3 PUFA ratio contributing to the prevention of atherosclerosis has been well shown, but the effect of the ratio on postprandial metabolism has not been fully investigated. The aim of this study was to investigate the effects of the n-6/n-3 PUFAs ratio on postprandial metabolism in hypertriacylglycerolemia patients, comparing them to healthy controls.

Methods

Test meals with 0.97 (high n-3) and 8.80 (low n-3) n-6/n-3 PUFAs ratio were administered in a randomized crossover design to 8 healthy and 8 hypertriacylglycerolemia subjects. Blood samples were collected for 8 hours after meals to measure triglyceride (TG), total cholesterol (TC), HDL, ApoA, ApoB, glucose, insulin, inflammatory makers including tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6), endothelial function including nitric oxide (NO) and endothelin-1 (ET-1).

Results

According to repeated–measures ANOVA, the postprandial response of lipid, glucose, insulin, inflammation and endothelial function were not significantly different between meals. The postprandial TG and NO response were significantly different between healthy control (HC) and hypertriglyceridemia group (HTG) after both meals (P < 0.01). After both meals maximal change and iAUC for TG was all higher in HTG group than HC group, the difference was significant after low n-3 meal but not after high n-3 meal. The concentration of glucose, insulin, IL-6, TNFα and ET-1 at each time point was higher and NO was lower in HTG group, but the maximal change and iAUC had no significant difference except for iAUC of insulin, IL-6 and diAUC of NO after low n-3 meal.

Conclusions

The ratio of n-6 and n-3 maybe do not acutely influence the postprandial metabolism, inflammatory response and endothelial function, but the low n-3 meal can strengthen the difference between HTG and HC group.

The latest on the effect of prior exercise on postprandial lipaemia

This review examines the effect of prior exercise on postprandial triacylglycerol (pTAG) concentrations, an independent risk factor for cardiovascular diseases. Numerous studies have shown that a single bout of exercise reduces pTAG concentrations; however, several modulators such as exercise energy expenditure/deficit, mode of exercise (aerobic/resistance/high intensity/intermittent exercise or combinations), type of meal (moderate or high fat), time frame between exercise and meal and target group may individually or in conjunction influence this effect. On the other hand, at least for aerobic exercise, training reduces pTAG concentrations transiently (~2 days); therefore, exercise sessions should be frequent enough to maintain this clinically significant improvement. For the healthy population, it seems that a subject's preference and ability determine which type of exercise to undertake to attenuate pTAG concentrations; an energy expenditure of ~30 kJ/kg of body mass (or ~2-2.5 MJ) not combined with a corresponding increase in energy intake is required; for resistance or intermittent exercise, for those following a moderate rather than a high-fat diet, and for those with obesity (expressed as kJ/kg of body mass), a smaller energy expenditure is probably sufficient. More studies are needed to investigate dose-response/plateau effects, as well as the threshold of energy expenditure in those with diabetes mellitus and other high-risk populations. Finally, investigation of the underlying mechanisms may be clinically helpful in individualizing the appropriate intervention.

Effect of short-term reduced physical activity on cardiovascular risk factors in active lean and overweight middle-aged men

OBJECTIVES

An experimental reduction in physical activity is a useful tool for exploring the health benefits of physical activity. This study investigated whether similarly-active overweight men show a more pronounced response to reduced physical activity than their lean counterparts because of their atherogenic phenotype (i.e., greater abdominal adiposity).

METHODS

From 115 active men aged 45-64years, we recruited nine active lean (waist circumference <84cm) and nine active central overweight men (waist circumference >94cm). Fasting blood samples and responses to an oral glucose tolerance test (OGTT) were measured at baseline and following one week of reduced physical activity to simulate sedentary levels (removal of structured exercise and reduced habitual physical activity).

RESULTS

Glucose and insulin areas under the curve (AUC), CRP, ALT, TAG were all higher in the overweight group and remained so throughout (P<0.05). Insulin and glucose AUC responses to an OGTT, as well as fasting triglyceride (TAG) concentrations, increased in both groups as a result of the intervention (P<0.05). There was no change in interleukin-6, C-reactive protein (CRP), Tumour Necrosis Factor-α, soluble intracellular adhesion molecule 1, or alanine transaminase (ALT).

CONCLUSION

One-week of reduced activity similarly-impaired glucose control and increased fasting TAG in both lean and overweight men. Importantly, in spite of very similar (high) levels of habitual physical activity, central overweight men displayed a poorer profile for various inflammatory and metabolic outcomes (CRP, ALT, TAG, glucose AUC and insulin AUC).

Effect of exercise on postprandial endothelial function in adolescent boys

The ingestion of high-fat meals induces a state of endothelial dysfunction in adults. This dysfunction is attenuated by prior exercise. The response of young people to these nutritional and physiological stressors has not been established. Thus, the purpose of the present study was to investigate if a bout of moderate-intensity exercise influenced endothelial function (as indicated by flow-mediated dilation (FMD)) following the ingestion of a high-fat breakfast and lunch in adolescent boys (aged 12·6–14·3 years). Two, 2 d main trials (control and exercise) were completed by thirteen adolescent boys in a counter-balanced, cross-over design. Participants were inactive on day 1 of the control trial, but completed 60 min of walking at 60 % peak oxygen uptake in the exercise trial. On day 2, endothelial function was assessed via FMD prior to, and following, ingestion of a high-fat breakfast and lunch. There was no difference in fasting FMD between the control and exercise trial (P= 0·449). In the control trial, FMD was reduced by 32 % following consumption of the high-fat breakfast and by 24 % following lunch. In the exercise trial, the corresponding reductions were 6 and 10 %, respectively (main effect trial, P= 0·002). These results demonstrate that moderate-intensity exercise can attenuate the decline in FMD seen following the consumption of high-fat meals in adolescent boys.

Effects of atorvastatin on human C-reactive protein metabolism

OBJECTIVE

Statins are known to reduce plasma C-reactive protein (CRP) concentrations. Our goal was to define the mechanisms by which CRP was reduced by maximal dose atorvastatin.

METHODS

Eight subjects with combined hyperlipidemia (5 men and 3 postmenopausal women) were enrolled in a randomized, placebo-controlled double-blind, cross over study. Subjects underwent a 15-h primed-constant infusion with deuterated leucine after 8 weeks of placebo and 80 mg/day of atorvastatin. CRP was isolated from lipoprotein deficient plasma, (density > 1.21 g/ml) by affinity chromatography. Isotopic enrichment was determined by gas chromatography/mass spectrometry. Kinetic parameters were determined using compartmental modeling. Paired t test and Wilcoxon signed ranks test were used to compare differences between placebo and atorvastatin.

RESULTS

Compared with placebo, atorvastatin decreased median CRP pool size by 28.4% (13.31 ± 3.78 vs 10.26 ± 3.93 mg; p = 0.16), associated with a median CRP fractional catabolic rate increase of 39.9% (0.34 ± 0.06 vs 0.50 ± 0.11 pools/day; p = 0.09), with no significant effect on median CRP production rate (0.050 ± 0.01 vs 0.049 ± 0.01 mg/kg/day; p = 0.78).

CONCLUSION

Our data indicate that maximal doses of atorvastatin lower plasma CRP levels by substantially decreasing the median CRP plasma residence time from 2.94 days to 2.0 days, with no significant effect on the median CRP production rate.

Detraining-induced alterations in metabolic and fitness markers after a multicomponent exercise-training program in older men

The aim of the present study was to investigate the effects of a 8-week detraining period after a 16-week multicomponent training program including strength and aerobic exercises on the main determinants of aerobic fitness, muscle strength and some metabolic markers in 24 older subjects (60.2 ± 3.0 years). The oxygen uptake at the second ventilatory threshold (VO2VT2) and at the end of exercise (VO2max), maximum voluntary contraction force (MVC) of knee extensors and some metabolic indexes, i.e., insulin sensitivity, blood lipid profile, inflammatory cytokines, and endothelial function, were evaluated at baseline and after the training and detraining periods. The training program induced significant improvements in VO2VT2 (16%, p < 0.05), VO2max (14%, p < 0.05), MVC (6.5%, p < 0.05), insulin sensitivity (16%, p < 0.05), and endothelial function (p < 0.05) but induced no significant change in lipid profile and inflammatory cytokines. Interestingly, VO2VT2 and VO2max (mL·min–1·kg–1) scores remained significantly above pretraining values after the 8-week detraining period. However, the detraining period reversed MVC values, the insulin sensitivity and endothelial function to baseline levels. To conclude, the 8-week detraining partially reversed the major components of aerobic fitness but totally abolished the gains in muscle strength and some metabolic indexes after a 16-week multicomponent training program in older men. Taken as a whole, the results of this study emphasize the importance of exercise prescriptions for older subjects and the need not to interrupt exercise-training over a prolonged period.

A physically active occupation does not result in compensatory inactivity during out-of-work hours

AIM

To examine differences in non-occupational physical activity behaviour in workers who engage in high and low occupational physical activity.

DESIGN

Cross-sectional survey of 112 otherwise comparable volunteers in active (56 walking postal delivery workers) or inactive (56 administrative postal workers) occupations in Glasgow (Scotland) in 2007.

METHODS

Twenty four-hour physical activity (steps and time standing, walking and sedentary) patterns were measured using activPAL™ for seven days. Comparisons were made during 8-hour work-shifts, during non-work hours on work-days and during the 2 non-work days.

RESULTS

Age and body mass index of delivery and office staff, respectively, were (means (SD)) 38 (9) years versus 40 (7) years and 26.3 (3) kg m(-2) versus 27.4 (4) kg m(-2). Delivery staff spent substantially longer time than office staff upright (6.0 (1.1) h versus 3.9 (1.5) h) and walking (3.1 (0.7) h versus 1.6 (0.7) h) and amassed more steps (16,035 (4264) versus 6709 (2808)) during 8-hour work-shifts and over 24h on work days. During non-work hours of work-days and during non-work days, there were no significant differences in physical activity between the groups. The results were unchanged when the 15 women were excluded.

CONCLUSION

Having a more active occupation is not associated with more inactivity during non-work hours.

Postprandial lipaemia, oxidative stress and endothelial function: a review

AIMS

Postprandial lipaemia-induced endothelial dysfunction is felt to be mediated by increases in oxidative stress. In this review, we have examined the cross-sectional relationships found among these three variables.

METHODS

We found 20 studies conducted by 16 independent investigative teams through a Medline search from 1980 to 2008; studies were required to report correlations between at least two of the three variables of interest in studies of humans. This review is divided into (i) discussions on the biomarkers and other measures of postprandial lipaemia, oxidative stress and endothelial function; (ii) associations reported among the three variables; and (iii) other considerations including alternative intervention studies.

RESULTS

Triglycerides and free fatty acids are robust and well-standardised biomarkers of lipaemia. Measures of oxidative stress ranged from electron spin techniques to measures of lipid peroxidation and are limited by lack of standardisation. Brachial artery flow-mediated dilatation is the most commonly used measure of endothelial function. The associations between postprandial lipaemia and oxidative stress and between postprandial lipaemia and endothelial function are strong and consistent. However, the association between postprandial oxidative stress and endothelial function appears weak, at least using current approaches to measurement of oxidative stress.

DISCUSSION AND CONCLUSIONS

These observations are consistent with the proposed concept that oxidative stress mediates the adverse effects of postprandial lipaemia on endothelial function; they are limited by the difficulties in measuring oxidative stress. Efforts directed at optimising and standardising the measurement of oxidative stress will be of value in future works in this area.

Sex differences in postprandial plasma tumor necrosis factor-alpha, interleukin-6, and C-reactive protein concentrations

Abdominal obesity and insulin resistance are characterized by low-level chronic inflammation most likely implicated in the increased cardiovascular disease risk associated with these conditions. However, not much is known of the acute regulation of circulating inflammatory markers in response to food intake. The aim of this study is to examine changes in inflammatory marker concentrations after the consumption of a high-fat meal in men and women. We measured tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and C-reactive protein concentrations in plasma samples collected at 0, 4, and 8 hours after consumption of the meal in 39 men and 41 women. Associations between these variations and physical as well as metabolic variables were then examined. We noted significant increases in plasma IL-6 concentrations at 4 and 8 hours after the meal in men (+34% and +107%, respectively; P < .005 vs 0 hour) and women (+78% and +153%, respectively; P < .0001 vs 0 hour). Postprandial plasma TNF-alpha concentrations significantly dropped at 4 hours after the high-fat meal in men (-9.5%, P < .0005 vs 0 hour) and women (-5.5%, P < .05 vs 0 hour). Plasma CRP concentrations were not affected by food intake in either men or women. We also found that postprandial plasma concentrations of IL-6 were lower in subjects with a normal glucose tolerance (n = 69) compared with individuals with an impaired glucose tolerance (n = 11). Results of the present study show that consumption of a high-fat meal is associated with a transient reduction in circulating concentrations of TNF-alpha in both men and women as well as an elevation of plasma IL-6 concentrations that was found to be greater in women than in men.

Free fatty acid kinetics in the late phase of postexercise recovery: importance of resting fatty acid metabolism and exercise-induced energy deficit

Free fatty acid (FFA) availability increases several-fold during exercise and remains significantly elevated for at least 3 to 6 hours after exercise cessation. Little, however, is known regarding the duration of the postexercise rise in FFA flux. In the present study, we used stable isotope-labeled palmitate infusion to examine fatty acid metabolism in 27 healthy untrained men and women (age, 29 +/- 7 years; body mass index, 25 +/- 4 kg/m2) between 13 to 16 hours and 21 to 24 hours after a single bout of moderate-intensity endurance exercise (1-2 hours at 60% of peak oxygen consumption), performed in the evening, and after a time-matched resting trial. Postabsorptive FFA rate of appearance (Ra) and FFA concentration in plasma were significantly greater after exercise than rest throughout the recovery period (P < .015), but the exercise-induced increases declined from approximately 40% at 13 to 16 hours to approximately 10% at 21 to 24 hours postexercise (P = .001). The magnitude of the exercise-induced increase in plasma FFA concentration was proportional to the increase in FFA Ra. Correlation analysis demonstrated that exercise-induced changes in plasma FFA Ra at 13 to 16 hours are (1) negatively associated with resting plasma FFA Ra and (2) positively associated with the net energy expenditure of exercise and the exercise-induced changes in whole-body fat oxidation rate (all P values < .05). In multivariate stepwise linear regression analysis, baseline plasma FFA Ra (P < or = .008) and net energy expenditure of exercise (P < or = .005) independently predicted the exercise-induced change in plasma FFA Ra at 13 to 16 hours. We conclude that the exercise-induced increase in FFA mobilization is (1) long-lived, persisting for 12 to 24 hours after exercise, with a progressive decline with time; (2) greater in subjects with low than high resting plasma FFA availability; and (3) greater after exercise with high than low energy demand.

Effect of prior exercise on postprandial lipemia and markers of inflammation and endothelial activation in normal weight and overweight adolescent boys

Postprandial lipemia (PPL) is associated with impaired endothelial function and inflammation. Acute exercise reduces PPL in adults. This investigation examined the effect of an acute bout of exercise on postprandial changes in triglycerides (TG), glucose, insulin, inflammation [white blood cell count (WBC), interleukin-6 (IL-6) tumor necrosis factor-alpha, C-reactive protein (CRP)] and endothelial activation [soluble intercellular adhesion molecule-1 (sICAM-1), vascular adhesion molecule-1 (sVCAM-1)] following a high-fat meal in adolescents. Ten normal weight (NW) (BMI, 20.9 +/- 1.7 kg m(-2); 15.6 +/- 0.7 years) and eight overweight (OW) (BMI, 28.3 +/- 3.6 kg m(-2); 15.9 +/- 0.4 years) adolescent boys underwent two 6-h oral fat tolerance tests (OFTT) separated by 7-10 days. On the evening prior to each OFTT, subjects either rested or completed a treadmill exercise bout (65% V(O)(2max); 600 kcal expended). Exercise reduced (P < 0.01) the postprandial TG area under the curve by approximately 20% in the NW and OW groups. The postprandial glucose and insulin response did not differ between the control and exercise trials or between the NW and OW groups. Circulating leukocytes and plasma IL-6 levels increased (P < 0.01) in the NW and OW groups 6 h following the OFTT in both experimental conditions. There were no changes in CRP, sVCAM-1 or sICAM-1 following the OFTT and there were no differences between experimental condition or NW and OW groups. In conclusion, a moderate exercise bout prior to a high-fat meal effectively reduces postprandial TG concentrations to a similar degree in both NW and OW adolescents, but does not reduce the concomitant postprandial increase in WBC or IL-6.

Active middle-aged men have lower fasting inflammatory markers but the postprandial inflammatory response is minimal and unaffected by physical activity status

Physical activity modifies some postprandial responses such as glycemic control, although it is unclear whether this translates into lower postprandial inflammation. Our objective in this study was to determine whether postprandial inflammatory markers are lower in active compared with sedentary middle-aged men. Thirteen active and twelve sedentary middle-aged men consumed a mixed meal on one occasion. Blood was taken via a cannula before and up to 8 h after the meal and with a single-use needle before and 8 h after the meal. Active men had lower fasted IL-6 (0.6 +/- 0.2 vs. 1.2 +/- 0.3 pg/ml; P = 0.004) and C-reactive protein (1.3 +/- 0.3 vs. 2.9 +/- 0.6 mg/l; P = 0.04) concentrations than sedentary men. Cannula blood IL-6 concentrations increased by 3.49 pg/ml in the 8 h following the meal (P < 0.001); however, this increase was minimal (0.36 pg/ml) in blood taken via a single-use needle from the contralateral arm (P = 0.013). The sedentary group had larger glucose (P = 0.034), insulin (P = 0.013), and triacylglycerol (P = 0.057) responses to the meal. These results provide further evidence that physical activity is associated with lower inflammatory marker concentrations in a fasted state and a lower postprandial metabolic response to a meal. However, this does not translate into lower postprandial inflammatory markers since the only evidence of postprandial inflammation (a large increase in serum IL-6) was actually due to the cannula used for blood sampling.

Oxidative stress in severely obese persons is greater in those with insulin resistance

The postprandial state seems to have a direct influence on oxidative status and insulin resistance. We determined the effect of an increase in plasma triglycerides after a high-fat meal on oxidative stress in severely obese patients with differing degrees of insulin resistance. The study was undertaken in 60 severely obese persons who received a 60-g fat overload with a commercial preparation. Measurements were made of insulin resistance, the plasma activity of various antioxidant enzymes, the total antioxidant capacity (TAC) and the plasma concentration of thiobarbituric acid reactive substances (TBARS). The patients with greater insulin resistance had a lower plasma superoxide dismutase (SOD) activity (P < 0.05) and a greater glutathione peroxidase (GSH-Px) activity (P < 0.05). The high-fat meal caused a significant reduction in SOD activity and an increase in the plasma concentration of TBARS in all the patients. Only the patients with lower insulin resistance experienced a significant increase in plasma catalase activity (2.22 +/- 1.02 vs. 2.93 +/- 1.22 nmol/min/ml, P < 0.01), remaining stable in the patients with greater insulin resistance. These latter patients had a reduction in plasma TAC (6.92 +/- 1.93 vs. 6.29 +/- 1.80 mmol/l, P < 0.01). In conclusion, our results show a close association between the degree of insulin resistance and markers of oxidative stress, both before and after a high-fat meal. The postprandial state causes an important increase in oxidative stress, especially in severely obese persons with greater insulin resistance. However, we are unable to determine from this study whether there is first an increase in oxidative stress or in insulin resistance.

Effects of continuous versus accumulated activity patterns on postprandial triacylglycerol concentrations in obese men

OBJECTIVE

There is limited information regarding the effects of short (<10 min) bouts of activity on postprandial lipaemia and no studies are available regarding the effects of short bouts of activity on postprandial lipaemia in obese men. The objective of this study was to compare the effects of accumulating ten, 3-min bouts of exercise versus one 30 min bout of exercise on postprandial serum triacylglycerol (TAG) concentrations in obese men.

DESIGN

Each subject completed three 2-day trials at least 1 week apart in a randomized, repeated-measures design. On day 1, subjects rested (no exercise) or cycled at 60% of maximum heart rate in either ten, 3-min bouts (30 min rest between each), or one continuous 30-min bout. On day 2 of each trial, after an overnight fast, the subjects consumed a standardized test meal for breakfast. Venous blood samples were obtained in the fasted state (0 h), and 2, 4 and 6 h postprandially on day 2.

SUBJECTS

Eight sedentary men (age: 27+/-2 years) with body mass index between 25 and 37 kg/m(2).

MEASUREMENTS

Postprandial TAG, non-esterified fatty acids, 3-hydroxybutyrate, insulin and glucose were determined.

RESULTS

Total area under the postprandial serum TAG concentrations versus time curve was 18% (P=0.042) and 15% (P=0.032) lower throughout day 2 of both the accumulated exercise trial and the continuous exercise trial, respectively, compared with the control trial with little difference between exercise trials.

CONCLUSION

At 30 min of moderate cycling (0.87 MJ per 30 min) accumulated in short bouts is equally effective in reducing postprandial serum TAG concentrations as one continuous 30 min bout of cycling in obese men.

A single 1-h bout of evening exercise increases basal FFA flux without affecting VLDL-triglyceride and VLDL-apolipoprotein B-100 kinetics in untrained lean men

Our group (Magkos F, Wright DC, Patterson BW, Mohammed BS, Mittendorfer B, Am J Physiol Endocrinol Metab 290: E355-E362, 2006) has recently demonstrated that a single, prolonged bout of moderate-intensity cycling (2 h at 60% of peak oxygen consumption) in the evening increases basal whole-body free fatty acid (FFA) flux and fat oxidation, decreases hepatic VLDL-apolipoprotein B-100 (apoB-100) secretion, and enhances removal efficiency of VLDL-triglyceride (TG) from the circulation the following day in untrained, healthy, lean men. In the present study, we investigated the effect of a single, shorter-duration bout of the same exercise (1 h cycling at 60% of peak oxygen consumption) on basal FFA, VLDL-TG, and VLDL-apoB-100 kinetics in seven untrained, healthy, lean men by using stable isotope-labeled tracer techniques. Basal FFA rate of appearance in plasma and plasma FFA concentration were approximately 55% greater (P < 0.05) the morning after exercise than rest, whereas resting metabolic rate and whole-body substrate oxidation rates were not different after rest and exercise. Exercise had no effect on plasma VLDL-TG and VLDL-apoB-100 concentrations, hepatic VLDL-TG and VLDL-apoB-100 secretion rates, and VLDL-TG and VLDL-apoB-100 plasma clearance rates (all P > 0.05). We conclude that in untrained, healthy, lean men 1) the exercise-induced changes in basal whole-body fat oxidation, VLDL-TG, and VLDL-apoB-100 metabolism during the late phase of recovery from exercise are related to the duration of the exercise bout; 2) single sessions of typical recreational activities appear to have little effect on basal, fasting plasma TG homeostasis; and 3) there is a dissociation between systemic FFA availability and VLDL-TG and VLDL-apoB-100 secretion by the liver.

Effect of a single high-fat meal on endothelial function in patients with the metabolic syndrome: role of tumor necrosis factor-alpha

BACKGROUND AND AIMS

A single high-fat meal may induce endothelial activation and dysfunction in both normal subjects and in patients with type 2 diabetes. The aim of this study was to assess the effect of a high-fat meal on endothelial function in patients with the metabolic syndrome.

METHODS AND RESULTS

Twenty-five patients with the metabolic syndrome (ATP III criteria) were matched for sex, age and body mass index with 25 subjects without the metabolic syndrome. All subjects ate under supervision a high fat meal (760 calories) with 59% energy from fat, 12% energy from protein and 29% energy from carbohydrates. Compared with the control group, subjects with the metabolic syndrome had reduced endothelial function, as assessed with the l-arginine test, and higher circulating levels of TNF-alpha. Following the high-fat meal, both triglyceride and TNF-alpha levels increased more in subjects with the metabolic syndrome than in subjects without, while endothelial function decreased more in subjects with the metabolic syndrome. There was a significant relation between increases in TNF-alpha levels and decreases in endothelial function score in subjects with the metabolic syndrome (r=-0.39, P=0.03).

CONCLUSION

TNF-alpha levels are increased in subjects with the metabolic syndrome; moreover, a high-fat meal produces further increase in its levels associated with endothelial dysfunction.

Effects of pioglitazone on fasting and postprandial levels of lipid and hemostatic variables in overweight non-diabetic patients with coronary artery disease

OBJECTIVES

To evaluate the effects of pioglitazone on insulin sensitivity and levels of biomarkers associated with thrombotic risk in overweight and obese, non-diabetic subjects with coronary artery disease.

BACKGROUND

Little information is available regarding the effects of thiazolidinediones in the absence of diabetes. Further, although postprandial hyperlipemia is a risk factor for cardiovascular diseases, there is limited information about the postprandial effects.

METHODS

Twenty overweight and obese, non-diabetic patients with coronary artery disease were enrolled in a randomized, placebo-controlled, double-blind study. Subjects were on atorvastatin for the duration of the study and received either placebo or pioglitazone (45 mg day(-1)) for 12 weeks and then crossed over to the alternative therapy for an additional 12 weeks. Insulin sensitivity, fasting and postprandial levels of lipid, hemostatic, and inflammatory variables were measured, and endothelial function was assessed.

RESULTS

Insulin sensitivity improved from 0.03 micromol kg(-1) x min pM(-1) on placebo to 0.04 on pioglitazone (P = 0.0002), and there were decreases in fasting levels of factor (F) VII:C (102 +/- 17% to 92 +/- 18%, P = 0.001), FVII:Ag (68 +/- 12% to 60 +/- 14%, P = 0.01) and in von Willebrand factor (VWF) (174 +/- 94% to 142 +/- 69%, P = 0.01). Pioglitazone lowered postprandial levels of FVII:Ag, FVII:C, plasminogen activator inhibitor-1, VWF, and triglycerides, and increased high-density lipoproteins (+9%, P = 0.02).

CONCLUSIONS

Pioglitazone improves insulin sensitivity and favorably modifies fasting and postprandial lipid, hemostatic and inflammatory markers of the metabolic syndrome in overweight and obese non-diabetic patients with coronary artery disease.

Suplementação de ácidos graxos ômega 3 em atletas de competição: impacto nos mediadores bioquímicos relacionados com o metabolismo lipídico

OBJETIVO: Avaliar o efeito da suplementação dos ácidos graxos ômega 3 em atletas de natação sobre indicadores bioquímicos. MÉTODOS: Nadadores de elite (n = 14) do sexo masculino foram avaliados em estudo randomizado, controlado por placebo pelo período de seis semanas (45 dias). O grupo placebo (GP) recebeu óleo mineral (n = 6) e o grupo suplementado (n = 8), óleo de peixe (GOP) contendo, no total, 950mg de ácido eicosapentaenóico e 500mg de ácido docosapentaenóico. Amostras de sangue foram coletadas imediatamente antes (T0), aos 15 (T15), aos 30 (T30) e aos 45 (T45) dias de suplementação para análise da composição dos ácidos graxos por cromatografia gasosa e para quantificação das lipoproteínas plasmáticas através de kits comerciais específicos. RESULTADOS: Os resultados revelaram um desajuste na dieta dos atletas considerando a ingestão g/kg de massa corporal dos macronutrientes. A análise do questionário de freqüência de consumo mostrou que os atletas não ingeriram regularmente fontes alimentares de ômega 3 e que o consumo de peixes, em 85% da amostra, era inferior ou igual a uma vez na semana. O perfil de ácidos graxos plasmáticos evidenciou aumento dos ácidos graxos poliinsaturados ômega 3 (P < 0,05) e redução do ácido araquidônico no grupo suplementado (P < 0,05). A suplementação com óleo de peixe ocasionou efeito hipocolesterolêmico, com redução nos teores sanguíneos de VLDL, LDL e colesterol total. Os valores de HDL não apresentaram diferenças significativas entre os grupos em nenhum momento estudado (P > 0,05). CONCLUSÃO: A suplementação de ácidos graxos N-3 em atletas nadadores altera os indicadores bioquímicos do metabolismo lipídico, influenciando na redução das lipoproteínas plasmáticas, ricas em colesterol e na prevenção de doenças cardiovasculares.

Effects of ingesting a high-fat diet upon exercise-training cessation on fat accretion in the liver and adipose tissue of rats

The purpose of the present study was to determine if exercise trained rats might benefit from protection against fat accumulation in response to an obesity stimulus initiated upon training cessation. Two groups of female rats were either treadmill trained for 8 weeks (DTr) or remained sedentary (Sed). They were then submitted either to a high-fat diet (HF; 42 E%) or kept on a standard diet (SD; 12.5 E% lipids) for another 6 weeks while remaining sedentary. Fat accumulation in liver and adipocytes along with fat-cell diameter and plasma free fatty acid (FFA) levels were measured 0, 2, and 6 weeks after training cessation. Immediately after the training period (t = 0), DTr rats exhibited similar body mass and higher dietary intake but smaller body fat content (4 fat pads) compared with Sed rats. DTr rats, under both diets, exhibited higher gains in body fat than Sed rats (DTr vs. Sed, 71% vs. 8% and 132% vs. 55% for SD and HF, respectively), such that fat mass in all 4 depots was similar to Sed rats 6 weeks after training cessation. Despite higher adipocyte fat accretion, liver lipid infiltration was not increased in DTr animals and plasma FFA levels were lower throughout the detraining period. In addition, plasma leptin levels remained lower in DTr animals throughout the detraining period under the HF diet condition. The present results indicate that previously exercise trained rats are not protected against adipocyte fat accumulation whether they ingest a standard or a high-fat diet.

Postprandial variations of plasma inflammatory markers in abdominally obese men

OBJECTIVE

Abdominal obesity is associated with a fasting proinflammatory condition. However, not much is known of the potential variations in circulating inflammatory markers after food intake. The purpose of the present study was to examine postprandial changes in plasma tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and C-reactive protein (CRP) concentrations in men and their potential associations with fat distribution and metabolic profile variables.

RESEARCH METHODS AND PROCEDURES

Thirty-eight men were given a high-fat meal in the morning after an overnight fast, and TNF-alpha, IL-6, and CRP levels were measured in plasma at 0, 4, and 8 hours after the meal. Physical and metabolic profiles were also assessed for each participant.

RESULTS

We observed a substantial increase in circulating IL-6 levels (p < 0.0001) after the meal. Although postprandial variations in circulating TNF-alpha levels across time failed to reach statistical significance (p = 0.02), we noted a significant decrease in plasma TNF-alpha concentrations 4 hours (-10%, p < 0.001 vs. 0 hours) after food intake. Plasma CRP levels were not affected by the fat load. We also noted that insulin-sensitive individuals displayed a less pronounced inflammatory response after food intake than insulin-resistant subjects.

DISCUSSION

Results of the present study show that consumption of a high-fat meal leads to an increase in plasma IL-6 concentrations and transient decrease in circulating TNF-alpha levels in overweight men. Our results suggest a possible role of insulin resistance in the modulation of the postprandial inflammatory response, which could, in turn, contribute to worsen the state of insulin resistance.

Effect of physical inactivity on the oxidation of saturated and monounsaturated dietary Fatty acids: results of a randomized trial

OBJECTIVES

Changes in the way dietary fat is metabolized can be considered causative in obesity. The role of sedentary behavior in this defect has not been determined. We hypothesized that physical inactivity partitions dietary fats toward storage and that a resistance exercise training program mitigates storage.

DESIGN

We used bed rest, with randomization to resistance training, as a model of physical inactivity.

SETTING

The trial took place at the Space Clinic (Toulouse, France).

PARTICIPANTS

A total of 18 healthy male volunteers, of mean age +/- standard deviation 32.6 +/- 4.0 y and body mass index 23.6 +/- 0.7 kg/m(2), were enrolled.

INTERVENTIONS

An initial 15 d of baseline data collection were followed by 3 mo of strict bed-rest alone (control group, n = 9) or with the addition of supine resistance exercise training every 3 d (exercise group, n = 9).

OUTCOME MEASURES

Oxidation of labeled [d(31)]palmitate (the main saturated fatty acid of human diet) and [1-(13)C]oleate (the main monounsaturated fatty acid), body composition, net substrate use, and plasma hormones and metabolites were measured.

RESULTS

Between-group comparisons showed that exercise training did not affect oxidation of both oleate (mean difference 5.6%; 95% confidence interval [95% CI], -3.3% to 14.5%; p = 0.20) and palmitate (mean difference -0.2%; 95% CI, -4.1% to 3.6%; p = 0.89). Within-group comparisons, however, showed that inactivity changed oxidation of palmitate in the control group by -11.0% (95% CI, -19.0% to -2.9%; p = 0.01) and in the exercise group by -11.3% (95% CI, -18.4% to -4.2%; p = 0.008). In contrast, bed rest did not significantly affect oleate oxidation within groups. In the control group, the mean difference in oleate oxidation was 3.2% (95% CI, -4.2% to 10.5%; p = 0.34) and 6.8% (95% CI, -1.2% to 14.7%; p = 0.08) in the exercise group.

CONCLUSIONS

Independent of changes in energy balance (intake and/or output), physical inactivity decreased the oxidation of saturated but not monounsaturated dietary fat. The effect is apparently not compensated by resistance exercise training. These results suggest that Mediterranean diets should be recommended in sedentary subjects and recumbent patients.

Physical activity, fitness and cardiovascular disease risk in adults: interactions with insulin resistance and obesity

There is a considerable body of evidence gathered from studies over the past half a century indicating that a high level of physical activity and a moderately high or high degree of cardiorespiratory fitness reduces the risk of CVD (cardiovascular disease). Recent data suggest that high levels of physical activity or fitness may be particularly beneficial to individuals with insulin-resistant conditions, such as the metabolic syndrome, Type II diabetes or obesity. These individuals, if unfit and sedentary, exhibit increased CVD risk, but their dose-response relationship for physical activity/fitness appears to be particularly steep such that, when they undertake high levels of activity (or have high fitness), their level of risk becomes closer to that of their normal weight or nondiabetic peers. This may be due to effects of physical activity in normalizing the metabolic dysfunction particularly associated with insulin-resistant conditions.

A comparison between active- and reactive-hyperaemia-induced brachial artery vasodilation

The measurement of brachial artery vasodilation in response to a hyperaemic stimulus has been used extensively to assess changes in endothelial function. However, whether or not similar changes occur in response to an active hyperaemic stimulus is unknown. The purpose of the present study was to compare brachial artery vasodilation in response to an active compared with a reactive hyperaemic stimulus following a known perturbation of endothelial function. Eight apparently healthy adults were assigned to four treatment conditions in a counter-balanced design: (i) low-fat meal with active hyperaemic stimulus (LFM-A), (ii) high-fat meal with active hyperaemic stimulus (HFM-A), (iii) low-fat meal with reactive hyperaemic stimulus (LFM-R), and (iv) high-fat meal with reactive hyperaemic stimulus (HFM-R). Meals were ingested at 08:00 hours on each treatment day. Brachial artery vasodilation was assessed via ultrasound 4 h after ingestion of each meal. The active hyperaemic stimulus was induced by 5 min of rhythmic handgrip exercise, whereas reactive hyperaemia was induced by 5 min of forearm occlusion. Brachial artery vasodilation was expressed as the percentage change in diameter from baseline to post-active/reactive hyperaemia. Using a 2x2 repeated measures ANOVA, a significant stimulusxmeal interaction (P=0.025) was found. Simple main effects revealed no difference (P=0.541) in brachial artery vasodilation between LFM-A (5.75+/-1.64%) and HFM-A (6.39+/-1.45%); however, a significant decrease (P=0.014) in brachial artery vasodilation was found in the HFM-R (4.29+/-1.64%) compared with the LFM-R (7.18+/-1.13%) treatment. In conclusion, the measurement of brachial artery vasodilation in response to active hyperaemia did not detect a change in endothelial function following a single perturbation meal, whereas reactive hyperaemia did.

The influence of walking performed immediately before meals with moderate fat content on postprandial lipemia

BACKGROUND

Postprandial lipemia is an independent risk factor for coronary heart disease. Single bouts of moderate exercise may lower this risk, but the minimum duration of moderate intensity exercise that still lowers postprandial lipemia is not known. We, therefore, performed a dose-response study with a normal, daily life setting, to identify the minimum duration of moderate intensity walking that lowers postprandial lipemia in sedentary, healthy young men.

METHODS

Sixteen men performed three activity trials (30, 60, or 90 min of treadmill walking at 50% of their individual VO2max) and a control trial with no physical activity in a repeated measures crossover design. The subjects walked immediately before ingestion of the first of two mixed meals, which were served 3 h apart. The meals had a moderate fat content (0.5 g per kg body mass and 33% of total energy per meal) and a macronutrient composition corresponding to current recommendations. Each meal provided one third of the subject's estimated daily energy requirement. Venous blood samples were taken in the fasted state, and then hourly for 6 h after the first meal to assess the postprandial phase. Postprandial lipemia (the incremental area under the curve (dAUC) of triacylglycerol) was compared with a mixed model analysis and Tukey's adjustment.

RESULTS

Postprandial lipemia (dAUC of triacylglycerol) was, compared to the control trial, +2% (P = 1.00), -14% (P = 0.24), and -15% (P = 0.23) in the 30, 60, and 90 min walking trials, respectively.

CONCLUSION

Moderate intensity walking of 60 and 90 min duration slightly, but insignificantly, reduced postprandial lipemia after two mixed meals with moderate fat content in sedentary, healthy young men, compared to inactivity. Therefore, it should be reconsidered if the acute exercise-induced reduction in postprandial lipemia usually observed in studies using high fat meals is of importance in a real, daily life setting.

Effects of a moderate exercise session on postprandial lipoproteins, apolipoproteins and lipoprotein remnants in middle-aged men

Prior moderate exercise reduces postprandial triglyceride concentrations. Its effects on the concentrations, compositions and potential atherogenicity of lipoprotein subfractions were investigated in the present study. Twenty normoglycaemic middle-aged men each underwent two fat tolerance tests (blood taken fasting and for 8 h after a meal containing 80 g fat and 70 g carbohydrate). On the afternoon before one test, subjects performed a 90-min treadmill walk (exercise); no exercise was performed before the control test. Prior exercise significantly reduced postprandial concentrations of chylomicrons (Sf >400) by 28.6% (absolute reduction 14.6 mg dl(-1)), of large VLDL1 (Sf 60-400) by 34.4% (39.7 mg dl(-1)) and of small VLDL2 (Sf 20-60) by 23.0% (9.6 mg dl(-1)). Over 95% of VLDL1 and VLDL2 comprised apolipoprotein (apo) B100-containing particles. Exercise also reduced postprandial remnant-like lipoprotein cholesterol (by 35%) and triglyceride concentrations (by 29%). Postprandial apo CIII/apo B and apo E/apo B ratios in VLDL1 were lower following exercise. Postprandial cholesteryl ester/triglyceride ratios were lower in VLDL1 and VLDL2 and higher in HDL2 following exercise. These data suggest that the effect of prior moderate exercise on VLDL1 is quantitatively greater than its effect on chylomicrons and that, in addition to reducing lipoprotein concentrations, exercise induces compositional changes to lipoprotein species which are likely to influence their metabolism and atherogenicity.