Acute effects of monounsaturated fatty acids with and without omega-3 fatty acids on vascular reactivity in individuals with type 2 diabetes

Individual and interaction effects of monounsaturated fatty acids on their associations with hypertension in Chinese residents

Currently, associations between dietary intakes of individual monounsaturated fatty acids (MUFAs) and hypertension were not well disclosed, and the interaction effects of MUFAs on their associations with hypertension were unknown. Obesity was correlated with both MUFAs and hypertension, while if anthropometric obesity indices performed mediating roles in associations between MUFAs and hypertension remained underdetermined. In our study, 8509 Chinese adults investigated from 2004 to 2011 were included. Dietary information collection and physical examinations were performed at baseline and each timepoint of follow-up. As we found, inverse associations of MUFA17, MUFA18 and MUFA20 with hypertension were statistically significant after adjustments, hazard ratios (HRs) were 0.87, 0.90 and 0.91, respectively. MUFA15 was positively associated with hypertension, with an HR of 1.07 (95% confidence interval: 1.01, 1.12). By performing principal component analysis (PCA) to estimate the joint effects of MUFAs on hypertension, the PCA score of MUFAs was only inversely associated with blood pressure. No joint effect was observed in g-computation analyses. Both linear and nonlinear interactions of MUFAs on their associations with hypertension were estimated using restricted cubic spline analysis. The association between MUFA15 and hypertension was interacted by MUFA17, and the association between MUFA20 and hypertension was interacted by MUFA18. The mediation effects of body mass index and waist circumference were found on associations of hypertension with MUFA15, MUFA17 and MUFA20. Our findings suggested that associations with hypertension were different among individual MUFAs, and mutual interactions existed, implying that the utility of individual MUFAs might be recommended for estimating relationships between MUFAs and diseases. Moreover, fat accumulation might potentially underlie associations between MUFAs and hypertension.

A single high-fat Western meal modulates vascular responsiveness to sympathetic activation at rest and during exercise in humans: a randomized controlled trial

A single high-fat Western meal transiently reduces endothelium-dependent vasodilation at rest, but the interaction with sympathetic vasoconstrictor activity during exercise remains unknown. Herein, we tested the hypothesis that a single high-fat Western meal would impair the ability of contracting skeletal muscle to offset vascular responsiveness to sympathetic activation during exercise, termed functional sympatholysis. In 18 (10 females/8 males) healthy young adults, forearm blood flow (Doppler ultrasound) and beat-to-beat arterial pressure (photoplethysmography) were measured during lower-body negative pressure (LBNP; -20 mmHg) applied at rest and simultaneously during low (15% maximum contraction) and moderate (30% maximum contraction)-intensity rhythmic handgrip exercise. The magnitude of sympatholysis was calculated as the difference of LBNP-induced changes in forearm vascular conductance (FVC) between handgrip and rest. Experiments were performed preprandial and 1 h, 2 h, and 3 h after a high- or low-fat meal. In the preprandial state, LBNP decreased resting FVC (Δ-54 ± 10%), and these responses were attenuated during low (Δ-17 ± 7%)- and moderate (Δ-8 ± 6%)-intensity handgrip exercise. Following a high-fat meal, LBNP induced attenuated decreases in resting FVC (3 h postprandial, Δ-47 ± 10%, P = 0.002 vs. preprandial) and blunted attenuation of FVC during low (3 h postprandial, Δ-23 ± 8%, P = 0.001 vs. preprandial)- and moderate (3 h postprandial, Δ-16 ± 6%, P < 0.001 vs. preprandial)-intensity handgrip exercise. The high-fat meal attenuated the magnitude of sympatholysis during low (preprandial, 38 ± 7 vs. 3 h postprandial, 23 ± 8%, P < 0.001)- and moderate (preprandial, 46 ± 11 vs. 3 h postprandial, 31 ± 10%, P < 0.001)-intensity handgrip exercise. The low-fat meal had no impact on these responses. In conclusion, a single high-fat Western meal modulates sympathetic vasoconstriction at rest and during low- and moderate-intensity handgrip exercise in young healthy adults.NEW & NOTEWORTHY We observed that a single high-fat Western meal, but not an isocaloric low-fat meal, attenuated the sympathetic vasoconstriction at rest and the ability of the active skeletal muscle to counteract the vascular responsiveness to sympathetic activation (i.e., functional sympatholysis) during low- and moderate-intensity rhythmic handgrip exercise in healthy young adults. Our findings highlight the potential deleterious vascular effect associated with the consumption of a Western diet.

Post-Prandial Cognitive and Blood Pressure Effects of a DHA-Rich Omega-3 Powder in Middle-Aged Males: A Pilot Study

The use of omega-3 polyunsaturated fatty acid (ω-3 PUFA) supplements is increasingly common among middle-aged and older adults. Users of ω-3 PUFA supplements often report using such supplements to support cognitive health, despite mixed findings reported within the ω-3 PUFA literature. To date, very few studies have explored cognitive effects in distinctly middle-aged (40 to 60 years) adults, and none have examined the acute effects (in the hours following a single dose) on cognitive performance. The current study evaluated whether a single dose of ω-3 PUFA (4020 mg docosahexaenoic acid and 720 mg eicosapentaenoic acid) influences cognitive performance and cardiovascular function in middle-aged males. Cognitive performance and cardiovascular function were assessed before and 3.5-4 h after consumption of a high dose of ω-3 PUFA (DHA + EPA) or placebo, incorporated into a standardized meal (i.e., single serve of Greek yogurt). In this study of middle-aged males, no significant differential treatment effects were observed for cognitive performance. However, a significant reduction in aortic systolic blood pressure (pre-dose to post-dose) was apparent following consumption of the ω-3 PUFA (DHA + EPA) treatment (mean difference = -4.11 mmHg, p = 0.004) but not placebo (mean difference = -1.39 mmHg, p = 0.122). Future replication in a sample comprising females, as well as patients with hypertension, is merited.

Pecan-enriched diet improves cholesterol profiles and enhances postprandial microvascular reactivity in older adults

Pecan-enriched diets have been linked to improved lipid metabolism; however, the impact of pecans on vascular health has yet to be examined. We hypothesized that 4 weeks of a pecan-enriched diet would improve fasting and postprandial blood lipids and vascular function compared with a nut-free diet. In this randomized control study, 44 older adults (59 ± 6 years) consumed 68 g of pecans/d (pecan; n = 21) or avoided all nuts (control; n = 23) for 4 weeks. At pre- and post-diet visits, fasting and postprandial blood lipids, macrovascular (by flow-mediated dilation), and microvascular (tissue saturation index reactive hyperemia [RH] kinetics by continuous-wave near-infrared spectroscopy) function were assessed. From the pre- to post-diet visit, there were greater reductions in fasting total cholesterol (pecan: -14 ± 4.0 vs control: -0.2 ± 5.4 mg/dL; P = .04), low-density lipoprotein (LDL) cholesterol (pecan: -15 ± 3.7 vs control: +1.9 ± 4.4 mg/dL; P = .01), non-high-density lipoprotein cholesterol (pecan: -15 ± 3.6 vs control: -0.5 ± 4.8 mg/dL; P = .02), LDL particle number (pecan: -126 ± 51 vs control: +43 ± 42 nmol/L; P = .01), and LDL medium (pecan: -34 ± 13 vs control: +16 ± 11 nmol/L; P < .01), for pecan vs control. Further, postprandial triglyceride was suppressed for pecan (P = .01) compared with control (P = .78). Postprandial RH slope (P = .04) and RH time to half (P = .004) was different by group, driven by improvements in pecan vs control. However, fasting macro- and microvascular function was unaffected. Daily pecan consumption for 4 weeks improved fasting and postprandial blood lipids and microvascular reactivity in older adults. Because changes in microvascular function typically precipitate macrovascular changes, long-term pecan consumption may improve vascular health and reduce risk for cardiovascular events. This trial was registered at clinicaltrials.gov (NCT04385537).

A single, high-fat meal adversely affects postprandial endothelial function: a systematic review and meta-analysis

BACKGROUND

Endothelial dysfunction is a predictive risk factor for the development of atherosclerosis and is assessed by flow-mediated dilation (FMD). Although it is known that NO-dependent endothelial dysfunction occurs after consuming a high-fat meal, the magnitude of the effect and the factors that affect the response are unquantified.

OBJECTIVES

We conducted a systematic review and meta-analysis exploring the quantitative effects of a single high-fat meal on endothelial function and determined the factors that modify the FMD response.

METHODS

Six databases were systematically searched for original research published up to January 2022. Eligible studies measured fasting and postprandial FMD following consumption of a high-fat meal. Meta-regression was used to analyze the effect of moderator variables.

RESULTS

There were 131 studies included, of which 90 were suitable for quantitative meta-analysis. A high-fat meal challenge transiently caused endothelial dysfunction, decreasing postprandial FMD at 2 hours [-1.02 percentage points (pp); 95% CI: -1.34 to -0.70 pp; P < 0.01; I2 = 93.3%], 3 hours [-1.04 pp; 95% CI: -1.48 to -0.59 pp; P < 0.001; I2 = 84.5%], and 4 hours [-1.19 pp; 95% CI: -1.53 to -0.84 pp; P < 0.01; I2 = 94.6%]. Younger, healthy-weight participants exhibited a greater postprandial reduction in the FMD percentage change than older, heavier, at-risk groups after a high-fat meal ( P < 0.05). The percentage of fat in the meals was inversely associated with the magnitude of postprandial changes in FMD at 3 hours (P < 0.01).

CONCLUSIONS

A single, high-fat meal adversely impacts endothelial function, with the magnitude of the impact on postprandial FMD moderated by the fasting FMD, participant age, BMI, and fat content of the meal. Recommendations are made to standardize the design of future postprandial FMD studies and optimize interpretation of results, as high-fat meals are commonly used in clinical studies as a challenge to assess endothelial function and therapeutics. This trial was registered at PROSPERO as CRD42020187244.

Effect of omega-3 polyunsaturated fatty acids in modulation of vascular tone under physiological and pathological conditions

Omega-3 polyunsaturated fatty acids (n-3 PUFAs), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are mainly found in marine fish oils and commercially available fish oil supplements. Several studies have documented that n-3 PUFAs can reduce the risk of cardiovascular diseases through anti-inflammatory, anti-thrombotic, and anti-atherosclerotic properties. Notably, regulation of vascular tone is one of the most important bases of cardiovascular health and especially for maintaining blood pressure within optimal physiological ranges. Recent clinical and animal studies indicate an association between n-3 PUFAs and vascular functions. In this regard, many clinical trials and basic experimental studies have been conducted so far to investigate the influence of n-3 PUFAs on vascular tone. In this review, we have summarized the results obtained from both clinical and basic studies that evaluated the effect of n-3 PUFAs under physiological and pathological conditions. Moreover, we also focus on verifying the underlying basic molecular mechanism of n-3 PUFAs on the vascular system.

Modulation of endothelial cell responses and vascular function by dietary fatty acids

Healthy and functional endothelial cells play important roles in maintaining vascular homeostasis, whereas endothelial dysfunction initiates and exacerbates vascular disease progression. Interventional studies with dietary fatty acids have shown that these molecules have varying effects on vascular function. It is hypothesized that the actions of dietary fatty acids on vascular function may be mediated in part through endothelial cells. This review summarizes the results of studies that have examined the acute and chronic effects of dietary fatty acids on endothelial function and vascular properties in humans, as well as the potential mechanisms by which n-3 polyunsaturated fatty acids regulate endothelial function. Altogether, this article provides an extensive review of how fatty acids contribute to vascular function through their ability to modulate endothelial cells and discusses relationships between dietary fatty acids and endothelial cells in the context of vascular dysfunction.

The Postprandial Appearance of Features of Cardiometabolic Risk: Acute Induction and Prevention by Nutrients and Other Dietary Substances

The purpose of this review is to provide an overview of diets, food, and food components that affect postprandial inflammation, endothelial function, and oxidative stress, which are related to cardiometabolic risk. A high-energy meal, rich in saturated fat and sugars, induces the transient appearance of a series of metabolic, signaling and physiological dysregulations or dysfunctions, including oxidative stress, low-grade inflammation, and endothelial dysfunction, which are directly related to the amplitude of postprandial plasma triglycerides and glucose. Low-grade inflammation and endothelial dysfunction are also known to cluster together with insulin resistance, a third risk factor for cardiovascular diseases (CVD) and type-II diabetes, thus making a considerable contribution to cardiometabolic risk. Because of the marked relevance of the postprandial model to nutritional pathophysiology, many studies have investigated whether adding various nutrients and other substances to such a challenge meal might mitigate the onset of these adverse effects. Some foods (e.g., nuts, berries, and citrus), nutrients (e.g., l-arginine), and other substances (various polyphenols) have been widely studied. Reports of favorable effects in the postprandial state have concerned plasma markers for systemic or vascular pro-inflammatory conditions, the activation of inflammatory pathways in plasma monocytes, vascular endothelial function (mostly assessed using physiological criteria), and postprandial oxidative stress. Although the literature is fragmented, this topic warrants further study using multiple endpoints and markers to investigate whether the interesting candidates identified might prevent or limit the postprandial appearance of critical features of cardiometabolic risk.

Protective Effects of Dietary MUFAs Mediating Metabolites against Hypertension Risk in the Korean Genome and Epidemiology Study

Background and Aims: Metabolites related to dietary factors can be used to identify biological markers to prevent metabolic disease. However, most studies have been conducted in the United States and Europe, and those in the Asian region are limited. We investigated the effects of dietary monounsaturated fatty acids (MUFAs) and metabolites on new-onset hypertension in the Korean Genome and Epidemiology Study. Method and Results: A total of 1529 subjects without hypertension were divided into tertiles of dietary MUFAs intake. After a 4-year follow-up, 135 serum metabolites were measured using the AbsoluteIDQ p180 kit. During the 4-year follow-up period, 193 new-onset hypertension incidences were observed. The highest MUFAs intake group was inversely associated with the risk of hypertension compared with the lowest MUFAs intake group (odds ratio (OR) = 0.49, (95% confidence interval (CI) = 0.29–0.82)). Of the 135 metabolites, eight were significantly associated with MUFAs intake. Phosphatidylcholine-diacyl (PC aa) C 38:1 and hydroxysphingomyelin (SM OH) C 16:1 were associated with a decrease in hypertension risk (PC aa C 38:1, OR = 0.60 (95% CI = 0.37–0.96); SM OH C 16:1, OR = 0.42 (95% CI = 0.20–0.90)). The highest MUFAs intake group had a significantly decreased risk of hypertension, even considering PC aa C 38:1 and SM (OH) C 16:1 as a mediator. Conclusion: We confirmed that dietary MUFAs intake, and PC aa C 38:1 and SM (OH) C 16:1 had protective effects against hypertension. Furthermore, high MUFAs intake combined with PC aa C 38:1 and SM (OH) C 16:1 has the most significant effect on reducing the risk hypertension.

Post-prandial hyperlipidaemia results in systemic nitrosative stress and impaired cerebrovascular function in the aged

Post-prandial hyperlipidaemia (PPH) acutely impairs systemic vascular endothelial function, potentially attributable to a free radical-mediated reduction in vascular nitric oxide (NO) bioavailability (oxidative–nitrosative stress). However, it remains to be determined whether this extends to the cerebrovasculature. To examine this, 38 (19 young (≤35 years) and 19 aged (≥60 years)) healthy males were recruited. Cerebrovascular function (middle cerebral artery velocity, MCAv) and cerebrovascular reactivity to hypercapnea (CVRCO2Hyper) and hypocapnea (CVRCO2Hypo) were determined via trans-cranial Doppler ultrasound and capnography. Venous blood samples were obtained for the assessment of triglycerides (photometry), glucose (photometry), insulin (radioimmunoassay), ascorbate free radical (A•−, electron paramagnetic resonance spectroscopy) and nitrite (NO2–, ozone-based chemiluminescence) in the fasted state prior to and 4 h following consumption of a standardized high-fat meal (1362 kcal; 130 g of fat). Circulating triglycerides, glucose and insulin increased in both groups following the high-fat meal (P<0.05), with triglycerides increasing by 1.37 ± 1.09 mmol/l in the young and 1.54 ± 1.00 mmol/l in the aged (P<0.05). This resulted in an increased systemic formation of free radicals in the young (P<0.05) but not the aged (P>0.05) and corresponding reduction in NO2– in both groups (P<0.05). While the meal had no effect on MCAv in either age group, CVRCO2Hyper was selectively impaired in the aged (P<0.05). These findings indicate that PPH causes acute cerebrovascular dysfunction in the aged subsequent to systemic nitrosative stress.

Each meal matters in the exposome: Biological and community considerations in fast-food-socioeconomic associations

Advances in omics and microbiome technology have transformed the ways in which the biological consequences of life in the 'ecological theatre' can be visualized. Exposome science examines the total accumulated environmental exposures (both detrimental and beneficial) as a means to understand the response of the 'total organism to the total environment' over time. The repetitive stimulation of compensatory physiological responses (immune, cardiovascular, neuroendocrine) in response to stress - including sources of stress highly relevant to socioeconomic disadvantage - may lead to metabolic dysregulation and cellular damage, ultimately influencing behavior and disease. The collective toll of physiological wear and tear, known as allostatic load, is not paid equally throughout developed societies. It is paid in excess by the disadvantaged. In the context of fast-food, human and experimental research demonstrates that the biological response to a single fast-food-style meal - especially as mediated by the microbiome- is a product of the person's total lived experience, including the ability to buffer the fast-food meal-induced promotion of inflammation and oxidative stress. Emerging research indicates that each meal and its nutritional context matters. As we discuss, equal weekly visits to major fast-food outlets by the affluent and deprived do not translate into biological equivalency. Hence, debate concerning reducing fast-food outlets through policy - especially in disadvantaged neighborhoods where they are prevalent - requires a biological context. The fast-food establishment and fast-food meal - as they represent matters of food justice and press upon non-communicable disease risk - are far more than physical structures and collections of carbohydrate, fat, sugar and sodium.

l-Arginine Supplementation Alleviates Postprandial Endothelial Dysfunction When Baseline Fasting Plasma Arginine Concentration Is Low: A Randomized Controlled Trial in Healthy Overweight Adults with Cardiometabolic Risk Factors

BACKGROUND

Vascular endothelial dysfunction, the hallmark of early atherosclerosis, is induced transiently by a high-fat meal. High doses of free l-arginine supplements reduce fasting endothelial dysfunction.

OBJECTIVE

We sought to determine the effects of a low dose of a sustained-release (SR) l-arginine supplement on postprandial endothelial function in healthy overweight adults with cardiometabolic risk factors and to investigate whether this effect may vary by baseline arginine status.

METHODS

In a randomized, double-blind, 2-period crossover, placebo-controlled trial (4-wk treatment, 4-wk washout), we compared the effects of 1.5 g SR-l-arginine 3 times/d (4.5 g/d) with placebo in 33 healthy overweight adults [body mass index (BMI, in kg/m(2)): 25 to >30] with the hypertriglyceridemic waist (HTW) phenotype [plasma triglycerides > 150 mg/dL; waist circumference > 94 cm (men) or > 80 cm (women)]. The main outcome variable tested was postprandial endothelial function after a high-fat meal (900 kcal), as evaluated by use of flow-mediated dilation (FMD) and Framingham reactive hyperemia index (fRHI), after each treatment. By use of subgroup analysis, we determined whether the effect was related to the baseline plasma arginine concentration.

RESULTS

In the total population, the effects of SR-arginine supplementation on postprandial endothelial function were mixed and largely varied with baseline fasting arginine concentration (P-interaction < 0.05). In the lower half of the population (below the median of 78.2 μmol arginine/L plasma), but not the upper half, SR-arginine supplementation attenuated the postprandial decrease in both FMD (29% decrease with SR-arginine compared with 50% decrease with placebo) and fRHI (5% increase with SR-arginine compared with 49% decrease with placebo), resulting in significantly higher mean ± SEM values with SR-arginine (FMD: 4.0% ± 0.40%; fRHI: 0.41 ± 0.069) than placebo (FMD: 2.9% ± 0.31%; fRHI: 0.21 ± 0.060) at the end of the postprandial period (P < 0.05).

CONCLUSIONS

Supplementation with low-dose SR-arginine alleviates postprandial endothelial dysfunction in healthy HTW adults when the baseline plasma arginine concentration is relatively low. The benefits of arginine supplementation may be linked to a lower ability to mobilize endogenous arginine for nitric oxide synthesis during a postprandial challenge. This trial was registered at clinicaltrials.gov as NCT02354794.

Differential effects of EPA versus DHA on postprandial vascular function and the plasma oxylipin profile in men

Our objective was to investigate the impact of EPA versus DHA on arterial stiffness and reactivity and underlying mechanisms (with a focus on plasma oxylipins) in the postprandial state. In a three-arm crossover acute test meal trial, men (n = 26, 35-55 years) at increased CVD risk received a high-fat (42.4 g) test meal providing 4.16 g of EPA or DHA or control oil in random order. At 0 h and 4 h, blood samples were collected to quantify plasma fatty acids, long chain n-3 PUFA-derived oxylipins, nitrite and hydrogen sulfide, and serum lipids and glucose. Vascular function was assessed using blood pressure, reactive hyperemia index, pulse wave velocity, and augmentation index (AIx). The DHA-rich oil significantly reduced AIx by 13% (P = 0.047) with the decrease following EPA-rich oil intervention not reaching statistical significance. Both interventions increased EPA- and DHA-derived oxylipins in the acute postprandial state, with an (1.3-fold) increase in 19,20-dihydroxydocosapentaenoic acid evident after DHA intervention (P < 0.001). In conclusion, a single dose of DHA significantly improved postprandial arterial stiffness as assessed by AIx, which if sustained would be associated with a significant decrease in CVD risk. The observed increases in oxylipins provide a mechanistic insight into the AIx effect.

A single Mediterranean meal does not impair postprandial flow-mediated dilatation in healthy men with subclinical metabolic dysregulations

Cardiovascular risk factors are known to exacerbate high-saturated fatty acid meal (HSFAM)-induced endothelial dysfunction, but the influence of subclinical metabolic dysregulations and the acute impact of a single mixed Mediterranean-type meal (MMM) remains unknown. Thus, this study has the objective to evaluate the metabolic and vascular effect of such meals in healthy subjects with or without subclinical fasting metabolic dysregulations. Twenty-eight healthy males without overt cardiovascular risk factors randomly ingested 1 of 2 isocaloric meals on separate days. Plasma metabolic markers, fatty acid (FA) profile, and endothelial function (flow-mediated dilatation; FMD) were assessed at baseline and 2 and 4 h after meal ingestion. Unsupervised hierarchical clustering identified 2 subgroups of participants (n = 11 and 17) differing by their baseline metabolic profiles. The MMM did not significantly alter postprandial endothelial function in all subjects, irrespective of baseline metabolic parameters. In contrast, the HSFAM induced postprandial endothelial dysfunction (Δ%FMDabsolute = -5.28 ± 2.54, p < 0.01 vs. MMM) in a subgroup of individuals with significantly greater body mass index, fasting insulinemia, and lipid parameters (n = 11). Finally, the postprandial plasma FA profiles were differentially enriched by the HSFAM and MMM, notably with saturated FAs and omega-3 polyunsaturated FAs, respectively. Collectively, our results highlight the detrimental impact of a single HSFAM on endothelial function in healthy individuals displaying subclinical fasting metabolic dysregulations. Such individuals could benefit from MMM, demonstrated herein to be without any acute detriment to endothelial function.

Postprandial Dysmetabolism and Oxidative Stress in Type 2 Diabetes: Pathogenetic Mechanisms and Therapeutic Strategies

Postprandial dysmetabolism in type 2 diabetes (T2D) is known to impact the progression and evolution of this complex disease process. However, the underlying pathogenetic mechanisms still require full elucidation to provide guidance for disease prevention and treatment. This review focuses on the marked redox changes and inflammatory stimuli provoked by the spike in blood glucose and lipids in T2D individuals after meals. All the causes of exacerbated postprandial oxidative stress in T2D were analyzed, also considering the consequence of enhanced inflammation on vascular damage. Based on this in-depth analysis, current strategies of prevention and pharmacologic management of T2D were critically reexamined with particular emphasis on their potential redox-related rationale.

Palmolein and olive oil consumed within a high protein test meal have similar effects on postprandial endothelial function in overweight and obese men: A randomized controlled trial

OBJECTIVE

This study assessed the postprandial effects of high fat, high protein meals containing either palmolein or olive oil on endothelial function in overweight/obese men.

DESIGN

28 men (32-65 yr; 25-35 kg/m(2)) consumed, in random order 1 wk apart, isocaloric high protein, high fat meals (2791 kJ, 40 g protein (∼3 g l-arginine), 44 g fat, 21 g carbohydrate) prepared with either 40 g palmolein or 40 g olive oil after an overnight fast. The SFA:MUFA:PUFA ratio of the oils were: palmolein, 42:47:12; olive oil, 17:76:7. Brachial artery flow-mediated dilatation (FMD), circulating endothelial function markers, nitrotyrosine (oxidative stress marker), triglycerides, glucose and insulin were assessed pre-meal and hourly for 5 h. Mixed model procedures were used to analyze the data.

RESULTS

Meal consumption increased serum triglycerides (time effect, P < 0.001); with no meal differences (meal × time interaction, P = 0.93). Serum insulin peaked 1 h post-consumption and returned to pre-meal concentrations by 5 h with both meals (time effect, P < 0.001; meal × time effect, P = 0.68). FMD, serum intercellular adhesion molecule-1 (ICAM-1) and E-selectin did not change (meal × time effect, P > 0.4). Olive oil transiently increased plasma nitrotyrosine after 1 h compared to palmolein (meal × time interaction, P = 0.002) whereas both meals increased serum vascular cell adhesion molecule-1 (VCAM-1) after 1 h (time effect, P < 0.001; meal × time interaction, P = 0.98). Both nitrotyrosine and VCAM-1 returned to pre-meal concentrations after 2 h.

CONCLUSION

In the context of a high protein meal, palmolein similarly to olive oil did not affect postprandial endothelial function in overweight/obese men.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry (ANZCTR) (http://www.anzctr.org.au/default.aspx). Trial ID: ACTRN12613000136707.

High-fat meals do not impair postprandial endothelial function in HIV-infected and uninfected men

Prior studies have demonstrated impaired endothelium-dependent flow-mediated dilation (FMD) in healthy subjects following a high-fat meal. Compared to uninfected individuals, HIV-infected persons have been shown to have impaired FMD. We examined the effect of two different high-fat meals on endothelial function in HIV-infected and uninfected men. We performed a randomized, parallel group crossover study comparing 47 white men [18 HIV-uninfected, 9 HIV-infected and antiretroviral therapy (ART)-naïve, and 20 HIV-infected men on ART]. Fasting participants consumed one of two randomly assigned high-fat meals of either saturated or polyunsaturated fat, followed at least 24 h later by the other meal. Brachial artery ultrasound measurements to assess vascular reactivity were performed before and 3 h after each dietary challenge. There was no significant difference in mean baseline or postprandial FMD between HIV-infected and HIV-uninfected participants (mean baseline FMD±SD, 9.0%±5 vs. 9.2%±5, p=0.9; mean postprandial FMD±SD, 9.0%±4.7 vs. 9.1%±4.7, p=0.96, respectively). No significant difference in baseline or postprandial change in FMD was found between meals or HIV treatment groups. Fasting lipids and glucose, CD4(+) count, and viral load did not predict FMD in HIV-infected participants. In contrast to previous reports, this study did not demonstrate impaired endothelium-dependent vasodilation after high-fat meals in either HIV-infected or HIV-uninfected men. Moreover, HIV infection itself may not be the primary explanation for the abnormal endothelial function reported in HIV-infected individuals.

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.

Effects of dark chocolate and cocoa consumption on endothelial function and arterial stiffness in overweight adults

The consumption of cocoa and dark chocolate is associated with a lower risk of CVD, and improvements in endothelial function may mediate this relationship. Less is known about the effects of cocoa/chocolate on the augmentation index (AI), a measure of vascular stiffness and vascular tone in the peripheral arterioles. We enrolled thirty middle-aged, overweight adults in a randomised, placebo-controlled, 4-week, cross-over study. During the active treatment (cocoa) period, the participants consumed 37 g/d of dark chocolate and a sugar-free cocoa beverage (total cocoa = 22 g/d, total flavanols (TF) = 814 mg/d). Colour-matched controls included a low-flavanol chocolate bar and a cocoa-free beverage with no added sugar (TF = 3 mg/d). Treatments were matched for total fat, saturated fat, carbohydrates and protein. The cocoa treatment significantly increased the basal diameter and peak diameter of the brachial artery by 6% (+2 mm) and basal blood flow volume by 22%. Substantial decreases in the AI, a measure of arterial stiffness, were observed in only women. Flow-mediated dilation and the reactive hyperaemia index remained unchanged. The consumption of cocoa had no effect on fasting blood measures, while the control treatment increased fasting insulin concentration and insulin resistance (P= 0·01). Fasting blood pressure (BP) remained unchanged, although the acute consumption of cocoa increased resting BP by 4 mmHg. In summary, the high-flavanol cocoa and dark chocolate treatment was associated with enhanced vasodilation in both conduit and resistance arteries and was accompanied by significant reductions in arterial stiffness in women.

Endothelial dysfunction in diabetes: pathogenesis, significance, and treatment

Type 2 diabetes (T2D) markedly increases the risk of cardiovascular disease. Endothelial dysfunction (ED), an early indicator of diabetic vascular disease, is common in T2D and independently predicts cardiovascular risk. Although the precise pathogenic mechanisms for ED in T2D remain unclear, at inception they probably involve uncoupling of both endothelial nitric oxide synthase activity and mitochondrial oxidative phosphorylation, as well as the activation of vascular nicotinamide adenine dinucleotide phosphate oxidase. The major contributing factors include dyslipoproteinemia, oxidative stress, and inflammation. Therapeutic interventions are designed to target these pathophysiological factors that underlie ED. Therapeutic interventions, including lifestyle changes, antiglycemic agents and lipid-regulating therapies, aim to correct hyperglycemia and atherogenic dyslipidemia and to improve ED. However, high residual cardiovascular risk is seen in both research and clinical practice settings. Well-designed studies of endothelial function in appropriately selected volunteers afford a good opportunity to test new therapeutic interventions, paving the way for clinical trials and utilization in the care of the diabetic patient. However, based on the results from a recent clinical trial, niacin should not be added to a statin in individuals with low high-density lipoprotein cholesterol and very well controlled low-density lipoprotein cholesterol.

Postprandial effect of dietary fat quantity and quality on arterial stiffness and wave reflection: a randomised controlled trial

Background

Arterial stiffness is a component of vascular function and an established risk factor for cardiovascular disease. There is a lack of conclusive evidence on the effect of a meal rich in monounsaturated fat (MUFA) compared with an isoenergetic meal rich in saturated fat (SFA) on postprandial vascular function and specifically on arterial stiffness.

Methods

Twenty healthy, non-smoking males (BMI 24 ± 2 kg/m²; age 37.7 ± 14.4 y) participated in this single-blind, randomised, cross-over dietary intervention study. Each subject was randomised to receive a high-fat test-meal (3 MJ; 56 ± 2 g fat) at breakfast on 2 separate occasions, one rich in oleic acid (MUFA-meal) and one rich in palmitic acid (SFA-meal), and the meals were isoenergetic. Blood pressure (BP), arterial stiffness (PWV) and arterial wave reflection (augmentation index, AIx) were measured using applanation tonometry at baseline and every 30 minutes up to 4 hours after the ingestion of the test-meals.

Results

All subjects completed both arms of the dietary intervention. There was no significant difference in BP parameters, PWV or AIx at baseline between the two treatments (P > 0.05). There was a significant increase in brachial and aortic BP, mean arterial pressure (MAP), heart rate and PVW (time, P < 0.05) over the four hours after consumption of the fat-rich test-meal although the increase in PWV was no longer significant when adjusted for the increase in MAP. There was no difference in PWV between the two treatments (treatment*time, P > 0.05). There was a significant reduction in AIx (time, P < 0.05) over the four hour postprandial period although this was no longer significant when adjusted for the increase in heart rate and MAP (time, P > 0.05). There was no difference in AIx between the two treatments (treatment*time, P > 0.05). However, the reduction in heart rate corrected augmentation index (AIx₇₅) was significant when corrected for the increase in MAP (time, P < 0.01) with no differential effect of the treatments (treatment*time, P > 0.05).

Conclusions

This study has demonstrated a BP dependent increase in PWV and a decrease in arterial wave reflection in the four hour period in response to a high-fat meal. There was no evidence however that replacement of some of the SFA with MUFA had a differential effect on these parameters. The study highlights the need for further research to understand the effects of the substitution of SFA with MUFA on non-serum, new and emerging risk factors for CVD such as arterial stiffness.

The role of oxidative stress in postprandial endothelial dysfunction

Endothelial dysfunction is a turning point in the initiation and development of atherosclerosis and its complications and is predictive of future cardiovascular events. Ingestion of high-carbohydrate or high-fat meals often results in postprandial hyperglycaemia and/or hypertriacylglycerolaemia that may lead to a transient impairment in endothelial function. The present review will discuss human studies evaluating the impact of high-carbohydrate and high-fat challenges on postprandial endothelial function as well as the potential role of oxidative stress in such postprandial metabolic alterations. Moreover, the present review will differentiate the postprandial endothelial and oxidative impact of meals rich in varying fatty acid types.

Evidence of health benefits of canola oil

Canola oil-based diets have been shown to reduce plasma cholesterol levels in comparison with diets containing higher levels of saturated fatty acids. Consumption of canola oil also influences biological functions that affect various other biomarkers of disease risk. Previous reviews have focused on the health effects of individual components of canola oil. Here, the objective is to address the health effects of intact canola oil, as this has immediate practical implications for consumers, nutritionists, and others deciding which oil to consume or recommend. A literature search was conducted to examine the effects of canola oil consumption on coronary heart disease, insulin sensitivity, lipid peroxidation, inflammation, energy metabolism, and cancer cell growth. Data reveal substantial reductions in total cholesterol and low-density lipoprotein cholesterol, as well as other positive actions, including increased tocopherol levels and improved insulin sensitivity, compared with consumption of other dietary fat sources. In summary, growing scientific evidence supports the use of canola oil, beyond its beneficial actions on circulating lipid levels, as a health-promoting component of the diet.

ω-3 polyunsaturated fatty acid supplementation does not influence body composition, insulin resistance, and lipemia in women with type 2 diabetes and obesity

To evaluate the influence of ω-3 polyunsaturated fatty acid (ω-3 PUFA) supplementation on body composition, insulin resistance, and lipemia of women with type 2 diabetes, the authors evaluated 41 women (60.64 ± 7.82 years) with high blood pressure and diabetes mellitus in a randomized and single-blind longitudinal intervention study. The women were divided into 3 groups: GA (2.5 g/d fish oil), GB (1.5 g/d fish oil), and GC (control). The capsules with the supplement contained 21.9% of eicosapentaenoic acid and 14.1% of docosapentaenoic acid. Biochemical (glucose, glycated hemoglobin, total and fractional cholesterol, triglycerides, and insulin) and anthropometric (body mass, stature, waist circumference [WC], and body composition) evaluations were performed before and after the 30 days of intervention. Homeostasis model assessment-insulin resistance and the Quantitative Insulin Sensitivity Check Index were used to evaluate the insulin resistance and insulin sensitivity (IS), respectively. GB presented a greater loss of body mass and WC (P < .05), greater frequency of glycemic and total cholesterol reduction, and an increase of high-density lipoprotein cholesterol compared with GA. Thus, a high dose of ω-3 PUFA can reduce IS. A lower dose of ω-3 PUFA positively influenced body composition and lipid metabolism.

A comparison of the changes in cardiac output and systemic vascular resistance during exercise following high-fat meals containing DHA or EPA

Long-chain n-3 PUFA can lower blood pressure (BP) but their acute effects on cardiac output, BP and systemic vascular resistance (SVR) in response to dynamic exercise are uncertain. We compared the effects of high-fat meals rich in EPA (20 : 5n-3), DHA (22 : 6n-3) or oleic acid (control) on cardiac output, BP and SVR in response to exercise stress testing. High-fat meals (50 g fat) containing high-oleic sunflower oil enriched with 4·7 g of either EPA or DHA v. control (high-oleic sunflower oil only) were fed to twenty-two healthy males using a randomised cross-over design. Resting measurements of cardiac output, heart rate and BP were made before and hourly over 5 h following the meal. A standardised 12 min exercise test was then conducted with further measurements made during and post-exercise. Blood samples were collected at fasting, 5 h postprandially and immediately post-exercise for the analysis of lipid, glucose and 8-isoprostane-F2α (8-iso-PGF2α). Plasma concentrations of EPA and DHA increased by 0·22 mmol/l 5 h following the EPA and DHA meals, respectively, compared with the control (P < 0·001). Resting cardiac output and 8-iso-PGF2α increased similarly following all meals and there were no significant differences in cardiac output during exercise between the meals. SVR was lower at 5 h and during exercise following the DHA but not EPA meal, compared with the control meal, by 4·9 % (95 % CI 1·3, 8·4; P < 0·01). Meals containing DHA appear to differ from EPA with regard to their effects on cardiovascular haemodynamics during exercise.

Effect of meal content on heart rate variability and cardiovascular reactivity to mental stress

Little is known about transient effects of foods and nutrients on reactivity to mental stress. In a randomized crossover study of healthy adults (n=20), we measured heart rate variability (respiratory sinus arrhythmia), blood pressure, and other hemodynamic variables after three test meals varying in type and amount of fat. Measurements were collected at rest and during speech and cold pressor tasks. There were significant postmeal changes in resting diastolic blood pressure (-4%), cardiac output (+18%), total peripheral resistance (-17%), and interleukin-6 (-27%). Heart rate variability and hemodynamic reactivity to stress was not affected by meal content. We recommend that future studies control for time since last meal and continue to examine effects of meal content on heart rate variability.

A review of the evidence for the effects of total dietary fat, saturated, monounsaturated and n-6 polyunsaturated fatty acids on vascular function, endothelial progenitor cells and microparticles

Vascular dysfunction is recognised as an integrative marker of CVD. While dietary strategies aimed at reducing CVD risk include reductions in the intake of SFA, there are currently no clear guidelines on what should replace SFA. The purpose of this review was to assess the evidence for the effects of total dietary fat and individual fatty acids (SFA, MUFA and n-6 PUFA) on vascular function, cellular microparticles and endothelial progenitor cells. Medline was systematically searched from 1966 until November 2010. A total of fifty-nine peer-reviewed publications (covering fifty-six studies), which included five epidemiological, eighteen dietary intervention and thirty-three test meal studies, were identified. The findings from the epidemiological studies were inconclusive. The limited data available from dietary intervention studies suggested a beneficial effect of low-fat diets on vascular reactivity, which was strongest when the comparator diet was high in SFA, with a modest improvement in measures of vascular reactivity when high-fat, MUFA-rich diets were compared with SFA-rich diets. There was consistent evidence from the test meal studies that high-fat meals have a detrimental effect on postprandial vascular function. However, the evidence for the comparative effects of test meals rich in MUFA or n-6 PUFA with SFA on postprandial vascular function was limited and inconclusive. The lack of studies with comparable within-study dietary fatty acid targets, a variety of different study designs and different methods for determining vascular function all confound any clear conclusions on the impact of dietary fat and individual fatty acids on vascular function.

Effects of diets high in walnuts and flax oil on hemodynamic responses to stress and vascular endothelial function

BACKGROUND

Polyunsaturated fatty acids (PUFA) have beneficial effects on cardiovascular risk, although the mechanisms are incompletely understood. In a previous article, we showed significant reductions in low-density lipoprotein cholesterol and several markers of inflammation with increasing intake of alpha-linolenic acid (ALA) from walnuts and flax.

OBJECTIVE

To examine effects of ALA on cardiovascular responses to acute stress, flow-mediated dilation (FMD) of the brachial artery, and blood concentrations of endothelin-1 and arginine-vasopressin (AVP).

DESIGN

Using a randomized, crossover study design, cardiovascular responses to acute stress were assessed in 20 hypercholesterolemic subjects, a subset of whom also underwent FMD testing (n  =  12). Participants were fed an average American diet (AAD) and 2 experimental diets that varied in the amount of ALA and linoleic acid (LA) that they contained. The AAD provided 8.7% energy from PUFA (7.7% LA, 0.8% ALA). On the LA diet, saturated fat was reduced, and PUFA from walnuts and walnut oil provided 16.4% of energy (12.6% LA, 3.6% ALA). On the ALA diet, walnuts, walnut oil, and flax oil provided 17% energy from PUFA (10.5% LA, 6.5% ALA).

RESULTS

The ALA and LA diets significantly reduced diastolic blood pressure (-2 to -3 mm Hg) and total peripheral resistance (-4%), and this effect was evident at rest and during stress (main effect of diet, p < 0.02). FMD increased (+34%) on the diet containing additional ALA. AVP also increased by 20%, and endothelin-1 was unchanged.

CONCLUSIONS

These results suggest novel mechanisms for the cardioprotective effects of walnuts and flax, and further work is needed to identify the bioactives responsible for these effects.

Impact of n-3 fatty acids on endothelial function: results from human interventions studies

PURPOSE OF REVIEW

Dysfunction of the endothelium plays an integral role in atherogenesis. This review summarizes recent findings on the effects of marine [eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA)] and plant [alpha-linolenic acids (ALA)] n-3 polyunsaturated fatty acids (PUFAs) on endothelial function in healthy individuals and in patients with cardiovascular disease (CVD) risk factors or manifest CVD.

RECENT FINDINGS

We identified 33 intervention trials investigating the effects of n-3 PUFA on fasting and/or postprandial endothelial function. In healthy individuals regular supplementation of EPA/DHA or ALA shows inconsistent results on endothelial function, whereas markers of endothelial function seem to be improved in overweight dyslipidaemic patients and type 2 diabetics. Conflicting results are observed in CVD patients. Reasons for discrepancies between the study results include the health status and age of participants, duration of supplementation, dose and fatty acid composition of the administered n-3 PUFAs as well as methods used to assess endothelial function.

SUMMARY

In individuals with CVD risk factors including overweight, dyslipidemia and type 2 diabetes n-3 PUFAs may improve endothelial function. However, the evidence for a clinical efficacy is not strong enough to make final recommendations with respect to a specific dose and the duration of supplementation.

Dose-response effects of omega-3 fatty acids on triglycerides, inflammation, and endothelial function in healthy persons with moderate hypertriglyceridemia

BACKGROUND

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been shown to reduce cardiovascular mortality at a dose of ≈1 g/d. Studies using higher doses have shown evidence of reduced inflammation and improved endothelial function. Few studies have compared these doses.

OBJECTIVE

The objective of this study was to compare the effects of a nutritional dose of EPA+DHA (0.85 g/d) with those of a pharmaceutical dose (3.4 g/d) on serum triglycerides, inflammatory markers, and endothelial function in healthy subjects with moderately elevated triglycerides.

DESIGN

This was a placebo-controlled, double-blind, randomized, 3-period crossover trial (8 wk of treatment, 6 wk of washout) that compared the effects of 0.85 and 3.4 g EPA+DHA/d in 23 men and 3 postmenopausal women with moderate hypertriglyceridemia (150-500 mg/dL).

RESULTS

The higher dose of EPA+DHA lowered triglycerides by 27% compared with placebo (mean ± SEM: 173 ± 17.5 compared with 237 ± 17.5 mg/dL; P = 0.002), whereas no effect of the lower dose was observed on lipids. No effects on cholesterol (total, LDL, and HDL), endothelial function [as assessed by flow-mediated dilation, peripheral arterial tonometry/EndoPAT (Itamar Medical Ltd, Caesarea, Israel), or Doppler measures of hyperemia], inflammatory markers (interleukin-1β, interleukin-6, tumor necrosis factor-α, and high-sensitivity C-reactive protein), or the expression of inflammatory cytokine genes in isolated lymphocytes were observed.

CONCLUSION

The higher dose (3.4 g/d) of EPA+DHA significantly lowered triglycerides, but neither dose improved endothelial function or inflammatory status over 8 wk in healthy adults with moderate hypertriglyceridemia. The trial was registered at clinicaltrials.gov as NCT00504309.

The evidence for medical nutrition therapy for type 1 and type 2 diabetes in adults

This article reviews the evidence and nutrition practice recommendations from the American Dietetic Association's nutrition practice guidelines for type 1 and type 2 diabetes in adults. The research literature was reviewed to answer nutrition practice questions and resulted in 29 recommendations. Here, we present the recommendations and provide a comprehensive and systematic review of the evidence associated with their development. Major nutrition therapy factors reviewed are carbohydrate (intake, sucrose, non-nutritive sweeteners, glycemic index, and fiber), protein intake, cardiovascular disease, and weight management. Contributing factors to nutrition therapy reviewed are physical activity and glucose monitoring. Based on individualized nutrition therapy client/patient goals and lifestyle changes the client/patient is willing and able to make, registered dietitians can select appropriate interventions based on key recommendations that include consistency in day-to-day carbohydrate intake, adjusting insulin doses to match carbohydrate intake, substitution of sucrose-containing foods, usual protein intake, cardioprotective nutrition interventions, weight management strategies, regular physical activity, and use of self-monitored blood glucose data. The evidence is strong that medical nutrition therapy provided by registered dietitians is an effective and essential therapy in the management of diabetes.

The effect of acute fish-oil supplementation on endothelial function and arterial stiffness following a high-fat meal

This study examined whether a commercially available fish-oil supplement offers protection from the acute effects of a high-fat meal (HFM) on endothelial function and arterial stiffness. An HFM causes acute impairments in endothelial function, whereas the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have a variety of cardioprotective effects. However, little is known about the efficacy of moderate fish-oil supplementation on the endothelial dysfunction induced by an HFM. Endothelial function (brachial artery flow-mediated dilation (FMD)), forearm blood flow (FBF), total hyperemia, central and peripheral blood pressure, and central artery stiffness were assessed in 20 healthy men (n = 10) and women (n = 10) at rest and 4 h after an HFM supplemented with either placebo or approximately 1 g EPA and DHA. Brachial artery FMD normalized for shear rate was significantly impaired (p = 0.033) following the HFM with placebo but remained unchanged compared with baseline following the HFM with the fish-oil supplement (p = 0.039; condition x time interaction). Resting FBF (p = 0.020) and total hyperemia (p = 0.014) were elevated following the HFM. All other vascular and hemodynamic measurements were unchanged in both trials. Commercially available fish-oil supplements taken with an HFM appear to preserve endothelial function following an HFM.

Dietary fatty acids and the risk of hypertension in middle-aged and older women

Dietary intake of various fats may have different effects on blood pressure. We conducted a prospective cohort study to examine the association between intake of subtype and individual fatty acids (FAs) and the risk of developing hypertension among 28 100 US women aged ≥39 years and free of cardiovascular disease and cancer. Baseline intake of FAs was assessed using semiquantitative food frequency questionnaires. Incident hypertension was identified from annual follow-up questionnaires based on self-reported physician diagnosis, medication use, and blood pressure levels. A total of 13 633 women developed incident hypertension during 12.9 years of follow-up. After adjusting for demographic, lifestyle, and other dietary factors, intake of saturated FAs, monounsaturated FAs, and trans-unsaturated FAs (trans FAs) was positively associated with the risk of hypertension. The multivariable relative risks and 95% CIs of hypertension in the highest compared with the lowest quintile of intake were 1.12 (1.05 to 1.20) for saturated FAs, 1.11 (1.04 to 1.18) for monounsaturated FAs, and 1.15 (1.08 to 1.22) for trans FAs. After additional adjustment for body mass index and history of diabetes mellitus and hypercholesterolemia, these associations were attenuated and remained statistically significant only for trans FAs (relative risk in the highest quintile: 1.08; 95% CI: 1.01 to 1.15). Intake of polyunsaturated FAs, including ω3 and ω6 polyunsaturated FAs, was not significantly associated with the risk of hypertension. In conclusion, higher intake of saturated FAs, monounsaturated FAs, and trans FAs was each associated with increased risk of hypertension among middle-aged and older women, whereas only association for trans FAs remained statistically significant after adjustment for obesity-related factors.

Health benefits of nut consumption

Nuts (tree nuts and peanuts) are nutrient dense foods with complex matrices rich in unsaturated fatty and other bioactive compounds: high-quality vegetable protein, fiber, minerals, tocopherols, phytosterols, and phenolic compounds. By virtue of their unique composition, nuts are likely to beneficially impact health outcomes. Epidemiologic studies have associated nut consumption with a reduced incidence of coronary heart disease and gallstones in both genders and diabetes in women. Limited evidence also suggests beneficial effects on hypertension, cancer, and inflammation. Interventional studies consistently show that nut intake has a cholesterol-lowering effect, even in the context of healthy diets, and there is emerging evidence of beneficial effects on oxidative stress, inflammation, and vascular reactivity. Blood pressure, visceral adiposity and the metabolic syndrome also appear to be positively influenced by nut consumption. Thus it is clear that nuts have a beneficial impact on many cardiovascular risk factors. Contrary to expectations, epidemiologic studies and clinical trials suggest that regular nut consumption is unlikely to contribute to obesity and may even help in weight loss. Safety concerns are limited to the infrequent occurrence of nut allergy in children. In conclusion, nuts are nutrient rich foods with wide-ranging cardiovascular and metabolic benefits, which can be readily incorporated into healthy diets.

Health benefits of nut consumption

We investigated the effect of a mixture of long-chain fructo-oligosaccharides, galacto-oligosaccharides and acidic oligosaccharides on the number and consistency of stools and on immune system biomarkers in 104 supplemented and non-supplemented subjects (aged 9-24 months) with acute diarrhea. Interleukin-1 (IL-1), IL-1RA, IL-6, IL-8, IL-10, TNF-α and sIL-2R cytokine levels were determined. The significant decrease in number of stools and increase in stool consistency in the supplemented group was of little clinical relevance. The only significant change in pro- and anti-inflammatory cytokines was decreased TNF-α levels in the supplemented group. Prebiotic supplementation during acute diarrhea episodes did not influence the clinical course.

Effects of n-3 fatty acids on macro- and microvascular function in subjects with type 2 diabetes mellitus

BACKGROUND

Recent evidence supports the protective effects of n-3 (omega-3) fatty acids (n-3 FAs), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), on vascular function.

OBJECTIVE

We investigated the effects of EPA and DHA on postprandial vascular function in subjects with type 2 diabetes mellitus.

DESIGN

In a double-blind, placebo-controlled, randomized, crossover manner, 34 subjects with type 2 diabetes mellitus received daily either 2 g purified EPA/DHA (termed n-3 FAs) or olive oil (placebo) for 6 wk. At the end of this period, we measured macrovascular (brachial ultrasound of flow-mediated dilatation; FMD) and microvascular [laser-Doppler measurements of reactive hyperemia (RH) of the hand] function at fasting and 2, 4, and 6 h after a high-fat meal (600 kcal, 21 g protein, 41 g carbohydrates, 40 g fat).

RESULTS

Fasting vascular function remained unchanged after n-3 FAs and placebo. Postprandial FMD decreased from fasting after placebo, with a maximum decrease (38%) at 4 h-an effect that was significantly reduced (P = 0.03 for time x treatment interaction) by n-3 FA supplementation (maximum decrease in FMD was at 4 h: 13%). RH remained unchanged after placebo, whereas it improved significantly (P = 0.04 for time x treatment interaction) after n-3 FA supplementation (maximum increase was at 2 h: 27%).

CONCLUSIONS

In subjects with type 2 diabetes mellitus, 6 wk of supplementation with n-3 FAs reduced the postprandial decrease in macrovascular function relative to placebo. Moreover, n-3 FA supplementation improved postprandial microvascular function. These observations suggest a protective vascular effect of n-3 FAs.

Noninvasive assessment of subclinical atherosclerosis in children and adolescents: recommendations for standard assessment for clinical research: a scientific statement from the American Heart Association

Deterioration in endothelial function and arterial stiffness are early events in the development of cardiovascular diseases. In adults, noninvasive measures of atherosclerosis have become established as valid and reliable tools for refining cardiovascular risk to target individuals who need early intervention. With limited pediatric data, the use of these techniques in children and adolescents largely has been reserved for research purposes. Therefore, this scientific statement was written to (1) review the current literature on the noninvasive assessment of atherosclerosis in children and adolescents, (2) make recommendations for the standardization of these tools for research, and (3) stimulate further research with a goal of developing valid and reliable techniques with normative data for noninvasive clinical evaluation of atherosclerosis in pediatric patients. Precise and reliable noninvasive tests for atherosclerosis in youth will improve our ability to estimate future risk for heart attack and stroke. Currently, large longitudinal studies of cardiovascular risk factors in youth, such as the Bogalusa and Muscatine studies, lack sufficient adult subjects experiencing hard outcomes, such as heart attack and stroke, to produce meaningful risk scores like those developed from Framingham data.

The impact of age on the postprandial vascular response to a fish oil-enriched meal

Although chronic fish oil intervention had been shown to have a positive impact on vascular reactivity, very little is known about their acute effects during the postprandial phase. Our aim was to examine the impact of a fish oil-enriched test meal on postprandial vascular reactivity in healthy younger ( < 50 years) v. older ( > or = 50 years) men. Vascular reactivity was measured at baseline (0 h), 2 and 4 h after the meal by laser Doppler iontophoresis and blood samples taken at 0 and 4 h for the measurement of plasma lipids, total nitrite, glucose and insulin. Acetylcholine- (ACh, endothelial-dependent vasodilator) and sodium nitroprusside (SNP, endothelial-independent vasodilator)-induced reactivities were greater at 4 h than at baseline or 2 h in the younger men (P < 0.04). These changes were not observed in the older men. Comparison of the male groups revealed significantly greater responses to ACh (P = 0.006) and SNP (P = 0.05) at 4 h in the younger compared with the older males. Postprandial NEFA concentrations were also greater at 4 h in the younger compared with the older men (P = 0.005), with no differences observed for any of the other analytes. Multiple regression analysis revealed age to be the most significant predictor of both ACh and SNP induced reactivity 4 h after the meal. In conclusion, the ingestion of a meal enriched in fish oil fatty acids was shown to improve postprandial vascular reactivity at 4 h in our younger men, with little benefit evident in our older men.

Dietary saturated and unsaturated fats as determinants of blood pressure and vascular function

The amount and type of dietary fat have long been associated with the risk of CVD. Arterial stiffness and endothelial dysfunction are important risk factors in the aetiology of CHD. A range of methods exists to assess vascular function that may be used in nutritional science, including clinic and ambulatory blood pressure monitoring, pulse wave analysis, pulse wave velocity, flow-mediated dilatation and venous occlusion plethysmography. The present review focuses on the quantity and type of dietary fat and effects on blood pressure, arterial compliance and endothelial function. Concerning fat quantity, the amount of dietary fat consumed habitually appears to have little influence on vascular function independent of fatty acid composition, although single high-fat meals postprandially impair endothelial function compared with low-fat meals. The mechanism is related to increased circulating lipoproteins and NEFA which may induce pro-inflammatory pathways and increase oxidative stress. Regarding the type of fat, cross-sectional data suggest that saturated fat adversely affects vascular function whereas polyunsaturated fat (mainly linoleic acid (18 : 2n-6) and n-3 PUFA) are beneficial. EPA (20 : 5n-3) and DHA (22 : 6n-3) can reduce blood pressure, improve arterial compliance in type 2 diabetics and dyslipidaemics, and augment endothelium-dependent vasodilation. The mechanisms for this vascular protection, and the nature of the separate physiological effects induced by EPA and DHA, are priorities for future research. Since good-quality observational or interventional data on dietary fatty acid composition and vascular function are scarce, no further recommendations can be suggested in addition to current guidelines at the present time.

Differential effects of two isoenergetic meals rich in saturated or monounsaturated fat on endothelial function in subjects with type 2 diabetes

OBJECTIVE

To examine the acute effects of consumption of monounsaturated (MUFAs) and saturated fatty acids (SAFAs) on endothelial function in subjects with type 2 diabetes.

RESEARCH DESIGN AND METHODS

A total of 33 participants were examined after consumption of two different isocaloric meals: one rich in MUFA and one rich in SAFA, in the form of extra-virgin olive oil and butter, respectively. Endothelial function was assessed by determination of flow-mediated dilatation (FMD).

RESULTS

FMD did not change significantly after the MUFA-rich meal but declined after the SAFA-rich meal. The FMD during the experiment, expressed as incremental area under the curve, increased after the MUFA-rich meal by 5.2 +/- 2.5% and decreased after the SAFA-rich meal by 16.7 +/- 6.0% (Delta = -11.5 +/- 6.4%; P = 0.008).

CONCLUSIONS

Consumption of an SAFA-rich meal is harmful for the endothelium, while a MUFA-rich meal does not impair endothelial function in subjects with type 2 diabetes.

Impaired postprandial endothelial function depends on the type of fat consumed by healthy men

Postprandial lipemia impairs endothelial function possibly via an oxidative stress mechanism. A stearic acid-rich triacylglycerol (TAG) (shea butter) results in a blunted postprandial increase in plasma TAG compared with an oleic acid-rich TAG; however, its acute effects on endothelial function and oxidative stress are unknown. A randomized crossover trial (n = 17 men) compared the effects of 50 g fat, rich in stearic acid [shea butter blend (SA)] or oleic acid [high oleic sunflower oil (HO)], on changes in endothelial function [brachial artery flow-mediated dilatation (FMD)], arterial tone [pulse wave analysis (PWA), and carotid-femoral pulse wave velocity (PWV(c-f))], and oxidative stress (plasma 8-isoprostane F2alpha) at fasting and 3 h following the test meals. The postprandial increase in plasma TAG was lower (66% lower incremental area under curve) following the SA meal [28.3 (9.7, 46.9)] than after the HO meal [83.4 (57.0, 109.8); P < 0.001] (geometric means with 95% CI, arbitary units). Following the HO meal, there was a decrease in FMD [-3.0% (-4.4, -1.6); P < 0.001] and an increase in plasma 8-isoprostane F2alpha [10.4ng/L (3.8, 16.9); P = 0.005] compared with fasting values, but no changes followed the SA meal. The changes in 8-isoprostane F2alpha and FMD differed between meals and were 14.0 ng/L (6.4, 21.6; P = 0.001) and 1.75% (0.10, 3.39; P = 0.02), respectively. The reductions in PWA and PWV c-f did not differ between meals. This study demonstrates that a stearic acid-rich fat attenuates the postprandial impairment in endothelial function compared with an oleic acid-rich fat and supports the hypothesis that postprandial lipemia impairs endothelial function via an increase in oxidative stress.

The role of tree nuts and peanuts in the prevention of coronary heart disease: multiple potential mechanisms

Epidemiologic and clinical trial evidence has demonstrated consistent benefits of nut and peanut consumption on coronary heart disease (CHD) risk and associated risk factors. The epidemiologic studies have reported various endpoints, including fatal CHD, total CHD death, total CHD, and nonfatal myocardial infarct. A pooled analysis of 4 U.S. epidemiologic studies showed that subjects in the highest intake group for nut consumption had an approximately 35% reduced risk of CHD incidence. The reduction in total CHD death was due primarily to a decrease in sudden cardiac death. Clinical studies have evaluated the effects of many different nuts and peanuts on lipids, lipoproteins, and various CHD risk factors, including oxidation, inflammation, and vascular reactivity. Evidence from these studies consistently shows a beneficial effect on these CHD risk factors. The LDL cholesterol-lowering response of nut and peanut studies is greater than expected on the basis of blood cholesterol-lowering equations that are derived from changes in the fatty acid profile of the diet. Thus, in addition to a favorable fatty acid profile, nuts and peanuts contain other bioactive compounds that explain their multiple cardiovascular benefits. Other macronutrients include plant protein and fiber; micronutrients including potassium, calcium, magnesium, and tocopherols; and phytochemicals such as phytosterols, phenolic compounds, resveratrol, and arginine. Nuts and peanuts are food sources that are a composite of numerous cardioprotective nutrients and if routinely incorporated in a healthy diet, population risk of CHD would therefore be expected to decrease markedly.

Fish oil fatty acids improve postprandial vascular reactivity in healthy men

Chronic fish oil intervention had been shown to have a positive impact on endothelial function. Although high-fat meals have often been associated with a loss of postprandial vascular reactivity, studies examining the effects of fish oil fatty acids on vascular function in the postprandial phase are limited. The aim of the present study was to examine the impact of the addition of fish oil fatty acids to a standard test meal on postprandial vascular reactivity. A total of 25 men received in a random order either a placebo oil meal (40 g of mixed fat; fatty acid profile representative of the U.K. diet) or a fish oil meal (31 g of mixed fat and 9 g of fish oil) on two occasions. Vascular reactivity was measured at baseline (0 h) and 4 h after the meal by laser Doppler iontophoresis, and blood samples were taken for the measurement of plasma lipids, total nitrite, glucose and insulin. eNOS (endothelial NO synthase) and NADPH oxidase gene expression were determined in endothelial cells after incubation with TRLs (triacylglycerol-rich lipoproteins) isolated from the plasma samples taken at 4 h. Compared with baseline, sodium nitroprusside (an endothelium-independent vasodilator)-induced reactivity (P=0.024) and plasma nitrite levels (P=0.001) were increased after the fish oil meal. In endothelial cells, postprandial TRLs isolated after the fish oil meal increased eNOS and decreased NADPH oxidase gene expression compared with TRLs isolated following the placebo oil meal (P</=0.03). In conclusion, meal fatty acids appear to be an important determinant of vascular reactivity, with fish oils significantly improving postprandial endothelium-independent vasodilation.