Acute Peanut Consumption Alters Postprandial Lipids and Vascular Responses in Healthy Overweight or Obese Men.

Background: Postprandial hyperlipidemia is associated with impaired endothelial function. Peanut consumption favorably affects the lipid and lipoprotein profile; however, the effects on endothelial function remain unclear.Objective: The purpose of the study was to evaluate the effects of acute peanut consumption as part of a high-fat meal on postprandial endothelial function.Methods: We conducted a randomized, controlled, crossover postprandial study to evaluate the effect of acute peanut consumption on postprandial lipids and endothelial function as assessed by flow-mediated dilatation (FMD) of the brachial artery in 15 healthy overweight or obese men [mean age: 26.7 y; mean body mass index (in kg/m2): 31.4]. Participants consumed, in a randomized order, a peanut meal containing 3 ounces (85 g) ground peanuts (1198 kcal; 40.0% carbohydrate, 47.7% fat, 19.4% saturated fat, 13.2% protein) and a control meal matched for energy and macronutrient content. Meals were in the form of a shake, scheduled ≥1 wk apart. Lipids, lipoproteins, glucose, and insulin were measured at baseline (0 min) and at 30, 60, 120, and 240 min after shake consumption. FMD was measured at baseline and at 240 min.Results: Acute peanut consumption blunted the serum triglyceride (TG) response 120 and 240 min after consumption compared with the control meal (means ± SEMs-120 min: 188.9 ± 19.4 compared with 197.5 ± 20.7 mg/dL; 240 min: 189.9 ± 24.3 compared with 197.3 ± 18.4 mg/dL; P < 0.05 for both). Total, LDL, and HDL cholesterol and glucose and insulin responses were similar between the test meals. Compared with baseline, only the control meal significantly decreased FMD at 240 min (control: -1.2% ± 0.5%; P = 0.029; peanut: -0.6% ± 0.5%; P = 0.3). Participants with higher baseline total (>150 mg/dL) and LDL (>100 mg/dL)-cholesterol concentrations showed a significant decrease in FMD after the control meal (-1.8%, P = 0.017; -2.0%, P = 0.038), whereas the peanut meal maintained endothelial function in all participants irrespective of total- and LDL-cholesterol concentrations.Conclusion: The inclusion of 85 g peanuts (3 ounces) as part of a high-fat meal improved the postprandial TG response and preserved endothelial function in healthy overweight or obese men. This trial was registered at clinicaltrials.gov as NCT01405300.

Effects of culinary spices and psychological stress on postprandial lipemia and lipase activity: results of a randomized crossover study and in vitro experiments.

BACKGROUND: Data suggest that culinary spices are a potent, low-calorie modality for improving physiological responses to high fat meals. In a pilot study (N = 6 healthy adults), we showed that a meal containing a high antioxidant spice blend attenuated postprandial lipemia by 30% compared to a low spice meal. Our goal was to confirm this effect in a larger sample and to consider the influence of acute psychological stress on fat metabolism. Further, we used in vitro methods to evaluate the inhibitory effect of spices on digestive enzymes. METHODS: In a 2 x 2, randomized, 4-period crossover design, we compared the effects of 14.5 g spices (black pepper, cinnamon, cloves, garlic, ginger, oregano, paprika, rosemary, and turmeric) vs. placebo incorporated into a high fat meal (1000 kcal, 45 g fat), followed by psychological stress (Trier Social Stress Test) vs. rest on postprandial metabolism in 20 healthy but overweight adults. Blood was sampled at baseline and at 105, 140, 180, and 210 minutes for analysis of triglycerides, glucose, and insulin. Additional in vitro analyses examined the effect of the spice blend and constituent spices on the activity of pancreatic lipase (PL) and secreted phospholipase A2 (PLA2). Mixed models were used to model the effects of spices and stress (SAS v9.3). RESULTS: Serum triglycerides, glucose and insulin were elevated following the meal (p < 0.01). Spices reduced post-meal triglycerides by 31% when the meal was followed by the rest condition (p = 0.048), but this effect was not present during stress. There was no effect of the spice blend on glucose or insulin; however, acute stress significantly increased both of these measures (p < 0.01; mean increase of 47% and 19%, respectively). The spice blend and several of the individual spices dose-dependently inhibited PL and PLA2 activity in vitro. CONCLUSIONS: Inclusion of spices may attenuate postprandial lipemia via inhibition of PL and PLA2. However, the impact of psychological stress negates any influence of the spice blend on triglycerides, and further, increases blood glucose and insulin. TRIAL REGISTRATION: ClinicalTrials.gov as NCT00954902 .

Hunger modulates perceptions of food health but not taste in restricted eaters.

Introduction: Food taste and health perceptions are of particular interest for their implications on food choice. Most in vivo food choice studies experimentally control for hunger via a set preload or fast. Methods: To explore how hunger may interact with these perceptions to impact food decisions, we compared taste and health perceptions of sweet and savory obesogenic food items among hungry or satiated participants with varying restrained eating tendencies. Results: In our sample of 232 adults (M BMI = 25.9; M age = 36.4 yrs), highly palatable foods were perceived as tasty but unhealthy. Tastiness ratings were high, consistent across restrained eating groups, and unassociated with hunger. Perceptions of health, however, were impacted by the interaction of restrained eating group and hunger. Amongst hungry participants only, a graded association between restrained eating group and perceptions of health emerged for both food types. Specifically, hungry and highly restrained eaters viewed sweet foods as 2.8x healthier and savory foods as 2.1x healthier than their satiated counterparts. Discussion: Our data suggest that hunger predicts differential health perceptions, but not tastiness ratings, among restrained eaters. We argue that the generalization of food perception data-especially among different eater types-may be limited if the continuum of hunger level is experimentally constrained. Therefore, hunger is a critical dynamic to consider in explorations of food perceptions and eating behavior in restrained eaters.

Test-retest reliability of pulse amplitude tonometry measures of vascular endothelial function: implications for clinical trial design.

Endothelial dysfunction is an important outcome for assessing vascular health in intervention studies. However, reliability of the standard non-invasive method (flow-mediated dilation) is a significant challenge for clinical applications and multicenter trials. We evaluated the repeatability of pulse amplitude tonometry (PAT) to measure change in pulse wave amplitude during reactive hyperemia (Itamar Medical Ltd, Caesarea, Israel). Twenty healthy adults completed two PAT tests (mean interval = 19.5 days) under standardized conditions. PAT-derived measures of endothelial function (reactive hyperemia index, RHI) and arterial stiffness (augmentation index, AI) showed strong repeatability (intra-class correlations = 0.74 and 0.83, respectively). To guide future research, we also analyzed sample size requirements for a range of effect sizes. A crossover design powered at 0.90 requires 28 participants to detect a 15% change in RHI. Our study is the first to show that PAT measurements are repeatable in adults over an interval greater than 1 week.

Effects of canola and high-oleic-acid canola oils on abdominal fat mass in individuals with central obesity.

OBJECTIVE: To determine the effect of diets low in saturated fatty acids and high in monounsaturated fatty acids (MUFA) or polyunsaturated fatty acids on body composition in participants at risk for metabolic syndrome (MetS). METHODS: This study was a randomized, crossover, controlled feeding study. Participants (n = 101, ages 49.5 ± 1.2, BMI 29.4 ± 0.4 kg/m2 ) were randomized to five isocaloric diets containing treatment oils: Canola, CanolaOleic, CanolaDHA, Corn/Safflower, and Flax/Safflower. Each diet period was 4 weeks followed by a 2- to 4-week washout period. RESULTS: Canola (3.1 kg, P = 0.026) and CanolaOleic oil diets (3.09 kg, P = 0.03) reduced android fat mass compared with the Flax/Saff oil diet (3.2 kg), particularly in men. The decrease in abdominal fat mass was correlated with the reduction in blood pressure after the Canola (systolic blood pressure: r = 0.26, P = 0.062; diastolic blood pressure: r = 0.38, P = 0.0049) and CanolaOleic oil diets (systolic blood pressure: r = 0.39 P = 0.004; diastolic blood pressure: r = 0.45, P = 0.0006). The decrease in abdominal fat mass also was associated with a reduction in triglyceride levels after the CanolaOleic oil diet (r = 0.42, P = 0.002). CONCLUSIONS: Diets high in MUFA (compared with PUFA) reduced central obesity with an accompanying improvement in MetS risk factors. Diets high in MUFA may be beneficial for treating and perhaps preventing MetS.

Effects of pistachios on the lipid/lipoprotein profile, glycemic control, inflammation, and endothelial function in type 2 diabetes: A randomized trial.

OBJECTIVE: The health benefits of regular nut consumption have been well-documented; however, effects on cardiovascular risk in diabetes are emerging. This study examined the effects of daily pistachio consumption on the lipid/lipoprotein profile, glycemic control, markers of inflammation, and endothelial function in adults with type 2 diabetes. MATERIALS/METHODS: We enrolled 30 adults (40-74 years) with well-controlled type 2 diabetes (mean glycated hemoglobin 6.2%) in a randomized, crossover, controlled feeding study. After a 2-week run-in period, participants consumed nutritionally-adequate diets with pistachios (contributing 20% of total energy) or without pistachios for 4 weeks each, separated by a 2-week washout. We assessed fasting lipids/lipoproteins, glycemic measures (while fasted and during a 75 g oral glucose tolerance test), inflammatory markers, and endothelial function after each diet period. RESULTS: Total cholesterol and the ratio of total to HDL cholesterol were significantly lower (p<0.05) following the pistachio diet (4.00 mmol/L and 4.06 mmol/L, respectively) compared to the control diet (4.15 mmol/L and 4.37 mmol/L, respectively). Triglycerides were significantly lower (p=0.003) following the pistachio diet (1.56 mmol/L) compared to the control diet (1.84 mmol/L). There were no treatment differences in fasting glucose and insulin, but fructosamine was significantly lower (p=0.03) following the pistachio diet (228.5 µmol/l) compared to the control diet (233.5 µmol/l). Inflammatory markers and endothelial function were unchanged. CONCLUSION: Daily pistachio consumption can improve some cardiometabolic risk factors in adults with well-controlled type 2 diabetes. Our findings support recommendations that individuals with diabetes follow healthy dietary patterns that include nuts.

Noninvasive assessment of hemodynamics: a comparative analysis of fingertip pulse contour analysis and impedance cardiography.

OBJECTIVE: Systemic hemodynamic assessment is useful for characterizing the underlying physiology of hypertension, selecting individualized treatment approaches, and understanding the underlying mechanisms of action of interventions. Invasive methods are not suitable for routine clinic or research use, and noninvasive methods such as impedance cardiography have technical and practical limitations. Fingertip pulse contour analysis using the Nexfin device is a novel alternative to noninvasive assessment of blood pressure and hemodynamics. Although both impedance cardiography and the Nexfin have been validated against invasive methods, the extent to which they are correlated with each other is unknown. This study is a comparative analysis of data simultaneously obtained by impedance cardiography and using the Nexfin device. METHODS: As part of a larger clinical trial, 13 adults with type 2 diabetes completed cardiovascular reactivity testing on three occasions: at study baseline and after two 4-week dietary treatment periods. Blood pressure, hemodynamics, and heart rate variability were assessed at rest and during acute mental stress. RESULTS: Blood pressure, heart rate, and heart rate variability data were significantly correlated between the two devices, but hemodynamic data (stroke volume, cardiac output, total peripheral resistance) were not significantly correlated. Both techniques detected treatment-related changes in blood pressure and total peripheral resistance, but significantly differed in the magnitude and/or direction of treatment effects. CONCLUSION: We conclude that Nexfin is not an appropriate alternative to impedance cardiography for measurement of underlying hemodynamics in psychophysiological research, but may be useful for beat-to-beat monitoring of blood pressure and heart rate variability.

Pistachio nut consumption modifies systemic hemodynamics, increases heart rate variability, and reduces ambulatory blood pressure in well-controlled type 2 diabetes: a randomized trial.

BACKGROUND: Managing cardiovascular risk factors is important for reducing vascular complications in type 2 diabetes, even in individuals who have achieved glycemic control. Nut consumption is associated with reduced cardiovascular risk; however, there is mixed evidence about the effect of nuts on blood pressure (BP), and limited research on the underlying hemodynamics. This study assessed the effect of pistachio consumption on BP, systemic hemodynamics, and heart rate variability in adults with well-controlled type 2 diabetes. METHODS AND RESULTS: We enrolled 30 adults (40 to 74 years) with type 2 diabetes in a randomized, crossover, controlled feeding study. After a 2-week run-in period, participants consumed a low-fat control diet (27% fat) containing low-fat/high-carbohydrate snacks and a moderate-fat diet (33% fat) containing pistachios (20% of total energy) for 4 weeks each, separated by a 2-week washout. Following each diet period, we assessed BP, systemic hemodynamics, and heart rate variability at rest and during acute mental stress, and, in a subset of participants (n=21), 24-hour ambulatory BP. BP at rest and during stress did not differ between treatments. The pistachio diet significantly reduced total peripheral resistance (-3.7±2.9%, P=0.004), increased cardiac output (3.1±2.3%, P=0.002), and improved some measures of heart rate variability (all P<0.05). Systolic ambulatory BP was significantly reduced by 3.5±2.2 mm Hg (P=0.046) following the pistachio diet, with the greatest reduction observed during sleep (-5.7±2.6 mm Hg, P=0.052). CONCLUSIONS: A moderate-fat diet containing pistachios modestly improves some cardiovascular risk factors in adults with well-controlled type 2 diabetes. CLINICAL TRIAL REGISTRATION URL: www.clinicaltrials.gov. Unique identifier: NCT00956735.

Test-retest reliability of peripheral arterial tonometry in the metabolic syndrome.

Endothelial dysfunction is an important contributor to atherosclerosis and cardiovascular disease. However, routine assessment via angiography or flow-mediated dilation is difficult due to technical limitations. Peripheral arterial tonometry (PAT) is a promising alternative method for non-invasive assessment of endothelial dysfunction. This study assessed the test-retest reliability of PAT in adults with the metabolic syndrome (n = 20) and provides sample size and power estimates for study design. Participants completed five PAT tests each separated by 1 week. The PAT-derived reactive hyperaemia index (RHI) showed robust repeatability (intra-class correlation = 0.74). A parallel-arm study powered at 0.90 would require 22 participants to detect an absolute change in RHI of 0.40 units (equal to ~25% change in this sample), whereas a crossover study would require 12 participants. In conclusion, we have demonstrated that PAT can be used to assess endothelial dysfunction in adults with the metabolic syndrome as reliably as in healthy samples.

Plasma fatty acid changes following consumption of dietary oils containing n-3, n-6, and n-9 fatty acids at different proportions: preliminary findings of the Canola Oil Multicenter Intervention Trial (COMIT).

BACKGROUND: The Canola Oil Multicenter Intervention Trial (COMIT) was a randomized controlled crossover study designed to evaluate the effects of five diets that provided different oils and/or oil blends on cardiovascular disease (CVD) risk factors in individuals with abdominal obesity. The present objective is to report preliminary findings on plasma fatty acid profiles in volunteers with abdominal obesity, following the consumption of diets enriched with n-3, n-6 and n-9 fatty acids. METHODS: COMIT was conducted at three clinical sites, Winnipeg, Manitoba, Canada, Québec City, Québec, Canada and University Park, Pennsylvania, United States. Inclusion criteria were at least one of the followings: waist circumference (≥90 cm for males and ≥84 cm for females), and at least one other criterion: triglycerides ≥1.7 mmol/L, high density lipoprotein cholesterol <1 mmol/L (males) or <1.3 mmol/L (females), blood pressure ≥130 mmHg (systolic) and/or ≥85 mmHg (diastolic), and glucose ≥5.5 mmol/L. Weight-maintaining diets that included shakes with one of the dietary oil blends were provided during each of the five 30-day dietary phases. Dietary phases were separated by four-week washout periods. Treatment oils were canola oil, high oleic canola oil, high oleic canola oil enriched with docosahexaenoic acid (DHA), flax oil and safflower oil blend, and corn oil and safflower oil blend. A per protocol approach with a mixed model analysis was decided to be appropriate for data analysis. RESULTS: One hundred and seventy volunteers were randomized and 130 completed the study with a dropout rate of 23.5%. The mean plasma total DHA concentrations, which were analyzed among all participants as a measure of adherence, increased by more than 100% in the DHA-enriched phase, compared to other phases, demonstrating excellent dietary adherence. CONCLUSIONS: Recruitment and retention strategies were effective in achieving a sufficient number of participants who completed the study protocol to enable sufficient statistical power to resolve small differences in outcome measures. It is expected that the study will generate important data thereby enhancing our understanding of the effects of n-3, n-6, and n-9 fatty acid-containing oils on CVD risks. TRIAL REGISTRATION: ClinicalTrials.gov NCT01351012.

DHA-enriched high-oleic acid canola oil improves lipid profile and lowers predicted cardiovascular disease risk in the canola oil multicenter randomized controlled trial.

BACKGROUND: It is well recognized that amounts of trans and saturated fats should be minimized in Western diets; however, considerable debate remains regarding optimal amounts of dietary n-9, n-6, and n-3 fatty acids. OBJECTIVE: The objective was to examine the effects of varying n-9, n-6, and longer-chain n-3 fatty acid composition on markers of coronary heart disease (CHD) risk. DESIGN: A randomized, double-blind, 5-period, crossover design was used. Each 4-wk treatment period was separated by 4-wk washout intervals. Volunteers with abdominal obesity consumed each of 5 identical weight-maintaining, fixed-composition diets with one of the following treatment oils (60 g/3000 kcal) in beverages: 1) conventional canola oil (Canola; n-9 rich), 2) high-oleic acid canola oil with docosahexaenoic acid (CanolaDHA; n-9 and n-3 rich), 3) a blend of corn and safflower oil (25:75) (CornSaff; n-6 rich), 4) a blend of flax and safflower oils (60:40) (FlaxSaff; n-6 and short-chain n-3 rich), or 5) high-oleic acid canola oil (CanolaOleic; highest in n-9). RESULTS: One hundred thirty individuals completed the trial. At endpoint, total cholesterol (TC) was lowest after the FlaxSaff phase (P < 0.05 compared with Canola and CanolaDHA) and highest after the CanolaDHA phase (P < 0.05 compared with CornSaff, FlaxSaff, and CanolaOleic). Low-density lipoprotein (LDL) cholesterol and high-density lipoprotein (HDL) cholesterol were highest, and triglycerides were lowest, after CanolaDHA (P < 0.05 compared with the other diets). All diets decreased TC and LDL cholesterol from baseline to treatment endpoint (P < 0.05). CanolaDHA was the only diet that increased HDL cholesterol from baseline (3.5 ± 1.8%; P < 0.05) and produced the greatest reduction in triglycerides (-20.7 ± 3.8%; P < 0.001) and in systolic blood pressure (-3.3 ± 0.8%; P < 0.001) compared with the other diets (P < 0.05). Percentage reductions in Framingham 10-y CHD risk scores (FRS) from baseline were greatest after CanolaDHA (-19.0 ± 3.1%; P < 0.001) than after other treatments (P < 0.05). CONCLUSION: Consumption of CanolaDHA, a novel DHA-rich canola oil, improves HDL cholesterol, triglycerides, and blood pressure, thereby reducing FRS compared with other oils varying in unsaturated fatty acid composition. This trial was registered at www.clinicaltrials.gov as NCT01351012.

Concurrent herb-prescription medication use and health care provider disclosure among university students.

OBJECTIVES: To determine the extent to which college students are intermixing mood-altering herbs with prescription medications and whether they are disclosing this information to their health care providers. DESIGN AND SETTING: A nonrandom sample was drawn from the student body of a Northwestern state university (n=305). METHODS: In November 2008 participants completed an online survey detailing herb use, disclosure to health care providers and herb/medicinal intermixing. RESULTS: There were no demographic differences between herb users and non-users. Most herb usage was self-prescribed (60%) and undisclosed to healthcare providers (only 25% of herb users disclosed to a healthcare provider). 34% of herb users used them to treat a mood disorder. Of herb users, 13% had simultaneously used herbs and prescription medication in the last year. In addition, herb users who intermixed herbs with prescription medications had higher depression and anxiety scores than those who did not intermix. CONCLUSIONS: College student herb use is primarily self prescribed and undisclosed to healthcare professionals, who may prescribe pharmaceuticals that interact negatively with herbals. Physician awareness and query is invaluable for the prevention of adverse herb and drug interactions.