Lieke Gijsbers

Effects of the pure flavonoids epicatechin and quercetin on vascular function and cardiometabolic health: a randomized, double-blind, placebo-controlled, crossover trial

BACKGROUND Prospective cohort studies showed inverse associations between the intake of flavonoid-rich foods (cocoa and tea) and cardiovascular disease (CVD). Intervention studies showed protective effects on intermediate markers of CVD. This may be due to the protective effects of the flavonoids epicatechin (in cocoa and tea) and quercetin (in tea). OBJECTIVE We investigated the effects of supplementation of pure epicatechin and quercetin on vascular function and cardiometabolic health. DESIGN Thirty-seven apparently healthy men and women aged 40-80 y with a systolic blood pressure (BP) between 125 and 160 mm Hg at screening were enrolled in a randomized, double-blind, placebo-controlled, crossover trial. CVD risk factors were measured before and after 4 wk of daily flavonoid supplementation. Participants received (-)-epicatechin (100 mg/d), quercetin-3-glucoside (160 mg/d), or placebo capsules for 4 wk in random order. The primary outcome was the change in flow-mediated dilation from pre- to postintervention. Secondary outcomes included other markers of CVD risk and vascular function. RESULTS Epicatechin supplementation did not change flow-mediated dilation significantly (1.1% absolute; 95% CI: -0.1%, 2.3%; P = 0.07). Epicatechin supplementation improved fasting plasma insulin (Δ insulin: -1.46 mU/L; 95% CI: -2.74, -0.18 mU/L; P = 0.03) and insulin resistance (Δ homeostasis model assessment of insulin resistance: -0.38; 95% CI: -0.74, -0.01; P = 0.04) and had no effect on fasting plasma glucose. Epicatechin did not change BP (office BP and 24-h ambulatory BP), arterial stiffness, nitric oxide, endothelin 1, or blood lipid profile. Quercetin-3-glucoside supplementation had no effect on flow-mediated dilation, insulin resistance, or other CVD risk factors. CONCLUSIONS Our results suggest that epicatechin may in part contribute to the cardioprotective effects of cocoa and tea by improving insulin resistance. It is unlikely that quercetin plays an important role in the cardioprotective effects of tea. This study was registered at clinicaltrials.gov as NCT01691404.

Consumption of dairy foods and diabetes incidence: a dose-response meta-analysis of observational studies

BACKGROUND A growing number of cohort studies suggest a potential role of dairy consumption in type 2 diabetes (T2D) prevention. The strength of this association and the amount of dairy needed is not clear. OBJECTIVE We performed a meta-analysis to quantify the associations of incident T2D with dairy foods at different levels of intake. DESIGN A systematic literature search of the PubMed, Scopus, and Embase databases (from inception to 14 April 2015) was supplemented by hand searches of reference lists and correspondence with authors of prior studies. Included were prospective cohort studies that examined the association between dairy and incident T2D in healthy adults. Data were extracted with the use of a predefined protocol, with double data-entry and study quality assessments. Random-effects meta-analyses with summarized dose-response data were performed for total, low-fat, and high-fat dairy, (types of) milk, (types of) fermented dairy, cream, ice cream, and sherbet. Nonlinear associations were investigated, with data modeled with the use of spline knots and visualized via spaghetti plots. RESULTS The analysis included 22 cohort studies comprised of 579,832 individuals and 43,118 T2D cases. Total dairy was inversely associated with T2D risk (RR: 0.97 per 200-g/d increment; 95% CI: 0.95, 1.00;P= 0.04;I(2)= 66%), with a suggestive but similar linear inverse association noted for low-fat dairy (RR: 0.96 per 200 g/d; 95% CI: 0.92, 1.00;P= 0.072;I(2)= 68%). Nonlinear inverse associations were found for yogurt intake (at 80 g/d, RR: 0.86 compared with 0 g/d; 95% CI: 0.83, 0.90;P< 0.001;I(2)= 73%) and ice cream intake (at ∼10 g/d, RR: 0.81; 95% CI: 0.78, 0.85;P< 0.001;I(2)= 86%), but no added incremental benefits were found at a higher intake. Other dairy types were not associated with T2D risk. CONCLUSION This dose-response meta-analysis of observational studies suggests a possible role for dairy foods, particularly yogurt, in the prevention of T2D. Results should be considered in the context of the observed heterogeneity.

Supplementation of the Pure Flavonoids Epicatechin and Quercetin Affects Some Biomarkers of Endothelial Dysfunction and Inflammation in (Pre)Hypertensive Adults: A Randomized Double-Blind, Placebo-Controlled, Crossover Trial

BACKGROUND Consumption of flavonoid-rich foods such as cocoa and tea may reduce cardiovascular disease risk. The flavonoids epicatechin (in cocoa and tea) and quercetin (in tea) probably play a role by reducing endothelial dysfunction and inflammation, 2 main determinants of atherosclerosis. OBJECTIVE We studied the effects of supplementation of pure epicatechin and quercetin on biomarkers of endothelial dysfunction and inflammation. METHODS Thirty-seven apparently healthy (pre)hypertensive men and women (40-80 y) participated in a randomized, double-blind, placebo-controlled crossover trial. Participants ingested (-)-epicatechin (100 mg/d), quercetin-3-glucoside (160 mg/d), or placebo capsules for a period of 4 wk, in random order. Plasma biomarkers of endothelial dysfunction and inflammation were measured at the start and end of each 4-wk intervention period. The differences in changes over time between the intervention and placebo periods (Δintervention - Δplacebo) were calculated and tested with a linear mixed model for repeated measures. RESULTS Epicatechin changed Δepicatechin - Δplacebo for soluble endothelial selectin (sE-selectin) by -7.7 ng/mL (95% CI: -14.5, -0.83; P = 0.03) but did not significantly change this difference (-0.30; 95% CI: -0.61, 0.01; P = 0.06) for the z score for endothelial dysfunction. Quercetin changed Δquercetin - Δplacebo for sE-selectin by -7.4 ng/mL (95% CI: -14.3, -0.56; P = 0.03), that for IL-1β by -0.23 pg/mL (95% CI: -0.40, -0.06; P = 0.009), and that for the z score for inflammation by -0.33 (95% CI: -0.60, -0.05; P = 0.02). CONCLUSIONS In (pre)hypertensive men and women, epicatechin may contribute to the cardioprotective effects of cocoa and tea through improvements in endothelial function. Quercetin may contribute to the cardioprotective effects of tea possibly by improving endothelial function and reducing inflammation. This trial was registered at clinicaltrials.gov as NCT01691404.

Dairy Consumption and Risk of Stroke: A Systematic Review and Updated Dose–Response Meta‐Analysis of Prospective Cohort Studies

Background A higher milk consumption may be associated with a lower stroke risk. We conducted a comprehensive systematic review and dose–response meta‐analysis of milk and other dairy products in relation to stroke risk. Methods and Results Through a systematic literature search, prospective cohort studies of dairy foods and incident stroke in stroke‐free adults were identified. Random‐effects meta‐analyses with summarized dose–response data were performed, taking into account sources of heterogeneity, and spline models were used to systematically investigate nonlinearity of the associations. We included 18 studies with 8 to 26 years of follow‐up that included 762 414 individuals and 29 943 stroke events. An increment of 200 g of daily milk intake was associated with a 7% lower risk of stroke (relative risk 0.93; 95% CI 0.88–0.98; P=0.004; I2=86%). Relative risks were 0.82 (95% CI 0.75–0.90) in East Asian and 0.98 (95% CI 0.95–1.01) in Western countries (median intakes 38 and 266 g/day, respectively) with less but still considerable heterogeneity within the continents. Cheese intake was marginally inversely associated with stroke risk (relative risk 0.97; 95% CI 0.94–1.01 per 40 g/day). Risk reductions were maximal around 125 g/day for milk and from 25 g/day onwards for cheese. Based on a limited number of studies, high‐fat milk was directly associated with stroke risk. No associations were found for yogurt, butter, or total dairy. Conclusions Milk and cheese consumption were inversely associated with stroke risk. Results should be placed in the context of the observed heterogeneity. Future epidemiological studies should provide more details about dairy types, including fat content. In addition, the role of dairy in Asian populations deserves further attention.

Effects of sodium and potassium supplementation on blood pressure and arterial stiffness: a fully controlled dietary intervention study

We performed a randomised, placebo-controlled, crossover study to examine the effects of sodium and potassium supplementation on blood pressure (BP) and arterial stiffness in untreated (pre)hypertensive individuals. During the study, subjects were on a fully controlled diet that was relatively low in sodium and potassium. After a 1-week run-in period, subjects received capsules with supplemental sodium (3 g d−1, equals 7.6 g d−1 of salt), supplemental potassium (3 g d−1) or placebo, for 4 weeks each, in random order. Fasting office BP, 24-h ambulatory BP and measures of arterial stiffness were assessed at baseline and every 4 weeks. Of 37 randomized subjects, 36 completed the study. They had a mean pre-treatment BP of 145/81 mm Hg and 69% had systolic BP ⩾140 mm Hg. Sodium excretion was increased by 98 mmol per 24 h and potassium excretion by 63 mmol per 24 h during active interventions, compared with placebo. During sodium supplementation, office BP was significantly increased by 7.5/3.3 mm Hg, 24-h BP by 7.5/2.7 mm Hg and central BP by 8.5/3.6 mm Hg. During potassium supplementation, 24-h BP was significantly reduced by 3.9/1.6 mm Hg and central pulse pressure by 2.9 mm Hg. Pulse wave velocity and augmentation index were not significantly affected by sodium or potassium supplementation. In conclusion, increasing the intake of sodium caused a substantial increase in BP in subjects with untreated elevated BP. Increased potassium intake, on top of a relatively low-sodium diet, had a beneficial effect on BP. Arterial stiffness did not materially change during 4-week interventions with sodium or potassium.

Effects of sodium and potassium supplementation on endothelial function: a fully controlled dietary intervention study

High Na and low K intakes have adverse effects on blood pressure, which increases the risk for CVD. The role of endothelial dysfunction and inflammation in this pathophysiological process is not yet clear. In a randomised placebo-controlled cross-over study in untreated (pre)hypertensives, we examined the effects of Na and K supplementation on endothelial function and inflammation. During the study period, subjects were provided with a diet that contained 2·4 g/d of Na and 2·3 g/d of K for a 10 460 kJ (2500 kcal) intake. After 1-week run-in, subjects received capsules with supplemental Na (3·0 g/d), supplemental K (2·8 g/d) or placebo, for 4 weeks each, in random order. After each intervention, circulating biomarkers of endothelial function and inflammation were measured. Brachial artery flow-mediated dilation (FMD) and skin microvascular vasomotion were assessed in sub-groups of twenty-two to twenty-four subjects. Of thirty-seven randomised subjects, thirty-six completed the study. Following Na supplementation, serum endothelin-1 was increased by 0·24 pg/ml (95 % CI 0·03, 0·45), but no change was seen in other endothelial or inflammatory biomarkers. FMD and microvascular vasomotion were unaffected by Na supplementation. K supplementation reduced IL-8 levels by 0·28 pg/ml (95 % CI 0·03, 0·53), without affecting other circulating biomarkers. FMD was 1·16 % (95% CI 0·37, 1·96) higher after K supplementation than after placebo. Microvascular vasomotion was unaffected. In conclusion, a 4-week increase in Na intake increased endothelin-1, but had no effect on other endothelial or inflammatory markers. Increased K intake had a beneficial effect on FMD and possibly IL-8, without affecting other circulating endothelial or inflammatory biomarkers.

Effects of potassium supplementation on markers of osmoregulation and volume regulation: results of a fully controlled dietary intervention study

Objective: Lifestyle measures including dietary sodium restriction and increased potassium intake are recognized to lower blood pressure (BP). Potassium was found to be effective in reducing BP at higher levels of sodium intake, but to have little effect when sodium intake is restricted. The humoral mechanisms underlying these sodium intake dependent effects of potassium are unknown. We investigated the effects of potassium supplementation on top of a fully controlled sodium-restricted diet on markers of osmoregulation and volume regulation. Methods: In this post-hoc analysis, we included 35 (pre)hypertensive individuals participating in a randomized, double-blind, placebo-controlled crossover trial. Individuals received capsules containing sodium [3.0 g (130 mmol)/day], potassium [2.8 g (72 mmol)/day], or placebo for three four-week periods. Linear mixed-effect models were used to estimate the effects of potassium supplementation compared with placebo. Skewed data were ln-transformed before analysis. Results: Increased potassium intake was associated with a significant decrease in 24-h BP (−3.6/−1.6 mmHg). Furthermore, we found a significant decrease in ln MR-proANP [−0.08 (95% confidence interval −0.15, −0.01) pmol/l, P = 0.03] and significant increases in 24-h heart rate [2.5 (0.9, 4.0) bpm, P = 0.002], ln plasma copeptin [0.11 (0.01, 0.20) pmol/l, P = 0.02], ln renin [0.34 (0.08, 0.60) &mgr;IU/ml, P = 0.01], and ln aldosterone [0.14 (0.07, 0.22) nmol/l, P < 0.001] compared with placebo. Conclusions: We found that potassium has BP-lowering effects during sodium restriction. These BP-lowering effects, however, seem mitigated by several counter regulatory mechanisms (i.e. increased secretion of vasopressin, stimulation of RAAS, and increased heart rate) that were activated to maintain volume homeostasis and counterbalance the decrease in BP.

5D.06: EFFECTS OF SODIUM AND POTASSIUM SUPPLEMENTATION ON ENDOTHELIAL FUNCTION AND INFLAMMATION IN UNTREATED (PRE)HYPERTENSIVES: A FULLY CONTROLLED DIETARY INTERVENTION STUDY.

Objective: High sodium and low potassium have been associated with detrimental effects on blood pressure. However, the role of these minerals in endothelial dysfunction and low-grade inflammation, which may predispose to cardiovascular disease, has not yet been established. We performed a randomized placebo-controlled crossover study to examine the effects of sodium and potassium supplementation on endothelial function and inflammation in untreated (pre)hypertensive adults. Design and method: During the study, subjects were on a fully controlled diet that contained on average 2.4 g of sodium and 2.3 g of potassium per day for a 2500 kcal intake. After one-week run-in, subjects were randomized to ingest capsules with supplemental sodium (3 g/d), supplemental potassium (3 g/d), or placebo, for four weeks each, in random order. After each intervention period, brachial artery flow-mediated dilation, and circulating biomarkers of endothelial function (e.g. nitric oxide, endothelin-1, cellular adhesion molecules) and inflammation (e.g. tumor necrosis factor-&agr;, C-reactive protein, interleukins) were measured. Results: Of 37 randomized subjects, 36 completed the study. Subjects had a mean pre-treatment blood pressure of 145/81 mmHg. Sodium supplementation increased serum endothelin-1 by 0.24 pg/ml (95% CI: 0.03, 0.45), but had no effect on other endothelial or inflammatory biomarkers, or flow-mediated dilation. Potassium supplementation reduced interleukin-8 levels by 0.28 pg/ml (95% CI: 0.03, 0.53), without affecting other circulating biomarkers. Flow-mediated dilation was 1.16% (95% CI: 0.37, 1.96) higher after potassium supplementation than after placebo, with 83% of the subjects showing an improvement (Figure). Conclusions: Sodium and potassium supplementation had little impact on circulating endothelial and inflammatory biomarkers, and only for potassium an effect on flow-mediated dilation was observed. This study suggests different actions for sodium and potassium in the pathophysiological processes leading to cardiovascular disease. Figure. No caption available.