Effects of coffee and tea on lipoproteins and prostanoids

Aro, Antti; Kostiainen, Ella; Huttunen, Jussi K.; Seppälä, Erkki; Vapaatalo, Heikki

doi:10.1016/0021-9150(85)90144-3

Cited by 46 publications

(19 citation statements)

References 20 publications

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“…52 Further, chocolate also contains linoleic and oleic acids, 2 fatty acids known to modulate cholesterol metabolism. 53 Therefore, although a study in smokers 54 and an early study in healthy subjects 55 showed no changes in serum total cholesterol and cholesterol fractions after black 54,55 or green tea, 54 our results are consistent with previous reports showing positive effects of flavonoids on serum lipid profiles.…”

Section: Discussionsupporting

confidence: 91%

Cocoa Reduces Blood Pressure and Insulin Resistance and Improves Endothelium-Dependent Vasodilation in Hypertensives

Grassi

Necozione²,

Lippi³

et al. 2005

Hypertension

490

393

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Abstract-Consumption of flavanol-rich dark chocolate (DC) has been shown to decrease blood pressure (BP) and insulin resistance in healthy subjects, suggesting similar benefits in patients with essential hypertension (EH). Therefore, we tested the effect of DC on 24-hour ambulatory BP, flow-mediated dilation (FMD), and oral glucose tolerance tests (OGTTs) in patients with EH. After a 7-day chocolate-free run-in phase, 20 never-treated, grade I patients with EH (10 males; 43.7Ϯ7.8 years) were randomized to receive either 100 g per day DC (containing 88 mg flavanols) or 90 g per day flavanol-free white chocolate (WC) in an isocaloric manner for 15 days. After a second 7-day chocolate-free period, patients were crossed over to the other treatment. O bservational studies suggest dietary flavonoids decrease the risk of death from coronary heart disease, 1 cancer, 1 and stroke. 2 Flavonoid-rich foods include fruits and vegetables as well as tea, red wine, and chocolate. 3 The high flavonoid content, particularly in flavanols (ie, catechins) and their procyanidin oligomers, of these foods may contribute to some of their putative cardiovascular benefits. 4,5 The antioxidant protection afforded by flavonoids in the vascular endothelium may reduce the risk for atherosclerosis, including their action of inhibiting the oxidative conversion of NO to peroxynitrite. 6 Accordingly, cocoa flavonoids decreased oxidant-induced peroxynitrite production in vitro 7 and increased NO synthase (NOS) expression and NO-dependent vasorelaxation in rabbit aortic rings. 8 In healthy adults, drinking flavanol-rich cocoa increased NO-dependent vasorelaxation in finger arteries, 9 and eating flavanol-rich dark chocolate (DC) improved flow-mediated dilation (FMD) in brachial arteries in association with an increase in plasma epicatechin. 10 Impaired NO-dependent vasorelaxation also contributes to a dysregulation of blood pressure (BP) 11 and a decrement of insulin-mediated glucose uptake. 12 In contrast, increased endothelial NOS expression and NO bioavailability ameliorate endothelial dysfunction, and thereby have the potential to decrease BP, increase insulin sensitivity, and slow down atherogenetic processes. In this regard, the anthocyanin cyanidin-3-glucoside was able to increase NOS expression and NO bioavailability in vascular endothelial cells. 13 We recently demonstrated decrements in BP and increments in insulin sensitivity in healthy volunteers after 15 days of DC intake. 14 Thus, we studied patients with essential hypertension (EH) to evaluate the effects of flavanol-rich DC on 24-hour ambulatory BP monitoring (ABPM), endotheliumdependent vasorelaxation via FMD of the brachial artery, insulin sensitivity via oral glucose tolerance tests (OGTTs), and 2 serum biomarkers of vascular inflammation: highsensitive C-reactive protein (hsCRP) and intercellular adhesion molecule-1 (ICAM-1).

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Section: Discussionsupporting

confidence: 91%

Cocoa Reduces Blood Pressure and Insulin Resistance and Improves Endothelium-Dependent Vasodilation in Hypertensives

Grassi

Necozione²,

Lippi³

et al. 2005

Hypertension

490

393

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“…A similar finding was reported by Aro et al in a shorter, noncontrolled study with black tea. 67 This is in contrast to data from cross-sectional epidemiological studies that show an association between an increased consumption of green or black tea and decreased plasma cholesterol and triglyceride levels. 36 -38 However, confounding effects cannot be excluded in the latter studies.…”

Section: Discussioncontrasting

confidence: 53%

No Effect of Consumption of Green and Black Tea on Plasma Lipid and Antioxidant Levels and on LDL Oxidation in Smokers

Princen

Duyvenvoorde

Buytenhek

et al. 1998

ATVB

164

115

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Abstract-Intake of flavonoids is associated with a reduced cardiovascular risk. Oxidation of LDL is a major step in atherogenesis, and antioxidants may protect LDL from oxidation. Because tea is an important source of flavonoids, which are strong antioxidants, we have assessed in a randomized, placebo-controlled study the effect of consumption of black and green tea and of intake of isolated green tea polyphenols on LDL oxidation ex vivo and on plasma levels of antioxidants and lipids. Healthy male and female smokers (aged 34Ϯ12 years, 13 to 16 per group) consumed during a 4-week period 6 cups (900 mL) of black or green tea or water per day, or they received as a supplement 3.6 grams of green tea polyphenols per day (equivalent to the consumption of 18 cups of green tea per day). Consumption of black or green tea had no effect on plasma cholesterol and triglycerides, HDL and LDL cholesterol, plasma vitamins C and E, ␤-carotene, and uric acid. No differences were found in parameters of LDL oxidation. Intake of green tea polyphenols decreased plasma vitamin E significantly in that group compared with the control group (Ϫ11% Pϭ.016) but had no effect on LDL oxidation ex vivo. We conclude that consumption of black or green tea (6 cups per day) has no effect on plasma lipids and no sparing effect on plasma antioxidant vitamins and that intake of a high dose of isolated green tea polyphenols decreases plasma vitamin E. Although tea polyphenols had a potent antioxidant activity on LDL oxidation in vitro, no effect was found on LDL oxidation ex vivo after consumption of green or black tea or intake of a green tea polyphenol isolate. (Arterioscler Thromb Vasc Biol. 1998;18:833-841.)

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“…When information on mean age was missing in one trial, an average of the minimum and maximum values for that trial was used. 17 Sensitivity analysis was conducted to investigate the influence of a single trial on the overall effect estimated by omitting one study in each turn. Univariate and multivariate meta-regression models were employed to explore the influence of coffee dose or study duration on net change in lipid profile.…”

Section: Discussionmentioning

confidence: 99%

“…Clinical trials used various intake levels of coffee consumption with varying type of coffee and different protocols. [7][8][9][10][11][12][13][14][15][16][17][18][19][20] Metaanalysis is a statistical technique in which results of separate studies are combined to increase statistical power, clarify results and more accurately estimate the size of treatment effects. To more precisely evaluate the effects of coffee intake on serum lipids and to clarify the active factors of coffee, we performed a meta-analysis of 12-RCTs.…”

Section: Introductionmentioning

confidence: 99%

The effect of coffee consumption on serum lipids: a meta-analysis of randomized controlled trials

et al. 2012

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BACKGROUND/OBJECTIVES: Numbers of epidemiological studies assessing coffee consumption and serum lipids have yielded inconsistent results. We aimed to evaluate the effects of coffee intake on serum lipids. SUBJECTS/METHODS: We searched several English and Chinese electronic databases up to September 2011 for randomized controlled trials of coffee on serum lipids. Weighted mean effect size was calculated for net changes in serum lipids by using random-effect models or fixed-effect models. Subgroup and meta-regression analyses were conducted to explore possible explanations for heterogeneity among trials. RESULTS: Twelve studies conducted in Western countries with a total of 1017 subjects were identified. Meta-analyses showed, on average, drinking coffee for 45 days was associated with an increase of 8.1 mg/dl (95% confidence interval (CI): 4.5, 11.6; Po0.001) for total cholesterol (TC), 5.4 mg/dl (95% CI: 1.4, 9.5; P ¼ 0.009) for low-density lipoprotein cholesterol (LDL-C) and 12.6 mg/dl (95% CI: 3.5, 12.6; P ¼ 0.007) for triglyceride (TG). The increase in TC were greater in trials using unfiltered coffee and caffeinated coffee as the treatment group. Those who had hyperlipidemia were more sensitive to the cholesterol-raising effect of coffee. Meta-regression analysis revealed a positive dose-response relation between coffee intake and TC, LDL-C and TG. CONCLUSION: The intake of coffee especially unfiltered coffee is contributed significantly to the increase in TC, LDL-C and TG, and the changes were related to the level of intake. Studies of coffee intake on serum lipids in Asian populations should be performed. Keywords: coffee; caffeine; lipids; meta-analysis; randomized controlled trials INTRODUCTIONCoffee is one of the most commonly consumed beverages and even small health effects of coffee could have considerable public health consequences. Controversies regarding its risks and benefits still exist as substances in coffee may have either unfavorable or beneficial effects on the cardiovascular system. 1 A large body of epidemiology studies, including recent studies, [2][3][4][5] examining the association between coffee consumption and serum lipids have yielded inconsistent results.A meta-analysis of nine randomized controlled trials (RCTs) published before December 1998 concluded that consumption of unfiltered, but not filtered, coffee increased serum levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C). 6 However, this meta-analysis was only based on English-language literature and the authors failed to include two important RCTs, 7,8 which included 345 participants. In addition, the active factors such as caffeine and coffee oils, which were responsible for the plasma lipoprotein-increasing effect of coffee, were not determined.To determine the effect of caffeinated coffee and decaffeinated coffee consumption on plasma lipoprotein cholesterol levels in healthy men, Fried et al. 9 performed a RCT by three intervention coffee including 720 ml/day of caffeinated coffee, 360 ml/day o...

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Effects of coffee and tea on lipoproteins and prostanoids

Cited by 46 publications

References 20 publications

Cocoa Reduces Blood Pressure and Insulin Resistance and Improves Endothelium-Dependent Vasodilation in Hypertensives

Cocoa Reduces Blood Pressure and Insulin Resistance and Improves Endothelium-Dependent Vasodilation in Hypertensives

No Effect of Consumption of Green and Black Tea on Plasma Lipid and Antioxidant Levels and on LDL Oxidation in Smokers

The effect of coffee consumption on serum lipids: a meta-analysis of randomized controlled trials

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