The Longevity Project » polyphenols

Effects of low habitual cocoa intake on blood pressure and bioactive nitric oxide: a randomized controlled trial

TLP — Thu, 12 Nov 2009 17:16:19 +0000

CONTEXT: Regular intake of cocoa-containing foods is linked to lower cardiovascular mortality in observational studies. Short-term interventions of at most 2 weeks indicate that high doses of cocoa can improve endothelial function and reduce blood pressure (BP) due to the action of the cocoa polyphenols, but the clinical effect of low habitual cocoa intake on BP and the underlying BP-lowering mechanisms are unclear. OBJECTIVE: To determine effects of low doses of polyphenol-rich dark chocolate on BP. DESIGN, SETTING, AND PARTICIPANTS: Randomized, controlled, investigator-blinded, parallel-group trial involving 44 adults aged 56 through 73 years (24 women, 20 men) with untreated upper-range prehypertension or stage 1 hypertension without concomitant risk factors. The trial was conducted at a primary care clinic in Germany between January 2005 and December 2006. INTERVENTION: Participants were randomly assigned to receive for 18 weeks either 6.3 g (30 kcal) per day of dark chocolate containing 30 mg of polyphenols or matching polyphenol-free white chocolate. MAIN OUTCOME MEASURES: Primary outcome measure was the change in BP after 18 weeks. Secondary outcome measures were changes in plasma markers of vasodilative nitric oxide (S-nitrosoglutathione) and oxidative stress (8-isoprostane), and bioavailability of cocoa polyphenols. RESULTS: From baseline to 18 weeks, dark chocolate intake reduced mean (SD) systolic BP by -2.9 (1.6) mm Hg (P < .001) and diastolic BP by -1.9 (1.0) mm Hg (P < .001) without changes in body weight, plasma levels of lipids, glucose, and 8-isoprostane. Hypertension prevalence declined from 86% to 68%. The BP decrease was accompanied by a sustained increase of S-nitrosoglutathione by 0.23 (0.12) nmol/L (P < .001), and a dark chocolate dose resulted in the appearance of cocoa phenols in plasma. White chocolate intake caused no changes in BP or plasma biomarkers. CONCLUSIONS: Data in this relatively small sample of otherwise healthy individuals with above-optimal BP indicate that inclusion of small amounts of polyphenol-rich dark chocolate as part of a usual diet efficiently reduced BP and improved formation of vasodilative nitric oxide.

JAMA. 2007 Jul 4;298(1):49-60.

Taubert D, Roesen R, Lehmann C, Jung N, Schömig E.

Department of Pharmacology, University Hospital of Cologne, Cologne, Germany. dirk.taubert@medizin.uni-koeln.de

Comment in:

Critique on: Evaluation of Phenolic Compounds in Commercial Fruit Juices and Fruit Drinks

TLP — Sun, 01 Apr 2007 16:46:17 +0000

What the Glasgow study on commercial juices doesn’t say is that purple grape juice contains more than 50 per cent more sugar than Coca Cola, which comes to 16.66 g of sugar (glucose and fructose) per 100 ml of drink. An excessive intake of fruit juices could be harmful altogether. Furthermore, juices are processed food, quality depending highly on the type of process. Why not simply eat fresh purple grape to take advantage of the polyphenols contained in the skin of these fruits?

Evaluation of Phenolic Compounds in Commercial Fruit Juices and Fruit Drinks

TLP — Sun, 01 Apr 2007 16:26:23 +0000

The total phenolic content of 13 commercially available fruit juices and juice drinks, selected to represent the most popular juice flavors in the United Kingdom, were analyzed using the Folin-Ciocalteu assay. Individual phenolic compounds were identified and quantified using HPLC-PDA-MS2. The catechin content and degree of polymerization of proanthocyanidins were also analyzed. Purple grape juice contained the largest number of individual phenolic compounds and also the highest concentration of total phenolics. The main components were flavan-3-ols, anthocyanins, and hydroxycinnamates, which accounted for 93% of the total phenolic content. In contrast, white grape juice, which contained principally hydroxycinnamates, had the lowest total phenolic content. Antioxidant activity was measured using the ORAC and FRAP assays, and the data obtained were in broad agreement with total phenol content. In view of the recent findings of the Kame project indicating that long-term fruit juice consumption can provide protection against Alzheimer’s disease (Dai et al. Am. J. Med. 2006, 379, 464-475), it is suggested that the protective effects may be enhanced by consumption of a combination of juices rich in phenolics and containing a diverse variety of individual phenolic compounds, namely, juices derived from purple grapes, grapefruit, cranberries, and apples.

Plant Products and Human Nutrition Group, Graham Kerr Building, Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom.

Polyphenols

TLP — Wed, 28 Mar 2007 11:59:58 +0000

Polyphenols are a group of chemical substances found in plants, characterized by the presence of more than one phenol group per molecule. Polyphenols are generally further subdivided into tannins, and phenylpropanoids such as lignins and flavonoids.

Is French red wine related to longevity?

TLP — Sat, 24 Mar 2007 16:43:53 +0000

It has been suggested that France’s high red wine consumption is a primary factor for the French longevity. It is believed that one of the active ingredients potentially related to this effect in red wine is resveratrol, but the concentration in wine seems too low to be significant. A study by Professor Roger Corder and team has identified a particular group of polyphenols, known as oligomeric procyanidins, which they believe offer the greatest degree of protection to human blood-vessel cells. Unlike resveratrol, procyanidins are present in wine in quantities that seem to be high enough to be significant as to lower blood pressure.

Red wine procyanidins, vascular health and longevity

TLP — Sat, 24 Mar 2007 15:55:23 +0000

A study by Professor Roger Corder (R. Corder et al., “Oenology: Red wine procyanidins and vascular health”, Nature vol. 444, p. 566; 30 November 2006) has identified a particular group of polyphenols, known as oligomeric procyanidins, which they believe offer the greatest degree of protection to human blood-vessel cells. Tests with 165 wines showed that these are found in greatest concentration in European red wines from certain areas (southwestern France and Sardinia), which correlates with longevity in those regions. The highest procyanidins are found in wines from the Tannat grape, grown in the Gers area of south-west France (the Madiran appellation requires at least 40 per cent Tannat). Clinical trials of grape seed extract have shown that 200 – 300 mg of procyanidins per day lower blood pressure. Two small glasses (125 ml glass) of a procyanidin-rich red wine, such as a Madiran, would then provide this amount.