Circulatory Function and Vascular Integrity

Supporting vascular integrity to enhance circulatory function

Originally enjoyed as a beverage, chocolate has come into its own as a tasty snack with health benefits. A review from Athens Medical School, Greece, noted dark chocolate and flavonoid-rich cocoa have beneficial acute and short-term effects on endothelial function, probably related to flavonoid content and mediated through increased NO bioavailability.⁵⁴ In vitro, cocoa flavanols also modulate platelet function, inhibiting aggregation and activation, while also inhibiting monocyte and neutrophil activation.^55,56

Researchers at the University of California, Davis, investigated whether chronic dietary consumption of flavonol-rich cocoa could improve endothelial function in hypercholesterolemic postmenopausal women (n=32).⁵⁷ Over the course of the six week, double blind study, women consumed a high-flavanol (446 mg) or a low-flavanol (43 mg) cocoa beverage. Brachial artery blood flow increased by 76 percent in the high-flavanol group, and by 32 percent in the low-flavanol group; the 2.4-fold increase among the high flavanol consumers correlated closely with a decrease in plasma levels of vascular cell adhesion molecule-1. German researchers found similar results in a seven-day study, in which 900 mg/d flavanols in a cocoa drink increased FMD and plasma nitrite levels.⁵⁸ In a Swiss study, acute consumption of flavonoid-rich dark chocolate (40 g) by heart transplant patients induced coronary vasodilation, improved vascular function and decreased platelet adhesion.⁵⁹

Another tasty treat with helpful qualities is olive oil, cited earlier for its role in the Mediterranean diet. Researchers from the Instituto de la Grassa, Seville, Spain, noted some of the minor components of virgin olive oil, such as polyphenols, sterols and triterpenoids, found in trace amounts may have specific activity on vascular dysfunction and may help modulate endothelial activity.⁶⁰ Among their cited activities are the release of NO, impact on adhesion molecules, and anti-inflammatory properties. The same research team investigated the impact of dietary pomace olive oil, with a higher proportion of oleanolic acid (OA), in rats; chronic intake of OA-rich olive oil increased eNOS protein expression and improved endothelial dysfunction.⁶¹ Olive oil may also benefit the blood itself, as an Italian in vitro study found olive oil flavonoids could inhibit aggregation of human platelets, with the flavonoids luteolin and oleuropein aglycone showing the most activity.⁶²

Another botanical found in the Mediterranean is citrus; its flavonoids have been studied and used pharmaceutically for treatment of vascular dysfunction. Greek researchers reported a micronized purified flavonoid fraction delivering hesperidin and diosmin (as Daflon) has the ability to inhibit endothelial activation, prevents inflammation linked to chronic venous insufficiency (CVI), protects microcirculation and prevents capillary damage.⁶³ A comparative study out of France found Daflon was more effective than just diosmin in supporting microcirculation in an animal model, decreasing permeability of the capillaries.⁶⁴ Australian researchers have also reported Daflon can help alleviate symptoms of CVI and protects the microcirculation from inflammation, reducing capillary hyperpermeability.⁶⁵

Italian researchers compared the efficacy of Daflon (1,000 mg/d) to 150 mg/d or 300 mg/d of French maritime pine bark extract (as Pycnogenol®, from Natural Health Science) in a group of 86 patients with severe CVI.⁶⁶ After eight weeks, Pycnogenol intervention reduced ankle swelling by 35 percent and edema by 64 percent, compared to 19 percent and 32 percent reductions, respectively, in the Daflon group. Additionally, there were no significant differences between the 150 and 300 mg/d dosages. Another study on patients with CVI found Pycnogenol (150 mg/d) improved the level of microangiopathy, significantly decreased capillary filtration and reduced edema.⁶⁷

Another trial involved 60 diabetic patients with microangiopathy, a condition in which capillary walls become thick and weakened, bleeding and leaking protein.⁶⁸ Patients received 150 mg/d of Pycnogenol or placebo for one month, and capillary blood flow measurements taken when the subjects were lying down and standing up. Intervention improved capillary blood flow when lying down by 34 percent, compared to 4.7 percent in the placebo group; when subjects were standing, there was a 68-percent improvement in capillary blood flow, compared to 8 percent in the placebo group. Treatment with Pycnogenol also improved capillary leakage, reducing ankle swelling by 17 percent after passing from lying down to standing up, compared to 2.6 percent in the placebo group.

Berries also support the vascular system. Indiana University researchers examined the vasoactive and vasoprotective properties of three anthocyanin-enhanced extract prepared from chokeberry, bilberry or elderberry (supplied by Artemis International) in swine coronary arterial rings.⁶⁹ Chokeberry and bilberry produced dose- and endothelium-dependent vasorelaxation; in addition, low doses of the extracts protected the arteries from oxidative damage.

Another botanical “berry,” the tomato, delivers powerful support through its high lycopene content, as well as synergistic nutrients. Researchers from the Rowett Research Institute, Aberdeen, Scotland, conducted a randomized, double blind, placebo-controlled, crossover study in which 90 healthy adults received tomato extract equivalent to two or six tomatoes.⁷⁰ A dose response to tomato extract was found at low levels of platelet stimulation, with the extract inhibiting platelet activation. Follow-up work by the researchers found tomatoes contain anti-platelet compounds that inhibit thrombin-induced platelet aggregation in addition to adenosine.⁷¹

Italian researchers investigated the effects of lycopene alone, with alpha-tocopherol or whole tomato lipophilic extract on endothelial cell function.⁷² Lycopene increased biosynthesis of platelet-activating factor only when it was found with alpha-tocopherol or the compounds in the whole lipophilic extract, leading the researchers to suggest several compounds work synergistically to modulate the atherogenic process in the vascular endothelium. Another study out of University of the Negev, Beer-Sheva, Israel, examined the impact of 250 mg/d tomato extract (as Lyc-O-Mato®, from LycoRed Ltd.) on blood pressure and oxidative stress markers in 31 subjects with grade-1 hypertension.⁷³ After the eight week intervention, systolic and diastolic blood pressures decreased, as did markers of lipid peroxidation.

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