Into the Heart

Concord Grapes, Beautiful Arteries

In laboratory, animal studies and in human trials the flavonoids found in grapes and grape products such as juice or wine have been known to generate cardio vascular benefit via antioxidant, anti-inflammatory, platelet inhibitory and arterial relaxing effects. This study noted below tested the effects of Concord grape juice consumption on blood pressure in hypertensive patients.

Forty subjects were given 5.5 ml/kg body weight per day of either Concord grape juice or a calorie-matched placebo beverage every day for eight weeks. Blood pressure was measured at the start of the study and during weeks four and eight. Compared to baseline, in the Concord grape juice group systolic blood pressure was reduced on average by 7.2 mm Hg and diastolic blood pressure was reduced on average by 6.2 mm Hg at the end of eight weeks.

Comparable changes in the group taking the placebo beverage were -3.5 mm Hg and -3.2 mm Hg. The findings of this study indicate consuming Concord grape juice, which is high in polyphenolic compounds, has favorable affects on blood pressure in hypertensive individuals. Concord grape juice nurtures cardiovascular health by nurturing the structure and function of arteries. Additionally, vibrant Concord grape juice provides a nice option or alternative for those who do not care for red wine.  Concord grape juice with no added sugar or artificial sweeteners is preferential.

It is also noteworthy, that consumption of flavonoid-containing foods is associated with a reduced risk for dementia. A small preliminary study (noted below) investigated the neurocognitive effects of Concord grape juice on humans. Twelve older adults with memory decline but not dementia were enrolled in a randomized, placebo-controlled, double-blind trial. Concord grape juice supplementation was for twelve weeks.

The study found a significant improvement in a measure of verbal learning and non-significant enhancement of verbal and spatial recall. Such preliminary findings suggest that supplementation with Concord grape juice has the potential to enhance cognitive function for older adults with early memory decline.

Sources:
Concord grape juice supplementation reduces blood pressure in Korean hypertensive men: double-blind, placebo controlled intervention trial.
Park YK, Kim JS, Kang MH.
Biofactors. 2004; 22(1-4):145-7.

Concord grape juice supplementation improves memory function in older adults with mild cognitive impairment.
Krikorian R, Nash TA, Shidler MD, Shukitt-Hale B, Joseph JA.
British Journal Nutr. 2010 Mar; 103(5):730-4.

Salt Sensitivity and Blood Pressure

In humans, the blood pressure response to an acute change of salt intake is referred to as "salt sensitivity." Those individuals in whom a severe sudden modification of salt intake or excretion causes the least change in arterial blood pressure are termed "salt resistant," whereas those in whom a severe sudden modification of salt intake induces large blood pressure changes are referred as "salt sensitive."

In general, people tend to become more salt sensitive as they age. Additionally, women age 50 plus also tend to become salt sensitive as estrogen production significantly diminishes due to menopause. It is helpful to be aware of changes regarding salt sensitivity because there is a strong relationship between sodium and the development of high blood pressure.

In response to excessive sodium vascular smooth muscle tone is stimulated . . . the artery remains tense. The arterial wall composition changes; the collagen, elastin and smooth muscle cells within the middle layer of the artery over develop contributing to arterial stiffness.

Sodium also interacts with aldosterone synthase and increases the expression of angiotensin type I receptors.

Additionally, excessive sodium impairs endothelial function (the protective lining within the artery) by reducing the production of nitric oxide, diminishing nitric oxide bioavailability and by stimulating nitric oxide synthase inhibitor (asymmetrical dimethylarginine) and enhancing NADPH oxidase: troublesome free radical cell activity.

Excessive dietary salt contributes to vascular stiffness with increasing age, and low sodium diets maintain healthy arterial function. It is helpful to keep in mind, while excessive sodium is troublesome to the arteries, potassium intake has a beneficial effect on arteries. In addition to providing artery strengthening vitamin C, orange juice is also abundant in potassium.

Sources:
Sodium Intake and Vascular Stiffness in Hypertension
Michel E. Safar MD 
Hypertension. 2009;54:203.

Mechanism, Pathophysiology, and Therapy of Arterial Stiffness
Susan J. Zieman MD,
Arteriosclerosis, Thrombosis and Vascular Biology 2005; 932-938