Grapes Fight Hypertension And Inflammation

New research suggests that eating grapes may help lower high blood pressure and combat inflammation, thus helping to lower the risk of cardiovascular disease.

A powdered grape formula made from green, red, and black grapes was tested on Dahl Salt-Sensitive rats. These rats developed high blood pressure when fed a diet high in salt. The rats were divided into 5 groups, each given a different diet for 18 weeks: low salt, low salt and grape powder, high salt, high salt and grape powder, or high salt and vasodilator (hydralazine).

Compared to rats fed with the high salt diet only, rats on the high salt plus grape powder diet had improved cardiac function, lower blood pressure, decreased systemic inflammation, and fewer signs of cardiac muscle damage. Rats on the high salt and hydralazine diet had lower blood pressure than the high salt diet rats, but did not exhibit lower levels of systemic inflammation of fewer signs of heart muscle damage.

The researchers believe that natural compounds known as flavanoids are primarily responsible for the antihypertensive effects of grapes. Flavanoids are found in all parts of the grape.

SOURCE: Seymour EM, Singer AAM, Bennink MR, Pariks RV, Kirakosyan A, Kaufman PB, Bolling SF. Chronic intake of a phytochemical-enriched diet reduces cardiac fibrosis and diastolic dysfunction caused by prolonged salt-sensitive hypertension. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences. 2008;63:1034-1042.

My Views

Grapes contain a wide variety of anti-oxidants that help prevent damage to our blood vessels. When that happens, the body’s inflammatory response reduces, and the secretion of nitric oxide (NO) increases. It is now known that normal cardiovascular contraction is biased in one direction, which is towards vessel constriction. This is the body’s way of maintaining the blood pressure at a slightly constricted state in order to channel adequate blood supply and oxygen delivery to the brain continuously. With the constant NO production by the endothelium, vessel dilation is sustained, and blood pressure is maintained at a normal systolic rate of around 120 mm Hg and a diastolic rate of around 80 mm Hg. Too much NO can lead to excessive vasodilatation and a fall in the blood pressure, while too little NO can lead to rise in blood pressure.

The vasodilatation effect of NO applies to all blood vessels. It can initiate erection of the penis by dilating the blood vessels to the erectile bodies. This knowledge has already led to the development of new drugs to treat impotency, such as Viagra.

In addition to helping the blood vessels relax, NO also helps to prevent the clogging of arteries in several ways. First, it prevents the white blood cells from sticking to the arterial wall. It also helps to prevent damage to the arterial wall by reducing the production of free radicals. In other words, it acts like an antioxidant. NO also helps to prevent the thickening of the middle (muscular) wall of the artery that can narrow the opening where the blood flows.

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