the effect of grape seed extract on blood pressure in people with pre-hypertension

Conditions: Hypertension

Summary: in this research study, the investigators are interested in learning how extracts from grape seeds can help those individuals with high blood pressure. the investigators also hope to learn how grape seed extract effects your blood and cell functions. the grape seed extract the investigators will use in the study will be provided either in a beverage or a capsule form and is currently available on the market. this study is also using a placebo; therefore the treatment subjects receive may or may not contain the grape seed extract. the purpose of this study is to determine if the grape seed extract (gse) will lower blood pressure in people with slightly high blood pressure (pre-hypertension).

elevated blood pressure, or hypertension, is a major risk factor for heart disease and stroke. systolic and diastolic blood pressures meeting criteria for "pre-hypertension" double the absolute risk of stroke and ischemic heart disease over an extended age range from the 4th to the 8th decade of life. lifestyle, particularly the diet, is critical in the prevention and management of hypertension. polyphenolic compounds from various plant foods can promote blood pressure regulation and vascular health through protection of the endothelium from oxidant and or inflammatory stress and or stimulation of smooth muscle relaxation. we will use a purified grape seed extract (gse) in the proposed trial. this extract has been granted generally recognized as safe (gras) status by food and drug administration (gras notice # grn 000125, dated 08/18/2003, fda, usa). furthermore, gse for use in the present trial has been used in previous human clinical trails and shown potent vasodilator properties in vitro and blood pressure lowering in metabolic syndrome patients. the proposed trial aims to verify the blood pressure lowering effect of gse in an 'at risk' population for hypertension and to explore the extent to which other pathways of chronic disease may be modulated by gse consumption. given this, the objectives of this study are as follows: 1. the primary objective of the proposed study is to demonstrate the effectiveness of gse to lower blood pressure in pre-hypertensive individuals. 2. secondary objectives will investigate the role of gse to improve inflammatory- and oxidative stress- status, as well as its effect on endothelium function.

Eligibility criteria:
inclusion criteria: * male and female * pre-hypertensive * systolic blood pressure (mmhg) 120 - 139 or * diastolic blood pressure (mmhg) 80 -89 * no clinical evidence of cardiovascular, respiratory, renal, gastrointestinal or hepatic disease exclusion criteria: * pregnant and or lactating * taking over the counter antioxidant supplements * taking prescription medications that may interfere with study procedures or endpoints * unusual dietary habits * actively trying to lose or gain weight * addicted to drugs and/or alcohol * medically documented psychiatric or neurological disturbances * smoker (past smoker may be allowed if cessation is \> 2 years)

Keywords: high blood pressure dietary supplements nutrition