Blueberry Consumption Improves Vascular Function and Lowers Blood Pressure in Postmenopausal Women With Pre- and Stage 1-hypertension

Cardiovascular disease (CVD) continues to be the leading cause of death in the U.S. Americans have been more concerned about their blood cholesterol levels and dietary cholesterol intakes rather than their overall cardiovascular health risk factors leading to CVD such as hypertension, vascular dysfunction, inadequate consumption of fruits and vegetables and physical activity. Statistics show that approximately 91% of individuals with CVD have vascular dysfunction which is attributed to endothelial and autonomic dysfunction leading to increased arterial stiffness.

The investigators long-term goal is to provide feasible and effective dietary ways for pre- and stage 1- hypertensive individuals to normalize their blood pressure (BP), improve vascular function and thereby reducing their cardiovascular risk and enhancing the quality of life. Blueberries are a rich source of phenolic compounds and these compounds may play an important role in promoting cardiovascular health. Considering the strong possibility that phytochemicals present in blueberry work additively or synergistically, it would be ideal to investigate the cardioprotective effects of blueberry as a whole. The investigators overall objective to bring forth evidence that blueberry consumption will reduce BP and cardiovascular risk factors including endothelial dysfunction, arterial stiffness, and autonomic dysfunction in pre- and stage 1-hypertensive postmenopausal women. The investigators hypothesize that blueberry supplementation will improve vascular function and will lower blood pressure in postmenopausal women with pre-hypertension. The findings of this study will provide a foundation for disseminating feasible, safe approaches for preventing and combating hypertension at its early stage which does not require drug therapy.

The purpose of this study is to examine the effects of 22 grams of freeze-dried blueberry intake on a daily basis for eight weeks in:

The purpose of the study is to examine the effects of 22 grams of freeze-dried blueberry intake on a daily basis for eight weeks on arterial function and blood pressure in postmenopausal women with pre- and stage 1-hypertension. The specific aims of the study are:

1. To investigate the extent to which daily consumption of 22 g blueberry drink-mix reduces blood pressure in individuals with pre- and stage 1-hypertension.
2. To determine whether daily consumption of 22 g blueberry drink-mix will improve the autonomic control of blood pressure and heart rate in individuals with pre- and stage 1-hypertension.
3. To measure serum markers of oxidative stress to determine whether increased antioxidant defense is in part responsible for blueberry's vascular protective effects.

Eligibility Criteria:
Inclusion Criteria:

* 40 women (1 to 10 years after natural menopause or bilateral oophorectomy) 45-65 years of age.
* Seated blood pressure ≥ 130/85 mm Hg but ≤ 160/90 mm Hg.

Exclusion Criteria:

* Blood pressure \>160/100 mmHg
* Taking insulin
* Cardiovascular disease
* Active cancer
* Asthma
* Glaucoma
* Thyroid disease
* Kidney disease
* Liver disease
* Pancreatic disease
* Enrollment in a weight loss program
* Heavy smokers (\>20 cigarettes per day)