: Grape Seed Extract Lowers Blood Pressure In Double-Blind Study
Posted December 18, 2015
By Michael T. Murray, ND
A simple dietary supplement has once again been shown to produce valuable health benefits. Specifically, a new study published in the British Journal of Nutrition has validated the effects of a previous study showing grape seed extract can effectively and safely normalize blood pressure in many subjects. This new study is very good news for the 74 million Americans with high blood pressure as it offers a safe alternative to the use of drugs to lower blood pressure, all of which carry a significant risk for side effect.
Grape seed extract contains flavonoid compounds known as procyanidolic oligomers (PCOs) or oligomeric proanthocyanidins (OPCs). Studies have shown that supplementation with PCOs for six weeks at daily dosages of 100 to 300 mg considerably improves the serum (blood) total antioxidant capacity and oxygen radical absorbance capacity score (ORAC). Grape seed and/or pine bark extract have shown significant benefits in clinical studies including in the following health conditions:
- Atherosclerosis, hypertension, metabolic syndrome, and type 2 diabetes
- Attention Deficit Disorder
- High blood pressure
- Male infertility
- Menopausal symptoms
- Periodontal disease
- Varicose veins, venous insufficiency and capillary fragility
- Visual function, retinopathy and macular degeneration
Blood pressure refers to the resistance produced each time the heart beats and sends blood coursing through the arteries. The peak reading of the pressure exerted by this contraction is the systolic pressure. Between beats the heart relaxes, and blood pressure drops. The lowest reading is referred to as the diastolic pressure.
A normal blood pressure reading for an adult is: 120 (systolic) / 80 (diastolic). High blood pressure (BP) readings can be divided into the following levels:
- Prehypertension (120-139/80-89)
- Borderline (120-160/90-94)
- Mild (140-160/95-104)
- Moderate 140-180/105-114)
- Severe (160+/115+)
In a previous double-blind study, grape seed extract (GSE) was shown to normalize high blood pressure in patients with initial blood pressure in the range of 150/95 mm Hg when combined with standard dietary guidelines. To follow up these impressive results, researchers from the Center for Nutrition Research at the Illinois Institute of Technology and the University of California, Davis, CA, sought to evaluate the ability of GSE to lower blood pressure (BP) in individuals with pre-hypertension (120-139/80-89 mm Hg).
A total of 36 subjects with pre-hypertension were randomized to ingest a juice containing 0 mg (placebo) or 150 mg GSE twice daily for 6 weeks preceded by a 2-week period where both groups took the placebo beverage and followed by 4-week no-beverage follow-up.
Patients were had their blood pressure (BP) measured at screening and at the 0, 6 and 10 weeks of the trial. Results showed that subjects taking the GSE for six weeks significantly reduced both their systolic (-5.6 percent) and diastolic BP (-4.7 percent). However, subjects with higher initial BP experienced greater BP reduction; nearly double the effect size. The majority of subjects were able to achieve normal BP measurements with GSE supplementation. In contrast, no effect was noted in the placebo group. BP returned to baseline levels after the 4-week discontinuation period of the GSE beverage indicating that the results are only apparent while the GSE is being consumed.
The researchers concluded "GSE was found to be safe and to improve BP in people with pre-hypertension."
Every effort through diet and supplementation should be made to get your blood pressure below 120/80 mm Hg. All of the current classes of blood pressure lowering drugs possess significant side effects and 80 percent of people with high BP can lower their blood pressure without drugs. In fact, in head-to-head comparisons, many nondrug therapies such as diet, exercise, relaxation therapies, and dietary supplements like GSE have proved superior to drugs in cases of prehypertension to mild high BP and are without side effects.
For moderate through severe hypertension, drug therapy may be necessary, but should be ideally used as a bridge therapy until dietary, lifestyle, and supplement strategies to lower blood pressure take hold. In patients with moderate through severe hypertension, drug therapy is appropriate, but should still be thought of as a secondary approach.
Dr. Michael T. Murray is one of the world's leading authorities on natural medicine and the author of more than 30 bestselling books, including The Encyclopedia of Natural Medicine.
He is a graduate and former faculty member, and serves on the Board of Regents, of Bastyr University in Seattle, Washington.
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