Grape Seed Extract and Blood Pressure, Latest Findings
In previous studies, grape seed extract in capsules was shown to be an effective natural alternative for lowering blood pressure. Now new research results are adding to that war chest, but how well did grape seed extract perform? Well enough to make you consider using it?
New grape seed extract study
The extract used in this study was added to beverages and not tested as capsules. In a 10-week, randomized, double-blind trial, 28 men and women with prehypertension (120-139 mmHg systolic and 80-89 mmHg diastolic) were given either 300 mg grape seed extract in two 40-calorie beverages each day for six weeks (12 participants) or a placebo (16 participants).
According to Britt Burton-Freeman, PhD, one of the study’s authors and director of the Center for Nutrition Research at the Illinois Institute of Technology Institute of Food Safety and Health, in a NutraIngredients-USA report:
- Overall, systolic blood pressure declined 7 mmHg and diastolic dropped 3.8 mmHg after six weeks of taking grape seed extract
- Blood pressure rose after ten weeks when participants had stopped taking the extract
- In a subset of individuals with a systolic blood pressure of 125 mmHg or greater, the decline in systolic pressure was 13.6 mmHg
- In a subset of individuals with a diastolic blood pressure of 83.5 mmHg or greater, the decline in diastolic pressure was 5.8 mmHg
The important messages from this study are that the “higher starting systolic or diastolic blood pressure group got the greatest benefit,” noted Burton-Freeman, and that even those with a milder prehypertension state saw improvements.
In an earlier placebo-controlled, double-blind study involving adults with prehypertension, 300 mg of grape seed extract in capsules taken for 8 weeks resulted in a decline in systolic and diastolic blood pressures of 8 mmHg and 5 mmHg, respectively. Individuals in the placebo group showed no improvements.
Grape seed extract bonuses
The researchers noted at least one potential bonus benefit from the study. They observed some marginally significant improvement in insulin sensitivity after six weeks of grape seed extract use, which suggests the supplement may be helpful in type 2 diabetes.
A previous study also hinted at a potential association between the extract and metabolic syndrome, which is a significant risk factor for type 2 diabetes. The small study found that 300 mg or grape seed extract significantly lowered glucose concentrations and had a positive effect on bad cholesterol, indications that the supplement might help people with metabolic syndrome.
For other grape seed extract bonuses, see:
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Edirisinghe I et al. Effect of grape seed extract on postprandial oxidative status and metabolic responses in men and women with the metabolic syndrome - randomized, cross-over, placebo-controlled study. Functional Foods in Health and Disease 2012; 2(12): 508-21