Quercetin Reduces Blood Pressure in Adults with Hypertension

Researchers at the University of Utah, in collaboration with USANA Health Sciences, conducted a randomized, double-blind, placebo-controlled, crossover study to test the effectiveness of quercetin supplementation in lowering unhealthy blood pressure levels. The subjects were divided into two groups: prehypertensives (120-139 mm Hg systolic/80-89 mm Hg diastolic) or stage 1 hypertensives (140-159 mm Hg systolic/90-99 mm Hg diastolic). Over 28 days, the participants were given either 730 mg quercetin/day or placebo.

Blood pressure remained unchanged in prehypertensives after supplementation with quercetin. In contrast, stage 1 hypertensive subjects showed significant reductions in both systolic (-7 mm Hg) and diastolic (-2 mm Hg) blood pressure after quercetin supplementation. This is the first published study to show that quercetin supplementation can reduce blood pressure in hypertensive adult humans. Additionally, it is important to note that quercetin supplementation did not influence the blood pressure of non-hypertensive individuals.

J. Nutr. 137:2405-2411, November 2007

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Omega–3 Fatty Acid Intake & The Incidence of Age-related Macular Degeneration

Omega-3 fatty acids are important for the vascular and neural health of the retina and may influence the risk of developing age-related macular degeneration (AMD). There are two forms of AMD: dry and wet. In the dry form, normal tissue in the macula slowly disappears, leaving a pale area referred to as central geographic atrophy (CGA). In the wet form, or neovascular (NV) AMD, abnormal blood vessels grow underneath the macula. These vessels leak serum or blood and eventually cause the normal macular tissue to be replaced by scar tissue.

Researchers recently investigated whether omega-3 fatty acid intake was associated with a reduced risk of developing both wet and dry forms of AMD. The study involved 1837 people from the Age-Related Eye Diseases Study (AREDS) who were at moderate to high risk of developing AMD. Clinical measurements were obtained in this group over a period of 12 years (from 1992 to 2005).

Participants who reported the highest omega–3 fatty acid intake were 35% less likely than their peers to develop dry (CGA) AMD, and 32% less likely to develop the more common, wet form (NV) AMD.

Over the 12 years of this study, the incidence of CGA and NV AMD was lowest for those reporting the highest consumption of omega-3 fatty acids, which are found primarily in oily fish, nuts and seeds, and fish oil supplements. If these results are applied to the general population, dietary intervention may have a significant preventive effect on the development and progression of AMD.

Am J Clin Nutr. 2009 Dec;90(6):1601-7