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Probing the value of isoflavones in patients at risk for cardiovascular complications

Isoflavones are one of the phytoestrogens found mainly in soybeans. Here’s a somewhat technical study from researchers at the Queen Mary Hospital in Hong Kong where isoflavones had beneficial effects on blood flow in people at risk for cardiovascular complications.

First, the details.

  • 126 adults at high risk of cardiovascular events (94% had coronary artery disease or stroke; 44% had diabetes) were studied.
  • Cardiovascular events included heart attack, unstable angina, blood clots, cardiac arrest, sudden or unexplained death, ischemic stroke, and transient ischemic attacks.
  • A food-frequency questionnaire was used to estimate their dietary intake after they achieved stable dietary patterns for 3 months.

And, the results.

  • The intake of isoflavone and soy protein ranged from 2 to 13 mg/day and 0.4 to 3 grams/day, respectively.
  • After adjusting for potential confounding factors, those with the highest isoflavone intake had better blood flow through the carotid artery leading to the brain.
  • This was the result of a 3% increase in flow-mediated dilation and a 14% decrease in the thickness at the carotid intima — the innermost lining of the carotid artery.
  • Soy intake was not associated with these positive effects.

Carotid intima-media thickness (IMT) is used as a marker of early atherosclerosis. Although this study didn’t measure a change in disease outcome (eg, stroke), for those at greatest risk it might makes sense to find ways to increase the isoflavones in your diet.

Check with your healthcare professional.

11/1/07 19:53 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.