Safiya Richardson presented results of her new study at American College of Cardiology’s 61st Annual Scientific Session, where cardiovascular specialists and cardiologists discuss the newest discoveries in the treatment and prevention of cardiologic diseases.
Previous studies have shown that soy isoflavones activate endothelial nitric oxide synthases, resulting in increased nitric oxide production and possibly lowered blood pressure. Richardson and her team investigated the relation between isoflavones and blood pressure in a biracial population cohort. They looked at data from the CARDIA study that followed more than 5,000 Americans for a period of 20 years, after which the participants completed their first dietary survey.
They found that patients with hypertension had lower isoflavone intake, especially among African Americans. The highest quartile of isoflavone intake (>2.5mg/day) was associated with 5.5mmHg lower systolic blood pressure. Consumption of soy products by people with a slightly raised blood pressure could even results in a drop of 10mmHg. The study concluded that a daily intake of 2.5 mg isoflavone is associated with a lower systolic blood pressure across the general population, but should be evaluated in future randomised controlled trials. We find it very surprising that such a low level of 2.5 mg isoflavones can be effective, considering the fact that Asians typically consume between 40 and 80 mg isoflavones per day.
Safiya Richardson et al. Dietary Isoflavone Intake is Associated with Lower Systolic Blood Pressure: the Coronary Artery Risk Development in Young Adults (CARDIA) Study. J Am Coll Cardiol, 2012; 59:1630