Addressing Hypertension via Nutrition (Stalking a Silent Killer)

The type of protein in the diet may also impact blood pressure. Soy, for example, has a heart healthy profile and approved health claim. Data from the Shanghai Women’s Health Study indicated long-term consumption of soy protein was inversely related to both systolic and diastolic BP, with the association growing stronger with age.⁶ And intervention work out of Beth Israel Deaconess Medical Center, Boston, showed substituting soy nuts for non-soy protein could significantly reduce blood pressure in both normotensive and hypertensive women.⁷ The researchers suggested the impact may be due to improved endothelial function and reduction in inflammation.

Certain compounds found in soy may also have an effect on blood pressure. Isoflavones, phenolic compounds found in soy, have been an area of focus. In one Korean study using hypertensive rats, adding 10 g/kg/d of soy powder, with 31-percent isoflavones, to a high-fat diet decreased oxidative damage, prevented incremental increases in blood pressure and augmented the production of nitric oxide (NO), which positively affects endothelial function.⁸ Another animal trial focused specifically on the isoflavone genistein, and found supplementation could improve aortic endothelial-derived NO, alleviating hypertension in the rats.⁹

Another soy-related compound is nattokinase, an enzyme originally isolated from the fermented soy food natto. The enzyme has the ability to break up blood fibrin, a protein involved in clotting. Japanese research has found consumption of 30 g of lyophilized natto extract could reduce both systolic and diastolic blood pressure in human volunteers. In fact, unpublished research on nattokinase (as NSK-SD®, from Japan Bio-Science Laboratories) has found the compound had significant effects on blood coagulation, improving blood flow, and also aids in reducing hypertension in adults with untreated high blood pressure.