A new study suggests that soy supplementation may not reduce blood pressure in menopausal women.
Soy contains protein, isoflavones and fiber, all thought to provide health benefits. Soy is an excellent source of dietary protein, including all essential amino acids. Soy is also a source of lecithin or phospholipid. Soy isoflavones and lecithin have been studied scientifically for numerous health conditions. Isoflavones such as genistein are believed to have estrogen-like effects in the body, and as a result are sometimes called "phytoestrogens."
There is limited human research on the effects of dietary soy on blood pressure. Some research suggests that substituting soy nuts for non-soy protein may help improve blood pressure. Further research is needed before a firm conclusion can be made.
In a new study, researchers randomly assigned 24 menopausal women with high normal blood pressure to receive 80 milligrams of soy isoflavones or placebo daily for six weeks. Changes in blood pressure and nitric oxide metabolism were evaluated as the main outcome measures through several methods, including forearm blood flow and 24-hour blood pressure monitoring.
After the six weeks of treatment, the researchers found that soy supplementation had no significant effects on blood pressure or nitric oxide metabolism when compared to the control group.
Larger-scale, well-designed clinical trials are needed to further evaluate these findings.
In addition to soy, many other integrative therapies have been studied for their effects on blood pressure. Numerous human studies report that garlic may lower blood pressure. Multiple human trials have also reported small reductions in blood pressure with intake of omega-3 fatty acids. Additionally, preliminary research suggests that CoQ10 causes small decreases in blood pressure (systolic and possibly diastolic). Low blood levels of CoQ10 have been found in people with hypertension, although it is not clear if CoQ10 "deficiency" is a cause of high blood pressure. Well-designed long-term research is needed.
For more information about integrative therapies for high blood pressure, please visit Natural Standard's Comparative Effectiveness Database.
For more information about soy, please visit Natural Standard's Foods, Herbs & Supplements Database.