Improve Your Blood Pressure with Soy Nuts?

By: Allison Stevens for Body1

A new study suggests post-menopausal women may reap health benefits from eating soy nuts. Soy has long been thought to play a role in the lower heart disease risk observed in Asian populations; so, studying the effect eating soy foods has on heart disease risk factors such as blood pressure and cholesterol levels makes sense. In this particular study, researchers from Beth Israel Medical Center in Boston aimed to determine whether adding soy nuts to the currently recommended heart healthy diet provided any benefits to post menopausal women. The results can be found in the May Archives of Internal Medicine.

Take Action

In this study, women ate ½ cup of soy nuts throughout the day. Although eating soy nuts alone can be an easy, crunchy snack, it can get boring. So if you want to incorporate more soy nuts into your diet, try: Trail Mix: For a tasty, portable snack, mix soy nuts with cereal and dried fruits such as cherries, cranberries, or raisins. Salad: Top your salad greens with soy nuts for an extra crunch and an isoflavone boost. But don’t limit adding soy nuts to green salads; they also go well in rice, barley, and other grain-based salads. Yogurt: Sprinkle yogurt with soy nuts and stir in berries or other fresh fruit for a simple, healthy breakfast that will fill you up until lunch.

The Study

For the study, 60 postmenopausal women were recruited, 12 with high blood pressure and 48 with normal blood pressure. Researchers randomly split the women into two groups. One group ate a traditionally recommended heart healthy diet and the other group ate the same diet, replacing some of the foods with ½ cup of soy nuts. After eight weeks, the two groups switched. Those eating soy nuts ate only the heart healthy diet. And those previously eating only the heart healthy diet then added soy nuts to their diet.

Results

When the women were eating soy nuts, their blood pressure was significantly reduced. For women who had high blood pressure, eating soy nuts reduced blood pressure an average of 10 percent for systolic and 7 percent for diastolic blood pressure. And for women with normal blood pressure, soy nut consumption reduced systolic blood pressure by five percent and diastolic by three percent.

Furthermore, soy nut consumption decreased levels of LDL, or bad cholesterol, an average of 11 percent in the women with high blood pressure.

Implications

These findings are promising since the blood pressure reductions observed in this study are comparable with reductions seen with antihypertensive drugs. Moreover, elevated blood pressure is a major risk factor for heart disease and stroke; and, reducing blood pressure has been associated with major reductions in stroke, heart attack, and heart failure.

Isoflavones?

The active component of soy responsible for the lowered blood pressure is unknown. But the researchers point out that “isoflavone content was higher on the soy diet compared with the control diet.” Isoflavones are a type of phytoestrogen, or plant hormone, that resembles human estrogen in structure, but are much weaker. The researchers go on to speculate that in this study the isoflavone content may have accounted for the observed differences in blood pressure. However, previous studies on isolated isoflavone tablets have found no effect on blood pressure.

Previous research and conclusions

According to the authors, this is the first study to directly compare the effects of a whole soy food in people with normal and high blood pressure. However, previous research in individuals with high blood pressure found a diet supplemented with soy milk lowered blood pressure in comparison to cow’s milk. Another found that soy protein compared to dairy protein lowered blood pressure in men, but not women. The authors pointed out that three other trials found no significant effect of whole soy foods compared with non-soy protein on blood pressure.

The positive results of this study, especially when put into context with previous mixed findings, certainly warrant further research into the relationship between soy and blood pressure.

For more recipes and information on soy nuts and other soy foods, visit the Soyfoods Association of North America: www.soyfoods.org

Last updated: 16-Jul-07