May lower blood pressure

Arginine is a common amino acid found in soybeans and meals produced from them, and it is thought to help control blood pressure. Isoflavones, another substance thought to have blood pressure-lowering properties, are also abundant in soybeans. In one study, it was shown that some, but not all, women's diastolic blood pressure (the bottom number of a blood pressure reading) decreased by around 8% when they had 1/2 cup (43 grams) of soy nuts daily.

Other studies show that persons with high blood pressure can lower their blood pressure by 3-6 mm Hg with daily soy isoflavone doses of 65–153 mg. It's unclear, though, if those with normal or high blood pressure can still benefit from these modest blood pressure-lowering effects. Both may benefit, according to some research, while others claim that only those with high blood pressure would notice this impact. Clearly, additional study is required, but for the time being, it seems that soy has very little, if any, influence on blood pressure.