**7. Soy and cardiovascular disease**

As mentioned previously, soy isoflavones are phytoestrogens. Estrogen is known to be cardioprotective, so it stands to reason that soy may also be cardioprotective. Many of the clinical trials investigating the effect of soy supplementation on heart health focus mainly on cholesterol levels. This may be due to the fact that the phytosterols, like those found in soy, compete with cholesterol for intestinal absorption [97]. A 2015 study [98] investigated the effect of 8 weeks of standard soymilk supplementation against the effect of 2 g/day of phytosterols and 10 g/day of inulin-enriched soymilk supplementation. While both groups did see a reduction in LDL-C in both groups, the study group supplementing with the extra phytosterols and inulin saw significantly better results. TC was also significantly reduced in the study group, compared to the control of regular soymilk.

Soy can be beneficial in many forms beyond that of soymilk. A study [99] that supplemented whole soy foods (3–4 servings per day) for 12 weeks found that the soy intervention significantly reduced total cholesterol, LDL-C, non-HDL cholesterol, and apoB even though BMI did not decrease. An earlier study [100] also found that soy protein supplementation resulted in decreased cholesterol levels. Prehypertensive women who supplemented 40 g of soy flour saw decreases in LDL-C and well as high sensitivity C-Reactive Protein (CRP), a marker of inflammation [101]. Interestingly, another study found that 1 month of soy nut supplementation modestly reduced arterial stiffness but did not improve inflammatory biomarkers [102]. Additionally, Lucas et al. [103] found that soy isoflavones prevented both hyperlipidemia and atherosclerotic lesions in ovariectomized Golden Syrian Hamsters.

While there are still gaps in the research for CVD and soy consumption, research generally points to a positive effect of soy on heart health, irrespective to its effect on cholesterol. Finding that soy significantly decreased the development of atherosclerotic lesion in a hamster model of postmenopausal CVD is particularly important since CVD remains the leading cause of death in the US.
