protein. Studies in the late 1990s demonstrated decreases in LDL and total cholesterol, and maintenance or increase of HDL cholesterol with soy protein. Studies varied in age and genetics of subjects, differences in study design and diets as well as types of soy preparations and amounts of soy consumption, length of the study period, and other factors which may have affected outcomes. Recent studies concluded that soy components such as isoflavones with their independent cholesterol lowering effect, contribute to the mechanism involved (Lichtenstein 1589-1590).
Soybean constituents include phytates, protease inhibitors, phytosterols, saponins, and isoflavonoids (Craig S1999). Three isoflavonic phytoestrogens or isoflavones are genistein, daidzein, and glycetein. The abundance of each varies according to the individual product and processing techniques. These compounds have demonstrated estrogenic and antiestrogenic effects. Human studies have shown that 45 mg of isoflavonoids affect cholesterol c
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