More research, however, is needed to confirm these claims. Soy protein contains phytoestrogens and isoflavones, nutrients that may have estrogen-like effects. Phytoestrogens have been likened to a weak form of plant estrogen. The potential effects of these nutritional elements are wide-ranging and require further scientific study. Phytosterol, a plant's counterpart to cholesterol, may help lower cholesterol levels by reducing cholesterol absorption.
Soybeans are an excellent source of phytosterols.
Isoflavones in soy may inhibit the growth of breast, endometrial, prostate, and colon cancers. Phytosterols may reduce colon cancer risk. High levels of estrogen have been related to escalated risks for breast cancer and other hormone-related cancers. By mimicking and interfering with estrogen, isoflavone may prevent estrogen from binding to cell receptors and thereby inhibit the cancer process. Soy protein contains less sulfuric amino acids and phosphorus than animal proteins.