This review is intended to provide information on recent research on the nutritional value of the soybean, how soy can be used in the vegetarian and vegan diet, its use in diet therapy for some diseases, and role of isoflavones in health outcomes. Soy consumption has also been well studied for meeting nutritional needs of vegetarians and vegans, and those with health issues such as chronic kidney disease, cardiovascular disease, diabetes, and cancer. Much research has been focused on the nutritional composition of soybeans in the past 30 years; in particular breeding and genetic engineering have the potential to alter soybeans. Finally, bioactive components of soybean, including isoflavones, have emerging role, but there are complicating results regarding correlations and effects on health outcomes, including reducing menopausal symptoms, reducing risk of bone disease and some cancers. The purpose of this review is to provide information regarding recent advances in the composition of soybean, its use in health and disease