With the advent of modern medicine and technology there has been great interest in understanding how natural substances that have been consumed for thousands of years affect the human physiology and molecular machinery. Environmental factors, most notably diet, are well known to influence a number of disease states including both metabolic syndromes and cardiovascular disorders. More recently, diet has been implicated in modulating the risk of cancer. The incidence of cancer varies among ethnic groups and even among individuals of the same ethnic group residing in different geographic regions when they consume a diet specific to that region. For example, Asian women who moved to the USA were found to ingest higher amounts of tofu than Asian–American women born in the USA , and US-born Japanese migrants have a significantly higher incidence of colorectal cancer compared with their foreign-born counterparts .
It has been suggested that populations consuming a soy-rich diet may have a lower risk of specific malignancies and extracts of soy have been investigated for the prevention and treatment of neoplasia. One of such extracts, genistein, was first isolated from a plant Genista tinctoria in 1899 and chemically synthesized in the 1920s. It is a plant-derived isoflavone and phytoestrogen found predominantly in soy products that has been studied for a potential role in colon cancer prevention and treatment.