Isoflavones in foods
A qualified healthcare provider should be consulted before making decisions about therapies and/or health conditions.
In 2000, Setchell discussed several studies investigating the effects of eating soy. The author found that the highest concentrations of isoflavones occurred between four and eight hours after eating soy. Isoflavones that were present in solid foods remained in the body longer than those that were eaten as part of a liquid. Based on an analysis of blood levels, the authors proposed that there may be a limit to the concentration of isoflavones that can circulate in the bloodstream.
In 2001, Setchell proposed that soy isoflavones should be classified as "natural selective estrogen receptor modulators (SERMs)," since these molecules may sometimes behave in ways that are similar to the hormone estrogen.
In 2006, Sacks et al. reviewed studies investigating the effects of soy protein (which contains isoflavones), and isoflavone supplements (in pill or liquid form) on heart health. The authors did not find a significant difference in certain medical measurements of heart health when study participants consumed soy or isoflavones. While the authors did not recommend taking isoflavone supplements, they did endorse eating foods that are high in isoflavones, such as soy.