With so many health products and practices promising to provide quick fixes to all that ails us, it can be difficult to discern which ones actually work. But for doctors and medical researchers, the question of effectiveness becomes an opportunity for clinical studies. To find out more about some of these studies, “Take Care” spoke with Dr. Joann Manson, a professor of medicine at Harvard University, and chief of the Division of Preventive Medicine at Brigham and Women’s Hospital.