The use of dietary supplements in the United States is very common. In the past decade, the number of people taking Vitamin D has increased 400% and omega-3 fatty acids 1000%. These products have been thought to possibly protect against heart disease and cancer. However, in two large randomized trials where patients either took the supplement or a placebo, neither Vitamin D not fatty acids showed any benefit against cardiac or cancer outcomes. Vitamin D still does contribute to overall bone health and mineral growth.