A study conducted over a period of 13 years showed that a high number of American adults take regular dietary supplements - 52 percent reported using a supplement in the last month at the onset of the study. That number remained high throughout the study, and afterward scientists even believed that they underestimated the total amount of U.S. adults taking dietary supplements for various reasons.
What did change throughout the study was the type of dietary supplement adults were taking, and the study results suggested that varying popularity of certain supplements often governed who took what supplement. The researchers also found that the choice of one supplement over another was most often based on new research. However, the same research studies that convinced people to take a certain supplement often struggled to show a clear benefit of taking the supplement over just taking a placebo.
Doctors and scientists consider the term "dietary supplement" to include a wide range of products: vitamins, minerals, botanicals, proteins, fish oils, probiotics, and more.