Dietary supplement companies are pushing to expand the types of ingredients they can use in their products. The Food and Drug Administration is holding a meeting Friday to discuss the issue. The changes sought by the industry could open the door to more supplements containing peptides, probiotics and other trendy wellness ingredients. Companies want the FDA to broaden its definition of a dietary ingredient to substances that aren't found in foods. The meeting follows vows from Health Secretary Robert F. Kennedy Jr. to "end the war at FDA" on dietary supplements and other popular wellness products.