(Source: US Senate Committee on Health, Education, Labor, and Pensions) WASHINGTON, D.C. - U.S. Senators Pat Roberts, R-Kan., and Lamar Alexander, R-Tenn., today sent a letter to U.S. Secretary of Agriculture Tom Vilsack and to U.S. Secretary of Health & Human Services Sylvia Burwell, urging them to base the final 2015 Dietary Guidelines for Americans on "sound scientific evidence and medical knowledge" and limit "agenda-driven" recommendations to nutrition and diet. In February, the Dietary Guidelines Advisory Committee (DGAC) sent to the Secretaries a nearly 600-page scientific report, which serves as a recommendation to the agencies as they develop the 2015 Dietary...