In 1901, Lenna graduated in nursing from the Battle Creek Sanitarium (a Seventh-day Adventist health institution) in Battle Creek, Michigan. It was there that she became a protégé of the famed vegetarian physician, Dr. John Harvey Kellogg, superintendent, and medical director of the sanitarium. During the early part of the twentieth century, the Battle Creek Sanitarium became world-famous as a leading medical center, spa-like wellness institute, and grand hotel that attracted thousands of patients actively pursuing health and well-being. The sanitarium served only vegetarian meals to its patients and visitors. People of all social classes from around the world flocked to the Sanitarium to personally experience its unique vegetarian diet and wellness program, which Dr. Kellogg called “biologic living”. The Sanitarium’s notable guests included Mary Todd Lincoln, Amelia Earhart, Booker T. Washington, Johnny Weissmuller, Henry Ford, Thomas Edison, John D. Rockefeller Jr., George Bernard Shaw, and J.C. Penney. Dr. Kellogg and his team of dietitians even worked with presidents such as William Howard Taft, Warren G. Harding, Herbert Hoover, and Franklin Delano Roosevelt.

Under the tutelage and inspiration of Dr. Kellogg and his wife, Ella Eaton Kellogg, Lenna first developed her love for the study of foods and their scientific preparation. Dr. Kellogg encouraged Lenna to go to the Drexel Institute in Philadelphia to study foods and food chemistry where she excelled in her studies. She later received her bachelor’s (1916) and master’s (1927) degrees from Columbia University.