**Author details**

Rajeev K. Tyagi

Department of Medicine, Division of Gastroenterology, Hepatology and Nutrition, Vanderbilt University Medical Centre (VUMC), Nashville, TN, USA

\*Address all correspondence to: rajeev.tyagi@vumc.org; rajeev.dbt@gmail.com

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
