Gastroenterology Associates of Western Michigan, PLC has been providing state-of-the-art care for our patients in the West Michigan region since 1985. Our experienced healthcare professionals are committed to providing you with an exceptional care experience.
Allan Coates, DO
Dr. Allan Coates is board certified in Gastroenterology and Internal Medicine. Dr. Coates earned a Bachelor’s Degree in Biology from Western Michigan University and a Doctor of Osteopathic Medicine from the College of Osteopathic Medicine & Surgery in Des Moines, Iowa. He completed his Internal Medicine internship and residency at the Grand Rapids Osteopathic Hospital in Grand Rapids, Michigan, and received his fellowship training in Gastroenterology from the University of Michigan Medical Center in Ann Arbor, Michigan.
Katherine Baker, FNP
Katherine Baker, FNP-C is a board-certified Family Nurse Practitioner and has been with Gastroenterology Associates since 2020. Katherine holds a special interest in metabolic associated liver disease and functional gastrointestinal disorders. As a provider, she enjoys and prioritizes giving her patients the time and attention to not only address their health concerns, but to establish connections in which the patient feels valued and comfortable. In addition to gastroenterology, her nursing experience has spanned medical-surgical, surgery, endoscopy, post anesthesia care, and weight management. She is a member of the American Academy of Nurse Practitioners and American College of Gastroenterology. Outside of the office, she loves to spend time with her husband and daughters, often chauffeuring and cheering the girls on in whichever sport they are in that season, explore outdoors, run, race triathlons, and read.
Julia Valdespina, FNP
Julia Valdespina, FNP-C is a a board-certified Family Nurse Practitioner and has been with Gastroenterology Associates of Western Michigan since February 2022. She received her Master of Science in Nursing degree from Olivet Nazarene University in Bourbonnais, Illinois. Julia enjoys the education aspect of nursing and helping patients understand what they are going through as well as assisting to find ways to improve and live a healthy lifestyle. In addition to seeing patients at Gastroenterology Associates, Julia is a Sub-Investigator on all clinical trials being conducted at West Michigan Clinical Research Center.
Natalie Orey, PA-C
Natalie Orey, PA-C joined our team in September 2025. Natalie is a board-certified Physician Assistant with over 13 years of experience in Gastroenterology. She earned her Bachelor of Science degree from Michigan State University, and her Master of Medical Science in Physician Assistant studies from Nova Southeastern University. Natalie is a Sub-Investigator on all clinical trials conducted at West Michigan Clinical Research Center.
Sharyn Coates, Dr. O.T., OTRL, BCB-PMD