About us

Dr. Robert A. Duca, Jr. founded Virginia Diagnostic and Natural Medicine Clinic, P.C. in northern Virginia more than thirty years ago. He is a functional medicine practitioner and clinical nutritionist, with a primary practice in Dunn Loring, Virginia and a consulting practice in Albuquerque, New Mexico.

Functional Medicine is a personalized and science-based approach to healthcare that focuses on identifying the underlying causes of disease and promoting optimal wellness. It utilizes patient-specific information, such as genetic, biochemical, and lifestyle factors, to create personalized treatment plans that lead to improved patient outcomes. The practice of clinical nutrition incorporates a biochemical and physiological understanding of nutrition and its role in health and disease. Clinical nutrition addresses the role of nutrition as a preventive, adjunctive, alternative strategy for the prevention and amelioration of specific health conditions.

Dr. Duca has a master’s degree in human nutrition from the University of Bridgeport and a Doctor of Chiropractic Medicine degree from the National University of Health Sciences. He is a certified practitioner of the Institute for Functional Medicine, board-certified in clinical nutrition by the American Clinical Board of Nutrition, a board-certified internist by the American Board of Chiropractic Internists, and board-certified in sports medicine by the American Board of Chiropractic Sports Physicians. He has also been published in the medical literature on topics such as methylation, nutritional considerations in ADHD, Crohn’s Disease, and gastrointestinal disease. Dr. Duca is a fellow of the International Academy of Medical Acupuncture and holds Advanced Practitioner Certification in the State of New Mexico. Dr. Duca is past president of the ACA Council on Diagnosis of Internal Disorders. Dr. Duca is an adjunct faculty member of the National University of Health Sciences.

We believe in a comprehensive approach to healthcare, and our team is dedicated to helping you achieve optimal health. Contact us today to schedule an appointment or learn more about our services.

Patient Testimonials

Our son has a rare autoimmune disease and we have been to every kind of doctor there is: hematologist, immunologist, rheumatologist, neurologist, psychologist, pulmonologist, gastroenterologist… We can honestly say that Dr Duca (in his capacity as nutritionist) has been THE best doctor and has…

Arlene B. in Purcellville, VA

Dr. Duca is a GREAT doctor. He has great bed side manners. He is very informational and most of all very caring and understanding. He takes his time w/his patients and make sure they understand everything. I would highly recommend him!


My Husband has been dealing with lung disease for 9 yrs.He has gone to the best,Georgetown University,John Hopkins,INova lung institute.NoONE could help him, all they would do is provide Prednisone.Dr.Duca has been the ONLY one that ever asked how did a man that went to Katrina,is a firearms…

Anna in Purcellville, VA

Dr. Duca is an excellent doctor. I was experiencing throbbing upper back pain. Dr. Duca came highly recommended by one of his patients. Dr. Duca took a lot of time with me and got to the root of the problem. He tested me for food allergies and I found out I was allergic to several foods I was…


So grateful to have found Dr. Duca!

Wow, so grateful to have found Dr. Duca (through ifm.org and he happens to take my insurance)! It has been an eye-opening experience – over the years, I have had symptoms I can’t explain and other doctors have always said I’m fine. Dr. Duca thinks outside the box and orders testing that others…


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