SIBO Center for Digestive Health at NCNM

Meet Our Providers

Steven Sandberg-Lewis, ND, DHANPssl_2013_188

Dr. Steven Sandberg-Lewis has been a practicing naturopathic physician for 36 years, previously on Orcas Island in Washington state and now exclusively at the NCNM Clinic.  Dr. Sandberg-Lewis receives referrals of patients with digestive diseases who desire naturopathic treatment options; often these are conditions that have defied diagnosis by other physicians. He understands the diseases of the gastrointestinal tract, but also can assess function and often find successful treatments to regain normal function of the digestive system.

DrS_whitecoat_webAllison Siebecker, ND, MSOM, LAc

Dr. Allison Siebecker is a 2005 graduate of National College of Natural Medicine, where she earned both her Naturopathic Doctorate and Masters in Oriental Medicine.  She has worked in the nutritional field since 1988 and taught on the subjects of gastroenterology, endocrinology, nutrition and natural beauty treatments. Since 2009 she has focused her practice on Small Intestine Bacterial Overgrowth (SIBO).  She is the author of an educational website on SIBO, is currently writing a book on SIBO and teaches continuing education to physicians on SIBO and related topics.

Melanie-Keller_webMelanie Keller, ND

Dr. Melanie Keller’s naturopathic approach utilizes: functional testing, nutrition, energetic psychology techniques and visceral and structural manipulation to address the whole person.

While attending NCNM Dr. Keller had the exceptional opportunity of an extensive internship with renowned Dr. Steven Sandberg-Lewis that greatly enhanced her education and her practice philosophy. Dr. Keller has also had the amazing opportunity of extended training in Small Intestine Bacterial Overgrowth (SIBO) with Dr. Allison Siebecker.

The SIBO-IBS Center wishes to thank Dr. Siebecker for her contribution of information about SIBO on this site. For more information about SIBO, visit her educational website at