Gastroenterology Conference Speakers

Lisa Shaver, ND, LAc

Lisa Shaver, ND, LAc has a passionate interest in digestive disorders with expertise in celiac disease and non-celiac gluten sensitivity. Other interests include hormonal imbalances, autoimmune conditions and neurotransmitter imbalances. Since 2012 Dr Shaver co-teaches NUNM’s Advanced Gastro course’s celiac disease/NCGS modules Dr. Shaver lectures at the AANP, SIBO Conferences, NUNM, AZNMA, amid other events. She is the Gluten Intolerance Group of Portland branch manager since 2008. She co-founded Hive Mind Medicine in Portland, OR.

Lela Altman, ND, LAc, EAMP

Lela Altman, ND, LAc, EAMP, received her Doctorate in Naturopathic Medicine and her Master of Science in Acupuncture at Bastyr University. She went on to complete a 3-year residency at the Bastyr Center for Natural Health. She currently serves as core faculty at Bastyr University where she teaches several classes, supervises clinic shifts at Bastyr University and has a private practice. Dr. Altman also began and currently supervises the Digestive Wellness Clinic at Bastyr University and sees patients in the Center for Integrative Medicine at Virginia Mason Medical Center. Dr. Altman’s practice focuses on digestive health and small intestinal bacterial overgrowth. She has written articles, given continuing medical education lectures and performed interviews in several venues on these topics.

Steven Sandberg-Lewis, ND, DHANP

Steven Sandberg-Lewis, ND, DHANP has been a practicing naturopathic physician since his graduation from the National University of Natural Medicine (NUNM) in 1978. He has been a professor since 1985, teaching a variety of courses but primarily focusing on gastroenterology and GI physical medicine. His private practice is at Hive Mind Medicine in Portland, Oregon.

He is a popular international lecturer at functional medicine seminars, presents webinars and is frequently interviewed on issues of digestive health and disease. He is the author of the near-monthly column entitled “Functional Gastroenterology Bolus” in the Townsend letter. He is the author or co-author of several Townsend Letter award winning articles (Hiatal Hernia Syndrome, Dysbiosis Has a New Name, Small Intestine Bacterial Overgrowth: Common but Overlooked Cause of IBS) and the author of the medical textbook Functional Gastroenterology: Assessing and Addressing the Causes of Functional Digestive Disorders, Second edition, 2017. In 2010 he co-founded the SIBO Center at NUNM which is one of only four centers in the USA for Small Intestine Bacterial Overgrowth diagnosis, treatment, education and research. In 2014 he was named one of the “Top Docs” in Portland monthly magazine’s yearly healthcare issue and in 2015 was inducted into the OANP/NUNM Hall of Fame.

Within gastroenterology, he has special interest and expertise in inflammatory bowel disease (including microscopic colitis), irritable bowel syndrome (including post-infectious IBS), Small Intestine Bacterial Overgrowth (SIBO), hiatal hernia, gastroesophageal and bile reflux (GERD), biliary dyskinesia, and chronic states of nausea and vomiting.

Many of the patients referred to Dr. Sandberg-Lewis have digestive conditions that have defied diagnosis and effective resolution. Often these patients desire naturopathic treatment options in lieu of the courses of treatments they have previously undergone. He understands diseases of the gastrointestinal tract, but also can assess function and often find successful treatments to regain a balance in the digestive system.

Dr. Sandberg-Lewis lives in Portland with his wife, Kayle. His interests include mandolin, guitar and voice; bicycling; writing and lecturing.

Debbie Rice, ND

Debbie Rice, ND, currently resides and maintains a private practice in Portland, OR. Dr. Debbie is originally from Colorado and completed her undergraduate degrees in Arizona. She has a passion for the outdoors and sunshine as well as movement including hiking, river running, and yoga. She became a strong advocate for her own healthcare at an early age and through much research and dedicated perseverance, she realized that Naturopathic Medicine was more her preference for her personal health care. Dr. Debbie finds passion with national and international cultures and has worked with Peace Corps and other communities and outreach. She is a strong believer that health care is a human right and works with like-minded organizations to bring love and caring to other communities as appropriate to their culture. She is passionate about lifestyle and least invasive treatment modalities as primary options and reaching for more conventional options when the need arises. Dr. Debbie enjoys working with patients to improve sex hormone imbalance, thyroid imbalance, autoimmune disorders, and gastrointestinal concerns. She is also honored to work as the Assistant Medical Director at Precision Analytical Laboratories, also known as the DUTCH test, which focuses on sex and adrenal hormone evaluation. You will usually find her soaking up some sunshine, sneaking kitty cuddles, or planting some plants/flowers to get her hands back into nature and feel more grounded.

Ilana Gurevich, ND, LAc

Ilana Gurevich, ND, LAC, graduated from the National University of Natural Medicine in 2007 and 2008. She is currently co-owner of two large integrative medical clinics, one in northwest Portland and one in northeast Portland. She runs a very busy private practice specializing in treating inflammatory bowel disease as well as IBS/SIBO and functional GI disorders.

She lectures extensively and teaches about both conventional and natural treatments for inflammatory bowel disease as well as SIBO and IBS. She is one of the foremost experts on the intersection of IBD and IBS and how treating one resolves the other. Dr. Gurevich also acts as a mentor in the naturopathic community educating about GI disorders. She supervises residents and consults with physicians about their most difficult GI cases. Dr. Gurevich was nominated as one of Portland Top Docs by the Portland Monthly in both 2014 and 2016.

Sabrina Kimball, ND, LAc

Sabrina Kimball, ND, LAc practices at Meridian Medicine in Seattle, Washington. She completed her graduate degrees at Bastyr University in 2008 and over the past decade Dr. Kimball has specialized in the diagnosis and treatment of complex gastrointestinal illness and hormone imbalances. She has completed post-graduate study in the diagnosis and treatment of irritable bowel syndrome (IBS), small intestinal bacterial overgrowth (SIBO), chronic constipation, heartburn and hypothyroidism. Dr. Kimball completed her Bachelors of Science degree in Nutrition from Bastyr University in 2002 and enjoys exploring the intersection between food, personal relationships and emotional health.

Crane Holmes, ND

Crane Holmes, ND, strives to provide high-quality, compassionate and individualized care to discover the underlying causes of system imbalances whether physical or emotional.

He has a private practice in Portland Oregon where he specializes in gastroenterology and men’s health. He is also the owner and operator of the SIBO Testing Center where he strives as a small business owner to educate naturopaths on the treatment and diagnosis of SIBO.

He completed two years of medical residency under Dr. Steven Sandberg-Lewis and NUNM Health Centers focusing on gastroenterology and primary care. His clinical internships included rotations with medical professionals in both the naturopathic and conventional medical fields allowing him to confidently integrate the modalities of nutrition, botanical medicine, homeopathy, nature cure, and pharmaceuticals into achieving optimal wellness.

He continues to collaborate with NUNM as an adjunct professor teaching dermatology, minor surgery and gastroenterology and is a board member of the GastroANP focusing on post-graduate education with the ultimate goal of creating a fellowship in naturopathic gastroenterology.

Mark Davis, ND

Mark Davis, ND is ranked faculty at Maryland University of Integrative Health, and practices at Capital Integrative Health in Bethesda, MD and via tele-health to Californians and Oregonians at He’s on the board of the GastroANP and the Fecal Transplant Foundation. His interests include fecal microbiota transplantation, helminthic therapy, evidence-informed practice, and his four kids.

Andrea McBeth, ND

Andrea McBeth, ND, posses a passion for shifting perspectives toward microbiome-centered health. She has an undergraduate degree in Biochemistry from the University of San Diego and worked for several years as a research scientist in molecular biology. In 2017 she graduated from the National University of National Medicine. She currently has a practice in Portland, OR that focuses on GI health and runs a stool bank that provides Fecal Microbiota Transplant. 

Heather Zwickey, PhD

Heather Zwickey, PhD, earned a PhD in Immunology and Microbiology from the University of Colorado Health Sciences Center. Dr. Zwickey went on to complete a postdoctoral fellowship and teach medical school at Yale University. At the National University of Natural Medicine in Portland, OR, Dr. Zwickey launched the Helfgott Research Institute and established the School of Graduate Studies, developing programs in research, nutrition, and global health among others. She currently leads an NIH funded clinical research training program. She teaches at NUNM, the University of Western States and Maryland University of Integrative Health. At Helfgott Research Institute, Dr. Zwickey applies her immunology expertise to natural medicine, with specific interest in the gut-brain axis in neuroinflammation.