Medical Staff

We are family doctors, trained to see patients of all ages and all conditions, and each of us is also trained and experienced in specialties such as integrative cancer care. We work with you to diagnose the underlying causes of disease, and restore optimal health. We emphasize education, prevention, and holistic treatment.

If your condition requires an outside specialist we will refer you to one, and provide supportive care of the whole person while you are being treated by conventional targeted therapies.

About Us

The doctors at Walnut Creek Naturopathic are trained in the art and science of natural health care at accredited medical colleges, and licensed by the state Bureau of Naturopathic Medicine. We recognize that the individual — body, mind, spirit — knows its own healing pathways, and we develop therapeutic programs for the individual that are designed to collaborate with natural healing. 

Dr. Heather Barrett

Owner & Medical Director
Dr. Barrett is a licensed Naturopathic Doctor who has always had a strong desire to be a healer.  With a background in social work, psychology, and competitive sports, she first learned about naturopathic healing while volunteering at an AIDS orphanage in Africa in 2006.


Full bio…


Photo of Dr. Tracey Thomas, FABNO, at Walnut Creek Naturopathic

Dr. Tracey Thomas


Dr. Tracey Thomas is a board-certified Naturopathic Doctor and Certified Nutrition Specialist who is passionate about helping improve the quality of life and longevity of individuals through personalized integrative medicine.


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Photo of Dr. Brian MyersDr. Brian Myers

Dr.Myers is a licensed naturopathic doctor who specializes in chronic diseases such as diabetes, weight management, autoimmune conditions, gastrointestinal disorders, hormone imbalances, allergies and asthma. He is available for telehealth through WCN.


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Photo of Dr. Melissa Gastellum
Dr. Melissa Gastellum

Dr. Mel is a licensed naturopathic doctor who utilizes special testing, natural modalities and lifestyle interventions to help patients with cancer, muscle and joint issues, autoimmune disease and digestive disorders.


Full bio…


Dr. Jamie Berner

Dr. Berner is a licensed Naturopathic Doctor who employs functional medicine to identify root causes in treating conditions such as chronic pain and opiod dependency, thyroid disease, gastrointestinal disease and autoimmune disease.


Full bio…


Dr. Berner will be available for telemedicine calls again starting in May, 2021.

Photo of Dawn PreisendorfDawn Preisendorf

Dawn Preisendorf is a certified nutritionist and health coach, with master’s degree in nutrition and health education, who is passionate about the healing power of food, healthy lifestyle practices, and nature-connection as pathways to restoring health.  

Full bio…


Support Staff

Photo of Shasmi Nisha, Patient Care Coordinator at Walnut Creek NaturopathicShasmi Nisha

Shasmi is our Lead Patient Care Coordinator at WCN, who will welcome you with a friendly and infectious smile. She was born on the Fiji Islands and migrated to the United States in 2010. She is a firm believer in Naturopathic Medicine and its Holistic approach towards lifelong wellness. She believes the key to success in every area of your life should be accomplished by having a positive attitude. She is currently enrolled in school pursuing her dream of becoming a Registered Trauma Nurse.  Outside of the office, she loves working out, spending time with her family, studying medicine and eating healthy.

Photo of Alicia Rae, Patient Care CoordinatorAlicia Rai

Alicia is a patient coordinator at WCN who will warmly welcome you.

She comes to us with a long history in the medical field starting out as a junior volunteer for 3 years, and has worked previously as a cardiology technician at John Muir. She believes in living and having a healthy lifestyle.  She enjoys working in the health field and helping people reach their goals of having a productive and positive outlook. In her free time she enjoys the outdoors and hiking.