Meet the Team

The Digestive Center is dedicated to providing you with the best natural digestive support so you can get back on your feet easily, and stay healthy naturally.

We partner with leading health experts—scientists, M.D., nutritionists– to produce groundbreaking, top quality products, from the latest scientific breakthrough.

We believe the right herbs and minerals can improve many digestive issues. We believe your body might react better to a more natural supplementation. Our formulas are free of GMOs and harsh chemicals so you can live a healthy natural life, free of invasive treatments, free of digestive discomfort.

Who We Are


Doctor Roberto Contreras, MD


Dr. Roberto Contreras is the founder of Digestive Center, Southern California’s leading resource for digestive wellness. He is also the Director at LaSalle Medical Associates and the founder of Electric Rose Toys, a toy line developed specifically for children with special needs, inspired by his daughter Olivia Rose.

Mark Bouzyk

Dr. Mark Bouzyk

Dr. Bouzyk was a Director of the Emory Biomarker Service Center (EBSC), Director, Basic Research Shared Core Resources, Emory Winship Cancer Institute, Emory University as well as Director of the Center for Medical Genomics at Emory University, Atlanta. These facilities were developed by Dr. Bouzyk as state of the art laboratory capabilities to enable high throughput genetic, genomic and microarray biomarker studies ranging from DNA, copy number variation, expression, miRNA and methylation profiling all supported by a robust and flexible data management infrastructure in a Clinical Laboratory Improvement Amendments (CLIA) environment.

Prior to joining Emory, Dr. Bouzyk spent approximately 9 years in a global pharmaceutical company, GlaxoSmithKline, where he served as Director of Genetic Laboratory Sciences leading the company’s high throughput genomic efforts in Europe. Dr. Bouzyk’s interests lie in Pharmacogenetics as well as candidate gene and genomic association studies to identify susceptibility genes for both common and rare diseases particularly in the areas of Oncology, Cardiology, Neurological and Psychiatric disorders.

Dr. Bouzyk holds a Ph.D. in Human Molecular Genetics from University of Hertfordshire and a Bachelor of Science with Honors in Biochemistry from University College London.


Brooke Mader

Certified Clinical Dietician

Brooke graduated from Maryland University of Integrative Health with a Master’s degree in Integrative Nutrition. She is fascinated by human nutrition and physiology. Brooke is a caring and dedicated individual who has the desire to connect, help and teach people. Areas of strength include digestion, detoxification, hormones, weight loss, women’s health and botanical medicine.


Sarah Jackson

Sarah’s academic career began at UC Riverside where she earned a degree in Psychology. After falling in love with nutrition, Sarah went back to school to earn her second bachelor’s degree in Nutrition Dietetics. She completed her dietetic internship through Oakwood University, which had a focus in medical nutrition therapy. Currently, Sarah is in her graduate program working to attain a master’s degree in Applied Nutrition while simultaneously working as a clinical dietitian. She is a Southern California native originally born in the San Fernando Valley and is truly passionate about food and it’s unique ability to prevent and treat nutrition-related diseases.

As a sufferer of digestive issues for as long as she can remember, Sarah has witnessed firsthand how powerful nutrition modification can be. She hopes to share her knowledge with others and help spread Hippocrates message of: “Let food be thy medicine and medicine be thy food”.


Erica Zellner

Integrative Nutritionist

Erica is an Experienced Nutritionist with a demonstrated history of working in the health wellness and fitness industry. Skilled in Motivational Interviewing, Chronic Illness, Clinical Nutrition, Chronic Fatigue, and Health Education. She is a strong healthcare services professional with a Master of Science (M.S.) focused in Nutrition and Integrative Health from Maryland University of Integrative Health.

Quality Ingredients Backed by Scientific Research

All of the Digestive Center’s products are custom-formulated on years of research. We study natural and traditional remedies from all around the world, analyze the scientific validity of each of their ingredients, then develop the best natural solutions to help you improve your digestive issues. Our goal is to make these formulas both high-quality and affordable, so you can easily and naturally transform your health and live a long, and happy life.