Ask The Scientists was created to help individuals understand and master the science behind USANA’s top-quality products. The company’s focus has always been creating high-quality nutritional products that are built on one simple idea: if you feed the cells in your body exactly what they need, your health will benefit. This concept has continued to fuel USANA’s endless drive to innovate and advance the science of cellular nutrition—putting a healthy, happy life within reach for all.

Along with developing some of the best health supplement products in the world, USANA is also educating the public about the human body, health, and how the company’s products impact the body. You can find that information here on You can read about everything from quick answers to some of your questions on USANA products, to tips on how you can take control of your health.

USANA’s Research and Development and Ask the Scientists Team Members

Rob Sinnott, PhD

Chief Scientific Officer

Rolando L. Maddela, MPH, MD, CCRP

Executive Director of Global Health Education and Nutrition Research

Russ Barton, MS, CNS, CISSN

Senior Nutrition Scientist

Austin Winegar

Senior Manager of Ask the Scientists

Kenny Tan

Director of Health and Science Education

David Baker

Senior Managing Editor

Dr. Brewer joined USANA in 2016 as a senior scientist, with a background in molecular biology and nutrition. She completed her bachelor’s degree in biological sciences at the University of Alaska Anchorage and her PhD at the University of Alabama at Birmingham. Her dissertation work investigated impacts of diet and nutrition on aging and longevity. Dr. Brewer’s interest in improving health through science led her to USANA. Since joining USANA, she has focused on all stages of product development, particularly products centered on the human microbiome—including research, design, and evaluation. She led the launch of the USANA Oral Probiotic, gives trainings and presentations internally and externally to associates, and guides new product development.

Rachel Brewer, PhD

Director of New Product Research

Jeremy Tian, PhD, MD

Director of New Product Research

Keijun Koh

Director of Product Development

Mark Levy, PhD

Director of Product Validation

Katie Burton

Sr Manager of Product Development

Sydney Sprouse

Product Content Specialist

Science has been a life-long passion for Sydney Sprouse. It all started with the microscope her parents gave her for Christmas at age eight and the science spark continues to grow in her today.  She loves to learn why and how biological processes influence daily life, and working with the team has given her an opportunity to continue her scientific education daily.

Sydney focuses her work on the product pages found at When she’s not researching how USANA products can support a healthy lifestyle, she likes to spend her time playing with her toddler, biking, hiking, and listening to podcasts. She’s an amateur watercolor painter and has dreams of going back to school.

Howard Gurney

Vice President of Product Development Process

For over 15 years, Howard Gurney has been a noteworthy leader in the nutritional and personal care industry, specializing in regulatory affairs, product development, and quality systems. With a master’s degree in bioscience from Johns Hopkins University, both Howard’s education and valuable experience have allowed him to hold various leadership roles throughout his career. His personal management style empowers Howard to effectively direct a team of nearly 100 employees in the United States and China.

Through his expertise in negotiating with government officials, he has achieved early product introduction into various markets, reduced registration timelines, and attained more competitive claims to differentiate products from the competition—all while focusing on the needs of the consumer. He prides himself in understanding all aspects of product development, enabling him to be remarkably resourceful, optimize processes, and remove redundancy.

Jim Eng

Director of Product Formulations

Jim has a degree in chemical engineering and over 38 years in the pharmaceutical and nutritional industry. Jim has worked in technical operations and manufacturing management in pharmaceutical production.

In 1996, Jim, his wife, and newborn daughter moved to Salt Lake City where Jim joined USANA Health Sciences. He has worked at various positions of increasing responsibilities in product manufacturing and product research and development.

Chuck Walton, MS

Lead Development Scientist

Chuck joined USANA’s Research and Development team in 2017. He has a master’s degree in marine science (focusing on microbiomes) from Nova Southeastern University, and a bachelor of science in microbiology from the University of Montana.

Chuck’s professional interests are in understanding microbial communities, how they interact with humans, and how that, in turn, impacts human health. His goal is then to leverage microbiome, proteomic, metagenomic, and metabolomic data for new product development.

His personal interests lead him outdoors with friends and family. He likes hiking, biking, snowboarding, scuba diving, and photography.