Why root?

The name Root stands for natural living, eating foods grown from the earth, feeling grounded and mindful, and getting to the root cause of the problem. Root reminds us that our roots are the foundation that leads to our overall wellbeing. 

What we treat

In our functional medicine and nutrition plans, we create a customized wellness plan for you. You will learn more about yourself through our testing, review, and in-depth evaluation to transform your lifestyle to feel well for the long term. We also make our food as medicine available to anyone in our community through Root Farmacy.

We focus on:

  • Gut health
  • Food sensitivities
  • Thyroid
  • PCOS
  • Skin health
  • Autoimmune conditions
  • Hormone balance

What We Do

At Root, we use the most advanced testing in functional medicine, genomics, and microbiome and apply the science to your individual plan to help you restore wellness.

We work with clients as consultants over a period of 3-6 months in order to find root causes and support you through holistic healing plan.

As doctors as dietitians, we use a true food as medicine approach. We use custom food plans for clients in our plans and offer a subscription take home meals service using our functional food plans and PCOS food plans.

Meet our Doctors and Dietitians

Erica Armstrong, MD, IFMCP

Dr. Erica Armstrong, MD, IFMCP is the founder and CEO of Root. She is board certified in family medicine and completed certification training through the Institute of Functional Medicine. She’s passionate about combining problem-solving and healing relationships with clients to heal illness at the Root.
Special Interests:
Thyroid, PCOS, Fertility, and Digestive health

Bethanie Thompson, MD

Dr. Bethanie Thompson, MD is board certified in family medicine and has completed extensive training through the Institute of Functional Medicine. She believes in the importance of listening to each person’s unique story to find hidden clues to imbalance in the system, and values her role as a partner and advocate for each patient’s journey toward balance and whole health.
Special Interests:
Anxiety and the gut-brain connection, Thyroid and adrenal health, Wellness optimization and disease prevention, Weight management including intermittent fasting, Digestive health, and Women’s health: hormone balance and replacement and preconception planning.

functional medicine doctor

Marzena Slater, MD

Dr. Marzena Slater, MD is a board-certified family medicine doctor and has completed extensive training through the Institute of Functional Medicine. The importance of a whole system or holistic approach to discover the underlying root cause for chronic disease is the ruling pillar in her integrative methods and healing mission. She is a partner with her patients throughout the healing process. She supports the natural healing power of food and the ability of every individual’s body to repair imbalances when provided the right ingredients.

Special Interests:

Digestive Disorders: irritable bowel syndrome (IBS) and Crohn's Disease (IBD)
Autoimmune Disorders, Weight loss and optimizing metabolism, Food allergies and sensitivities,
Optimal Nutrition, Nutrition to support and optimize athletic performance

Languages: English, Polish

grand rapids dietitian

Amy Masterson, MS, RD

Amy is a registered dietitian and functional nutritionist. She is a certified LEAP therapist and completed training on FODMAPs with Monash University. Amy enjoys simplifying the complex science of nutrition by focusing on real, whole foods in meals that are made at home. She believes that food is meant to nourish our bodies and give us energy to do the things we want to do. She has experience teaching many different meal prep classes and is passionate about nutrition and skin health.
Special Interests:
Gut health and SIBO/FODMAP diets, Food sensitivities, Skin health, Meal prep and Cooking at home

Kelsey Stricklen, MS, RD, CLT

Kelsey is a registered dietitian and functional nutritionist who has completed training with the Integrative and Functional Nutrition Academy. She is a certified LEAP therapist which means she is qualified to order MRT food sensitivity testing and devise custom elimination diets based on the results. She helps people get to the root of their health issues by translating nutrition science into practical and actionable advice.
Special Interests:
PCOS, Infertility, Preconception planning, Thyroid, Adrenal, Food sensitivities, Postpartum health

Jenn Fillenworth, MS, RD

Jenn is a registered dietitian and culinary medicine certified chef. Jenn focuses on putting nutrition education to practice in the kitchen. She creates delicious and healthy meals based on our clients’ personalized Root meal plans in our Get to the Root Plus plan. Jenn is ServSafe certified in safe food handling.
Special Interests: Food as Medicine, Culinary Medicine, Meal Prep and Planning