Nutritional Therapy Practitioner, Dietitian or Nutritionist: What’s the Difference?

A registered dietitian nutritionist (RDN) holds a clinical credential: a graduate degree, accredited coursework, supervised practice and a national exam.¹ A nutritional therapy practitioner (NTP) is trained by the Nutritional Therapy Association in food-based, whole-person nutrition and works alongside medical care. An NTP does not diagnose or treat disease.² “Nutritionist” is a general word with no single legal definition in Oregon.³

Which one you need depends on what you are dealing with. Here is how they differ.

Registered dietitian nutritionist (RDN)

To sit the registration exam, a dietitian now needs at least a graduate degree, coursework from an accredited program, and accredited supervised practice.¹ In Oregon, only a licensed dietitian may use the title “Licensed Dietitian” or the letters “L.D.”³

See a dietitian when you need medical nutrition therapy for a diagnosed condition, such as kidney disease, diabetes management, an eating disorder, or tube feeding, or when your doctor refers you to one.

Nutritional therapy practitioner (NTP)

NTPs are trained by the Nutritional Therapy Association. Their role, in the association’s words, is to evaluate a client’s intake information against their health goals and offer customized recommendations on food, lifestyle habits and supplements.² The work centers on nutrient-dense, varied whole foods, food journals, questionnaires and education.²

The same standards set clear limits. An NTP “may not diagnose, treat, prevent, prescribe, or cure any pathological condition, illness, or disease,” may not practice medical nutrition therapy, and may not imply that they are licensed or certified by the state.² When someone needs medical or mental health care, an NTP refers them to a licensed professional.²

An NTP can help when you want support with everyday eating, digestion, energy and stress, want time to look at the whole picture, or want help making a diet your doctor or dietitian has suggested work in your own kitchen.

“Nutritionist”

Oregon’s dietitian law protects the titles “Licensed Dietitian” and “L.D.” It does not define or restrict the word “nutritionist”.³ That means the training behind “nutritionist” varies widely. When you see the word, ask what credential the person holds and who issued it.

How to choose

• Start with your doctor if you have new, severe or unexplained symptoms. Nutrition support comes after that, not instead of it.
• Choose a registered dietitian for a diagnosed condition that needs medical nutrition therapy.
• Consider an NTP for food, digestion and lifestyle support, especially if you want someone to look at how stress, eating habits and food fit together.
• Ask any practitioner what their credential is, what they can and can’t do, and how they work with your other providers.

About Maria’s credential

Maria Zilka is a nutritional therapy practitioner (NTP). She is not a physician or a registered dietitian, and she works within the NTA’s scope: she does not diagnose or treat disease, and she refers clients to licensed providers when they need medical or mental health care. Her work runs alongside your medical care, not in place of it. See frequently asked questions or how working together looks.

Sources

1. Commission on Dietetic Registration, “RDN Eligibility Requirements”. cdrnet.org
2. Nutritional Therapy Association, “Scope of Practice”. nutritionaltherapy.com
3. Oregon Revised Statutes, chapter 691 (Dietitians), ORS 691.415 (2025 edition). oregonlegislature.gov

Maria Zilka, NTP
Maria has practiced nutritional therapy for more than fifteen years. Her work centers on the nervous system, digestion and chronic inflammation. She sees clients in person in Beaverton, Oregon, and by secure video. More about Maria