Q: What’s the difference between a “registered dietitian” and a “registered dietitian nutritionist”—and between a “dietitian” and a “nutritionist”? I need help changing my diet for a health condition, so is one better than others?
A: In short, there’s no difference between a registered dietitian (RD) and a registered dietitian nutritionist (RDN), but, as you’ll see below, a “nutritionist” is not a simple or straightforward designation.
The RD credential has been in use since 1970. The option for registered dietitians to use the initials RDN was added in 2013 because inclusion of the word “nutritionist” “communicates a broader concept of wellness (including prevention of health conditions beyond medical nutrition therapy) as well as treatment of conditions,” according to the Academy of Nutrition and Dietetics, the world's largest organization of food and nutrition professionals. Conferred by the Commission on Dietetic Registration (CDR), which is the Academy’s credentialing agency, the RD and RDN credentials can be used interchangeably.
The RDN designation also highlights the fact that all registered dietitians are nutritionists but not all nutritionists are registered dietitians. This is an important distinction because in some states you can call yourself a nutritionist without any formal nutrition education, training, licensing, or certification, but it’s illegal to call yourself a “dietitian” without proper credentialing.
That’s fair when you consider the requirements to become an RD/RDN: a bachelor’s degree, completion of an extensive nutrition curriculum, at least 1,200 hours of supervised practice, a comprehensive registration exam, and 75 continuing professional education credits per five-year cycle. In addition, the CDR offers special board certification to RD/RDNs in such areas as gerontological nutrition, oncology nutrition, sports dietetics, and obesity and weight management.
Most states also provide licensure or certification for RD/RDNs, and some offer this option to nutritionists who meet certain criteria. This is entirely separate from the credentialing given by the CDR, which is not a governmental agency. The education and training requirements for becoming licensed or certified as a nutritionist can be extensive, but unlike those for RD/RDNs, they vary from state to state (here’s a list of licensure agencies if you’d like more information about your home state). Someone with an RD/RDN generally meets a state’s licensing or certification criteria and can use those credentials—e.g. Jane Smith, RDN, CDN—for an extra fee (but not all state licensed nutritionists are qualified to be RD/RDNs).
To add even more complexity to this already confusing topic, another agency, the Board for Certification of Nutrition Specialists, provides the “certified nutrition specialist” (CNS) credential to nutritionists who have a master’s or doctoral degree in a related field and have completed 1,000 hours of supervised practice and passed an examination. Continuing professional education is also required.
Note: There are several other credentials that sound similar to some of the ones above but are actually far from equivalent. For example, a certified nutritionist (CN) needs only to successfully complete a two-year college degree or six-class distance learning program plus an exam in order to get the credential, and a certified nutritional consultant (CNC) only has to pass an open book exam.
Then there are some people who have a masters or doctoral degree in nutrition but forego licensing and certification altogether. Those who choose this route often go into academia or public health. Some may offer nutritional counseling to individuals, but even if they come from an accredited graduate school program, unless they are also certified or licensed, they may have little or no actual nutrition counseling experience.
Bottom line: If you want diet and nutrition advice, see a trained nutrition professional—not an uncredentialled “nutritionist.” Look for someone who has been practicing for at least a couple of years, has expertise in your particular health problem or condition, and has one or more of the credentials listed below. Equally important: Because discussing diet and health can be difficult, choose someone with whom you feel comfortable sharing personal information.
- Registered dietitian or registered dietitian nutritionist (RD/RDN; this online service provides referrals to experts in your area)
- Certified dietitian/nutritionist (CD/CDN)
- Licensed dietitian/nutritionist (LD/LDN)
- Certified nutrition specialist (CNS)