DietitiansDietitians are health professionals with either a bachelor or master's degree in nutrition and dietetics. In addition there are practical training requirements required before certification, and ongoing professional development training requirements have to be met to maintain their certification.
Using the title Dietitian is protected by law in many countries, including the U.S. and Canada, and as such anyone operating under the name is required to hold a certification that is in good standing. With their extensive knowledge and experience dietitians can provide extensive health guidance in diet and nutrition and also translate medical decisions and needs into their guidance. Many illnesses and diseases can be managed effectively through the dietary treatments recommended by a dietitian.
As dietitians are required to be certified and a member of a professional body there is some added reliability in terms of their conduct and the due care they provide. Dietitians found to be offside of their professional licenses can lose their licenses and ability to practice, so they have a major incentive to deliver quality service.
NutritionistsNutritionists can also provide many of the benefits provided by Dietitians but with some major differences. The title nutritionist is not regulated or protected by law in all cases. Some states do require a nutritionist to be licensed but not all do, and the requirements for licensing can vary greatly. As such there is a significant range of services that variety that may or may not be covered by a nutritionist from state to state.
It's recommended that before engaging a nutritionist you should review the guidance in your state to determine what exactly that title means. In unregulated states anyone can operate under the nutritionist title regardless of their experience. If you're in an unregulated state you may want to consider following up with the nutritionist in regards to their specific education and work experience. While this may seem like a serious issue that is not always the case. In states where nutritionists are required to be licensed in order to operate, and meet certification requirements, a nutritionist can be just as educated as a dietitian and have similar work experience.
So in essence every dietitian could be considered to be a nutritionist also, in term of the breadth of and are of knowledge. However, only some nutritionists are dietitians as there are more requirements in terms of education and qualification. When choosing the right solution for you ensure that you know what the requirements in your state are and also have a good idea of the work experience and background of the health professionals you are considering. A little research up front and asking some questions can ensure you get the care you need.