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NUTRITIONISTS. The field of nutrition is a broad one and has a wide variety of individuals working in it. Self-styled experts aboundbased on the premise that they have eaten all of their lives, have grown, and are healthy adults, they regard themselves as nutrition experts. Unfortunately, it is not quite this easy to become a nutritionist. Cooks, chefs, science teachers, and many allied health professionals may have taken a course or two in nutrition during their training, but this does not qualify them as nutritionists either. Nutritionists have undergone rigorous educational programs in the sciences and have studied nutrients and other components of food in depth.

For the purpose of this discussion, four different types of nutritionists will be described along with the educational pathways needed to qualify for each position. These include the nutrition scientist, the public health nutritionist, the dietitian (known in the United States as the registered dietitian or RD) and the dietetic technician (known as the dietetic technician, registered, or DTR in the United States). Each of these groups develops different skill sets, and each group is responsible for carrying out different functions in the broader field that is nutrition.

Nutrition Scientists

Nutrition scientists are those individuals who use the scientific method to study nutrients, both as individual compounds and as they interact in food and nutrition. The role of the nutrition scientist is to develop new knowledge related to nutrients or nutrition or to develop new processes or techniques to apply existing knowledge. For example, nutrition scientists have been involved in developing food preservation processes, determining nutrient requirements for various animal species, describing how individual nutrients function within the cells of the human body, and identifying nutrition-related problems in various populations.

Nutritionist scientists may have their basic training in nutrition or in a related field such as biochemistry, microbiology, cell biology, epidemiology, toxicology, agriculture, or food science. In most cases, they hold a PhD in their respective field of study. Sometimes, they hold another terminal degree such as an MD or a doctorate in public health (DrPH). Other nutrition scientists do not hold a terminal degree but are trained at the master's degree level and may assist in laboratories or in fieldwork. The characteristic that defines the nutrition scientist is not the field in which the training occurred, but the area in which the person is working. If scientists are conducting research with food, nutrients, or the nutritional status of groups, individuals, or animals, it is appropriate for them to be known as nutrition scientists. In the United States, the universities that train individuals to be nutrition scientists are regionally accredited, but the discipline-specific programs are not.

Public Health Nutritionists

Public health nutritionists are professionals who view the community as their client. They specialize in diagnosing the nutritional problems of communities and in finding solutions to those problems. Some classic examples of public health nutrition interventions include the fortification of salt with iodine to prevent goiter or the enrichment of grain products with B vitamins to prevent deficiency diseases like pellegra or beriberi.

Public health nutritionists are often dietitians who hold a bachelor's degree in applied nutrition. In addition, they study public health theory and practice at the master's degree level, earning a master's degree in public health (MPH). The curriculum for the MPH includes coursework in epidemiology, advocacy, public policy, program management, grant writing, and social marketing. Programs in public health nutrition may accept students whose bachelor's degree is in a field other than nutrition; in that case, they also do graduate work in nutrition. In the United States, there is an organization known as the Association of Graduate Programs in Public Health Nutrition, Inc. that establishes voluntary guidelines for knowledge, skills, and competencies for public health nutritionists.


Dietitians, RDs in the United States, are practitioners who translate the science of nutrition into practice for individuals and groups. Though dietitians may work in a variety of settings, they traditionally practice in the areas of clinical nutrition, food service, or community nutrition. RDs hold bachelor's degrees and have completed a supervised practice program known as a dietetic internship.

The profession of dietetics is self-regulating. Undergraduate dietetics programs in the United States are known as didactic programs in dietetics (DPDs) and are accredited by the Commission on Accreditation for Dietetics Education (CADE). DPDs are required to provide a curriculum that includes "foundation knowledge and skills" which are mandated by CADE for entry-level dietetic education programs.

Students who successfully complete a DPD may apply for entry into a supervised practice program. These dietetic internships, also accredited by CADE, are designed to meet the "competency statements" for the supervised practice component of entry-level dietetic education programs. Dietetic internships provide a minimum of 900 hours of supervised practice experience. Curricula for these programs include core competencies but also allow programs to train generalists or specialists in a particular practice area, such as nutrition therapy or foodservice systems management.

An alternate training route for dietitians is the Coordinated Program in Dietetics (CP). Coordinated programs provide the student with both the didactic and the supervised practice components of dietetics education in a single program. CPs may be offered in conjunction with either a bachelor's or master's degree.

After completion of both the didactic and supervised practice components of dietetics education, graduates sit for a national registration examination, which is administered under the auspices of the Commission on Dietitics Registration (CDR). Individuals who pass the examination may practice as RDs. Licensing is also required in some states; the same examination may be used for both purposes.

Dietitians who have completed their education in other countries may sit for the RD examination in the United States if their country has established reciprocity with CDR. Reciprocity requires that the course of study include both didactic and practice components. Some of the countries that have reciprocal agreements with the United States include Canada, Denmark, and the Philippines.

The RD credential is used to protect the public from practitioners whose educational and professional credentials are below published and accepted standards. In addition, that credential must be maintained to ensure that dietetics practitioners do not allow their knowledge base to become outdated. Every five years, the RD credential must be renewed by demonstrating that a program of planned learning activities has been undertaken to allow for continued competence. Dietitians who allow their credentials to lapse must retake the registration examination in order to reestablish their level of competence.

Dietetic Technicians

Dietetic technicians, DTRs in the United States, are dietetics practitioners who work with dietitians in all three areas of dietetics practice, clinical, foodservice, and community. They may work independently, if the expertise of a dietitian is not required for the specific task that is being done. For example, the dietetic technician could counsel a new mother on infant feeding practices but would not recommend a parenteral formula for the recipient of an organ transplant. DTRs hold at least an associate's degree and have attended a program that includes a supervised practice component.

In the United States, CADE accredits dietetic technician programs (DTs). The curriculum for these programs must include didactic content in the eight "foundation knowledge and skills." The specific requirements for DTs differ from those for DPDs in the depth involved. DTs include a supervised practice component of at least 450 hours, during which students develop the practice competencies set by CADE for DTRs.

Like RDs, DTRs are required to pass a national registration examination established by CDR. Passing the examination provides them with the credential to practice as dietetics professionals. DTRs are also required to demonstrate continued competence by engaging in planned learning activities and renewing their credential every five years.


Commission on Accreditation for Dietetics Education. CADE Accreditation Handbook. Chicago, Ill.: American Dietetic Association, 2002.

Competency Assurance Panel of the Commission on Dietetics Registration. "The Professional Development 2001 Portfolio." Journal of the American Dietetic Association 99 (1999): 612614.

Owen, Anita L., Patricia L. Splett, and George M. Owen. Nutrition in the Community: The Art and Science of Delivering Services. 4th ed. Boston: WCB McGraw Hill, 1999.

Winterfeldt, Esther A., Margaret L. Bogle, and Lea L Ebro. Dietetics: Practice and Future Trends. Gaithersburg, Md.: Aspen, 1998.

Nancy R. Hudson

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