Nutritionist Definition

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Nutritionist Definition

A nutritionist is someone who specializes in the study of nutrition . In the United States, the term is not legally protected; nutritionists range from people who write popular books about diet and nutrition issues without any specialized education in the field to persons who hold master's or doctoral degrees in nutrition or such related fields as public health, medicine, food science, agriculture, or biochemistry. The American College of Nutrition (ACN) defines a nutritionist as “a health specialist who devotes his/her professional activity exclusively to food/nutrition science, preventive nutrition, diseases related to nutrient deficiencies, and the use of nutrient manipulation to enhance the clinical response to human diseases.”

In contrast, the term dietitian is legally protected in the United States and is regulated by the American Dietetic Association (ADA). A registered dietitian (RD) must hold a bachelor's degree or higher in dietetics (the branch of science that applies the basic principles of nutrition to the diet) and pass a national examination in the field.


Dietitians in general promote good health through proper eating, which may take several forms:

  • Supervising food planning, preparation and delivery in cafeterias, restaurants, schools, and other facilities where meals are served to large groups of people.
  • Educating people about good nutrition and participating in wellness programs at camps, community agencies, health clubs, and the like.
  • Planning meals as part of medical nutrition therapy for hospital inpatients.
  • Consulting with physicians, nurses, and other health professionals in planning an individual patient's treatment regimen.
  • Planning and supervising tube feeding and intravenous feeding of patients who require these forms of artificial nutrition.
  • Carrying out research involving nutrition in certain disease states, the role of nutrition in preventive health care, or quality improvement in hospital dietary departments or food service.

Work settings

Registered dietitians may be found in hospitals, nursing homes , hospices , community health centers, and other places where seniors may go for health care. Some RDs work as independent consultants and visit seniors' homes as part of an assessment of the senior's nutritional needs.

Care team role

Clinical dietitians or nutritionists work closely together with physicians, pharmacists, occupational

therapists, and nurses in meeting seniors' needs for adequate nourishment while hospitalized or cared for in a nursing home or hospice. Clinical dietitians may coordinate their assessment with the patient's medical records in order to draw up a nutritional plan for a balanced diet. In smaller hospitals, the clinical dietitian may also be responsible for supervising the food service's preparation and delivery of the patients' meals.

An RD who has received specialized certification in gerontological nutrition from the ADA (see below) may be responsible for regulatory oversight of the food service in a nursing home or hospice. He or she may also serve as a consultant to a senior's primary physician.



In 1998 the American College of Nutrition (ACN) began to offer the credential of Certified Nutrition Specialist to holders of bachelor's or higher degrees in the field of nutrition or closely related subjects who can document that they have work experience in nutrition. They must then pass a comprehensive 200-question examination. CNSs must be recertified every 5 years and complete 75 hours of continuing education credits.

Registered dietitians (RDs) In the United States, RDs must hold either a bachelor's degree in dietetics from a college or university; a bachelor of science degree with a graduate diploma in dietetics; or a bachelor of science degree followed by a master's degree in dietetics. Candidates for registration must then complete a year-long internship of at least 900 hours in an accredited program before they can take the registration examination. Some states require an additional licensure procedure for the RD to work in certain health care settings. To maintain the registration credential, RDs must complete 75 units of continuing education credits every 5 years.

The ADA has a Dietetic Practice Group, or DPG, for specialists in nutrition for seniors. The ADA's Commission on Dietetic Registration began offering certification in gerontological nutrition in 2006. To qualify as a board-certified specialist in nutrition for the elderly, the RD must have practiced for a minimum of 3 years after registration and document 4,000 hours of practice in the specialty area in the past five years. In 2007 the Gerontological Nutritionists DPG changed its name to the Healthy Aging DPG. This specialty group maintains a website at


Artificial nutrition —A general term that includes tube feeding and intravenous feeding.

Dietetics —The science of applying the principles of nutrition to the human diet.

Dietitian —In the United States, a health care professional with one or more degrees in nutrition who has completed an internship and examination and is registered with the American Dietetic Association (ADA).

Nutritionist —A general term for a person with specialized education or on-the-job training in diet and nutrition, who may or may not be licensed or registered with a professional organization in the field.

Family teaching

Since RDs are trained to communicate with patients and family members as well as master the scientific information necessary to plan a nutritious diet for a senior, family members should expect a clear and timely explanation of the senior's diet plan, as well as advice on food choices, meal preparation, and helping the senior stick to the diet, if he or she is living at home or with family members. If the senior requires artificial nutrition (tube feeding or intravenous feeding), the family should be able to discuss the necessity of these measures and any complications resulting from them with the dietitian.



Edelstein, Sari, and Judith Sharlin. Life Cycle Nutrition: An Evidence-Based Approach. Sudbury, MA: Jones and Bartlett Publishers, 2008.

Winterfeldt, Esther A., Margaret L. Bogle, and Lea L. Ebro. Dietetics: Practice and Future Trends, 2nd ed. Sudbury, MA: Jones and Bartlett Publishers, 2005.


Endevelt, R., P. Werner, and O. Stone. “Dietitians' Attitudes-Regarding Elderly Nutritional Factors.” Journal of Nutrition for the Elderly 26 (January-February 2006): 45–58.

Enrione, E. B., and S. Chutkan. “Preferences of Registered Dietitians and Nurses Recommending Artificial Nutrition and Hydration for Elderly Patients.” Journal of the American Dietetic Association 107 (March 2007):416–421.

Zulkowski, K. “Nutrition and Aging: A Transdisciplinary Approach.” Ostomy/Wound Management 52 (October 2006): 53–57.


Commission on Dietetic Registration (CDR). Board Certification as a Specialist in Gerontological Nutrition. Chicago, IL: CDR, 2006. October 2006 [cited February 19, 2008].


American College of Nutrition (ACN), 300 S. Duncan Ave., Suite 225, Clearwater, FL, 33755, (727) 446-6086, (727) 446-6202, [email protected],

American Dietetic Association (ADA), 120 South Riverside Plaza, Suite 2000, Chicago, IL, 60606, (800) 877-1600,

Certification Board for Nutrition Specialists (CBNS), 300 S. Duncan Ave., Suite 225, Clearwater, FL, 33755, (727) 446-6086, (727) 446-6202, [email protected],

Jean Mayer USDA Human Nutrition Research Center on Aging, 711 Washington Street, Boston, MA, 02111, (617) 556-3000, (617) 556-3344,

Rebecca J. Frey Ph.D.

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Nutritionist Definition

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