What Is It?
How Does it Work?
What You Can Expect
Health Benefits
How To Choose a Practitioner
Evidence Based Rating Scale

What Is It?

The title certified nutritionist (C.N.) or certified clinical nutritionist (C.C.N.) indicates that a person has had extensive education and training in nutrition science, and has met national testing standards. Both C.N.s, and C.C.N.s work with clients to assess and analyze individual nutritional needs and develop personalized nutrition plans. During this process, they educate, advise, counsel, monitor, and provide support. Both conventional doctors and alternative health practitioners often refer their patients to nutritionists for dietary counseling.

The dietary information you receive from a certified nutritionist is most likely to be reliable and based on current knowledge in the field if the nutritionist has been working in the profession for a minimum of one year and holds one of the following certifications:

Certified Nutritionist (C.N.): C.N.s must earn a Bachelor of Science or higher degree in nutrition science from an accredited college or formal training program that is recognized by state licensing agencies. They must meet any state licensing or certification requirements in their state, and comply with all statutes related to the practice of nutrition counseling. C.N.s must also complete a series of examinations required by the National Institute of Nutritional Education.

Certified Clinical Nutritionist (C.C.N.): To earn the C.C.N. credentials, nutritionists must have received a Bachelor of Science degree or higher from an accredited college or formal training program recognized by the relevant state licensing agency. If they only hold a B.A. degree, they must also complete 900 hours of medical and clinical nutrition internship. To become a Certified Clinical Nutritionist (C.C.N.), they must also complete an examination sponsored by the Clinical Nutrition Certification Board (CNCB), or a series of examinations required by the National Institute of Nutritional Education. And, where applicable, C.C.N.s must meet state licensing or certification requirements and comply with statutes regarding the practice of nutritional counseling. Plus, C.C.N.s must have one year of experience as a nutritionist. They are then qualified to take case histories and use various tests and observations to assess an individual's nutritional needs. C.C.N.s may use the results of their assessments as the basis for referring clients to a licensed physician or other health-care professional.

How Does it Work?

Nutritionists study food and the science of how your body uses food – particularly how it is absorbed or metabolized. By studying the effects of food and an individual’s eating habits, genetics, and medical history, nutritionists can determine the best way to prevent disease and deficiencies, or how to use food to combat or treat disease. A nutritionist may also recommend nutritional supplements as part of the nutrition therapy in helping patients become healthier.

Nutritionists can help you learn how to buy groceries for a healthier diet, how to order healthful meals in restaurants, how to prepare healthy meals at home and even what times you should eat for optimal health.

What You Can Expect

Before seeing a nutritionist, you may want to get a check-up from your doctor so you know your current health stats, such as blood pressure and cholesterol levels. The nutritionist may also want to see a recent food diary and list of any medications and nutritional supplements you may be taking. The nutritionist will ask you questions about your medical history, family history and lifestyle, as well as detailed questions about your diet, digestion problems, weight issues, exercise regimes, and your sleep patterns. Some blood work or other laboratory tests might be necessary to determine any nutritional deficiencies or other problems. The more information you can tell your nutritionist, the better your evaluation will be. The nutritionist will recommend nutritional therapy, such as an eating plan and supplements, based on the information you provide and results from the tests.

Health Benefits

Your diet has direct influences on your health, and therefore, on diseases. What you eat can cause you to lose or gain weight, increase risk factors for heart disease by lowering cholesterol and blood pressure, and help control blood glucose levels in diabetics. Nutrition has also been important in managing AIDS, cancer, osteoporosis, lung disease, and kidney disease. A nutritionist can help prepare nutritional plans for patients who want to eat healthier, lose weight, or combat disease.

Specifically, a nutritionist may help you to:

Lower blood pressure. While high blood pressure, or hypertension, can be genetic, it often can be controlled in part by choosing a healthy lifestyle that includes good eating habits. For those who are overweight, losing weight will help lower blood pressure, and reducing sodium intake also is key to lowering blood pressure. A nutritionist can help calculate your body mass index to determine whether you need to lose weight, and develop a diet to help you lose weight and treat hypertension. For example, the DASH diet – the Dietary Approaches to Stop Hypertension, which focuses on eating a significant amount of low- or non-fat dairy foods and fruits and vegetables – is one of the most effective methods of treating high blood pressure. This nutrition plan, sponsored and researched by the National Institutes of Health, has been shown to lower blood pressure in as little as two weeks. (1) Eating a Mediterranean diet also can help lower blood pressure. The plan relies on a high consumption of vegetables, fish, and most notably olive oil in order to lower blood pressure. In fact, some studies have shown that the more olive oil you consume, the lower your level of hypertension. (2, 3) A 2007 study of 88 hypertensive patients treated for 12 months by an interdisciplinary team including a nutritionist found the care provided by the team may significantly improve the control of hypertension and associated risk factors. (4)

Manage diabetes. Eating a controlled diet can often be the sole factor in managing symptoms of diabetes. A nutritionist can help devise the right plan to regulate your blood glucose levels and prevent diabetes complications. Research has shown that people who employ measures aimed at complying with diet, exercise and behavior interventions can cut their risk of developing diabetes or diabetes related complications by 60 percent over three to four years. (5, 6)

Control weight. Along with exercise, a healthy diet is the best way to prevent weight gain and to lose unhealthy weight. A nutritionist can help identify your common eating pitfalls and determine how to easily meet your goals for creating a leaner healthier body. Specifically, a nutritionist can work with you to ensure the amount of calories you are taking in are being expended. One study found the continued motivation of a medical team – including consultation from a nutritionist – is necessary to achieve and maintain weight loss. (7)

Manage cholesterol. Cholesterol is absorbed from the food you eat, so a healthy diet is key to maintaining healthy levels. A nutritionist can help you create a diet plan that will be low in fat and cholesterol. Some studies even suggest that people who seek help from a nutritionist instead of their primary care physician alone fare better at lowering their cholesterol in the short to medium term. (8)

How To Choose a Practitioner

When you are looking for responsible nutrition advice, seek out a certified professional. Always bear in mind that the simple title "nutritionist," although used by many qualified nutrition and dietetics professionals, is a moniker that can also be adopted by virtually anyone who wants to hang up a shingle. Be wary of bogus qualifications, as well as of what seems to be extreme dietary advice. Because irresponsible information on nutrition can be dangerous to your health, be very careful to ask specific questions and verify the practitioner's education, training, and professional credentials.

Although most states require a license for professional dietitians (see the WholeHealthMD Reference Library entry for Registered Dietitian), the situation is murkier for nutritionists. This is why it's important to be sure any nutritionist you consult has one of the credentials listed above. These assure you of consistent standards of education, training, and professionalism.

If a nutritionist practices in a state that does not regulate their qualifications, you should still look for one of the above certifications, which are granted for C.C.N.s by the Clinical Nutrition Certification Board (CNCN), and for C.N.s by the National Institute of Nutritional Education. It is also a good sign if the nutritionist is a current member of the Society of Certified Nutritionists (SCN), which is working to establish national standards of practice while promoting continuing education in the field.


Nutritional supplements can interact with some medications, so consult a physician before you begin taking any dietary supplements.


  1. Sacks FM, Appel LJ, Moore TJ, et al. A dietary approach to prevent hypertension: a review of the Dietary Approaches to Stop Hypertension (DASH) Study. Clin Cardiol. 1999 Jul;22(7 Suppl)III6-10.
  2. Psaltopoulou T, Naska A, Orfanos P, Trichopoulos D, Mountokalakis T, Trichopoulou A. Olive oil, the Mediterranean diet, and arterial blood pressure: the Greek European Prospective Investigation in to Cancer and Nutrition (EPIC) study. Am J Clin Nutr. 2004 Oct;80(4):1012-8.
  3. Alonso A, de la Fuente C, Martin-Arnau AM, de Irala J, Martinez JA, Martinez-Gonzalez MA. Fruit and vegetable consumption is inversely associated with blood pressure in a Mediterranean population with a high vegetable-fat intake: the Seguimiento Universidad de Navarra (SUN) Stusdy. Br J Nutr. 2004 Aug;92(2):311-9.
  4. Didier MT, Guimaraes AC. Optimizing the treatment of hypertension in the primary care setting. Arq Bras Cardiol. 2007 Feb;88(2):218-24.
  5. Williamson DF, Vinicor F, Bowman BA; Centers for Disease Control and Prevention Primary Prevention Working Group. Primary prevention of type 2 diabetes mellitus by lifestyle intervention: implications for health policy. Ann Intern Med. 2004 Jun 1;140(11):951-7.
  6. Norris SL, Zhang X, Avenell A, Gregg E, Schmid CH, Lau J. Long-term non-pharmacological weight loss interventions for adults with prediabetes. Cochrane Database Syst Rev. 2005 Apr 18;(2):CD005270.
  7. Piziak VK. Medical management of obesity. Promoting healthy dieting. Postgrad Med. 1983 Nov;74(5):158-66, 171-3.
  8. Thompson RL, Summerbell CD, Hooper L, et al. Dietary advice given by a dietitian versus other health professional or self-help resources to reduce blood cholesterol. The Cochrane Database of Systematic Reviews. 2003, Issue 3. Art. No.: CD001366. DOI: 10.1002/14651858.CD001366.

Evidence Based Rating Scale 

The Evidence Based Rating Scale is a tool that helps consumers translate the findings of medical research studies with what our clinical advisors have found to be efficacious in their personal practice. This tool is meant to simplify which supplements and therapies demonstrate promise in the treatment of certain conditions. This scale does not take into account any possible interactions with any medication/ condition/ or therapy which you may be currently undertaking. It is therefore advisable to ask your doctor before starting any new treatment regimen.




















Cochrane study indicates strong evidence for reduced fat diets and nutritional management of disease.


















Meta-analyses and randomized controlled trials have proven efficacy for nutritional management of diabetes and obesity in both the short and long term.









High Blood Pressure




Date Published: 04/19/2005

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