Understanding the Nutrition Care Process and Diagnosis
Registered Dietitian Nutritionists (RDNs) utilize the four-step Nutrition Care Process (NCP): assessment, diagnosis, intervention, and monitoring/evaluation. Nutrition diagnosis is the crucial second step where an RDN identifies a nutrition-related problem that can be resolved or improved through nutrition intervention. This differs from a medical diagnosis, which physicians address; a nutrition diagnosis focuses solely on the nutritional aspects of a patient's health.
For consistency and clarity, dietitians use standardized terminology categorized into three main domains or classifications. These are the Intake, Clinical, and Behavioral-Environmental domains. A nutrition diagnosis is often documented formally using a PES statement (Problem, Etiology, Signs/Symptoms).
The Three Classifications of Nutrition Diagnosis
1. The Intake (NI) Domain
This domain addresses nutrition issues related to the actual intake of food, nutrients, fluids, and bioactive substances, including oral diets, enteral nutrition, and parenteral nutrition. Problems involve either inadequate or excessive consumption relative to needs. Addressing Intake domain issues is frequently a priority for RDNs due to the direct impact on patient health.
Common Classes within the Intake Domain:
- Energy Balance: Diagnoses concerning insufficient or excessive energy intake (e.g., "Excessive energy intake").
- Oral or Nutrition Support Intake: Issues with food and beverage consumption or intake from nutrition support (e.g., "Inadequate intake from enteral nutrition").
- Fluid Intake: Problems related to hydration status.
- Nutrient Intake: Issues involving specific nutrient consumption, such as fats, protein, vitamins, or minerals (e.g., "Inadequate protein intake").
2. The Clinical (NC) Domain
The clinical domain encompasses nutrition problems linked to medical or physical conditions. These diagnoses often involve functional, biochemical, or weight-related issues resulting from an underlying medical condition. The dietitian manages the nutritional aspect while the physician treats the medical condition.
Common Classes within the Clinical Domain:
- Functional: Diagnoses involving physical changes impacting nutritional status (e.g., "Swallowing difficulty").
- Biochemical: Problems indicated by altered lab values or metabolic capacity due to disease, medication, or surgery.
- Weight: Diagnoses related to body weight status (e.g., "Underweight" or "Obesity Class III").
- Malnutrition: Diagnoses identifying various forms and causes of malnutrition.
3. The Behavioral-Environmental (NB) Domain
This domain addresses nutrition issues connected to a patient's knowledge, beliefs, attitudes, environment, or food access. These are often underlying causes for issues in the Intake or Clinical domains and are key for developing sustainable interventions.
Common Classes within the Behavioral-Environmental Domain:
- Knowledge and Beliefs: Diagnoses stemming from insufficient nutrition knowledge or misunderstandings (e.g., "Food and nutrition-related knowledge deficit").
- Physical Activity and Function: Problems related to activity levels or the ability to manage food-related tasks (e.g., "Limited ability to prepare food").
- Food Safety and Access: Issues concerning food safety, security, or availability (e.g., "Limited access to food").
Comparison of Nutrition Diagnosis Domains
| Feature | Intake (NI) Domain | Clinical (NC) Domain | Behavioral-Environmental (NB) Domain |
|---|---|---|---|
| Focus | Actual consumption of food, nutrients, fluids, and bioactive substances. | Nutritional issues caused by or related to medical or physical conditions. | Knowledge, beliefs, attitudes, environment, or food access that impact nutrition. |
| Problem Type | Too much or too little of a specific nutrient or energy. | Functional changes, altered lab values, weight issues, or malnutrition. | Knowledge gaps, undesirable food choices, physical inactivity, or food insecurity. |
| Etiology (Cause) | Often linked to behavioral or environmental factors. | Stem from medical diagnoses (e.g., disease, injury, surgery). | Psychological or social factors that drive nutritional behavior. |
| Intervention Target | The patient's actual dietary intake. | Managing the nutritional symptoms of a medical condition. | The root-cause behaviors and environmental factors. |
| PES Example | Problem: Excessive energy intake related to frequent consumption of large, high-calorie meals as evidenced by BMI of 35.1 kg/m². | Problem: Swallowing difficulty related to recent cerebrovascular accident as evidenced by observation of coughing while eating and nurse report. | Problem: Food and nutrition-related knowledge deficit related to no prior nutrition education as evidenced by patient questions regarding appropriate portion sizes. |
| Outcome Measured | Changes in kilocalorie or nutrient consumption. | Improvement in lab values, weight status, or physical symptoms. | Increased knowledge, improved food choices, or greater food security. |
Documenting the Diagnosis: The PES Statement
The PES statement format (Problem, Etiology, Signs/Symptoms) is standard for documenting nutrition diagnoses. This format ensures clear, evidence-based articulation of the diagnosis, vital for effective intervention planning and communication. The Problem uses standard terminology, the Etiology identifies the cause, and the Signs/Symptoms provide supporting data. Formulating accurate PES statements is a core skill for RDNs.
Conclusion
The three classifications of nutrition diagnosis—Intake, Clinical, and Behavioral-Environmental—provide RDNs with a structured framework to identify and address patient nutrition issues. By categorizing problems related to consumption, medical conditions, and underlying behaviors, dietitians can develop effective, targeted interventions. This systematic approach within the NCP improves patient outcomes and enhances communication and documentation in healthcare. The classifications ensure comprehensive nutrition care tailored to individual needs.
