17.4: Nutritional Assessment
By the end of this section, you will be able to:
- Describe steps of the nursing assessment for nutritional status
- Understand diagnostic testing for nutritional assessment
- Recall conditions causing imbalanced nutritional status
Nutritional assessment is an important skill in nursing. The assessment begins with the gathering of subjective data, focusing on individual lifestyle behaviors and underlying medical conditions. A thorough health history is vital. The nurse must also collect physical cues that help determine overall nutritional status and trends. These include anthropometric measures such as BMI and growth charts. Weight trends are vitally important, as are underlying conditions that affect the digestion, absorption, and metabolism of nutrients. Lab work helps confirm and prioritize nutritional concerns and hydration status. Last, the results from pertinent diagnostic tests, such as swallow studies and x-rays, should be reviewed and recorded. Once all data are collected, the nurse can analyze both subjective and objective cues and develop a prioritized plan of care that is individualized for the patient.
This section describes the steps of a nutrition assessment and discusses specific medical conditions associated with impaired nutrition. Because many conditions impact nutritional status, it is important for the nurse to understand the physiological adaptation that occurs with a given health condition and anticipate the nutritional needs required to restore homeostasis. Having a sound understanding of how nutrition impacts the human body is an essential aspect of nursing care.
Nursing Assessment for Nutritional Status
A thorough nursing nutrition assessment is foundational to the holistic care of all patients. A nutrition assessment includes subjective data, including demographic and sociocultural data, lifestyle cues, and medical history. It also includes objective data gathered from physical exams, labs, and diagnostic tests. The physical exam should focus on data from anthropometric measures (such as height, weight, and BMI), skin integrity, and gastrointestinal and urinary functions. Lab trends must be noted and results from pertinent diagnostic tests documented if indicated. When conducting a nutrition assessment, it is vital to know the overall state of health, including all chronic diseases, and to allow this holistic understanding to guide critical thinking, especially those disease states that promote the greatest risk in association with malnutrition or chronic disease progression.
Collecting Subjective Data
A thorough health history provides needed subjective data to guide nutritional planning and intervention (as discussed in Chapter 4 Obtaining a Complete Health History). A health history begins with demographic data, which are important when considering nutritional status as nutrient needs differ based on biological sex and age. Sociocultural factors have a significant effect on access and food choice. The patient’s religious preference, ethnicity and culture, educational level, occupation, and geographic location should all be documented as they impact overall health and nutritional status. Support systems, including food assistance programs and weight control support groups, should be reviewed.
A thorough discussion of dietary patterns and lifestyle behaviors is essential. Dietary patterns can be assessed using a variety of patient-friendly tools. A twenty-four-hour food recall is a simple measure to gauge usual daily food intake. A three-day food tracker is an even better measure, as it helps identify eating patterns and trends. There are a variety of apps and website food trackers that provide a structured way to document and review intake over time. The health history should reflect usual dietary patterns and include information related to food access or food insecurity , food shopping trends, utilization of food assistance programs, and attitudes toward cooking and food preparation.
In addition to dietary patterns, lifestyle behaviors must be reviewed and documented. Assessment of activity levels or levels of assistance needed with activities of daily living is vital to understanding caloric and nutritional needs as well as barriers to care. Utilization of health tracker apps with activity logs and stress level recordings can be insightful. Document any sensory impairment (vision or taste) that impacts activity or affects the ability to shop or cook safely. Ask about smoking history and use of alcohol or illicit drugs.
Identify past medical history that impacts nutritional health. Ask about weight trends and whether there is a history of dieting, utilization of weight loss programs, or bariatric surgery. Medical conditions to note include gastrointestinal disease, food allergies, history of diabetes, heart disease, liver disease, history of chemotherapy or radiation, and mental illness. Document if there is a family history of diabetes, heart disease, or obesity. Review all medications and discuss any medication effects on nutrition or hydration status.
Last, allow time to discuss the patient’s current health concerns. These include unintentional weight loss, weight gain, change in appetite, difficulty chewing or swallowing, nausea, vomiting, stool changes, and abdominal pain. Discuss current life stressors (divorce, unemployment, recent hospitalization) that present as obstacles to a healthy lifestyle. Explore attitudes toward healthy eating and assist the patient in identifying barriers to healthy living. All documentation must be accurate and professional, devoid of any bias or personal opinion.
Collecting Objective Data
The physical exam begins with assessment of vital signs, height, and weight. Compare findings to those previously documented, if available. Complete a head-to-toe assessment, emphasizing systems that relate to nutritional status (Table 17.7).
| Category | Areas to Assess |
|---|---|
| General | Body frame, hygiene, coordination, adequate vision and hearing, dentition |
| Mentation | Orientation, alertness, ability to converse and follow commands, mood stability |
| Skin | Turgor, pallor, cyanosis, nonhealing wounds, bruising or bleeding, edema, condition of hair and nails |
| Gastrointestinal/genitourinary | Abdominal girth, abdominal distension, epigastric or abdominal tenderness, ascites, bladder distension, urine output |
| Musculoskeletal | Muscle tone and strength, gait |
| Anthropometric measures | BMI, waist circumference, skinfold test |
| Other | Presence of enteral tubes, twenty-four-hour intake and output |
Diagnostic Tests for Nutritional Status
There are several diagnostic procedures specific to nutrition. Imaging studies include routine x-rays used to verify placement of NG and PEG tubes. Computed tomography scans can identify anatomical anomalies, such as intestinal blockages and tumors. A dual-energy x-ray absorptiometry (DEXA) scan is a bone density test performed under low-dose x-ray. The DEXA is a measure of calcium and other mineral deposits that provide a relative measure of bone strength. A modified barium swallow study (MBSS) views the anatomical and swallowing physiology of a bolus of food under video fluoroscopy. The MBSS allows for real-time evaluation of swallowing function and safety under the guidance of a speech-language pathologist.
An esophageal duodenostomy (EGD) is an invasive procedure performed under anesthesia. During an EGD, an endoscopic tube is advanced through the pharynx, esophagus, and gastric pouch to check for anomalies such as esophageal strictures and peptic ulcers. In some cases, an upper-gastrointestinal endoscopy can advance into the upper jejunum and obtain a biopsy of the intestinal wall to identify celiac disease.
Laboratory Tests
Diagnostic and lab work results can provide important clues about a patient’s overall nutritional status and should be used in conjunction with a thorough subjective and objective assessment to provide an accurate picture of the patient’s overall health status. Common lab tests include hemoglobin (hgb), hematocrit (HCT), white blood cell (WBC) count, albumin, prealbumin, and transferrin.
Anemia is a medical condition diagnosed by low hemoglobin levels. Hemoglobin is important for oxygen transport throughout the body. Anemia can be caused acutely by hemorrhage, but it is often the result of chronic iron deficiency, vitamin B12 deficiency, or folate deficiency. Iron supplements, vitamin B12 injections, folate supplements, and increased iron or folate intake in the diet can help increase hemoglobin levels.
Albumin and prealbumin are proteins in the bloodstream. They maintain oncotic pressure so that fluid does not leak out of blood vessels into the extravascular space. The most abundant protein circulating in the blood is albumin , which is used as a marker for protein status. Albumin and prealbumin levels are used as markers of malnutrition , but these levels can also be affected by medical conditions such as liver failure, kidney failure, inflammation, and zinc deficiency. Low albumin levels can indicate prolonged protein deficiency intake over several weeks, whereas prealbumin levels reflect protein intake over the previous few weeks. For this reason, prealbumin is often used to monitor the effectiveness of PN therapy.
Transferrin is a protein required for iron transport on red blood cells. Transferrin levels increase during iron deficiency anemia and decrease with kidney or liver failure and infection.
A patient’s amount of muscle wasting due to malnutrition is measured by a twenty-four-hour urine creatinine level (Hood, 2020). If insufficient calories are consumed, the body begins to break down its own tissues in a process called catabolism. BUN and creatinine are released as a by-product. A twenty-four-hour urine collection measures these by-product levels to assess the degree of catabolism occurring.
WBCs will decrease with malnourishment, specifically with protein and vitamins C, D, and E and B-complex deficiencies. Low WBCs place the patient at risk for infection because adequate WBCs are necessary for a fully functioning immune system. See Table 17.8 for a description of selected lab values associated with nutritional status. As always, refer to facility lab reference ranges when providing patient care.
| Lab | Normal Range | Nursing Considerations* |
|---|---|---|
|
Hemoglobin
(hgb) |
Females:
12–16 g/dL Males: 14–17.4 g/dL |
Hemoglobin measures the oxygen-carrying capacity of blood.
Decreased levels occur due to hemorrhage or deficiencies in iron, folate, or vitamin B12. 10–14: mild anemia 6–10: moderate anemia <6: severe anemia |
| Hematocrit (HCT) | 37–50 percent |
Hematocrit is normally three times the patient’s hemoglobin level during normal fluid status. Increased levels occur with dehydration,
and decreased levels occur with fluid overload or hemorrhage. |
|
White blood cells
(WBCs) |
5,000–10,000
mm 3 |
Increased levels occur due to infection. Decreased levels occur due to prolonged stress, poor nutrition, and vitamins C, D, and E and B-complex deficiencies.
<4,000: at risk for infection or sepsis > 11,000: infection present |
| Magnesium |
1.6–2.6
mEq/L |
Decreased level with poor nutrition or alcohol abuse. Increased levels due to kidney dysfunction.
Critical values can cause cardiac complications: <1.2 mg/dL or >4.9 mg/dL |
| Albumin | 3.4–5.4 g/dL |
Increased with dehydration.
Decreased level due to zinc deficiency, corticosteroid use, protein deficiency over several weeks, or conditions resulting in muscle wasting/muscle loss. |
| Prealbumin | 15–36 mg/dL |
Increased levels with corticosteroid or contraceptive use.
Decreased levels due to inflammation, poor immunity, protein depletion over a few weeks. |
| Transferrin |
250–450
mcg/dL |
Increased levels due to dehydration and iron deficiency.
Decreased levels due to anemia; vitamin B12, folate, and zinc deficiency; protein depletion; and conditions resulting in muscle wasting/muscle loss. |
|
24-hour urine
creatinine |
Males: 0.8–1.8 g/24 hours
Females: 0.6–1.6 g/24 hour |
Increased levels with kidney disease and muscle breakdown.
Decreased levels with progressive malnutrition as muscles atrophy. |
|
*Bolded items are critical conditions and require immediate healthcare provider notification. |
Conditions Causing Imbalanced Nutritional Status
Every cell in the body is affected by nutrition. Nutrient deficiencies and excesses affect every body system. Some disease states cause nutritional imbalances, while others result from a nutritional imbalance. Disease states that affect metabolic rates result in significant physiological compromise and increase the risk of developing chronic disease. Infections, inflammatory disease, metabolic conditions, and eating disorders are all medical conditions that have a direct effect on nutritional status. This section reviews the effects that infections, inflammatory disease, metabolic conditions, and eating disorders have on nutritional status.
Infections
Infectious organisms in the body increase demand for energy. Healing from an infectious disease occurs when metabolic conditions allow the immune system to control and limit the effects of the disease. Healing is compromised when nutritional deficits are present, preventing immune-modulating cells from functioning properly. Foodborne organisms can cause infection when hygiene and safety standards are not followed. Viruses, bacteria, and protozoa are all organisms that can create an infectious state.
In some cases, chronic infections can develop, stressing the nutritional demands of the body. Chronic infections commonly occur in the urinary tract, in chronic wounds, and in both the upper and lower respiratory tracts. When increased nutritional demands are not met, the patient’s nutritional status becomes compromised, and the body is unable to overcome the infectious agent. Chronic infectious states often benefit from a high- calorie , high-protein diet to meet elevated energy demands.
Inflammatory Diseases
Inflammatory disease occurs when the body’s natural defenses are hyperreactive and cause damage to tissues. Inflammation is caused by organisms, injuries, and toxins in the environment. Inflammatory disease affects every body system and is a driving force for malnutrition. Inflammation can decrease appetite and lead to decreased dietary intake and anorexia. It can cause catabolic metabolism of muscle tissue, reduce insulin sensitivity of body cells, and impair nutrient absorption. Food allergies, Crohn disease, and celiac disease are all associated with inflammatory processes. Many chronic illness states have an inflammatory component. This often presents as low-grade inflammation and leads to unintentional weight loss, decreased muscle mass, and poor quality of life. Heart disease, chronic obstructive pulmonary disease, and rheumatoid arthritis are examples of chronic disease states associated with low-grade inflammation.
Metabolic Conditions
Metabolic conditions are multifocal and associated with digestive dysfunction, malabsorption, and poor utilization of nutrients. Disorders that result in poor digestion include cognitive dysfunction, dysphagia , and mental illness that leads to poor dietary intake. Acute gastrointestinal distress (nausea, vomiting, and diarrhea) can interfere with intake and digestion. Poor digestion and decreased intake over time lead to malnutrition . Some disorders affect the absorption of nutrients within the small intestines. Bowel obstructions, diabetes, pernicious anemia, cystic fibrosis, and celiac disease cause malabsorption leading to nutrient deficits. Some diseases affect the metabolic rate, such as thyroid disease. An overactive thyroid can lead to a hypermetabolic state, while an underactive thyroid can lead to a hypoactive metabolic rate. It is important to review every patient’s medical history and identify medical conditions and treatments that have a direct effect on nutritional status.
Metabolic abnormalities can be risk factors for heart disease, diabetes, and stroke. Metabolic syndrome is a cluster of conditions known to increase risk of chronic disease when presented together; it is characterized by abdominal obesity, elevated lipid levels, elevated blood glucose, and elevated blood pressure. When three of these four symptoms are present, the individual is considered to be at metabolic risk. Fortunately, metabolic syndrome can be reversed with consistent lifestyle changes, including healthy dietary patterns of eating and increased physical activity, thereby decreasing overall health risks.
Eating Disorders
Eating disorders are often associated with maladaptive coping skills. Anorexia nervosa and bulimia are two diseases that have direct effects on patient nutrition. Patients who have anorexia nervosa are very focused on their weight to the point that they obsess about their diet. They will appear underweight and have great fear about gaining weight. Bulimic patients will eat in secret and then engage in self-induced vomiting to get rid of the food they ate. It is a cycle of secret binging, shame, and then self-induced vomiting called purging. It is episodic but recurrent. Patients with bulimia typically maintain weight but suffer from dental caries due to loss of tooth enamel. They also have menstrual irregularities and electrolyte imbalances as a result of persistent purging and laxative overuse. Both anorexia and bulimia can have severe consequences on the patient’s physical, mental health, and self-image.
While eating disorders can affect all people, they are more common in females between the ages of 12 and 35 years. Research has indicated that eating disorders among teens have doubled since the pandemic. Increased social media use has been linked to higher incidences of body dysmorphia and eating disorders in adolescents and young adults (Harriger et al., 2022).
Eating disorders can lead to physiological complications and are often accompanied by anxiety and guilt. Anorexia nervosa is a life-threatening body image disturbance that results in a state of emaciation. Anorexia is often associated with control and an intense fear of becoming obese. Bulimia is a compulsive eating disorder associated with binge eating followed by purging. It is episodic but recurrent. Patients with bulimia typically maintain weight but suffer from dental caries due to loss of tooth enamel, menstrual irregularities, and electrolyte disturbances as a result of persistent purging (forced vomiting and laxative overuse).
Eating disorders are complex and require the nurse to consider both physiological and psychological stressors in the body. Nursing care is prioritized according to safety needs and risk reduction. Maladaptive eating patterns often accompany stress, anxiety, and depression. It is important to analyze underlying stressors and utilize physiological and psychological interventions when caring for all patients with eating disorders.