That old saying, “You are what you eat,” is true, indeed; but one could change it a bit to read, “You are and will be what you eat.” Good nutrition is essential for the attainment and maintenance of good health. Determining whether a person is at risk requires completion of a nutrition assessment, which should, in fact, become part of a routine exam done by a registered dietitian or other health care professional specifically trained in thediagnosis of at-risk individuals. A proper nutrition assessment includes anthropometric measurements, clinical examination, biochemical tests, and dietary-social history.
Anthropometric measurements include height and weight and measure-ments of the head (for children), upper arm, and skinfold (Figure 1-3). The skinfold measurements are done with a caliper. They are used to determine the percentage of adipose and muscle tissue in the body. Measurements out of line with expectations may reveal failure to thrive in children, wasting (catabo-lism), edema, or obesity, all of which reflect nutrient deficiencies or excesses.
During the clinical examination, signs of nutrient deficiencies are noted. Some nutrient deficiency diseases, such as scurvy, rickets, iron deficiency, and kwashiorkor, are obvious; other forms of nutrient deficiency can be far more subtle. Table 1-4 lists some clinical signs and probable causes of nutrient defi-ciencies.
Biochemical tests include various blood, urine, and stool tests. A defi-ciency or toxicity can be determined by laboratory analysis of the samples. The tests allow detection of malnutrition before signs appear. The following are some of the most commonly used tests for nutritional evaluation.
· Serum albumin level measures the main protein in the blood and isused to determine protein status.
· Serum transferrin level indicates iron-carrying protein in the blood.The level will be above normal if iron stores are low and below normal if the body lacks protein.
· Blood urea nitrogen (BUN) may indicate renal failure, insufficient re-nal blood supply, or blockage of the urinary tract.
· Creatinine excretion indicates the amount of creatinine excreted inthe urine over a 24-hour period and can be used in estimating body muscle mass. If the muscle mass has been depleted, as in malnutrition, the level will be low.
· Serum creatinine indicates the amount of creatinine in the blood andis used for evaluating renal function.
Examples of other blood tests are hemoglobin (Hgb), hematocrit (Hct), red blood cells (RBCs), and white blood cells (WBCs). A low Hgb and Hct can indicate anemia. Not a routine test, but ordered on many clients with heart conditions, is the lipid profile, which includes total serum cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and serum triglycerides. Urinalysis also can detect protein and sugar in the urine, which can indicate kidney disease and diabetes.
The dietary-social history involves evaluation of food habits and is very im-portant in the nutritional assessment of any client. It can be difficult to obtain an accurate dietary assessment. The most common method is the 24-hour recall. In this method, the client is usually interviewed by the dietitian and is asked to give the types of, amounts of, and preparation used for all food eaten in the 24 hours prior to admission (PTA). Another method is the food diary. The client is asked to list all food eaten in a 3–4-day period. Neither method is totally accurate because clients forget or are not always totally truthful. They are sometimes inclined to say they have eaten certain foods because they know they should have done so. Computer analysis of the diet is the best way to determine if nutrient intake is ap-propriate. It will reveal any nutrient deficiencies or toxicities.
The dietary-social history is important to determine whether the client has the financial resources to obtain the needed food and the ability to properly store and cook food once home. After completing the dietary-social history, the dietitian can assess for risk of food–drug interactions that can lead to malnutri-tion (see Appendix E). Clients need to be instructed by a dietitian on possible interactions, if any.
When the preceding steps are evaluated together, and in the context of the client’s medical condition, the dietitian has the best opportunity of making an accurate nutrition assessment of the client. This assessment can then be used by the entire health care team. The doctor will find it helpful in evaluating the client’s condition and treatment. The dietitian can use the information to plan the client’s dietary treatment and counseling, and other health care pro-fessionals will be able to use it in assisting and counseling the client.