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Part II Nutrition Assessment, Consequences, and Implications

anemic. Hypothyroidism and hyperthyroidism may be associated with pernicious anemia; both conditions may also lead to a correctable anemia, but most older adults with thyroid abnormalities are not anemic. Unless the person is a strict vegetarian, poor food intake has limited effect on B-12 deficiency, although the presence of iron and copper, which are strong oxi- dizing elements, can destroy vitamin B-12 (30). The most common etiology is due to a gastric mucosa defect, resulting in inadequate secretion of intrinsic factor (IF). When B-12 is ingested, it combines with IF and is absorbed in the distal part of the ileum. Without IF, B-12 cannot be absorbed, body stores are depleted, and the body produces enlarged, immature RBCs. It is categorized as a macrocytic normochromic anemia; however, about 40% of the cases are normocytic (16,31-33). Drugs often consumed by older adults that can also contribute to vitamin B-12 deficiency include metformin and stomach acid blockers. The laboratory values for pernicious anemia are very similar to megaloblastic anemia. Lower-than- normal values are seen for hemoglobin, hematocrit, and serum B-12. However, elevated levels are seen in serum iron, serum folate, ferritin, and homocysteine. MCV may be elevated or normal. The only definitive laboratory test is methyl malonic acid, which is ele- vated in B-12 deficiency and normal in megaloblastic anemia. Because the methyl malonic acid test is avail- able in only a few laboratories in the United States, diagnosis is typically done without it (34,35). Table 11.7 shows laboratory values that are typically seen in pernicious anemia. Treatment for pernicious anemia is based on

its etiology. Supplementation can be either parenteral or oral. Oral B-12 supplements are effective if the body can produce adequate levels of intrinsic factor. However, if the body is unable to produce intrinsic factor, then monthly injections of B-12 are recom- mended. The intramuscular dose is 1,000 μg provided daily for 1 week to increase levels, followed by weekly doses for 1 month and monthly thereafter (36).

IMPLICATIONS FOR PRACTICE While anemia may be common among older adults, it is important for the RDN to remember the importance of proper identification and recommendation of inter- ventions. All forms of nutritional anemia have physi- cal manifestations that will make adequate nutritional intakes more difficult for the already at-risk older adult population. It is essential to identify the under- lying cause before effective therapy can be adminis- tered. Because symptoms are common to different kinds of anemias, laboratory assessment is essential. Reevaluation of intervention strategies is important to

TABLE 11.7 Laboratory Test Results for Pernicious Anemia

Laboratory Test

Vitamin B-12 Deficiency

Macrocytic megaloblastic pernicious

Hemoglobin (g/dL) Hematocrit (%)

Mean corpuscular volume (mm3)

Mean corpuscular hemoglobin (pg/cell)

Mean corpuscular hemoglobin concentration (g/dL)

Serum iron (mg/dL) Ferritin (ng/mL) Transferrin

Total iron binding capacity (mg/dL)

Serum folate (mg/mL)

Serum vitamin B-12 (pg/mL) Homocysteine (mmol/L)

↓ ↓

↑ / ↔ ↑ ↑ / ↔

↑ ↑ ↑

—

↑ ↓ ↑

determine whether the plan is working or whether the anemia is an early symptom of another disease process. Normal values for laboratory tests for anemia can be found in Table 11.8 (see page 168).

REFERENCES 1. American Society of Hematology. Anemia & older adults. www.hematology.org/Patients/Blood-Disorders /Anemia/5226.aspx. Accessed October 15, 2014.

2. Artz AS, Besa EC. Anemia in elderly persons. http:// emedicine.medscape.com/article/1339998- overview?src=emailthis. Published August 29, 2013. Accessed December 29, 2015.