Lehne Ch 81 Vitamins

Pyridoxine (Vitamin B6)

Coenzyme in the metabolism of amino acids and proteins Must first be converted to its active form, pyridoxal phosphate Sources Fortified breakfast cereals, meat, fish, poultry, white potatoes, other starchy vegetables, noncitrus fruits

Vitamin E

Antioxidant properties Dietary sources: Fresh greens, seeds, oils Toxicity may increase risk for bleeding Increased risk of hemorrhagic stroke

Vitamin B Complex Cyanocobalamin (vitamin B12) and folic acid

Both essential factors in the synthesis of DNA Deficiency of either manifests as megaloblastic anemia Cyanocobalamin deficiency also results in neurologic damage

Vitamin A (Retinol)

Multiple functions in the eyes Toxicity Teratogenic, birth defects, hypervitaminosis liver injury, bone-related disorders Deficiency results in: Night blindness Xerophthalmia Keratomalacia Blindness Therapeutic uses

Intake of Vitamins

Recommended dietary allowances (RDAs) for vitamins are set by the Food and Nutrition Board of the National Academy of Sciences RDAs represent the average daily dietary intake sufficient to meet the nutrient requirements of nearly all healthy individuals (97% to 98%) in a particular life stage or gender group

Vitamin D

Regulates calcium and phosphorus Deficiency causes rickets or osteomalacia

A nurse is preparing a class on vitamin supplementation. What statement will be included in the class content?

Vitamin K is required to prevent bleeding. •Rationale: Vitamin K is required for the synthesis of prothrombin and other clotting factors. Antioxidants such as vitamins E and C do not reduce the risk of cancer. Folic acid supplements during pregnancy reduce the risk of neural tube defects. No evidence supports the use of multivitamins to prevent chronic diseases.

In which patient will the nurse suspect a thiamin deficiency?

A 42-year-old with alcoholism who has diplopia, ataxia, and memory loss •Rationale: Thiamin deficiency occurs most often in alcoholic patients with symptoms of neurologic and motor deficits.

6. An adult who has been self-medicating, using nutritional therapy for an elevated cholesterol level, complains of repeated episodes of flushing. The nurse suspects that the patient has been taking: a. niacin. b. thiamine. c. riboflavin. d. pyridoxine.

ANS: A Niacin is used to reduce cholesterol levels. When taken in large doses, nicotinic acid can cause vasodilation, with resultant flushing, dizziness, and nausea. Flushing is not a side effect of thiamine, riboflavin, or pyridoxine because they do not cause vasodilation. PTS: 1 DIF: Cognitive Level: Application REF: pp. 992-993

4. The nurse is assessing a patient who is malnourished and has a history of poor nutrition. The patient reports difficulty seeing at night. This patient is likely to be deficient in which fat-soluble vitamin? a. A (retinol) b. D c. E (alpha-tocopherol) d. K

ANS: A Vitamin A is needed for dark adaptation; night blindness often is the first indication of deficiency. Night blindness is not a sign of deficiency of vitamins D, E, or K. PTS: 1 DIF: Cognitive Level: Application REF: pp. 988-989

1. Which of the following vitamins can be stored by the body? (Select all that apply.) a. Vitamin E (alpha-tocopherol) b. Vitamin C (ascorbic acid) c. Cyanocobalamin (vitamin B12) d. Folic acid e. Vitamin D

ANS: A, C, E The fat-soluble vitamins (A, D, E, and K) are stored in massive amounts in the body. Of the water-soluble vitamins, B12 can be stored; all others must be replenished with frequent ingestion. PTS: 1 DIF: Cognitive Level: Comprehension REF: pp. 987-988

2. What are the potential beneficial effects of taking vitamin E (alpha-tocopherol) supplements? (Select all that apply.) a. Delayed progression of macular degeneration b. Improved blood clotting c. Lowered risk of developing Alzheimer's disease d. Reduced risk of cardiovascular disease e. Reduced risk of colds in elderly patients

ANS: A, E Studies to determine the potential benefits of vitamin E supplements show a decreased risk of colds in elderly patients when vitamin E is combined with vitamin C, beta-carotene, zinc, and copper, and a potential delay in the progression of macular degeneration. Vitamin E may actually increase the risk of bleeding. Studies have not shown a decrease in the risk of Alzheimer's disease or cardiovascular disease. PTS: 1 DIF: Cognitive Level: Analysis REF: pp. 990-991

14. A nursing student asks a nurse about the recommendations for vitamin supplements to prevent cancer. Which statement by the student indicates a need for further teaching? a. "Foods rich in antioxidant vitamins may confer protection by other means." b. "Observational studies provide clear proof that some antioxidants reduce the risk of cancer." c. "Randomized controlled studies have not demonstrated cancer prevention benefits." d. "Some vitamins have an increased cancer risk associated with too low and too high amounts."

ANS: B No clear evidence indicates that antioxidant vitamins lead to a reduced risk of cancer. Some observational studies show a link between the consumption of foods high in antioxidants and lower cancer rates, but this link may be related to other components of these diets, such as the high fiber also found in such foods. Some vitamins are linked to higher cancer rates when consumed in both too-low and too-high amounts. PTS: 1 DIF: Cognitive Level: Analysis REF: p. 990

10. A patient who is malnourished has scaling, cracked skin on the arms and face. The patient is irritable, anxious, and has difficulty sleeping. The patient complains of soreness of the tongue and mouth. When teaching this patient about vitamin therapy for this disorder, the nurse will tell the patient to report which side effects? a. Abdominal cramps and diarrhea b. Flushing, dizziness, and nausea c. Migraine headaches d. Numbness of feet and hands

ANS: B This patient shows signs of niacin deficiency. Side effects of niacin deficiency include flushing, dizziness, and nausea secondary to vasodilation. Abdominal cramps, diarrhea, migraines, and numbness of extremities are not side effects of niacin deficiency. PTS: 1 DIF: Cognitive Level: Analysis REF: pp. 992-993

12. A patient who is known to be a heavy drinker is brought to the emergency department with ataxia and confusion. The patient cannot remember the events of the previous day. The examination reveals nystagmus, and the patient reports having double vision. The nurse will expect to administer which vitamin to this patient? a. Ascorbic acid (vitamin C) IV b. Intramuscular pyridoxine (vitamin B6) c. Intravenous thiamine (vitamin B1) d. Nicotinic acid (niacin) PO

ANS: C Alcoholics who are malnourished have a form of thiamine deficiency called Wernicke-Korsakoff syndrome, which is characterized by nystagmus, diplopia, ataxia, confusion, and short-term memory loss. Parenteral thiamine is indicated for treatment. Ascorbic acid is given to treat vitamin C deficiency, or scurvy. Pyridoxine is given for vitamin B6 deficiency, also common in alcoholics, but this patient does not have the symptoms of seborrheic dermatitis and peripheral neuropathy. Nicotinic acid is used for niacin deficiency, which is characterized by severe dry, rough skin. PTS: 1 DIF: Cognitive Level: Application REF: p. 993

9. A patient with hyperlipidemia has been told by the provider to take extra niacin. The nurse will tell the patient to: a. increase servings of poultry, fish, and cereals. b. take nicotinamide supplements. c. take nicotinic acid supplements. d. take tryptophan supplements.

ANS: C Nicotinic acid is given in high doses to treat hyperlipidemia. Increasing dietary niacin is not sufficient to treat hyperlipidemia. Nicotinamide does not affect plasma lipoproteins. Dietary tryptophan is converted by the body into nicotinic acid, but not in sufficient amounts to treat hyperlipidemia. PTS: 1 DIF: Cognitive Level: Application REF: pp. 992-993

7. A patient will begin taking iron supplements to treat anemia. The nurse will recommend that the patient take the iron with which food to facilitate absorption? a. Cereal b. Dairy products c. Orange juice d. Red meats

ANS: C Orange juice is a good source of vitamin C, and vitamin C facilitates the absorption of iron. Cereals often are fortified with iron but do not facilitate its absorption. Calcium interferes with the absorption of iron. Red meats are a natural source of iron. PTS: 1 DIF: Cognitive Level: Analysis REF: p. 992

11. Which B vitamin deficiency is associated with cheilosis, glossitis, vascularization of the cornea, and itchy dermatitis of the scrotum and vulva? a. Niacin (nicotinic acid) b. Pyridoxine (vitamin B6) c. Riboflavin (vitamin B2) d. Thiamine (vitamin B1)

ANS: C Riboflavin deficiency produces the symptoms described and can be treated with riboflavin supplements. These signs do not indicate deficiencies of niacin, pyridoxine, or thiamine. PTS: 1 DIF: Cognitive Level: Application REF: p. 993

5. A nursing student asks a nurse working in the newborn nursery how vitamin K deficiency is treated in newborns. Which response by the nurse is correct? a. "A newborn infant's intestinal flora will produce vitamin K." b. "If coagulation studies show a bleeding disorder, oral menadione is given." c. "Menadione is given intravenously shortly after delivery." d. "Phytonadione is given intramuscularly immediately after delivery."

ANS: D A normal infant is born vitamin K deficient, and all infants are given an IM injection of phytonadione immediately after delivery. Newborns have not developed the intestinal flora needed to produce sufficient amounts of vitamin K. Menadione is not used in infants because of the increased risk of hyperbilirubinemia associated with its use. PTS: 1 DIF: Cognitive Level: Application REF: p. 991

13. A patient asks how she can consume optimal amounts of folate, because she is trying to get pregnant. The nurse will advise this patient to do what? a. Eat foods naturally high in folate. b. Stop worrying, because folate is present in many foods. c. Take synthetic folate on an empty stomach. d. Take synthetic folate in addition to foods high in folate.

ANS: D All women of child-bearing age need 400 to 800 mg of synthetic folate in addition to dietary sources to help prevent neural tube defects in the fetus. The bioavailability of synthetic folate is increased in the presence of food. Dietary folate is not sufficient to prevent neural tube defects, even when these foods are consumed in increased amounts. Taking folate on an empty stomach reduces the amount absorbed. PTS: 1 DIF: Cognitive Level: Application REF: p. 994

1. A nurse is discussing nutrition with a patient who expresses concern about not always consuming vitamins in amounts consistent with the recommended dietary allowances (RDAs). What will the nurse tell this patient? a. The RDA is only an estimate of the amount of vitamins required and does not represent a scientific number. b. The RDA is the amount of vitamin needed by 50% of the population regardless of age or gender. c. The RDA represents the highest amount that can be consumed safely, so amounts less than this can be sufficient. d. The RDA represents an average, so low intake one day can be compensated for by increased amounts on another day.

ANS: D The recommended dietary allowance is the average daily dietary intake sufficient to meet the nutrient requirements of nearly all healthy individuals. Because it represents an average, a low amount one day can be compensated for by an increased amount on another day. The RDA values are determined through extensive experimental data and are not estimates. The estimated average requirement (EAR) is the level that meets the nutritional requirements of 50% of healthy individuals. The tolerable upper intake level (UL) is the highest average daily intake that can be consumed without risk of adverse effects. PTS: 1 DIF: Cognitive Level: Analysis REF: p. 987

8. A nurse is caring for a patient who recently immigrated from a Third World country. The patient is thin and appears malnourished. The nurse notes that the patient has loose and missing teeth, gingivitis, and bleeding gums. The patient has multiple sores and ecchymoses. The nurse will expect the provider to order: a. cyanocobalamin (vitamin B12). b. high-dose nicotinic acid. c. intramuscular thiamine for 1 to 2 weeks. d. intravenous ascorbic acid.

ANS: D This patient has scurvy with acute, severe symptoms and needs intravenous vitamin C. The patient does not have signs of vitamin B12 deficiency, niacin deficiency, or thiamine deficiency. PTS: 1 DIF: Cognitive Level: Application REF: p. 992

2. A pregnant patient is discussing nutrition and vitamin supplements with the nurse. Which statement by the patient indicates an understanding of the use of nutrition and supplements during pregnancy? a. "I can get adequate folic acid by consuming foods fortified with synthetic folate." b. "I need reduced amounts of vitamin C while pregnant to lower my risk of hemorrhage." c. "I should take vitamin K so my baby won't be vitamin K deficient at birth." d. "Excessive amounts of vitamin A [retinol] can cause birth defects in my baby."

ANS: D Vitamin A in high doses can cause birth defects, so pregnant women should be cautioned about exceeding the UL and probably the RDA for vitamin A while pregnant. Pregnant women need to take 400 to 800 mg of supplemental folic acid in addition to that in food. Vitamin C deficiency, not excess, can lead to bleeding disorders. Maternal intake of vitamin K will not prevent infants from being born vitamin K deficient. PTS: 1 DIF: Cognitive Level: Application REF: pp. 988-989 | pp. 991-992 | p. 994

3. A child is diagnosed with rickets. The nurse knows that this child is most likely deficient in which vitamin? a. Niacin (nicotinic acid) b. Thiamin (vitamin B1) c. Vitamin C (ascorbic acid) d. Vitamin D

ANS: D Vitamin D plays a critical role in the regulation of the metabolism of calcium and phosphorus. Classical effects of deficiency are rickets in children and osteomalacia in adults. Niacin, thiamin, and vitamin C do not play a role in the prevention of rickets. PTS: 1 DIF: Cognitive Level: Analysis REF: p. 990

Vitamin C

Action required for production of collagen and other compounds that bind cells together Part of the biochemical reaction for the synthesis of adrenal steroids Sources Citrus fruits/juices, tomatoes, potatoes, strawberries, melons, spinach, broccoli Has antioxidant properties Facilitates iron absorption Deficiency can lead to scurvy

Vitamin K

Action required for synthesis of prothrombin and other clotting factors Deficiency produces bleeding Adverse effects Hypersensitivity reaction Hyperbilirubinemia in parenteral administration to newborns Therapeutic use Correction or prevention of hypoprothrombinemia and bleeding caused by vitamin K deficiency Control of hemorrhage caused by warfarin

Thiamin (Vitamin B1)

Actions Coenzyme for carbohydrate metabolism Requirements increased slightly during pregnancy and breast-feeding Deficiency Beriberi Wernicke-Korsakoff syndrome

Riboflavin (Vitamin B2)

Actions Involved in numerous enzymatic reactions First, must be changed to flavin adenine dinucleotide (FAD) or flavin mononucleotide (FMN) Adverse effects None for humans, no UL Therapeutic uses Riboflavin deficiency Migraine headaches

Niacin (Nicotinic Acid) (Cont.)

Adverse effects Small doses devoid of adverse effects Large doses •Vasodilation with flushing, dizziness, nausea Therapeutic uses As a vitamin, used only as treatment for niacin deficiency If given in large doses, can decrease cholesterol

Pyridoxine (Vitamin B6) (Cont.)

Deficiency May result from poor diet, isoniazid use, inborn errors of metabolism Symptoms Seborrheic dermatitis, microcytic anemia, peripheral neuritis, convulsions, depression, confusion Dietary deficiency of vitamin B6 is rare in the United States except in alcoholics

Niacin (Nicotinic Acid)

Deficiency Pellagra: Dermatitis characterized by scaling and cracking of the skin in areas exposed to the sun GI disturbances Central nervous system (CNS) •Irritability, insomnia, memory loss, anxiety, dementia

Biotin

Essential cofactor for several reactions involved in the metabolism of carbohydrates and fats

Pantothenic Acid

Essential component of two biologically important molecules: Coenzyme A and acyl carrier protein

A patient who is in the early stages of Wernicke-Korsakoff syndrome has been admitted to the healthcare facility. Upon assessment of the patient, the nurse expects to find all but which manifestation?

Fixed, dilated pupils •Rationale: Fixed, dilated pupils are associated with severe neurologic damage or opiate drug overdose. Wernicke-Korsakoff syndrome is a serious disorder of the central nervous system, caused by thiamin deficiency, that has neurologic and psychologic manifestations. Symptoms include nystagmus, diplopia, ataxia, and inability to remember the recent past. Failure to correct the deficiency may result in irreversible brain damage.

Folic Acid

Food folate versus synthetic folate Synthetic form is more stable U.S. Food and Drug Administration (FDA) ordered synthetic folate to be added to all enriched grain products Deficiency of folic acid during pregnancy can impair CNS development Can result in neural tube defects, anencephaly, spina bifida Important for any patient who may become pregnant to take additional folic acid

Vitamin B Complex

Niacin (nicotinic acid) Riboflavin (vitamin B2) Thiamin (vitamin B1) Pyridoxine (vitamin B6) Cyanocobalamin (vitamin B12) Folic acid

Vitamins

Organic compounds Required in minute amounts for growth and maintenance of health Are not a source of energy Essential for energy transformation and regulation of metabolic processes Several vitamins are inactive in native form and must be converted to active compounds in the body

Intake of Vitamins (Cont.)

The Tolerable Upper Intake Level (UL) for a vitamin is the highest average daily intake that can be consumed by nearly everyone without significant risk of adverse effects The UL is an index of safety; it is not a recommendation to exceed the RDA The estimated average requirement (EAR) is the level of intake that meets nutritional requirements for 50% of the healthy individuals in any life stage or gender group The acceptable macronutrient distribution range (AMDR) is a range of macronutrients (eg, proteins, carbohydrates, fats) associated with optimal health. Intake of a nutrient below the established range for that nutrient increases the risk of malnourishment. Intake of a nutrient above the established range for that nutrient increases the risk of chronic diseases

Thiamin (Vitamin B1) (Cont.)

Wernicke-Korsakoff syndrome (caused by alcoholism) Alcoholism is the most common cause of thiamin deficiency in the United States Serious CNS disorder (neurologic and psychologic) •Nystagmus, diplopia, ataxia, inability to remember recent past

A deficiency of which vitamin is most likely to result in visual disturbances?

Vitamin A •Rationale: Vitamin A deficiency can cause night blindness, xerophthalmia (a dry, thickened condition of the conjunctiva), and keratomalacia (degeneration of the cornea with keratinization of the corneal epithelium). Vitamin D plays a critical role in the regulation of calcium and phosphorus metabolism and may help protect against breast cancer, colorectal cancer, type 1 diabetes, and overall mortality. In children, vitamin D deficiency causes rickets. In adults, deficiency causes osteomalacia. High-dose vitamin E (more than 200 IU/day) increases the risk of hemorrhagic stroke. Vitamin K is required for synthesis of prothrombin and other clotting factors. Vitamin K deficiency causes bleeding tendencies. Severe deficiency can cause spontaneous hemorrhage.

Water-Soluble Vitamins

Vitamin C Members of the vitamin B complex: Thiamin, riboflavin, niacin, pyridoxine, pantothenic acid, biotin, folic acid, and cyanocobalamin

Thiamin (Vitamin B1) (Cont.)

Wet beriberi Fluid accumulation in the legs Cardiovascular complications (palpitations, electrocardiograph [ECG] abnormalities, high-output heart failure) May progress to circulatory collapse and death Recovery is dramatic with replacement therapy Dry beriberi Neurologic and motor deficits, no edema or cardiovascular symptoms Recovery is slow

Water soluble vitamins

•Vitamin C •Vitamin B complex: Thiamin, riboflavin, niacin, pyridoxine, pantothenic acid, biotin, folic acid, cyanocobalamin

Vitamins Fat soluble

•Vitamins A, D, E, K