Chapter 15 Vitamin and Mineral Replacement

The Dietary Reference Intakes (DRI) nutrient recommendations include the following:

1.Adequate intake (AI) is the amount determined to be sufficient in the absence of scientific information. The AI is based on data about the levels of vitamin intake that seem to maintain a healthy status. 2.Estimated average requirement (EAR) is the amount thought to provide a sufficient intake in one half of healthy persons in a defined group. 3.Recommended dietary allowance (RDA) is the amount thought to provide the needs of 98% of well children and adults of specific age group and gender. RDAs were developed to prevent deficiencies and may not be reflective of all groups, such as older adults. 4.Tolerable upper intake level (UL) is the maximum amount considered not likely to be a risk for healthy persons in a specified group. This is not a recommended level to take.

Pyridoxine(B6)

Administered to correct vitamin B6 deficiency. It may also help alleviate the symptoms of neuritis caused by isoniazid (INH) therapy for tuberculosis. Vitamin B6 is an essential building block of nucleic acids, red blood cell formation, and synthesis of hemoglobin. Used to treat neonates with seizures refractive to traditional therapy. Vitamin B6 deficiencies may occur in alcoholics along with deficiencies of other B-complex vitamins. Pyridoxine is readily absorbed in the jejunum and stored in the liver, muscle, and brain. It is metabolized in the liver and excreted in the urine.

Do not confuse...

Aquasol A or Aquasol E with Anusol, an antiinflammatory generally used to treat hemorrhoid

Herbal Alert 15-1 Iron

Chamomile, feverfew, peppermint, and St. John's wort interfere with the absorption of iron and other minerals.

Chromium

Chromium is said to be helpful in the control of type 2 diabetes. It is thought that this mineral helps to normalize blood glucose by increasing the effects of insulin. The dose of an oral hypoglycemic drug or insulin may need to be decreased. Some patients with an impaired glucose tolerance or patients who do not have diabetes may benefit by taking chromium. In addition, chromium claims to promote weight loss and muscle building. Multivitamin and mineral preparations contain chloride salt of chromium. There is no RDA for chromium; however, 50 to 200 mcg/day is considered within the normal range for adults and children older than 6 years of age. Foods rich in chromium include meats, whole-grain cereals, and brewer's yeast.

Copper

Copper is needed for the formation of RBCs and connective tissues. Copper is a cofactor of many enzymes, and its function is in the production of the neurotransmitters norepinephrine and dopamine. Excess serum copper levels may be associated with Wilson's disease(allows for large amounts of copper to accumulate in the liver, brain, cornea [brown or green Kayser-Fleischer rings], or kidneys). A prolonged copper deficiency may result in anemia, which is not corrected by taking iron. Abnormal blood and skin changes caused by a copper deficiency include a decrease in white blood cell count, glucose intolerance, and a decrease in skin and hair pigmentation. Mental retardation may also occur in the young. The RDA for copper is 1.5 to 3 mg/day. Most adults consume about 1 mg/day. Foods rich in copper are shellfish (crab, oysters), liver, nuts, seeds (sunflower, sesame), legumes, and cocoa.

Folic Acid (Folate)

Folic acid is absorbed from the small intestine, and the active form of folic acid (folate) is circulated. One third of folate is stored in the liver. Eighty percent of folate is excreted in bile and 20% in urine. Folic acid is essential for deoxyribonucleic acid (DNA) synthesis, and without folic acid there is a disruption in cellular division. Chronic alcoholism, poor nutritional intake, malabsorption syndromes, pregnancy, and drugs that cause inadequate absorption (phenytoin, barbiturates) or folic acid antagonists (methotrexate, triamterene, trimethoprim) are causes of folic acid deficiencies. Symptoms of folic acid deficiencies include anorexia, nausea, stomatitis, diarrhea, fatigue, alopecia, and blood dyscrasias (megaloblastic anemia, leukopenia, thrombocytopenia). These symptoms are usually not noted until 2 to 4 months after folic acid storage is depleted. Folic acid deficiency during the first trimester of pregnancy can affect the development of the central nervous system (CNS) of the fetus. This may cause neural tube defects (NTDs) such as spina bifida (defective closure of the bony structure of the spinal cord) or anencephaly (lack of brain mass formation). All women who may become pregnant consume 400 mcg of supplemental folic acid each day—in addition to the folate they get with food. Synthetic folate is more stable than food. Evidence that 400 to 800 mcg (0.4 to 0.8 mg) of folic acid per day can decrease the incidence of coronary artery disease (CAD). Folic acid may also offer some protection from colorectal cancer. Excessive doses of folic acid may mask signs of vitamin B12 deficiency. Patients taking phenytoin (Dilantin) to control seizures should be cautious about taking folic acid. This vitamin can lower the serum phenytoin level, which could increase the risk of seizures. It is thought that 1 mg or less per day of folic acid is safe in patients with controlled epilepsy.

Iron

Iron (ferrous sulfate, gluconate, or fumarate) is vital for hemoglobin regeneration. Sixty percent of the iron in Hgb. One of the causes of anemia is iron deficiency. A normal diet contains 5 to 20 mg of iron per day. Foods rich in iron include liver, lean meats, egg yolks, dried beans, green vegetables (e.g., spinach), and fruit. Food and antacids slow the absorption of iron, and vitamin C increases iron absorption. During pregnancy, an increased amount of iron is needed, but during the first trimester of pregnancy megadoses of iron are contraindicated. The dose of iron for infants and children 6 months to 2 years of age is 1.5 mg/kg of body weight. For the adult, 50 mg/day is needed for hemoglobin regeneration. One tablet of ferrous sulfate is sufficient as a daily iron dose when indicated. Although food decreases absorption by 25% to 50%, it may be necessary to take iron preparations with food to avoid GI discomfort. Vitamin C at doses > 500 mg may slightly increase iron absorption, whereas tetracycline, quinolone antibiotics (ciprofloxacin, levoflaxicin, etc.), and antacids can decrease absorption. Iron replacement is given primarily to correct or control iron-deficiency anemia. Positive findings for this anemia are microcytic (small), hypochromic (pale) erythrocytes (red blood cells [RBCs]). Clinical signs and symptoms include fatigue, weakness, shortness of breath, pallor, and, in cases of severe anemia, increased GI bleeding. The dosage of ferrous sulfate for prophylactic use is 300 to 325 mg/day; for therapeutic use, the dosage is 600 to 1200 mg/day. The onset of action for iron therapy takes days, and its peak action does not occur for days or weeks. Iron toxicity is a serious cause of poisoning in children. As few as 10 tablets of ferrous sulfate (3 g) taken at one time can be fatal within 12 to 48 hours. Hemorrhage due to the ulcerogenic effects of unbound iron leads to shock.

Megadoses

Megadoses of vitamins are available, advertised for specific health conditions; these high doses can be toxic. Megadoses of fat-soluble vitamins (A, D, E, and K) may cause toxic effects. Megadoses of water-soluble vitamins are eliminated via the urine and thus are generally not toxic. Adverse reactions (kidney stones and nerve damage, respectively) have been reported from Vitamin C and Vitamin B6. However, it is also claimed that B vitamins may positively influence metabolism in older adults.

Nicotinic acid, or Niacin(B3)

Niacin is given to alleviate pellagra and hyperlipidemia, for which large doses are required. However, large doses may cause GI irritation and vasodilation, resulting in a flushing sensation.

TABLE 15-1 JUSTIFICATION FOR VITAMIN SUPPLEMENTS

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TABLE 15-2 VITAMINS: FUNCTIONS, SUGGESTED FOOD SOURCES, AND SELECTED DEFICIENCY CONDITIONS

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Prototype Drug Chart 15-1 Vitamin A

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Prototype Drug Chart 15-2 Vitamin C

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Nursing Process: Vitamins

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Prototype Drug Chart 15-3 Iron

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Nursing Process: Antianemia, Mineral: Iron

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Riboflavin(B2)

Riboflavin may be given to manage dermatologic problems such as scaly dermatitis, cracked corners of the mouth, and inflammation of the skin and tongue. To treat migraine headache, riboflavin is given in larger doses than for dermatologic concerns.

Selenium

Selenium acts as a cofactor for an antioxidant enzyme that protects protein and nucleic acids from oxidative damage. Selenium works with vitamin E. It is thought that selenium has an anticarcinogenic effect, and doses lower than 200 mcg may reduce the risk of lung, prostate, and colorectal cancer. Excess doses of more than 200 mcg might cause weakness, hair loss, dermatitis, nausea, diarrhea, and abdominal pain. Also, there may be a garlic-like odor from the skin and breath. The RDA for selenium is 40 to 75 mcg (lower dose for women, higher dose for men). Foods rich in selenium include meats (especially liver), seafood, eggs, and dairy products.

Fat-Soluble Vitamins

The fat-soluble vitamins are A, D, E, and K. Metabolized slowly; can be stored in fatty tissue, liver, and muscle in significant amounts; and are excreted in the urine slowly. Vitamins A and D are toxic if taken in excessive amounts over time. Vitamins E and K were thought to be less toxic than vitamins A and D. Vitamin E was once considered a "wonder" drug, supposedly beneficial for the heart and brain, but it was later determined that vitamin E was an independent risk factor for the development of heart failure.

Thiamine(B1)

Thiamine deficiency can lead to the polyneuritis and cardiac pathology seen in beriberi or to Wernicke's encephalopathy that progresses to Korsakoff's syndrome, conditions most commonly associated with alcohol abuse. Wernicke-Korsakoff syndrome is a significant central nervous system disorder characterized by confusion, nystagmus, diplopia, ataxia, and loss of recent memory. IV administration of thiamine is recommended for treatment of Wernicke-Korsakoff syndrome. Thiamine must be given before giving any glucose to avoid aggravation of symptoms.

Minerals

Various minerals, such as iron, copper, zinc, chromium, and selenium, are needed for body function.

Vitamin A

Vitamin A is essential for bone growth and the maintenance of epithelial tissues, skin, eyes, and hair. It has been used for the treatment of skin disorders such as acne. Excessive amounts of vitamin A (>6000 international units) might have a teratogenic effect (birth defects). IM administration is used only in acutely ill patients or patients refractory to the oral route, such as those with gastrointestinal (GI) malabsorption. When a person is deficient in vitamin A, the vitamin is absorbed faster. A portion of vitamin A is stored in the liver. Massive doses of vitamin A may cause hypervitaminosis A, symptoms of which are hair loss, peeling skin, anorexia, abdominal pain, lethargy, nausea, and vomiting. The UL for vitamin A is 3000 mcg daily (3000 mcg daily = 10,000 international units). Excess vitamin A is stored in the liver for up to 2 years. Vitamin A toxicity affects multiple organs, especially the liver. The dose for healthy patients should not be greater than 7500 international units. Vitamin A is excreted through the kidneys and feces. Vitamin A aids in the formation of the visual pigment needed for night vision. This vitamin is needed in bone growth and development, and it promotes the integrity of the mucosal and epithelial tissues. An early sign of vitamin A deficiency (hypovitaminosis A) is night blindness. This may progress to dryness and ulceration of the cornea and to blindness.

Vitamin B Complex

Vitamin B1 (thiamine) 1.1-1.2, vitamin B2 (riboflavin) 1.1-1.2, vitamin B3 (nicotinic acid, or niacin) 1.1-1.3, and vitamin B6 (pyridoxine) are four of the vitamin B-complex members. This B-complex group is water-soluble. It is a common group of vitamins administered in the clinical setting, especially to patients with alcoholism.

Vitamin B12(cyanocobalamin)

Vitamin B12, like folic acid, is essential for DNA synthesis. Vitamin B12 aids in the conversion of folic acid to its active form. With active folic acid, vitamin B12 promotes cellular division. It is also needed for normal hematopoiesis (development of red blood cells in bone marrow) and to maintain nervous system integrity, especially the myelin. An intrinsic factor is necessary for the absorption of vitamin B12 through the intestinal wall. Vitamin B12 binds to the protein transcobalamin II and is transferred to the tissues. Most vitamin B12 is stored in the liver. Vitamin B12 is slowly excreted, and it can take 2 to 3 years for stored vitamin B12 to be depleted. Vitamin B12 deficiency is uncommon unless there is a disturbance of the intrinsic factor and absorption. Pernicious anemia (lack of the intrinsic factor) is the major cause of vitamin B12 deficiency. Vitamin B12 deficiency can also develop in strict vegetarians who do not consume meat, fish, or dairy products. B12 deficiency is commonly seen with metformin and proton pump inhibitors (e.g., omeprazole). Symptoms may include numbness and tingling in the lower extremities, weakness, fatigue, anorexia, loss of taste, diarrhea, memory loss, mood changes, dementia, psychosis, megaloblastic anemia with macrocytes (overenlarged erythrocytes [red blood cells]) in the blood, and megaloblasts (overenlarged erythroblasts) in the bone marrow. To correct vitamin B12 deficiency, cyanocobalamin in crystalline form can be given intramuscularly for severe deficits. It cannot be given intravenously because of possible hypersensitive reactions. Cyanocobalamin can be given orally and is commonly found in multivitamin preparations. Subcutaneous possible.

Vitamin C

Vitamin C (ascorbic acid) is absorbed from the small intestine. Vitamin C aids in the absorption of iron and in the conversion of folic acid. Vitamin C is not stored in the body. A high serum vitamin C level that results from excessive dosing of vitamin C is excreted by the kidneys unchanged. The recommended daily dose of vitamin C for an adult is 50 to 100 mg/day. Massive doses of vitamin C can cause diarrhea and GI upset. Vitamin C is absorbed readily through the GI tract and is distributed throughout the body fluids. The kidneys completely excrete vitamin C. Vitamin C is needed for carbohydrate metabolism and protein and lipid synthesis. Collagen synthesis also requires vitamin C for capillary endothelium, connective tissue and tissue repair, and osteoid tissue of the bone. Large doses of vitamin C (>5 to 10 g) may decrease the effect of oral anticoagulants. Smoking decreases serum vitamin C levels. Vitamin C (in doses >500 mg) aids iron absorption. The use of megavitamin therapy, massive doses of vitamins, is questionable at best. Most authorities believe that vitamin C does not cure or prevent the common cold; rather, they believe that vitamin C has a placebo effect. Moreover, megadoses of vitamin C taken with aspirin or sulfonamides may cause crystal formation in the urine (crystalluria). Excessive doses of vitamin C can cause a false-negative occult (blood) stool result and false-positive sugar result in the urine. A gradual reduction of dosage is necessary to avoid vitamin deficiency.

Vitamin D

Vitamin D has a major role in regulating calcium and phosphorus metabolism and is needed for calcium absorption in the GI tract. Requires bile salts for absorption. There are two compounds of vitamin D: vitamin D2, ergocalciferol (a synthetic fortified vitamin D), and vitamin D3, cholecalciferol (a natural form of vitamin D influenced by ultraviolet sunlight through the skin). OTC vitamin D usually contain vitamin D3. Vitamin D is converted to calcifediol (also known as 25-hydroxycholecalciferol) in the liver. Calcifediol is then converted to an active form, calcitriol, in the kidneys. Studies have suggested that vitamin D, taken with calcium, can reduce the incidence of fractures. Calcitriol, the active form of vitamin D, functions as a hormone and, with parathyroid hormone (PTH) and calcitonin. Calcitriol and PTH stimulate bone reabsorption of calcium and phosphorus. Excretion of vitamin D is primarily in bile. If serum calcium levels are low, more vitamin D is activated; when serum calcium levels are normal, activation of vitamin D is decreased. Excess vitamin D ingestion (>40,000 international units) results in hypervitaminosis D and may cause hypercalcemia (an elevated serum calcium level). Anorexia, nausea, and vomiting are early symptoms.

Vitamin E

Vitamin E has antioxidant properties that protect cellular components from being oxidized and red blood cells from hemolysis. Vitamin E depends on bile salts, pancreatic secretion, and fat for its absorption. Vitamin E is stored in all tissues, especially the liver, muscle, and fatty tissue. About 75% of vitamin E is excreted in bile. 400 to 800 international units of vitamin E per day reduces the number of nonfatal myocardial infarctions (MIs). 200 international units per day for several years can reduce the risk of coronary artery disease (CAD), but questionable. Many still state that this vitamin protects the heart and arteries and aids in the prevention of macular degeneration because of its antioxidant effects (i.e., it inhibits the oxidation of other compounds by blocking a group of harmful chemicals called free radicals). Side effects of large doses of vitamin E may include fatigue, weakness, nausea, GI upset, headache, and breast tenderness. Vitamin E may prolong the prothrombin time (PT). Patients taking warfarin should have their PT monitored closely. Iron and vitamin E should not be taken together because iron can interfere with the body's absorption and use of vitamin E.

Vitamin K

Vitamin K1 (phytonadione) is the most active form; vitamin K2 (menaquinone) is synthesized by intestinal flora; and vitamin K3 (menadione) and vitamin K4 (menadiol) have been produced synthetically. Vitamins K1 and K2 are absorbed in the presence of bile salts. Vitamins K3 and K4 do not need bile salts for absorption. After vitamin K is absorbed, it is stored primarily in the liver. Half of vitamin K comes from the intestinal flora. Vitamin K is needed for synthesis of prothrombin and the clotting factors VII, IX, and X. Vitamin K1 (phytonadione) is the only vitamin K form available for therapeutic use and is most effective in preventing hemorrhage. The commercial drugs available for vitamin K1 are called Mephyton and AquaMEPHYTON. Vitamin K is used for two reasons: (1) as an antidote for oral anticoagulant overdose and (2) to prevent and treat the hypoprothrombinemia of vitamin K deficiency. Newborns are vitamin K deficient; thus, a single dose of phytonadione is recommended immediately after delivery. This practice is common in the United States but controversial in other countries. This can elevate the bilirubin level and cause hyperbilirubinemia with a risk of kernicterus. IV administration is dangerous and may cause death.

Vitamins

Vitamins are organic chemicals that are necessary for normal metabolic functions and for tissue growth and healing. The sale of vitamins in the United States is a multibillion-dollar business. Numerous vitamins and herbal medications are available for specialized needs. People may take vitamins to relieve tiredness or to improve general overall health; these are inappropriate indications for vitamin therapy. Vitamin supplements are not necessary if the individual is healthy and consumes a well-balanced daily diet on a regular basis; however, patients may take vitamins as a sort of "insurance". Vitamin deficiencies can cause cellular and organ dysfunction that may result in slow recovery from illness. The U.S Food and Drug Administration (FDA) requires that all vitamin products be labeled according to the amount of vitamin content and the proportion of the RDA provided by the vitamin product.

Water-Soluble Vitamins

Water-soluble vitamins are the B-complex vitamins and vitamin C. This group of vitamins is not usually toxic. Water-soluble vitamins are not stored by the body, so consistent, steady supplementation is required. Protein binding of water-soluble vitamins is minimal. Foods that are high in vitamin B are grains, cereal, bread, and meats. There are reports that B vitamins may promote a sense of well-being and increased energy as well as decreased anger, tension, and irritability. Citrus fruits and green vegetables are high in vitamin C.

Zinc

Zinc is important to many enzymatic reactions and is essential for normal growth and tissue repair, wound healing, and taste and smell. Some believe zinc can alleviate symptoms of the common cold and shorten its duration. The adult RDA is 12 to 19 mg/day. Foods rich in zinc include beef, lamb, eggs, and leafy and root vegetables. Large doses, more than 150 mg, may cause a copper deficiency, a decrease in high-density lipoprotein (HDL) cholesterol ("good" cholesterol), and a weakened immune response. Zinc can inhibit tetracycline absorption. Patients taking zinc and an antibiotic should not take them together; zinc should be taken at least 2 hours after taking an antibiotic. Patients on long-term parenteral nutrition are at risk for zinc deficiency.