chapter 53 vitamins and minerals copyright © 2014 by mosby, an imprint of elsevier inc

Chapter 53

Vitamins and Minerals

Copyright © 2014 by Mosby, an imprint of Elsevier Inc.

Organic molecules needed in small quantities for normal metabolism and other biochemical functions, such as growth or repair of tissue

Attach to enzymes or coenzymes and help them activate anabolic (tissue-building) processes

Natural sources from both plants and animals Insufficient amounts result in various

deficiencies

Vitamins

Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 2

B-complex group and vitamin C Can be dissolved in water Easily excreted in the urine Cannot be stored by the body in large amounts Daily intake required to prevent deficiencies

Water-Soluble Vitamins


Vitamins A, D, E, K Stored in the liver and fatty tissues Deficiencies occur only after prolonged

deprivation from an adequate supply or from disorders that prevent their absorption

Daily intake not required, unless one is deficient

Fat-Soluble Vitamins


Nutrient megadosing Toxic hypervitaminosis RDAs DRIs

Vitamins: Other Issues


Fat soluble Vitamin A (retinol) food sources: liver, fish, dairy

products, egg yolks, dark green leafy vegetables, and yellow-orange vegetables and fruits

Vitamin A comes from carotenes, which are found in plants (green and yellow vegetables and yellow fruits)

Retinol, retinyl palmitate, and retinyl acetate

Vitamin A


Required for growth and development of bones and teeth (morphogenesis)

Essential for night and normal vision (rhodopsin) Necessary for other processes

Reproduction Integrity of mucosal and epithelial surfaces Cholesterol and steroid synthesis

Vitamin A: Functions


Dietary supplement Infants and pregnant and nursing women

Deficiency states Hyperkeratosis of the skin Night blindness Other conditions

Skin conditions Acne, psoriasis, keratosis follicularis isotretinoin

Vitamin A: Indications


Ingestion of excessive amounts causes toxicity Irritability, drowsiness, vertigo, delirium, vomiting,

other symptoms Increased intracranial pressure in infants Generalized peeling of the skin and erythema over

several weeks

Vitamin A: Toxicity


Fat soluble “Sunshine vitamin” Responsible for proper utilization of calcium and

phosphorus Vitamin D2 (ergocalciferol)

Plant vitamin D Obtained through dietary sources

Vitamin D3 (cholecalciferol) Produced in the skin by ultraviolet irradiation

Vitamin D


Vitamin D2-containing foods Fish liver oils, saltwater fish Fortified foods: milk, orange juice, cereals Animal livers, eggs, butter, dairy products

Endogenous synthesis in the skin

Vitamin D (cont’d)


Works with parathyroid hormone to regulate absorption of and use of calcium and phosphorus

Necessary for normal calcification of bone and teeth

Vitamin D: Functions


Dietary supplement Treatment of vitamin D deficiency Treatment and correction of conditions related to

long-term deficiency: rickets, tetany, osteomalacia

Prevention of osteoporosis Other uses: treatment of osteodystrophy,

hypocalcemia, hypoparathyroidism, pseudohypoparathyroidism, hypophosphatemia

Vitamin D: Indications


Long-term ingestion of excessive amounts causes toxicity Hypertension, weakness, fatigue, headache Anorexia, dry mouth, metallic taste, nausea, vomiting,

abdominal cramps Ataxia and bone pain Can progress to impairment of renal function and

osteoporosis if left untreated

Vitamin D: Toxicity


calcifediol (Calderol) calcitriol (Rocaltrol) dihydrotachysterol (Hytakerol) ergocalciferol (Drisdol)

Forms of Vitamin D


Fat soluble Four forms: alpha, beta, gamma, and delta

tocopherol Dietary plant sources

Fruits, grains, fortified cereals, vegetable oils, wheat germ, nuts

Animal sources Eggs, chicken, meats, fish

Vitamin E


Exact biologic function of vitamin E is unknown Believed to act as an antioxidant Unproved theory that vitamin E has beneficial

effects for patients with cancer, heart disease, premenstrual syndrome, and sexual dysfunction

American Heart Association no longer recommends the use of high-dose vitamin E to prevent heart disease

Vitamin E: Functions


Dietary supplement Antioxidant Treatment of deficiency

Highest risk of deficiency in premature infants

Vitamin E: Indications


Very few acute adverse effects GI tract CNS effects

Vitamin E: Adverse Effects


Fat soluble Three types: phytonadione (vitamin K1),

menaquinone (vitamin K2), and menadione (vitamin K3)

Body does not store large amounts of vitamin K Vitamin K2 is synthesized by the intestinal flora

Dietary sources of K1

Green leafy vegetables (broccoli, cabbage, spinach, kale), cheese, soybean oils

Vitamin K


Essential for synthesis of blood coagulation factors in the liver

Vitamin K–dependent clotting factors factor II (prothrombin) factor VII (proconvertin) factor IX (Christmas factor) factor X (Stuart-Prower factor)

Vitamin K: Functions


Dietary supplementation Treatment of deficiency states (rare)

Antibiotic therapy Malabsorption

Given prophylactically to newborn infants Reverses the effects of certain anticoagulants

(warfarin) Patient becomes unresponsive to warfarin for

approximately 1 week after vitamin K administration

Vitamin K: Indications


Vitamin K1 (phytonadione, AquaMEPHYTON)

Vitamin K3 (menadione)

Forms of Vitamin K


Vitamin B complex Thiamine (B1)

Riboflavin (B2)

Niacin (B3)

Pantothenic acid (B5)

Pyridoxine (B6)

Folic acid (B9)

Cyanocobalamin (B12)

Vitamin C Ascorbic acid

Water-Soluble Vitamins


Can dissolve in water Excessive amounts excreted in the urine, not

stored in the body Toxic reactions are very rare Act as coenzymes or oxidation-reduction agents

Water-Soluble Vitamins (cont’d)


Water soluble Food sources

Enriched whole grain breads and cereals, liver, beans, yeast

Deficiencies Beriberi Wernicke’s encephalopathy

Vitamin B1 (Thiamine)


Beriberi Brain lesions, polyneuropathy of peripheral nerves,

serous effusions, cardiac anatomic changes Wernicke’s encephalopathy

Also known as cerebral beriberi

Vitamin B1 (Thiamine): Deficiencies


Poor diet Extended fever Hyperthyroidism Liver disease Alcoholism Malabsorption Pregnancy and breastfeeding

Vitamin B1 (Thiamine):Causes of Deficiencies


Essential for Carbohydrate metabolism Many metabolic pathways, including Krebs cycle

Maintains integrity of: Peripheral nervous system Cardiovascular system GI tract

Vitamin B1 (Thiamine):Functions


Treatment of thiamine deficiency Beriberi Wernicke’s encephalopathy Peripheral neuritis associated with pellagra Neuritis of pregnancy

Metabolic disorders Malabsorption Management of poor appetite, ulcerative colitis,

chronic diarrhea, and cerebellar syndrome or ataxia Oral insect repellent

Vitamin B1 (Thiamine):Indications



Green, leafy vegetables Eggs, dairy products Nuts, legumes Meats, liver Yeast, enriched whole-grain products

Vitamin B2 (Riboflavin)


Alcoholism is a major cause Deficiency also caused by:

Intestinal malabsorption Long-term infections Liver disease Malignancy Probenecid therapy

Vitamin B2 (Riboflavin):Causes of Deficiency


Converted into enzymes essential for tissue respiration

Required to activate vitamin B6 (pyridoxine) Converts tryptophan into niacin Maintains erythrocyte integrity Needed for normal respiratory functions

Vitamin B2 (Riboflavin):Functions


Deficiency results in: Cutaneous, oral, and corneal changes

• Cheilosis (chapped or fissured lips)

• Seborrheic dermatitis

• Keratitis

Vitamin B2 (Riboflavin):Deficiency


Dietary supplement Treatment of deficiency Microcytic anemia Acne Migraine headaches Many other uses

Vitamin B2 (Riboflavin):Indications


No adverse or toxic effects Large doses will discolor urine to a yellow-

orange

Vitamin B2 (Riboflavin):Adverse Effects



Beans, turkey, tuna, liver, yeast Enriched whole-grain breads and cereals, wheat germ

Also synthesized from tryptophan (an essential amino acid obtained from protein digestion)

Vitamin B3 (Niacin)


Once ingested, converted to nicotinamide Nicotinamide is converted to two coenzymes These enzymes are required for:

Glycogenolysis, tissue respiration Lipid, protein, and purine metabolism

Vitamin B3 (Niacin):Functions


Prevention and treatment of pellagra Antihyperlipidemic drug

Lowers serum cholesterol and triglyceride levels by reducing VLDL synthesis

Doses required for this effect are higher than those required for its nutritional and metabolic effects

Vitamin B3 (Niacin):Indications


Pellagra: niacin deficiency Mental: various psychotic symptoms Neurologic: neurasthenic syndrome Cutaneous: crusting, erythema Inflammation of mucous membranes: oral, vaginal,

and urethral lesions; glossitis GI: diarrhea or bloody diarrhea

Vitamin B3 (Niacin):Deficiency


Adverse effects seen when higher doses are used in the treatment of hyperlipidemia Flushing Pruritus GI distress

Vitamin B3 (Niacin):Adverse Effects


Classroom Response Question

A patient is taking isoniazid for tuberculosis. The nurse anticipates supplementation with which vitamin for the prevention of drug-induced neuritis?

A. Vitamin C (ascorbic acid)

B. Vitamin B6 (pyroxidine)

C. Vitamin K (AquaMEPHYTON)

D. Vitamin E (d-alpha tocopherol)


Water soluble Sources

Whole grains, wheat germ, yeast Fish, organ meats, poultry, meats, eggs Peanuts, nuts, vegetables, bananas

Vitamin B6 (Pyridoxine)


Composed of three compounds Pyridoxine Pyridoxal Pyridoxamine

Vitamin B6 (Pyridoxine) (cont’d)


Necessary for many metabolic functions Protein, lipid, and carbohydrate utilization Conversion of tryptophan to niacin

Necessary for integrity of peripheral nerves, skin, mucous membranes, hematopoietic system

Vitamin B6 (Pyridoxine):Function


Signs and symptoms Sideroblastic anemia Neurologic disturbances Seborrheic dermatitis Cheilosis (chapped, fissured lips) Glossitis, stomatitis Epileptiform convulsions Hypochromic microcytic anemia

Vitamin B6 (Pyridoxine): Deficiency


Inadequate intake Poor absorption Uremia, alcoholism, cirrhosis, hyperthyroidism,

malabsorption, heart failure Drug induced (isoniazid, hydralazine, others)

Vitamin B6 (Pyridoxine):Causes of Deficiency


Prevent and treat vitamin B6 deficiency Seizures that are unresponsive to usual therapy Morning sickness during pregnancy Various metabolic disorders may respond to

pyridoxine therapy

Vitamin B6 (Pyridoxine):Indications


Toxic effects occur with large doses, especially neurotoxicity

Vitamin B6 (Pyridoxine):Toxicity


Water soluble Synthesized by microorganisms present in the

body Food sources

Liver, kidney, fish, shellfish, poultry, milk Eggs, blue cheese, fortified cereals

Contained in minimal amounts in plants

Vitamin B12 (Cyanocobalamin)


Present as two different coenzymes Required for many metabolic pathways

Fat and carbohydrate metabolism Protein synthesis Growth, cell replication Hematopoiesis Nucleoprotein and myelin synthesis

Vitamin B12 (Cyanocobalamin): Function


The most common manifestation of untreated cyanocobalamin deficiency is pernicious anemia

Deficiency leads to: Neurologic damage Megaloblastic anemia

Deficiency states caused by: Malabsorption Poor dietary intake (vegetarians)

Vitamin B12 (Cyanocobalamin): Deficiency


Oral absorption of vitamin B12 (extrinsic factor) requires presence of the intrinsic factor

The intrinsic factor is a glycoprotein secreted from the gastric parietal cells

Vitamin B12 (Cyanocobalamin): Oral Absorption



Which vitamin does the nurse expect to be ordered for a patient diagnosed with Wernicke’s encephalopathy?

A. Vitamin B1 (thiamine)

B. Vitamin B6 (pyroxidine)

C. Vitamin B9 (folic acid)

D. Vitamin B12 (cyanocolbalamin)


Water soluble Natural sources

Citrus fruits and juices, strawberries Tomatoes, potatoes Broccoli, spinach, Brussels sprouts Cabbage, green peppers Liver

Can also be synthesized

Vitamin C (Ascorbic Acid)


Acts in oxidation-reduction reactions Required for several metabolic activities

Collagen synthesis Maintenance of connective tissue Tissue repair Maintenance of bone, teeth, and capillaries Folic acid metabolism Erythropoiesis

Vitamin C (Ascorbic Acid):Functions


Enhances absorption of iron Required for the synthesis of:

Lipids Proteins Steroids

Aids in cellular respiration Aids in resistance to infections

Vitamin C (Ascorbic Acid):Functions (cont’d)


Prolonged deficiency results in scurvy Gingivitis and bleeding gums Loss of teeth Anemia Subcutaneous hemorrhage Bone lesions Delayed healing of soft tissues and bones

Vitamin C (Ascorbic Acid):Deficiency


Dietary supplement Prevention and treatment of scurvy Urinary acidifier Most large controlled studies have shown that

ascorbic acid has little or no value as a prophylactic for the common cold

Vitamin C (Ascorbic Acid):Indications


Megadoses may cause: Nausea, vomiting, headache, abdominal cramps Acidified urine, with possible stone formation

Discontinuing megadoses may result in scurvy-like symptoms

Vitamin C (Ascorbic Acid):Megadoses



The nurse identifies which vitamin as most often indicated for the prevention and treatment of vision alterations?

A.Vitamin A

B.Vitamin B

C.Vitamin C

D.Vitamin D


Inorganic elements or salts Bind with enzymes or other organic molecules Help to regulate many bodily functions

Minerals


Building blocks for many body structures Required for intracellular and extracellular body

fluid electrolytes Macrominerals Microminerals, or trace elements

Minerals (cont’d)


Most abundant mineral element in the body Accounts for 2% of body weight Highest concentration in bones and teeth Efficient absorption requires adequate amounts

of vitamin D Calcium requirements high for

Growing children Women who are pregnant or breastfeeding

Calcium


Found in many foods Especially milk and dairy products Fortified cereals Calcium-fortified orange juice Sardines, salmon

Calcium: Food Sources


Essential for normal maintenance and function of Nervous, muscular, skeletal systems Cell membrane and capillary permeability

Catalyst in many enzymatic reactions

Calcium: Function


Essential in many physiologic processes Transmission of nerve impulses Contraction of cardiac, smooth, and skeletal muscles Renal function, respiration, and blood coagulation

Several other functions

Calcium: Function (cont’d)


Calcium deficiency: hypocalcemia Infantile rickets Adult osteomalacia Osteoporosis Many other conditions associated with calcium

deficiency

Calcium Deficiency


Inadequate intake of calcium or vitamin D Hypoparathyroidism Malabsorption syndrome Many other causes

Calcium: Causes of Deficiency


Calcium: Indications

Achlorhydria Alkalosis Chronic diarrhea Hyperphosphatemia Hypoparathyroidism Menopause Pancreatitis

Pregnancy and lactation

Premenstrual syndrome

Renal failure Sprue Steatorrhea Vitamin D deficiency


Adult osteomalacia Hypoparathyroidism Infantile rickets or tetany Muscle cramps Osteoporosis Renal insufficiency

Calcium: Indications (cont)


Hypercalcemia may occur with therapy Anorexia Nausea Vomiting Constipation

Severe hypercalcemia can cause: Cardiac irregularities Delirium Coma

Calcium: Toxicity


ChelationCalcium salts will bind (chelate) with tetracyclines to produce an insoluble complexIf hypercalcemia is present in patients taking digoxin, serious cardiac dysrhythmias can occur

Calcium: Drug Interactions


One of the principal cations of intracellular fluid Essential for enzyme systems associated with

energy metabolism Required for:

Nerve physiology Muscle contraction

Magnesium


Dietary sources Green, leafy vegetables Meats, seafood, milk, cheese, yogurt Bran cereal, nuts

Required in higher amounts for those with diets high in protein-rich foods, calcium, and phosphorus

Magnesium (cont’d)


Hypomagnesemia Malabsorption Alcoholism Long-term IV feedings Diuretics Metabolic disorders (hyperthyroidism, diabetic

ketoacidosis)

Magnesium:Causes of Deficiency


Nutritional supplement Treatment of magnesium deficiency

Anticonvulsant in magnesium deficiency Preeclampsia and eclampsia Tocolytic drug for inhibition of uterine contractions in

premature labor Pediatric acute nephropathy Cardiac dysrhythmias Short-term treatment of constipation

Magnesium: Indications


Adverse effects caused by hypermagnesemia Tendon reflex loss Difficult bowel movements CNS depression Respiratory distress Heart block Hypothermia

Magnesium: Adverse Effects


Widely distributed in foods Milk Yogurt Cheese Peas Meat Fish Eggs

Dietary deficiency is rare

Phosphorus


Deficiency caused by nondietary causes Malabsorption Extensive diarrhea or vomiting Hyperthyroidism Long-term use of aluminum or calcium antacids Hepatic disease

Phosphorus Deficiency


Required precursor for the synthesis of essential body chemicals

Building block for body structures Required for the synthesis of:

Nucleic acid ADP AMP ATP

Phosphorus: Functions


Responsible for cellular energy transfer Necessary for the development and

maintenance of the skeletal system and teeth Several other functions

Phosphorus: Functions (cont’d)


Treatment of deficiency states Dietary supplement

Phosphorus: Indications


Diarrhea Nausea and vomiting Other GI disturbances Confusion Weakness Breathing difficulties

Phosphorus: Adverse Effects


Trace element Essential in metabolic reactions of proteins and

carbohydrates Important for normal tissue growth and repair,

especially wound repair Found in

Red meats, liver, oysters, milk products, eggs, beans, nuts, whole grains, fortified cereals, certain seafoods

Zinc



The nurse identifies which food as high in zinc?

A.Dark green, leafy vegetables

B.Yeast

C.Peas

D.Oysters


Assess nutritional status Assess baseline lab values (H&H, WBC, RBC,

protein, albumin levels) Assess history and medication history Assess for contraindications

Nursing Implications



The nurse is providing education about the use of vitamins and minerals at a community health center. One of the participants who is a vegetarian asks if he is at risk for any deficiencies. The nurse identifies which deficiency of which substance as the most common nutritional deficiency in vegetarians?

A. Vitamin K

B. Magnesium

C. Vitamin B12

D. Calcium


Follow specific guidelines for administration, especially if parenteral

Provide nutritional counseling about necessary foods to include in the diet

Nursing Implications (cont’d)


Monitor for therapeutic responses Will vary for each vitamin and mineral

Monitor for adverse effects

Nursing Implications (cont’d)



Which substance does the nurse identify as useful in the treatment of hyperlipidemia?

A.Vitamin K

B.Magnesium

C.Vitamin B3 (Niacin)

D.Calcium


chapter 53 vitamins and minerals copyright © 2014 by mosby, an imprint of elsevier inc

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