2© paradigm publishing, inc. chapter 16 nutrition and drugs for metabolism

© Paradigm Publishing, Inc. 2

Chapter 16

Nutrition and Drugs for Metabolism


Chapter 16

Topics

• Physiology of Nutrition• Micronutrient Abnormalities• Enteral and Parenteral Nutrition• Obesity• Herbal and Alternative Therapies


Physiology of Nutrition

Evaluating Nutrition Status• Both external and internal physiological processes are

involved in weight maintenance• To evaluate nutrition status, compare “normal” body

weight for a patient’s age and development with ABW Someone within the normal range

Shows no signs of vitamin or nutrient deficiency Maintains an appropriate body weight and makeup

• Best indicator of nutrition status in children is appropriate growth (including height and weight by age) Growth charts with population averages are used



IBW (Adults)• IBW is the weight for a given height that is associated with

maximum longevity and health• To assess basic nutritional status, compare patient’s ABW

with IBW• Many times, IBW is used to determine proper weight-

based dose (sometimes ABW can be used)

To Calculate IBW in Adults

Males: IBW (kg) = 50 + (2.3 × height in inches over 5 feet)Females: IBW (kg) = 45.5 + (2.3 × height in inches over 5 feet)



BMI• Another way to assess appropriate weight for height

Used to identify both undernutrition and overnutrition• Due to increased muscle mass, some males and athletes

may not be considered overweight until BMI reaches 27• In children and teens, BMI must be compared to averages

in growth for age to be interpreted correctly

To Calculate BMI

BMI = weight (kg) / [height (m)]2



Calories• Good nutritional status is maintained through appropriate

energy intake and expenditure• Energy intake is measured in calories (kcal/kg)• Appropriate daily caloric needs depend on age

For adults, an intake of 25 kcal/kg of body weight a day is usually adequate to maintain basal metabolic rate

Malnourished and critically ill patients need more calories



Nutrients• In addition to calories, the body needs appropriate

amounts of protein, carbohydrates, fluids, micronutrients• Protein needs vary depending on age, disease state, and

clinical condition• Micronutrients include vitamins and minerals (electrolytes

and trace elements); key role in many metabolic processes• In 2005, federal government published RDIs for vitamins

and essential trace elements RDI values of micronutrients measured in mg, mcg, IU Vitamins, hormones, and other medications are in IU



Obesity and Malnutrition• Obesity is overnutrition; an obese body composition has

significantly more fat than is considered normal or healthy• Malnutrition is a lack of adequate nutrient intake to supply

basic metabolic needs; related to two conditions Overall lack of calorie or protein consumption Specific micronutrient (vitamins, minerals) deficiency

• Malnutrition is most prevalent in underdeveloped countries and in children.

• In the U.S., malnutrition is associated with disease states, acute illness, and sometimes drug therapy.



Malnutrition Conditions• Marasmus is a chronic condition caused by inadequate

caloric and protein intake over a prolonged time• Cachexia is the wasting away of muscle and fat tissue due

to starvation and the effects of cancer• Kwashiorkor is a condition in which caloric intake is

adequate, but protein intake is deficient Patients appear well nourished, but fluid accumulates

in the abdomen and feet


Micronutrient Abnormalities

About Micronutrients• Deficiencies or excesses of vitamins, minerals, and

essential fatty acids can cause significant morbidity• Fat-soluble vitamins (A, D, E, and K) accumulate in fatty

tissue and can build up in the body over time• Water-soluble vitamins (eight B vitamins and vitamin C)

are easily excreted in urine; overdose is uncommon• Vitamin and mineral deficiencies measured with lab tests• Vitamins and minerals are dietary supplements used to

treat or prevent malnutrition; they are not regulated• For signs of deficiency and toxicity, see Table 16.4



Vitamin A• Part of a family of compounds called retinoids• Necessary for vision, growth, bone formation,

reproduction, immune system function, and skin health • Sources: eggs, whole milk, butter, meat, and fish

One compound, beta carotene, can be found in vegetables (especially carrots) and fruits

• Indications: cases of deficiency; cataracts; reducing complications of HIV, measles, and malaria



Thiamin (B1) • Important coenzyme involved in carbohydrate metabolism• Sources: pork, cereal, grains, peas, beans, and yeast• Indications: cases of deficiency, which are most common

during pregnancy and during alcohol withdrawal

Riboflavin (B2) • Coenzyme in tissue respiration and normal cell metabolism• Sources: milk, cereal, green vegetables, and some meats;

made in the intestines by bacteria• Indications: cases of deficiency, migraine headaches



Niacin (B3) or Nicotinic Acid• Essential vitamin B complex for body reactions that

produce adenosine triphosphate (molecule in cellular energy production)

• Necessary for the regulation of cholesterol production and activity

• Sources: yeast, lean meats, peanuts, peas, beans, whole grains, and potatoes

• Indications: cases of deficiency, lowering of cholesterol (lowers triglycerides and LDL and raises HDL)



Pantothenic Acid (B5)• Precursor of coenzyme A• Necessary for the proper metabolism of carbohydrates,

proteins, and lipids• Sources: vegetables, yeast, cereal, organ meats (liver,

kidney, heart)• Indications: cases of deficiency



Pyridoxine (B6)• B vitamin that the body converts to the coenzymes

responsible for amino acid metabolism• Sources: most foods of plant or animal origin• Indications: cases of deficiency; types of anemia and

seizure disorders; alcoholic patients with nerve damage; patients with TB who take isoniazid, which depletes B6



Biotin (B7)• Coenzyme involved in metabolism• Deficiencies of it are associated with altered absorption,

such as short gut syndrome• Sources: green leafy vegetables, liver, carrots, almonds• Indications: cases of deficiency



Folate (B9) or Folic Acid • Essential for intracellular metabolism and the breakdown

of homocysteine (amino acid associated with CV disease); involved in serotonin (a neurotransmitter) production

• Deficiencies cause anemia and neural tube defects in a developing fetus; deleterious effects on the cardiovascular system

• Sources: green leafy vegetables, red meat; food additive• Indications: cases of deficiency, pregnant women or those

planning to get pregnant, end-stage kidney disease, depression, chronic fatigue syndrome, vitiligo



Cyanocobalamin (B12)• Coenzyme necessary for cell reproduction, normal growth,

and red blood cell production• Necessary for proper use of folate in the body; deficiency

causes pernicious anemia• Sources: meats, fish, milk, bread• Indications: cases of deficiency (common in elderly, strict

vegetarians); pernicious anemia; end-stage renal disease



Vitamin C (Ascorbic Acid) • Important in immune system function and as an

antioxidant (reduce DNA mutations that lead to cancer)• Sources: vegetables and fruits, especially citrus fruits• Indications: cases of deficiency (scurvy), improvement of

iron absorption• Indications (other): protein metabolism in premature

infants, macular degeneration, seasonal allergies, prevention of the common cold



Vitamin D • It maintains calcium and phosphate levels in the blood;

enhances intestinal absorption of calcium (bone health)• Possible role in cardiovascular health, development of

cancer, and respiratory disease• Two active forms: ergocalciferol and cholecalciferol

Ergocalciferol is in plants and yeasts; cholecalciferol is made in the skin in response to sunlight

• Sources: fortified milk, some eggs, tuna, sardines• Indication: maintenance of bone health• Taken with calcium supplements to improve absorption



Vitamin E (Alpha Tocopherol) • Fat-soluble vitamin• Sources: vegetable oils, cereals, grains, animal fat, meat,

poultry, eggs, fruits, and vegetables• Indications (topical): improvement of skin health• Indications (supported by studies): macular degeneration,

Alzheimer’s disease, reduction of risk for some types of cancer and dementia

• Indications (controversial): improvement of immune system function, diabetic retinopathy, cardiovascular disease



Vitamin K or phytonadione• Coenzyme for hepatic production of blood clotting factors• Sources: green leafy vegetables, broccoli, brussels sprouts,

plant oils, margarine• Deficiency can be caused by drug therapy• Indication: cases of deficiency, enhanced blood clotting,

reversal of the effects of warfarin (an anticoagulant)



Vitamins: Side Effects and Cautions• Side Effects: most result from excess intake and mimic

conditions of vitamin toxicity (see Table 16.4)• Side Effects (niacin products, common): flushing, hot

flashes, a sensation of prickly skin• Cautions: doses higher than the RDI of vitamin A are

category X (contraindicated) in pregnant women Vitamin A in excess of 800 mcg a day has been

associated with birth defects


Your Turn

Question 1: A patient who is undergoing chemotherapy and radiation says food does not taste good, and he seldom feels hungry. He is not eating enough calories and protein, and his muscle and fat tissue are disappearing. What is the likely diagnosis of this condition?

Answer: This condition is called cachexia. Question 2: A patient is trying to get pregnant. Her physician recommends that she take folate (B9) supplements. What is the purpose of these supplements?

Answer: Taking folate as a fetus develops can greatly reduce birth defects such as neural tube defects.



Trace Elements • Essential minerals needed for normal physiologic functions• RDI is low; easy to obtain from normal food consumption• Supplements are used mainly as additives to enteral and

parenteral nutrition formulas

Trace Elements: Chromium • Part of a complex of molecules that help regulate glucose

tolerance and insulin levels• Sources: canned foods, meat, fish, brown sugar, coffee,

tea, whole wheat bread, rye bread• Indications: case of deficiency (parenteral nutrition)



Trace Elements: Copper• Catalyst and coenzyme in various chemical reactions• Without copper, RBCs and WBCs would decline and cause

anemia, leukopenia, neutropenia• Sources: organ meats, seafood, nuts, seeds, wheat bran

cereals, grains, cocoa• Indications: cases of deficiency (parenteral nutrition)



Trace Elements: Iodine• Used to make thyroid hormones, which regulate metabolic

rates• Sources: seafood, seaweed; added to salt in developed

countries• Indications: cases of deficiency such as thyroid conditions,

radiation emergencies in which radioactive iodides were used



Trace Elements: Iron• Iron is in hemoglobin of RBCs and in myoglobin of muscle• Cofactor for neurotransmitter production; part of the

functional groups of many important enzymes• Without iron, RBC production and oxygen-carrying

capacity are reduced• Sources: red meat, poultry, fish; in some vegetables (but

many cooking and storage methods reduce its availability)• Indications: anemia (chronic disease and iron-deficiency)• Too much iron can cause hemochromatosis (a liver

condition)



Trace Elements: Manganese• Cofactor in many metabolic and enzymatic reactions• Sources: legumes, seeds, tea, whole grains, green leafy

vegetables• Indication: cases of deficiency

Trace Elements: Selenium• Incorporated into amino acids; reduces oxidative stress• Sources: broccoli, garlic, onions• Indication: additive parenteral nutrition



Trace Elements: Zinc• Cofactor in many physiologic processes, including the

synthesis of DNA and protein• Important role in immune function, wound healing, blood

clotting, reproduction, and appropriate growth• Sources: meat, seafood, dairy products, nuts, legumes,

whole grains• Indications: cases of deficiency, immune function booster,

wound healing catalyst, Wilson’s disease• Indications (lozenges): symptoms of common cold• Indication (topical): healing of burn and skin wounds



Trace Elements: Side Effects• Most side effects result from excess intake• Side effects mimic conditions of toxicity (see Table 16.4)


Enteral and Parenteral Nutrition

Nutritional Needs of Patients• Alternative ways to supply nutrition must be used when a

patient cannot be fed normally• Malnutrition will occur if a patient goes longer than 7 to 10

days without food or nutrition

Enteral Nutrition • Feeding a patient through a tube into the GI tract• Liquid nutrient is put through the tube in bolus doses

(mimics eating a meal) or continuously with enteral pump• Indications: bowel obstruction, short gut syndrome,

Crohn’s disease



Enteral Nutrition (continued)• Indication: patients in long-term care who cannot swallow

food voluntarily due to stroke or coma• IV fluids are usually given in addition to enteral feeding to

maintain hydration status• Technicians often order enteral feeding formulas

Requirement: label enteral feeding preparations with a warning not to administer them through an IV

• Enteral feeding is preferred to parenteral feeding; keeps the GI tract functional and prevents abdominal infections



Enteral Tube Feeding Sites• A manually inserted

NG tube is not comfortable ; this tube is used on a short-term basis• A surgically placed G

tube or J tube delivers enteral nutrition via the stomach or jejunum, respectively



Parenteral Nutrition • Often called TPN• Involves feeding a patient through an IV when the

digestive tract cannot be used Used for severe burns, intolerance to enteral feeding,

anorexia nervosa, IBD, pancreatitis, severe diarrhea Sometimes used in pregnancy, AIDs, cancer

• Supplies all needed fluids, electrolytes, nutrients (carbohydrates, proteins, and fats), vitamins, minerals

• Technicians in specialty or home-infusion pharmacies mix TPN solutions



Mixing of Parenteral Nutrition Solutions• Order of mixing is important

Mix all clear ingredients before cloudy ingredients Add some electrolytes and trace minerals separating to

reduce precipitating out of solution Precipitates occur when minerals bind together

and form specks that could block capillary flow Add vitamins last, just before administration

• Important to properly agitate and mix each TPN bag• TPN solutions usually administered through a surgically

placed central line



Mixing of Parenteral Nutrition Solutions (continued)

Two-in-one Mixtures

• Contain proteins (amino acids) and carbohydrate (dextrose)

• Good for 21 days if refrigerated and 7 days at room temperature

Three-in-one Mixtures

• Contain proteins, carbohydrates, lipids (fats)• Lipids are cloudy; can hide precipitates• Less stable solutions as two-in-one• Good for 7 days if refrigerated and 24 hours

at room temperature


Obesity

About Obesity• The CDC estimates that approximately 34% of adults in the

United States are obese Obesity in males: ABW is 25% or more above IBW Obesity in females: ABW is 35% or more above IBW

• Morbid obesity is when ABW is more than twice IBW• Causes of obesity: environmental, genetic, physiological,

and psychological factors• Obesity is associated with serious health risks and

mortality (see Table 16.5)


Obesity

About Obesity (continued)• Centrally distributed fat is adipose tissue that accumulates

in the abdominal area vs. in the hips, thighs, or buttocks Linked to heart disease and diabetes

• Obese people have more depression and psychological disturbances

Drugs for Obesity• Preferred treatment for obesity is lifestyle and dietary

changes; changes must be permanent to control weight• Indication (prescription): BMI over 30 (or over 27 if other

risk factors)


Obesity

Drugs for Obesity: Appetite Suppressants• Mechanism of Action: stimulate CNS; stimulate dopamine

and norepinephrine and prevent reuptake of serotonin; signal sense of fullness and satisfaction

• Route: oral; all CNS stimulants are controlled substances• Side Effects (common): headache, stomachache, insomnia,

nervousness, irritability• Side Effects (other): difficulty urinating, constipation• Caution: do not take with other drugs that also increase

serotonin (e.g., antidepressants) Could cause serotonin syndrome (dangerous condition)


Obesity

Drugs for Obesity: Lipase Inhibitor• Mechanism of Action: prevents enzymes in the intestines

from breaking down fats into a form that can be absorbed Fat then passes through intestines out of the rectum

• Indication: patients who are overweight• Routes: all are oral• Side Effects (common): fatty or oily stools, fecal

incontinence or urgency, gas, diarrhea• Caution: potential vitamin deficiencies

Technicians can help patients locate a supplement containing fat-soluble vitamins


Your Turn

Question 1: What is the reason enteral feeding is preferred to parenteral feeding?

Answer: Enteral feeding keeps the GI tract functional and prevents abdominal infections.

Question 2: A physician is writing an order for drug therapy for a morbidly obese patient who wants to lose weight. The patient is already taking an antidepressant that works by increasing the amount of serotonin in the brain. What drug therapy will not be prescribed? Why?

Answer: An appetite suppressant will not be prescribed. If taken with the antidepressant, serotonin syndrome, a serious side effect, could result.


Herbal and Alternative Therapies

• Fiber is a natural substance in fruits and vegetables Creates a sense of fullness and speeds GI motility; this

limits fat and calorie absorption Produces laxative effects, lowers cholesterol, promotes

colon health• Ephedra (also known as ma huang) is banned from sale in

the United States It is a CNS stimulant with anorexiant effects Serious effects, and even death, occurred from OTC use


Summary• Estimate body composition by comparing ABW to a

calculated IBW or by determining BMI• Recommended daily intake values are published for all

vitamins and minerals• A lack of vitamins can cause illness • Toxicity can occur with excess of fat-soluble vitamins or

some minerals• Enteral and parenteral nutrition used for malnutrition• Appetite suppressants and lipase inhibitors are for obesity

2© paradigm publishing, inc. chapter 16 nutrition and drugs for metabolism

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