Nutrition Exam Review Notes
Essential Nutrients and Energy
Essential nutrients definition: nutrients that the body cannot make in adequate amounts and must be supplied daily in the diet.
Some essential nutrients can provide energy (calories) to the body.
Six essential nutrients: carbs, fats, proteins, vitamins, minerals, water.
Only three of the six provide energy: carbs, fats, and proteins.
Carbohydrates: ext{energy per gram} = 4 ext{ kcal/g}
Proteins: ext{energy per gram} = 4 ext{ kcal/g}
Fats: ext{energy per gram} = 9 ext{ kcal/g}
Functions of essential nutrients (three jobs):
Provide energy
Support metabolism/metabolic reactions
Build and repair tissues (proteins are most important for tissue synthesis)
Roles of adipose tissue and fats beyond energy:
Insulation against temperature extremes
Cushioning and protection of vital organs
Involvement in cell membranes, hormones, and overall cell function
Physiological relevance for exam: monitor weight/BMI for health risk assessment; knowledge of digestion/absorption and metabolism is foundational.
Carbohydrates, Glycogen, and Glucose Metabolism
Main function of carbohydrates: provide energy (carbohydrates as fuel). When broken down, body uses glucose as its energy source.
Glycogen: stored form of carbohydrates (stored glucose).
Primary storage site: liver (reserve of glucose)
Secondary storage: muscles
Excess glycogen storage can be converted to adipose tissue (fat) if energy needs are exceeded.
Glycogen use: activated when blood glucose is low.
Hormone that converts glycogen to glucose to raise blood sugar: glucagon (produced by the pancreas). Opposite of insulin, which lowers blood glucose.
Dietary fiber: a carbohydrate that the body cannot digest for energy but provides bulking/roughage to stool; helps with satiety, constipation prevention, and colon health. Fiber is not broken down into glucose.
Monosaccharides and absorption: most carbohydrates (except fiber) are broken down into monosaccharides (single sugar units) before absorption and conversion to glucose in the bloodstream.
Normal fasting blood glucose range: 70 ext{ to } 110 ext{ mg/dL}
Hypoglycemia: blood glucose below the normal range (below 70 ext{ mg/dL}).
Glycogen Storage, Use, and Hormonal Regulation
When energy needs are met, excess carbohydrates are converted into glycogen and stored in the liver and muscles.
When glycogen stores in liver/muscle are full, excess carbohydrates are converted to fats (adipose tissue).
Glucagon raises blood glucose by promoting glycogenolysis (glycogen to glucose).
Insulin lowers blood glucose by promoting glucose uptake and storage.
Dietary Fiber and Glycemic Control
Dietary fiber: carbohydrate that isn’t digested for energy; provides bulk to stool, satiety, and health benefits.
Benefits of dietary fiber:
Weight management (satiety)
Reduces constipation risk
May reduce risk of colon-related diseases
Energy Balance, Lipids, and Fat Metabolism
Fat is the most concentrated energy source: 9 ext{ kcal/g}
Adipose tissue: body’s stored fat; serves for energy storage, insulation, and cushioning.
Satiety: feeling of fullness; fats contribute to satiety and meal satisfaction.
Fat-soluble vitamins: A, D, E, K
Stored in the liver
Higher risk of toxicity with excessive intake (A and D are the most problematic in practice)
Lipids, Cholesterol, and Digestion
Body fat and cholesterol:
LDL (low-density lipoprotein): often labeled as “bad” cholesterol; promotes plaque buildup in arteries (atherosclerosis).
HDL (high-density lipoprotein): labeled as “good” cholesterol; helps remove cholesterol from arteries and reduce plaque risk.
Saturated fats tend to raise LDL and total cholesterol and increase atherosclerosis risk.
Unsaturated fats are preferred for heart health.
Digestion of fats: emulsification is required to break fats into smaller droplets.
Bile, produced by the liver and stored in the gallbladder, emulsifies fats in the small intestine.
Important clinical note: in nutrition-focused nursing, monitor fat intake quality (saturated vs unsaturated) to manage cardiovascular risk.
Nutrients and Body Structure
Minerals and their roles:
Calcium: bone/teeth health; helps prevent osteoporosis; also involved in clotting and muscle contraction.
Iron: essential component of hemoglobin; iron deficiency can cause anemia and reduced oxygen delivery.
Potassium: essential electrolyte; critical for nerve impulses, muscle contraction (including the heart); deficiency can cause life-threatening dysrhythmias; sources include bananas, sweet potatoes, cantaloupe.
Sodium: electrolyte; high intake can cause hypertension and edema; restrict in certain conditions (e.g., heart disease, kidney disease).
Iodine: component of table salt; required for synthesis of thyroid hormones T3 and T4.
Hormonal and metabolic interactions:
Thyroid hormones (T3/T4) depend on iodine; iodine-rich salt contributes to thyroid function.
Electrolyte balance (sodium and potassium) influences fluid balance, blood pressure, and cardiac function.
Fluid and Diet Modification in Practice
DASH diet: a commonly used low-sodium dietary approach to support cardiovascular health.
High-sodium foods to avoid: canned foods, fried foods, pickled items, processed meats, deli meats, etc.
Low-sodium foods: baked or grilled items tend to be lower in sodium.
Sodium and iodine in table salt: iodized salt supports thyroid hormone production.
Potassium watch: adequate intake supports cardiac rhythm; excessive intake can also have issues; balance is key.
Nutrition in Special Populations and Life Stages
Infants (0-6 months and beyond):
Iron-fortified cereals are commonly introduced after 4–6 months to replenish iron stores; they have a low allergy risk.
Introduce new foods one at a time, about every 2–3 days, to monitor for allergies.
Infants have an airway roughly the size of a pinky; aspiration risk is high; never leave a baby unattended while eating.
Avoid high-risk choking foods for infants (hot dogs, grapes, carrots, popcorn).
Adolescents: iron and calcium deficiencies are common, especially in females due to menstruation; ensure adequate intake.
Dietetics workflow in practice:
Initial nutrition assessment is performed by the RN.
Dietitian/nutritionist consult is not automatic; only when there is a nutritional need or problem.
LVNs perform ongoing assessments.
Diet orders and modification:
A diet order is required to modify any diet (frequency, texture/consistency, or nutrient value).
Diets can be advanced as tolerated (GI assessment focused): look for bowel sounds, passage of flatus, bowel movements, hunger, absence of nausea/vomiting, abdominal distension, etc.
If patient cannot tolerate a diet, revert to previous level.
Diet types and transitions:
Clear liquid diet: post-op until peristalsis resumes; see-through at room temperature; acceptable items include bouillon, clear juices (apple juice), gelatin, popsicles, black coffee/tea, and certain sips.
Full liquid diet: transition after clear liquids; includes any liquid at room temperature (e.g., dairy-based liquids, creamy soups strained, ice cream, juice without pulp); low in fiber and iron.
Soft/low-residue diet: intermediate step between liquids and regular diet; nutritionally adequate but generally low in fiber.
High-fiber diet: used to treat constipation; includes nuts/seeds, legumes, and high-fiber fruits/vegetables (skin on produce often provides more fiber).
Fluid restriction and risk for overload:
Highest risk conditions: end-stage renal disease (kidney failure) and congestive heart failure (heart pump function).
In fluid-restricted patients, strategies to manage thirst include: offering iced chips, oral care, cold fruits/vegetables, gum or hard candies, and scheduled sips as allowed.
Eating disorders:
Anorexia nervosa: self-imposed starvation; marked restriction and fear of weight gain; possible excessive exercise.
Bulimia nervosa: binge eating followed by purging or other weight-control behaviors; loss of control during binge episodes.
Diabetes mellitus nutrition:
Type 1 diabetes mellitus (T1DM): autoimmune, insulin-dependent; cannot produce adequate insulin; needs daily insulin.
Type 2 diabetes mellitus (T2DM): insulin resistance or insufficient insulin production; managed with lifestyle changes and/or medications; carbohydrate counting is a practical education point.
Hypoglycemia risk: if a person on insulin does not consume enough carbohydrates, hypoglycemia can occur; glucose targets typically 70 ext{ to } 110 ext{ mg/dL}.
Hypoglycemia symptoms can involve brain function (headache, disorientation, blurred vision, lightheadedness, vertigo, weakness, anxiety); monitor glucose levels when symptoms arise.
Alcohol and hypoglycemia: alcohol increases hypoglycemia risk by promoting insulin release and impeding liver glucose production; it should be consumed with food.
Dumping syndrome: can occur after partial or total gastrectomy; contents empty into the small intestine too quickly; symptoms include diarrhea, blood pressure shifts, etc.; management includes lying down after meals, small frequent meals, and avoiding rapid gastric emptying.
Lactose intolerance: lack of lactase enzyme; lactose sugar digestion is impaired.
Nutritional support modalities:
Oral nutrition preferred; when insufficient, enteral nutrition (tube feeding) is preferred over parenteral; parenteral nutrition is IV-based
Enteral nutrition (tube feeding): uses GI tract; feeding ostomy (G-tube, J-tube) may be required for certain patients
Parenteral nutrition (PN): IV nutrients; two main forms: peripheral PN (PPN) and total PN (TPN)
PPN: peripheral vein; typically short-term (<3 weeks) and not nutritionally complete
TPN/central PN: central venous catheter (often via superior vena cava); nutritionally complete and used when long-term or full nutrition is needed
NG tube placement checks and safety:
Placement verification: gold standard is radiographic confirmation (X-ray)
Alternative checks: pH testing of aspirate (pH 4–5 indicates gastric placement); oscillatory method as a supplementary check (not universally recommended by ATI)
Safety: keep head of bed at 30 degrees or higher during tube feedings (Semi-Fowler/Low-Fowler)
Malnutrition risk in care settings:
Highest risk in patients unable to feed themselves (complete dependence)
Risk amplified by aging populations (thirst mechanism decreases, dietary restrictions, physical or cognitive impairment, wound healing demands)
Nursing role includes advocating for patients and coordinating with CNAs to ensure adequate nutrition and feeding support
Abbreviations and terminology:
CPN: central parenteral nutrition; often used interchangeably with TPN in practice
TPN: total parenteral nutrition; nutritionally complete, delivered via a central line
GI tract functioning matters for enteral feeding; if the GI tract is nonfunctional, parenteral nutrition is indicated
Quick recall for test readiness:
Identify energy sources and their calories per gram: 4 ext{ kcal/g (carbs)}, 4 ext{ kcal/g (protein)}, 9 ext{ kcal/g (fat)}
Know the six essential nutrients and the three energy-providing ones
Be able to explain glycogen storage and the role of glucagon and insulin in glucose regulation
Distinguish between LDL and HDL with simple memory aids: LDL = “loser” cholesterol; HDL = “healthy” cholesterol
Understand the differences between clear liquid and full liquid diets, as well as when each is used in post-operative care
Recognize red-flag foods for infants (aspiration risk) and the rationale for one-new-food-at-a-time introduction
Differentiate Type 1 and Type 2 diabetes and the importance of carbohydrate counting
Recall the main indications for enteral vs parenteral nutrition and the placement/safety checks for NG tubes
Summary of Practical Exam Points and Scenarios
If a patient has high sodium intake foods (canned, fried, processed, deli meats, pickled), choose lower-sodium options (baked/grilled, fresh produce) and consider DASH diet recommendations.
For a patient with risk factors for cardiovascular disease, emphasize the shift from saturated to unsaturated fats and monitor LDL/HDL implications.
In pediatric nutrition, always assess for aspiration risk and avoid hazardous foods for infants; introduce foods gradually with allergy monitoring.
In diabetes management, emphasize carbohydrate counting and monitoring for hypoglycemia, especially when insulin doses may not be matched to carbohydrate intake or alcohol is consumed.
In malnutrition risk scenarios, remember that patients who cannot feed themselves are at the highest risk and require proactive nursing support and nutrition interventions.
In tube feeding, always verify placement, ensure safe head-of-bed angle, and monitor GI tolerance before advancing the diet; know when to switch from enteral to parenteral if GI function fails.
Key Terms and Concepts to Memorize
Glucagon, insulin, hypoglycemia, hyperglycemia, peristalsis, T3/T4, iodine, thyroid hormones, DASH diet, ostomy, feeding ostomy, G-tube, J-tube, NG tube, X-ray placement, pH testing, oscillatory method, anorexia nervosa, bulimia nervosa, type 1 diabetes, type 2 diabetes, carbohydrate counting, dumping syndrome, lactose intolerance, enteral nutrition, parenteral nutrition, PPN, TPN, central venous catheter, BMI, metabolic rate, satiety, adipose tissue, LDL, HDL, vegetarian/vegan nutrition considerations, essential amino acids.