Nutrition and Digestive System - Final Exam Review (Notes 1-16)

A comprehensive set of Q&A flashcards derived from the lecture notes covering nutrition basics, energy-yielding nutrients, label reading, DRIs, digestion, macronutrients and micronutrients, metabolism, and common disorders.

How do you determine the percentage of calories from fat on a nutrition label?

Multiply grams of fat by 9 kcal/g to get fat calories, then divide by total calories and multiply by 100.

How do you calculate the percentage of calories from carbohydrates or protein in a day?

Carbohydrates or protein calories divided by total daily calories, then multiply by 100 (e.g., 800/2000 × 100 = 40%).

What are the energy-yielding macronutrients and their calories per gram?

Carbohydrates 4 kcal/g, Protein 4 kcal/g, Fat 9 kcal/g. Alcohol provides 7 kcal/g but is not a nutrient.

Name the six classes of nutrients.

Carbohydrates, lipids, protein, water, vitamins, minerals.

Which nutrients are energy-yielding?

Carbohydrates, proteins, fats (and alcohol provides energy but is not a nutrient).

What is a kilocalorie?

The amount of heat needed to raise the temperature of 1 kg (or 1 L) of water by 1°C; commonly called a 'calorie' in nutrition; 1 kcal = 1000 calories.

Define nutrient density.

The amount of nutrients provided per calorie; nutrient-dense foods deliver more nutrients per calorie.

What does ‘organic’ mean in nutrition terms?

Relates to carbon-containing compounds; in food, often linked to farming methods but broadly means carbon-containing nutrients.

List the dietary principles: adequacy, nutrient density, variety, moderation, calorie control, and balance.

Core guidelines for a healthy diet: adequacy (enough nutrients), nutrient density (nutrients per calorie), variety (different foods), moderation (not excess), calorie control (energy intake), and balance (appropriate proportions of food groups).

What is fortified food vs enriched grains?

Fortified: nutrients added to a food. Enriched: nutrients added back to grains that were lost during processing.

What are dietary supplements?

Products containing vitamins, minerals, plant-derived compounds, amino acids, or concentrates/extracts intended to supplement the diet.

What is a phytochemical?

Plant-derived compounds not nutrients but may promote health benefits.

What are whole grains?

Grains with intact or minimally processed seeds (e.g., whole grains) that retain bran, germ, and endosperm.

DRIs and the related standards: RDA, AI, UL, EAR, EER, AMDR.

DRIs are reference intakes; RDAs meet nearly all healthy individuals; AI used when insufficient data for RDA; UL is max unlikely to harm; EAR meets 50%; EER estimates energy needs; AMDR provides carbohydrate, fat, and protein ranges.

What is AMDR?

Acceptable Macronutrient Distribution Ranges for carbs, fats, and proteins (e.g., carbs 45–65%, fat 20–35%, protein 10–35%).

What information is required on all U.S. food labels?

Product name, manufacturer's name and address, amount in package, ingredients list (by weight), and country of origin; claims may include health, structure/function, and nutrient content claims.

What is Daily Value (DV)?

A labeling reference based on RDAs for a 2,000 kcal diet, used to help gauge nutrient intake for labeling purposes.

What is an essential nutrient?

A nutrient the body cannot produce in adequate amounts and must be obtained from the diet.

Define ‘refined’ vs. ‘whole’ foods.

Refined foods have been processed to remove parts of the grain or nutrient-rich components; whole foods retain more natural nutrients and fiber.

What is the purpose of the six macronutrient and calorie framework in nutrition policy?

DRIs and AMDRs guide population adequacy, dietary planning, evaluation of intakes, and product labeling.

What are the 6 nutrient classes and which are energy-yielding?

Carbohydrates, lipids, protein, water, vitamins, minerals; energy-yielding are carbohydrates, lipids, and protein (and alcohol provides energy).

What is a calorie vs a kilocalorie in nutrition labeling?

A kilocalorie (often called a calorie on labels) is the energy needed to raise the temperature of 1 kg of water by 1°C.

What are the two main types of essential fatty acids and examples?

Linoleic acid (omega-6) and alpha-linolenic acid (omega-3); found in vegetable oils, seeds, and certain fats.

What are the two primary organs that secrete bile and bicarbonate to aid digestion?

Liver produces bile; pancreas releases bicarbonate and digestive enzymes; gallbladder stores bile.

Where does carbohydrate digestion begin and which enzyme is involved?

In the mouth; salivary amylase starts starch digestion.

Where does fat digestion begin and which enzyme acts in the intestine?

Primarily in the small intestine; pancreatic lipase acts on fats after emulsification by bile.

Where does protein digestion begin and which enzyme activates in the stomach?

In the stomach; hydrochloric acid denatures proteins and activates pepsinogen to pepsin.

What are the three main macronutrient digestion enzymes in the small intestine?

Lipase (fats), proteases (proteins), carbohydrases (carbohydrates).

What are the roles of the small intestinal villi and microvilli?

Villi absorb nutrients into blood and lymph; microvilli (brush border) host final digestion enzymes and further increase surface area.

What are chylomicrons and how do fats enter circulation?

Fats are reassembled into triglycerides in enterocytes, packaged into chylomicrons, which enter the lymphatic system via lacteals and then the bloodstream.

What is lipogenesis?

Conversion of excess carbohydrates and proteins into fatty acids and stored as fat.

What is beta-oxidation?

Breakdown of fatty acids in mitochondria to produce ATP for energy.

Are fats used directly by the brain for energy?

The brain primarily uses glucose; fats contribute to brain structure and can form ketones during fasting.

What is olestra and what are its pitfalls?

A synthetic fat substitute; can cause digestive issues and block absorption of fat-soluble vitamins; labeling warnings required.

What are common fat-related label terms and their meanings?

Fat-free (<0.5 g fat per serving); saturated fat-free (<0.5 g sat fat); low-fat (≤3 g fat per serving); light (≥50% less fat or ≥1/3 fewer calories).

What are the three lipids and their roles?

Triglycerides (energy storage and fuel), phospholipids (cell membranes and lipoprotein transport), sterols (cholesterol; hormone and vitamin D synthesis).

Describe the energy density of fats and how it compares to carbs and protein.

Fat provides 9 kcal/g, more energy-dense than carbs or protein (4 kcal/g each).

What are the three elements that make up lipids and how do they differ from carbohydrates?

Carbon, hydrogen, oxygen; lipids have less oxygen, which makes them more energy-dense than carbohydrates.

What is the difference between saturated, monounsaturated, polyunsaturated, and trans fats?

Saturated: all single bonds; typically solid at room temperature. Monounsaturated: one double bond. Polyunsaturated: two or more double bonds. Trans fats: partially hydrogenated fats with trans double bonds.

What is hydrogenation in fats?

Addition of hydrogen to unsaturated fats to make them more solid and shelf-stable, creating potential trans fats.

What are essential fatty acids and examples?

Essential fats that must be obtained from the diet: linoleic acid (LA, omega-6) and alpha-linolenic acid (ALA, omega-3).

What is oxidation in food and its significance?

Loss of electrons; in foods, leads to free radicals and potential nutrient damage if not controlled.

What are antioxidants and give examples?

Compounds that prevent oxidative damage; vitamin E, vitamin C, beta-carotene, polyphenols, etc.

What is the role of the lipid bilayer in the cell membrane as an emulsifier?

Hydrophilic heads face water, hydrophobic tails face inward, creating a barrier that also helps emulsify fats during digestion.

What is the function of the liver, gallbladder, pancreas in digestion?

Liver makes bile; gallbladder stores and releases bile; pancreas provides bicarbonate and digestive enzymes.

What are chylomicrons, VLDL, LDL, and HDL?

Chylomicrons transport dietary fats via lymph; VLDL transports triglycerides from liver; LDL carries cholesterol to tissues (often 'bad'); HDL carries cholesterol to the liver (often 'good').

What is the AMDR for protein and an example calculation for a 2000 kcal diet?

AMDR for protein: 10–35% of total calories; 2000 kcal → 50–175 g protein per day (since 1 g protein = 4 kcal).

What are complete vs incomplete proteins?

Complete proteins contain all 9 essential amino acids in adequate amounts (e.g., meat, dairy, soy); incomplete lack one or more essential amino acids (most plant foods).

What are the two main protein digestion stages and what happens in the stomach?

In the stomach, HCl denatures proteins and activates pepsinogen to pepsin, which begins breaking proteins into polypeptides.

What is Kwashiorkor vs Marasmus?

Kwashiorkor: protein deficiency with edema; Marasmus: energy deficiency with severe wasting.

What are complete plant proteins?

Some plant foods are complete (e.g., quinoa, soy) because they provide all essential amino acids in adequate amounts.

How are amino acids absorbed and used after digestion?

Amino acids are absorbed into the bloodstream, transported to the liver, then released to cells for protein synthesis or energy as needed.

What is the role of proteins beyond energy and structure?

Enzymes, hormones, transport molecules (e.g., hemoglobin), antibodies, fluid balance, and immune function.

How do you calculate daily protein needs using ideal weight?

Convert weight to kg, then multiply by 0.8 g/kg; example: 150 lb → 68.2 kg; 68.2 × 0.8 ≈ 55 g/day.

What is the process of fat absorption in the small intestine?

Fat is emulsified by bile, digested by pancreatic lipase, absorbed as fatty acids and monoglycerides, reassembled into triglycerides, packed into chylomicrons, and enter the lymph.

What are metabolic pathways for alcohol metabolism?

ADH (alcohol dehydrogenase) and MEOS (microsomal ethanol-oxidizing system) — both convert alcohol to acetaldehyde and then acetate.

Is alcohol considered a nutrient?

No; it provides calories (7 kcal/g) but is a toxic metabolic byproduct and not a nutrient.

What are the health risks of excessive alcohol consumption?

Liver disease, nutrient deficiencies, increased risk of certain cancers, brain damage, fetal alcohol spectrum disorders during pregnancy.

What is a standard drink in alcohol terms?

About 13–14 grams of ethanol (roughly 5 oz wine, 12 oz beer, 1.5 oz 80-proof liquor).

What are electrolytes and the three major ones?

Electrolytes regulate fluid balance and nerve/muscle function; major ones are sodium, potassium, and chloride.

What happens with electrolyte imbalance?

Symptoms include confusion, fatigue, headaches, muscle cramps, nausea, and more.

What percentage of the body is water and where is it located?

About 50–75% of body weight; distributed in blood, muscles, brain, bones, and adipose tissue.

What are the main functions of water in the body?

Solvent, transporter, waste removal, lubricant, temperature regulation, digestion participation, and pH balance.

What is the difference between water-soluble and fat-soluble vitamins?

Water-soluble vitamins dissolve in water, are not stored in large amounts, and are excreted in urine; fat-soluble vitamins are stored in liver/adipose tissue and can accumulate.

List the water-soluble vitamins.

Thiamin (B1), Riboflavin (B2), Niacin (B3), Vitamin B6, Pantothenic acid, Folate, Biotin, Vitamin B12, and Vitamin C.

List the fat-soluble vitamins.

Vitamins A, D, E, and K.

What is bioavailability?

The extent to which a nutrient is absorbed and utilized by the body.

What are the major minerals and an example of a trace mineral?

Major minerals: calcium, chloride, magnesium, phosphorus, potassium, sodium. Trace minerals: chromium, fluoride, copper, iodine, iron, manganese, molybdenum, selenium, zinc.

Where is most calcium stored in the body?

In bones and teeth (about 99% of bodily calcium).

What is the difference between heme and non-heme iron?

Heme iron (from animal sources) is more readily absorbed; non-heme iron (from plants/fortified foods) is less bioavailable.

How can vegan/vegetarian diets affect iron status and why?

Plant-based iron (non-heme) has lower bioavailability; absorption is influenced by other dietary factors.

What is ferritin, transferrin, and the transferrin receptor used for?

Ferritin stores iron; transferrin transports iron in blood; transferrin receptor helps measure iron status.

What is osteoporosis and what nutrient deficiency contributes?

A condition of brittle bones due to loss of bone tissue, often linked to calcium and vitamin D deficiencies.

What is the role of vitamin D in bone health?

Supports calcium absorption and bone health; produced in skin or obtained from diet/supplements.

What is biliary function in fat digestion?

Bile emulsifies fats to increase surface area for lipase to act.

What is the role of the pancreas in digestion?

Releases bicarbonate to neutralize intestine contents and enzymes that digest carbohydrate, protein, and fat.

What is a disaccharide and give examples?

A carbohydrate made of two monosaccharides; examples: maltose, sucrose, lactose.

What is a monosaccharide?

Simple sugar units such as glucose, fructose, and galactose.

What is a polysaccharide?

Carbohydrates made of many monosaccharide units; examples include starch, glycogen, and cellulose.

What is raffinose and stachyose?

Nondigestible oligosaccharides that occur in some beans and legumes.

What is glycogen and where is it stored?

A highly branched storage polysaccharide stored in liver and muscles.

What is the difference between dietary fiber and functional fiber?

Dietary fiber occurs naturally in foods; functional fiber is isolated or synthesized and added to foods for health benefits.

What are soluble vs insoluble fiber and their benefits?

Soluble fiber dissolves in water and can help regulate blood glucose and cholesterol; insoluble fiber adds bulk and aids bowel regularity.

What is the function of the large intestine in relation to water absorption?

Absorbs water and electrolytes; houses gut bacteria and forms feces.

What are some common GI disorders listed in the notes?

Celiac disease, cystic fibrosis, constipation, diarrhea, diverticular disease, IBS, IBD, hemorrhoids, leaky gut syndrome.

What is gastroenteritis and what are common causes?

Gastrointestinal infections caused by viruses, bacteria, or parasites.

What is a gastric bypass and its nutritional implications?

Surgical procedure that alters stomach and intestine; can lead to iron and vitamin B12 deficiencies and longer-term mineral deficiencies.

What is dysbiosis?

An imbalance in the gut microbiota.

What are probiotics, prebiotics, and postbiotics?

Probiotics: live beneficial microbes; prebiotics: substrates that promote growth of beneficial microbes; postbiotics: metabolic by-products of microbiota.

What is the role of carbohydrates in blood cholesterol and heart health?

High-fiber, whole-grain carbs can lower LDL and support heart health; carbohydrate quality affects cholesterol levels.

What is the difference between simple and complex carbohydrates?

Simple: monosaccharides and disaccharides; Complex: polysaccharides and oligosaccharides.

How can you estimate starch content from a nutrition label?

Subtract dietary fiber and sugars from total carbohydrates to approximate starch per serving.

What is the function of enzymes in digestion?

Enzymes catalyze the breakdown of macronutrients (amylases, proteases, lipases) in the digestive system.

What is water's role in digestion and metabolism?

Acts as solvent, participates in chemical reactions, transports nutrients, and helps regulate temperature.

What is meant by the term “thirst mechanism”?

The physiological process that signals the need to drinkwater when body fluids are low.

What is the role of the brain in hunger and appetite regulation?

Ghrelin increases hunger; leptin signals fullness; hormones and neural pathways coordinate hunger and appetite.

What is atherosclerosis?

Chronic disease where plaque builds up in arteries, narrowing and hardening them.

What is a myocardial infarction (heart attack)?

Blockage of blood flow to part of the heart muscle causing tissue damage.

What is a stroke?

Interruption of blood flow to part of the brain, leading to brain cell death if not resolved.

What is the role of dietary fats in heart health according to the notes?

Healthy fats (MUFA and PUFA, including omega-3/6) can support heart health; limit saturated and trans fats.