Nutrition Final Study Guide

Six Classes of Nutrients

Carbohydrates, Lipids (fats), Proteins, Vitamins, Minerals, and Water.

Calorie Content

Carbohydrates (4 kcal/g), Protein (4 kcal/g), Fat (9 kcal/g), Alcohol (7 kcal/g).

AMDRs

Carbs: 45–65%; Fat: 20–35%; Protein: 10–35%

Scientific Method

Observation, Hypothesis, Experiment, Results, and Theory.

Credible Sources

Peer-reviewed journals, Registered Dietitians (RD/RDN), and government/university sites (.gov, .edu).

Food Choice Factors

Taste, cost, convenience, culture, emotions, and health benefits.

Phytochemicals

Non-nutrient plant compounds (like lutein or lycopene) that reduce disease risk.

DRI Types

EAR: Group requirements (50%), RDA: Individual goals (98%), AI: Used when RDA isn't set, and UL: Maximum safe limit.

2020-2025 Dietary Guidelines

Follow a healthy pattern at every life stage; focus on nutrient density; stay within calorie limits.

MyPlate

Visual guide: 1/2 plate fruits/veg, 1/4 grains, 1/4 protein, plus dairy

Label Reading

Ingredients are listed by weight (descending). %DV based on a 2,000-calorie diet (5% is low, 20% is high).

Nutrition Claims

Nutrient Content: "Low fat," "High fiber." ; Health: Links food to disease (e.g., "Soluble fiber may reduce heart disease"). ; Structure/Function: Cannot mention disease (e.g., "Calcium builds strong bones").

Organs

Mouth (chewing), Esophagus (transit), Stomach (churning/acid), Small Intestine (primary absorption), Large Intestine (water reabsorption).

Accessory Organs

Liver (makes bile), Gallbladder (stores bile), Pancreas (makes enzymes & bicarbonate).

Secretions

Enzymes (breakdown), Bicarbonate (neutralizes acid), HCl (denatures protein), Bile (emulsifies fat).

Microbiota

Trillions of bacteria in the gut. Probiotics are live bacteria; Prebiotics are "food" for them (fiber).

GERD

Acid reflux into esophagus.

Celiac

Immune reaction to gluten; damages villi.

Lactose Intolerance

Lack of lactase enzyme to break down milk sugar.

Types of Carbohydrates

Monosaccharides, Disaccharides, and Polysaccharides

Monosaccharide

Glucose, Fructose, Galactose.

Disaccharide

Sucrose, Lactose, Maltose.

Polysaccharide

Starch, Glycogen, Fiber.

Fiber

Soluble (lowers cholesterol) vs. Insoluble (aids bowel movements).

Ways Fiber can help:

• Better Digestion: They add bulk to stool, preventing constipation and keeping you regular.

• Heart Health: They help lower cholesterol by trapping it in the gut so it can't be absorbed.

• Blood Sugar Control: They slow down sugar absorption, which prevents energy crashes and helps manage weight by keeping you full longer.

Refined carbs can cause:

• Quick Hunger: They digest so fast you don't stay full, which can lead to weight gain.

• Sugar Spikes: They cause your blood sugar to "crash and burn"—a quick energy high followed by an energy crash.

• Health Issues: Eating too many over time increases your risk for Type 2 diabetes and heart disease.

unrefined carbs can provide:

• Long-Lasting Energy: They digest slowly, giving you a steady flow of energy instead of a quick spike and crash.

• Weight Control: The fiber keeps you fuller for longer, so you’re less likely to overeat.

• Disease Prevention: They help lower the risk of heart disease, Type 2 diabetes, and digestive issues.

Digestion and Absorption of Carbs

1. Mouth: Digestion starts here. Chewing breaks food down, and an enzyme in your saliva starts breaking starches into smaller sugars.

2. Stomach: Not much happens here for carbs; the stomach acid actually stops the saliva enzyme from working.

3. Small Intestine: This is the main event. The pancreas sends in more enzymes to break all carbs down into monosaccharides (single sugars like glucose).

4. Absorption: Those single sugars pass through the wall of the small intestine and enter your bloodstream.

5. Liver: The blood carries the sugars to the liver, which converts them all into glucose to be used for energy or stored.

How does insulin and glucagon help regulate blood glucose?

Insulin lowers blood glucose; Glucagon raises it.

Diabetes types

Type 1 (no insulin made); Type 2 (insulin resistance).

causes and health consequences of type 1 diabetes

• Cause: An autoimmune issue where the body’s immune system attacks and destroys the cells in the pancreas that make insulin. The body ends up with no insulin.

• Consequence: Without insulin, glucose (sugar) stays trapped in the blood instead of entering cells for energy.

causes and health consequences of type 2 diabetes

• Cause: Insulin resistance. The body makes insulin, but the cells "ignore" it. This is usually linked to genetics, inactivity, and excess body fat.

• Consequence: The pancreas wears out from trying to overproduce insulin, leading to high blood sugar levels.

Carbohydrate Sources

• Starches: Bread, rice, pasta, potatoes, corn, and oats.

• Sugars: Fruits (fructose), milk (lactose), honey, and table sugar (sucrose).

• Legumes: Beans, lentils, and peas (these are "double duty" as they have protein too).

Fiber Sources

(All come from plants)

• Whole Grains: Brown rice, quinoa, oatmeal, and 100% whole-wheat bread.

• Legumes: Black beans, chickpeas, and lentils (some of the highest fiber sources).

• Fruits: Berries (especially raspberries), apples, and pears (keep the skin on!).

• Vegetables: Broccoli, leafy greens, carrots, and Brussels sprouts.

Triglycerides (95% of the fats you eat)

These are the main form of energy storage in the body. They consist of a "backbone" with three fatty acids attached.

Saturated Fat

Solid at room temperature. Found in animal fats (butter, lard, fatty meats) and tropical oils (coconut oil).

Unsaturated Fat

Liquid at room temperature (healthy fats). Found in vegetable oils (olive, canola), nuts, seeds, and avocados.

Trans Fat

Man-made and unhealthy. Found in fried foods and packaged snacks.

Phospholipids

These act as emulsifiers, meaning they help water and oil mix. They make up your cell membranes.

Sources: Found naturally in egg yolks, soybeans, and peanuts. (The most common one is called Lecithin).

Sterols (Cholesterol)

Characteristics: These don't provide energy. They are used to make bile, vitamin D, and hormones (like testosterone).

Sources:

• Found ONLY in animal products (meat, eggs, dairy).

• Plants have "plant ____" which can actually help lower your cholesterol.

Digestion and absorption of lipids

• Digestion:

• Mouth & Stomach: Very little happens here. The fat mostly just floats on top of other stomach contents.

• Small Intestine: This is where the real work happens.

  • Bile: The gallbladder squirts bile into the small intestine. Bile acts like dish soap—it emulsifies (breaks up) big fat globs into tiny droplets so enzymes can reach them.

  • Pancreatic Lipase: The pancreas sends in an enzyme called lipase to chop the tiny fat droplets into smaller pieces (fatty acids).

• Absorption:

  • The small pieces are absorbed into the cells of the small intestine.

  • The Twist: Unlike carbs or protein, most fats are too big to go straight into the blood. They are packed into "transport ships" called chylomierons and enter the lymph system first before eventually reaching the blood.

Lipoproteins

carry cholesterol and triglycerides to cells in your body. Types are: LDL (bad—drops cholesterol in arteries); HDL (good—removes cholesterol).

Lipid functions

• Energy Storage

• Protection & Insulation

• Cell Structure

• Hormone Production

• Nutrient Transport

Effects of lipids on health

Heart Disease (The Main Concern):

• Saturated Fats (butter, fatty meats) and Trans Fats (processed snacks) can raise LDL ("bad") cholesterol, which clogs arteries.

• Unsaturated Fats (olive oil, fish, nuts) help lower LDL and raise HDL ("good") cholesterol, protecting your heart.

• Weight Management: Because fats are energy-dense (9 kcal/g), eating too many—even healthy ones—can lead to weight gain and obesity.

• Brain & Eye Health: Certain lipids (like Omega-3s from fish) are essential for brain function and keeping your vision sharp.

• Inflammation:

  • Trans fats can increase inflammation in the body.

  • Omega-3s help reduce inflammation.

CVD Risk

High LDL, smoking, inactivity, hypertension, saturated fat intake.

Mediterranean Diet

High in healthy fats (olive oil, nuts), fish, and plants; low in red meat.

Alcohol

1 drink = 12oz beer, 5oz wine, or 1.5oz liquor. Moderate:1/day for women, 2/day for men.

Alcohol metabolism in men vs. women

Men break down alcohol faster because they have more of the "cleaning" enzyme in their stomachs to destroy it before it hits the blood. Women have less of this enzyme and less water in their bodies to water the alcohol down. This means women’s bodies hold onto more alcohol, making it hit their systems harder and stay there longer

Protein Structure

Chains of amino acids. Denaturation is the unfolding of protein (by heat/acid).

Absorption and Digestion of Proteins

• Mouth: Digestion is mostly mechanical here; chewing crushes the food, but no enzymes break down protein in the mouth.

• Stomach: This is where the real work starts. Strong acid (HCl) unfolds the protein strings, and an enzyme called pepsin starts chopping them into smaller chains.

• Small Intestine: This is the main event. The pancreas sends in more enzymes to finish the job, breaking those chains down into individual amino acids.

• Absorption: The individual amino acids pass through the wall of the small intestine and enter the bloodstream.

• Liver: The blood carries the amino acids to the liver, which decides where to send them to build new tissues or provide energy.

Protein Synthesis

the process where your body takes the amino acids you ate and "assembles" them into new proteins for your own use.

• DNA: Your DNA (located in the cell nucleus) acts as the master instruction manual for every protein your body needs to build.

• The Messenger (mRNA): A copy of the instructions is made and sent out of the nucleus to the "construction site" of the cell.

• The Assembly (Ribosome): At the construction site, amino acids are linked together in the exact order specified by the instructions.

• The Final Product: Once the chain is finished, it folds into a specific shape to become a muscle fiber, an enzyme, a hormone, or an antibody.

Protein Quality

Complete (all essential AAs; animal/soy); Incomplete (missing some; most plants).

Types of Vegetarians

• Lacto-Ovo Vegetarian: Eats dairy and eggs; avoids meat, poultry, and fish.

• Lacto-Vegetarian: Eats dairy; avoids eggs and meat.

• Ovo-Vegetarian: Eats eggs; avoids dairy and meat.

• Vegan: Avoids all animal products (no meat, dairy, eggs, or honey).

• Flexitarian: Mostly eats plant-based foods but occasionally eats meat or fish

Pros and Cons of Vegetarian diet

Pros

• Lower Disease Risk: Usually linked to lower rates of heart disease, Type 2 diabetes, and high blood pressure.

• Weight Management: Often higher in fiber and lower in calories, which helps with a healthy weight.

• Better Digestion: High fiber intake from plants keeps the digestive system regular. [1, 2, 3, 4, 5]

Cons

• Nutrient Gaps: Without careful planning, it can be hard to get enough Vitamin B12, Iron, Zinc, and Omega-3s (which are mostly found in animal products).

• Protein Quality: Many plant proteins are "incomplete," so vegetarians must eat a variety of plants to get all essential amino acids.

• Processed Foods: Some "vegetarian" diets rely on highly processed meat substitutes that are high in sodium and saturated fat

Water Soluble and Fat-soluble vitamins

Fat-soluble (A, D, E, K—stored in liver/fat); Water-soluble (B, C—excreted).

Antioxidants

Vitamins C, E, and Beta-carotene (neutralize free radicals).

Blood Health

Folate, B12 (DNA/cells), Vitamin K (clotting), Iron (oxygen).

Fluid Balance

Electrolytes (Sodium, Potassium, Chloride). ADH/Aldosterone signal kidneys to retain water/sodium.

Bones

Calcium, Phosphorus, Magnesium, Vitamin D. Peak bone mass reached by age 30.

Iron

Heme (animal sources—highly absorbed) vs. Non-heme (plant sources).

TEE

Sum of BMR (60-75%), Thermic Effect of Food, and Physical Activity.

BMR Factors

Increases with lean muscle/fever; decreases with age/starvation.

BMI Categories

Underweight (

Hormones

Leptin (fullness); Ghrelin (hunger).

Eating Disorders

Anorexia (self-starvation), Bulimia (binge/purge), Binge-eating (binge without purge).

Math

1 lb of body fat ≈ 3,500 calories.

Danger Zone

40°F – 140°F (bacteria multiply rapidly).

Cross-contamination

Transfer of bacteria from one surface/food to another.