Basic Nutrition (Chapters 1 & 2)
Six Classes of Nutrients
Carbohydrates – Main source of energy (found in grains, fruits, vegetables).
Proteins – Build and repair tissues (found in meat, dairy, legumes).
Fats – Provide long-term energy and cell functions (found in oils, nuts, fatty fish).
Vitamins – Regulate body processes, support immunity (fat-soluble: A, D, E, K; watersoluble: B, C).
5. Minerals – Support body structures and chemical reactions (e.g., calcium, iron,
potassium).
6. Water – Essential for hydration, transport of nutrients, temperature regulation.
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Caloric Content of Energy Nutrients
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Carbohydrates = 4 kcal/g
Proteins = 4 kcal/g
Fats = 9 kcal/g
Alcohol = 7 kcal/g
Acceptable Macronutrient Distribution Ranges (AMDRs)
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Carbohydrates: 45-65% of daily calories
Fats: 20-35% of daily calories
Proteins: 10-35% of daily calories
Nutrient Density
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Nutrient-dense foods provide high levels of vitamins and minerals per calorie (e.g.,
vegetables, whole grains).
Low-nutrient-density foods are high in calories but low in nutrients (e.g., candy, soda).
Scientific Method in Nutrition Research
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Observation – Identifying a phenomenon.
Hypothesis – Making an educated guess.
Experimentation – Testing with controlled studies.
Analysis & Conclusion – Evaluating results.
Credible Sources of Nutrition Information
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Peer-reviewed scientific journals (e.g., Journal of Nutrition)
Registered dietitians (RDs)
Government agencies (e.g., USDA, FDA, CDC)
Medical associations (e.g., American Heart Association)
Factors Affecting Food Choices
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Personal preferences (taste, texture)
Cultural influences (traditional diets)
Economic factors (food cost and accessibility)
Health considerations (dietary restrictions, allergies)
Phytochemicals (Plant-based compounds promoting health)
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Act as antioxidants, anti-inflammatory agents, and immune boosters.
Found in colorful fruits & vegetables (e.g., flavonoids in berries, lycopene in tomatoes).
Dietary Reference Intakes (DRIs)
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RDA (Recommended Dietary Allowance) – Daily intake for health.
AI (Adequate Intake) – Used when RDA isn’t available.
UL (Tolerable Upper Limit) – Highest safe nutrient intake.
EAR (Estimated Average Requirement) – Average intake for 50% of people.
Dietary Guidelines for Americans (2020-2025)
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Focus on whole, nutrient-dense foods.
Limit added sugars, saturated fats, sodium.
Balance protein, grains, fruits, vegetables, dairy.
MyPlate Recommendations
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½ plate fruits & vegetables
¼ plate grains (half should be whole grains)
¼ plate protein sources
Dairy for calcium needs
Food Labels
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Ingredients listed in descending order by weight.
% Daily Value (%DV) – Based on 2,000-calorie diet.
Sugar listing – Includes added sugars separately.
Digestion & Absorption (Chapter 3)
Organs & Functions in the GI Tract
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Mouth – Chewing & salivary enzymes (amylase for starch digestion).
Esophagus – Transports food via peristalsis.
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Stomach – Secretes hydrochloric acid (HCl) & pepsin to begin protein digestion.
Small intestine – Main absorption site. Villi and microvilli increase surface area.
Large intestine – Absorbs water, houses gut microbiota, forms waste.
Accessory Organs & Their Roles
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Liver – Produces bile to aid in fat digestion.
Pancreas – Produces digestive enzymes (amylase, protease, lipase) & bicarbonate.
Gallbladder – Stores and releases bile.
Digestive Secretions & Their Roles
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Enzymes – Breakdown food (e.g., amylase for starch, lipase for fats).
Hydrochloric Acid (HCl) – Activates pepsin for protein digestion.
Bile – Emulsifies fats for absorption.
Methods of Nutrient Absorption
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Passive Diffusion – No energy needed (water, small lipids).
Facilitated Diffusion – Uses transport proteins (fructose).
Active Transport – Requires energy (amino acids, glucose).
Gut Microbiota, Prebiotics & Probiotics
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Microbiota – Beneficial bacteria in the gut, aid in digestion & immunity.
Prebiotics – Fiber that nourishes gut bacteria (found in onions, bananas).
Probiotics – Live beneficial bacteria (found in yogurt, kefir).
Common Gastrointestinal Disorders
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GERD – Acid reflux due to weakened esophageal sphincter.
Celiac Disease – Autoimmune reaction to gluten.
Gallstones – Bile accumulation forming stones.
Constipation – Lack of fiber, water, or exercise.
Lactose Intolerance – Lack of lactase enzyme, causing difficulty digesting dairy.
Metabolism (Chapters 3-9)
Steps of Energy Metabolism
1. Glycolysis – Breakdown of glucose for ATP.
2. Citric Acid Cycle (Krebs Cycle) – Further breakdown producing ATP.
3. Electron Transport Chain – Final ATP production step.
Metabolism During Fasting vs. Feasting
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Feasting – Excess energy stored as fat.
Fasting – Body breaks down stored glycogen, then fat, then protein.
Fat Metabolism
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Fatty acids broken down for ATP via beta-oxidation.
Protein Metabolism
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Only used for energy when carbs & fats are insufficient.
Deamination – Removes nitrogen from amino acids; excreted as urea.
How Body Uses Macronutrients for Energy
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Carbs = Primary fuel source.
Fats = Long-term energy storage.
Protein = Last resort for energy (used for tissue repair first).
B-Vitamins in Metabolism
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Act as coenzymes for energy-producing reactions.