BAD

Part 1 – Nutrients

Definition of Nutrients

• Definition: Nutrients are substances in food that are needed for the growth, maintenance, and repair of the body.
• Purpose: They provide metabolic fuel, build cell structures, and support molecular synthesis.

Categories of Nutrients

1. Macronutrients

• Definition: Macronutrients are nutrients required in large amounts that make up the bulk of ingested food.
• Main Types:
    - Carbohydrates: Provide energy.
    - Lipids (Fats): Store energy and protect organs.
    - Proteins: Build and repair tissues.

Trace Elements

• Definition: Trace elements are chemical elements present in very small amounts in the body but essential for various biological functions.
• Characteristics:
    - Present in very small amounts (typically less than 0.1% by volume).
    - Crucial for various biological functions.
• Examples: Iron, copper, zinc, selenium, iodine, and chromium.
• Importance: Essential for optimal health, despite being needed in tiny quantities.

Caloric Concepts

Definition of Calorie

• Definition: A calorie is the amount of heat energy needed to raise the temperature of 1 kilogram of water by 1°C.
• Kilocalories in Nutrition: In nutritional contexts, we refer to kilocalories (kcal) where one dietary “Calorie” (with a capital C) is equivalent to 1 kilocalorie (kcal) = 1,000 small calories.
• Function: Kilocalories measure the energy the body obtains from food and drinks, which powers:
    - Bodily functions: Breathing, circulation, temperature regulation.
    - Physical activity: Movement and exercise.
    - Metabolic processes: Digestion, cell repair, and growth.

Daily Recommended Caloric Intake in Adults (kcal)

USDA’s MyPlate Dietary Guidelines

• Purpose: A visual guide to promote balanced, nutrient-rich eating based on food groups.
• Representation: Shown as portions on a dinner plate to illustrate ideal meal proportions.
• Food Groups:
    - Fruits: Provide vitamins, minerals, and fiber.
    - Vegetables: Supply essential nutrients and antioxidants.
    - Grains: Emphasize whole grains for sustained energy.
    - Protein: Supports tissue repair and muscle health.
    - Dairy: Source of calcium and vitamin D for bone strength.
• Core Dietary Principles:
    - Eat only what your body needs (moderation).
    - Choose fruits, vegetables, and whole grains more often.
    - Limit added sugars, saturated fats, and processed foods.

Macronutrients: Carbohydrates

Dietary Sources of Carbohydrates

• Main Source: Carbohydrates come almost entirely from plants; only small traces are found in animal products such as lactose (milk sugar) in dairy and glycogen in animal tissues.
• Types of Carbohydrates:
    - Sugars (Mono- & Disaccharides): Found in fruits, sugarcane, sugar beets, honey, and milk.
    - Starch (Polysaccharides): Found in grains, legumes, and vegetables; it is the main plant energy storage form.
    - Insoluble Fiber: Indigestible cellulose in vegetables that adds bulk to stool and promotes bowel health.
    - Soluble Fiber: Found in oats, apples, and citrus, it helps reduce blood cholesterol and regulate blood sugar.

Functions of Carbohydrates

• Primary Energy Source: Provide glucose, which is the main fuel for body cells, particularly the brain and red blood cells.
• Energy Storage: Excess glucose is stored as glycogen in the liver and muscles for later use.
• Protein Sparing Effect: Adequate carbohydrate intake prevents proteins from being broken down for energy.
• Fat Metabolism Aid: Carbohydrates are required for complete oxidation of fats, and lack of carbs can lead to ketone formation.
• Dietary Fiber Benefits: Supports digestive health, maintains bowel regularity, and lowers cholesterol (particularly soluble fiber).

Additional Notes on Carbohydrates

• Glucose: It is the primary fuel used by most cells for ATP production, with specific reliance on glucose observed in neurons and red blood cells. Cells that lack access to oxygen will rely on glucose for energy through anaerobic processes.
• Conversion of Sugars: Excess glucose can be converted into glycogen or fat and stored in the liver for later use, and fructose and galactose are converted into glucose by the liver before entering circulation.

Summary of Nutrients

Lipids

Dietary Sources of Lipids

• Triglycerides: Form the main dietary lipids, found in both animal and plant sources, which are primarily comprised of saturated and unsaturated fats.
    - Saturated Fats: Present in meat, dairy, and some tropical plants; they raise LDL cholesterol.
    - Unsaturated Fats: Common in seeds, nuts, and most vegetable oils; considered heart-healthy.
• Cholesterol: Found in animal foods; synthesized in the liver and important for hormonal functions and cell structure.

Types of Lipids and Their Functions

Omega-3 Fatty Acids

• Definition: Essential fats that cannot be produced by the body and must be obtained through diet.
• Types:
    - ALA: Found in plant oils like flaxseed, chia, and walnuts.
    - EPA: Found in fatty fish such as salmon and sardines.
    - DHA: Also from fish and vital for brain and eye health.
• Health Benefits: Omega-3 fatty acids can reduce inflammation, support bone and brain health, and aid in mental health.
• Common Sources: Fish, seafood, flaxseeds, chia seeds, and walnuts.

Lipids in the Body

• Uses:
• Function as structural components (e.g., phospholipids in cell membranes).
• Store energy as fat for future use.
• Protect organs and offer insulation through adipose tissue.
• Cholesterol is crucial for cell membrane stability and acts as a precursor to various hormones.

Dietary Requirements for Lipids

• Fats: Comprise 20-35% of total caloric intake; saturated fats should be kept below 10%. Cholesterol intake should be minimal to reduce heart disease risk.
• Lipoproteins:
    - LDL: Low-Density Lipoprotein, often referred to as