DeBruyne_7e_PPT_ch04

Major Roles of Fat in the Body:
- Identify essential functions of fats.
Chemical and Physical Properties:
- Compare saturated, monounsaturated, polyunsaturated fats, phospholipids, and sterols.
Fat Digestion and Absorption:
- Understand digestion processes and absorption mechanisms.
Health Relationships:
- Discuss the links between different types of fats, cholesterol, and chronic diseases with recommendations.
Sources and Types of Fats:
- Identify food sources of solid and unsaturated fats and their health impacts.

Health Impact:
- Both excess and deficiency in dietary fat can affect health.
Functions of Lipids:
- Energy Provision:
  - Primary energy storage; body's capacity to store fat is nearly unlimited.
- Muscle Fuel:
  - Significant energy source for muscular work.
- Padding:
  - Protects internal organs from shock.
- Insulation:
  - Maintains body temperature by insulating under the skin.
- Cell Membranes:
  - Major component of cellular structures.
- Raw Materials:
  - Converts fats into hormones, bile, and vitamin D as required.

Triglycerides:
- Main form of fat in foods and body; composed of glycerol and three fatty acids.
- Formation: Glycerol + 3 Fatty Acids = Triglyceride.
Fatty Acids:
- Chains differing in length and saturation.
- Types:
  - Saturated:
    - Fully hydrogenated, single bond between carbon atoms.
  - Unsaturated:
    - Missing hydrogen, containing points of unsaturation.
    - Monounsaturated: One point of unsaturation (e.g., oleic acid in olive oil).
    - Polyunsaturated: Two or more points of unsaturation (e.g., linoleic, linolenic acids).
Hard vs. Soft Fats:
- Degree of saturation influences texture and health.
- Short-chain or unsaturated fats are softer at room temperature.
Hydrogenation:
- Adding hydrogen to unsaturated fats to increase saturation.
- Produces trans-fatty acids, which affect cholesterol levels negatively.

Requirements:
- Polyunsaturated fatty acids that must come from the diet.
- Examples:
  - Linoleic (Omega-6): Found in plant oils.
  - Linolenic (Omega-3): Usually from fish oils, important in health and disease prevention.

Phospholipids:
- Compose about 5% of dietary lipids, e.g., lecithins used as emulsifiers.
Sterols:
- Complex molecules, e.g., cholesterol, synthesized in the liver.
- Vital for cell membranes and metabolic functions.

Goals:
- Break down triglycerides into absorbable units.
Process:
- Begins in the mouth with lingual lipase; continues in the stomach and small intestine.
- Emulsification by bile; lipases convert fats to monoglycerides and free fatty acids.

Heart Health:
- Role of LDL and HDL in heart disease risk.
- Recommendations:
  - Replace saturated fats with unsaturated fats.
- Dietary cholesterol impacts varies among individuals.
Fats and Health Recommendations:
- Daily fats from oils, limit to 20-35% of energy intake.

Sensory Appeal:
- Enhance flavor, aroma, and texture, assist in carrying fat-soluble vitamins (A, D, E, K).
Nutritional Contributions:
- Essential fatty acids and energy dense.
- Fats stimulate appetite and increase feelings of fullness.
Sources of Fat:
- Differentiation between healthy and harmful fat sources.

Daily Fat Intake:
- Include preferred oils; limit saturated and trans fats.
- Monitor labels for fat content.
Healthier Meat Choices:
- Opt for lean cuts and control portion sizes; avoid fried and high-fat processed meats.

Continuous evaluation of dietary fats emphasizes switching to beneficial fats while reducing harmful types. The understanding of fat in nutrition has evolved, focusing on quality rather than quantity.