Nutrition: Key Concepts in Macronutrients, Micronutrients, and Body Regulation

Nutrient

A substance in food that provides energy, structure, or regulates body processes.

Macronutrients

Nutrients needed in large amounts.

Micronutrients

Nutrients needed in small amounts.

Carbohydrates

Main energy source (glucose).

Lipids (Fats)

Long-term energy storage, insulation & protection, hormone production.

Proteins

Build/repair tissues, enzymes, hormones, antibodies.

Recommendation for Carbohydrates

Approximately 45-65% of daily calories.

Recommendation for Lipids

Approximately 20-35% of daily calories.

Recommendation for Proteins

Approximately 10-35% of daily calories.

Types of Carbohydrates

Monosaccharides, Disaccharides, Polysaccharides.

Fiber

Indigestible carbohydrate.

Soluble Fiber

Dissolves in water, lowers cholesterol, stabilizes blood sugar.

Insoluble Fiber

Adds bulk to stool, helps digestion & prevents constipation.

Importance of Fiber

Promotes gut health, reduces risk of heart disease, helps control blood sugar.

Glycogenesis

Glucose → glycogen (storage).

Glycogenolysis

Glycogen → glucose.

Gluconeogenesis

Making glucose from non-carb sources.

Types of Fats

Saturated, Unsaturated (Monounsaturated, Polyunsaturated), Trans fats.

LDL

Low-density lipoprotein, known as 'bad' cholesterol.

HDL

High-density lipoprotein, known as 'good' cholesterol.

Cholesterol Functions

Cell membrane structure, hormone production, vitamin D synthesis, bile production.

Complete Proteins

Contain all essential amino acids (animal sources).

Incomplete Proteins

Missing some amino acids (plant sources).

Vitamins

Organic compounds (made by living organisms).

Minerals

Inorganic elements (from soil/water).

Bulk (Major) Minerals

Needed in large amounts (e.g., Calcium, Potassium, Sodium, Magnesium).

Trace Minerals

Needed in small amounts (e.g., Iron, Zinc, Iodine).

Fat-Soluble Vitamins

Vitamins A, D, E, K (stored in body).

Water-Soluble Vitamins

Vitamin C and B-complex (not stored, excess excreted).

Absorptive State

After eating, nutrients absorbed, insulin active, energy stored.

Postabsorptive State

Fasting state where body uses stored energy, glucagon active.

Ketosis

Normal process where body uses fat for energy → ketones.

Ketoacidosis

Dangerous condition (often in diabetes) where excess ketones make blood acidic.

Regulation of Intake

Controlled by hypothalamus, hormones (ghrelin, leptin), blood glucose levels, psychological & environmental factors.