Foundations of Nutrition

The three macronutrients supply energy and building materials.

• Carbohydrates are the body's main energy source (4 kcal/g).
• Fats are the most energy-dense (9 kcal/g) and cushion organs.
• Proteins (4 kcal/g) build and repair tissue.
• A balanced diet includes all three.

Micronutrients are needed in small amounts but are essential.

• Water-soluble vitamins (B, C) aren't stored.
• Fat-soluble vitamins (A, D, E, K) are stored in fat.
• Minerals support bones, nerves, and metabolism.
• Deficiencies cause specific conditions.

Water and electrolytes keep the body stable.

• Water is about 60% of body weight.
• Electrolytes maintain fluid and nerve function.
• Intake should match output.
• Both dehydration and overhydration are harmful.

Nutritional needs change at every life stage.

• Infants need milk/formula; children need steady nutrients.
• Adolescents need extra calories, calcium, and iron.
• Pregnancy raises folate, iron, and protein needs.
• Older adults often need more calcium and vitamin D.

Food is broken down, absorbed, and used.

• Digestion breaks food into nutrients.
• Absorption occurs mainly in the small intestine.
• Metabolism builds and breaks down for energy.
• The liver and pancreas assist.

Culture shapes how and what people eat.

• Food reflects tradition, religion, and geography.
• Some follow dietary laws or vegetarian diets.
• Respect cultural food practices in care.
• Cost and access affect habits.

Some foods cause illness or reactions.

• Foodborne illness comes from pathogens; safe handling prevents it.
• Intolerance (e.g., lactose) is a digestive issue.
• Allergies are immune reactions that can be severe.
• Reading labels reduces risk.

Special diets manage medical conditions.

• Diabetes: control carbohydrates.
• Heart disease: limit fat and sodium.
• Kidney disease: manage protein and minerals.
• Dietitians design therapeutic diets.