Nutrition Fundamentals: Food, Nutrients, and Health

Posted on Mar 31, 2025 in Human Nutrition and Dietetics

Understanding Nutrition and Food Groups

Food Groups Overview

A balanced diet includes various food groups, often visualized in a pyramid or plate model. Key groups include:

• Meat and Alternatives: Red meat, poultry, fish, eggs, legumes, nuts.
• Dairy and Alternatives: Milk, cheese, yogurt.
• Fruits: Various fresh fruits.
• Vegetables: A wide variety of vegetables.
• Grains: Bread, rice, pasta, couscous, polenta, other cereals, potatoes.
• Fats and Oils: Olive oil, other vegetable oils, fats found in foods.
• Sweets/Sugars: To be consumed sparingly.

Food Groups and Primary Nutrients

Organic Nutrients Breakdown

Nutrient Details

• Carbohydrates: Provide energy. Simple carbohydrates are sugars; complex carbohydrates include starch and cellulose (fiber).
• Lipids: Include fats and oils. Saturated fats are typically from animal sources, while unsaturated fats come from vegetable sources (like oils). Lipids are crucial for cell membranes and act as precursors for some vitamins and hormones.
• Proteins: Built from 20 different amino acids, 8 of which are essential (must be obtained from the diet). Found in animal products (meat, dairy, eggs) and plant sources (legumes). They constitute about 50% of the body’s dry weight and have structural and regulatory roles.
• Vitamins: Essential organic compounds needed in small quantities. They are sensitive to degradation by light and heat. Classified as fat-soluble (A, D, E, K) or water-soluble (B complex, C).

Key Vitamins: Functions and Sources

Note: RDA (Recommended Daily Allowance) values can vary based on age, sex, and life stage. Consult official guidelines for specific recommendations.

Water, Minerals, and Energy Balance

Inorganic Nutrients

• Minerals (Salts): Inorganic substances vital for structure (e.g., calcium in bones) and regulating body functions (e.g., sodium in nerve function).
• Water: Constitutes about 63% of body mass. Essential for regulating body temperature, transporting nutrients, providing a medium for metabolic reactions, and removing waste. Intake comes from drinks and food; loss occurs via urine, respiration (ventilation), sweat, and feces.

Energy Metabolism

• Energy Value: Measured in kilocalories (kcal) or kilojoules (kJ). 1 kcal ≈ 4.186 kJ.
• Macronutrient Energy: Approximate energy provided per gram:
  • Carbohydrates: ~4 kcal/g (sometimes cited as 3.75)
  • Proteins: ~4 kcal/g
  • Fats: ~9 kcal/g
• Basal Metabolic Rate (BMR): The minimum energy required to keep the body functioning at rest (typically measured under specific conditions: 12 hours fasting, resting state, neutral temperature). BMR depends on factors like body mass, height, age, and sex. Specific formulas (e.g., Harris-Benedict) exist to estimate BMR.
• Total Energy Expenditure: Includes BMR plus energy used for physical activity and the thermic effect of food.

Dietary Principles and Considerations

Achieving a Balanced Diet

• Diversify: Eat a wide variety of foods to ensure intake of all necessary nutrients.
• Quantify: Pay attention to portion sizes to manage energy intake.
• Prioritize Freshness: Emphasize fresh foods, especially vegetables. Limit highly processed or refined foods.
• Include Fiber: Ensure adequate daily fiber intake for intestinal transit, satiety, and cholesterol management.
• Choose Healthy Fats: Favor unsaturated fats (like those in vegetable oils) over saturated and trans fats.

The Mediterranean Diet

• Core Foods: Abundant olive oil (especially extra virgin), cereals (often whole grain), legumes, fish, vegetables, and fruits. Moderate dairy and meat.
• Benefits: Associated with prevention of various diseases, including obesity, circulatory problems (e.g., high cholesterol), and digestive issues (e.g., constipation, potentially colon cancer).

Dietary Considerations

• Cholesterol Management: Dietary cholesterol is found in animal products like beef, seafood, egg yolks, and animal fats. High intake can raise blood cholesterol levels. Oily fish (rich in omega-3s) and vegetable oils (unsaturated fats) are generally considered better choices for heart health.
• Specific Diets:
  • Therapeutic Diets: Modifications to diet (e.g., for diabetes, obesity, allergies) should be guided by a healthcare professional or registered dietitian to prevent or manage health conditions.
  • Vegetarian Diets: Exclude meat and fish. Lacto-ovo vegetarians include eggs and dairy products.
• Fiber: Important for digestive health and managing conditions like obesity and diabetes.

Potential Causes of Chest Pain

Chest pain can arise from various sources, some requiring urgent medical attention. Potential causes include:

Cardiac Causes

• Ischemic Heart Disease: Angina (stable or unstable), Myocardial Infarction (AMI – Heart Attack)
• Hypertensive Emergency
• Aortic Dissection
• Pericarditis

Pulmonary (Lung) Causes

• Pneumonia
• Pulmonary Embolism (PE)
• Pneumothorax (Collapsed Lung)
• Lung Tumors
• Pleural Diseases

Musculoskeletal Causes

• Injuries (e.g., muscle strain, rib fracture)
• Costochondritis
• Osteoarthritis
• Bone Tumors

Digestive Causes

• Gastroesophageal Reflux Disease (GERD)
• Hiatal Hernia (HH)
• Esophageal Spasms, Ulcers, or Tumors
• Stomach Ulcers or Tumors
• Gallbladder Disease

Psychogenic Causes

• Anxiety or Panic Attacks
• Depression
• Somatization

Disclaimer: This information is for educational purposes only and does not constitute medical advice. Seek immediate medical attention for chest pain.