Nutrition et Thérapie Diététique

Basic Nutrition and Diet Therapy

• The presentation covers basic nutrition and diet therapy.
• The source is from Dr. Safynaz Shalaby, Professor of Public Health, Preventive & Social Medicine, Tanta University.

Terms Related

• Nutrition
• Food
• Nutrient

Composition of Food

• Macronutrients: protein, carbohydrates (CHO), lipids (fats)
• Micronutrients: minerals, vitamins
• Water

Energy Requirements

• Depend on energy expenditure
• Balance between energy requirements and expenditure is necessary
• Approximately 3000 kcal for a reference man and 2200 kcal for a reference woman.
• Reference man: Young adult male, aged 25, weighing 65 kg, works 8 hours/day in a comfortable temperature
• Reference woman: Young adult female, aged 25, weighing 55 kg, works 8 hours/day in a comfortable temperature
• Factors affecting energy expenditure: age, sex, climate, and physical activity

Meal Planning

• Combining foodstuff from different food groups to create a meal
• The basis for constructing a balanced diet.
• Important considerations:
  • Presence of essential elements in balanced proportions
  • Individual nutritional requirements
  • Economic, social, and health conditions

A Healthy Balanced Diet

• Provides adequate amounts of all nutrients in a balanced proportion

Example for Reference Man

• Carbohydrate supply: 3000 kcal x 60% = 1800 kcal / 4 kcal/g = 450 g
• Fat supply: 3000 kcal x 30% = 900 kcal / 9 kcal/g = 100 g
• Protein supply: 3000 kcal x 10% = 300 kcal / 4 kcal/g = 75 g

Tools Used

• Food groups
• Food guide pyramid
• Food composition tables
• Nutrient and energy density
• Dietary guidelines
• Exchange lists

Food Grouping

• Building (proteins)
• Energy supplying (carbohydrates, fats)
• Vitality (vitamins and minerals)

Macronutrients

• Types
• Dietary sources
• Function
• Requirements
• Deficiency
• Toxicity

Proteins

• Types: Animal protein (meat, egg, milk, fish) and Plant protein (peas, beans, lentils)
• Animal protein: High biological value, complete protein
• Plant protein: Low biological value, incomplete protein
• Increasing Value: Intake of a variety of plant foods throughout the day to supplement missing amino acids

Protein Functions

• Formation of both new and injured cells. Enzymes and hormones, and other essential compounds
• Fluid balance
• Acid-base balance
• Provide energy
• Transport molecules (e.g., lipoproteins)
• Contributing to immune function through antibody formation

Recommended Protein Intake

• Infants and children: 2-3 g/kg body weight
• Adults: 0.8-1 g/kg ideal body weight
• Pregnancy: 1.3-1.5 g/kg
• Lactation: 2 g/kg

Protein Deficiency

• General effects: loss of weight, debility, muscle wasting in adults
• Hypo-proteinaemia and nutritional edema in severe cases
• Fatty liver
• Kwashiorkor (pure protein deficiency in infants and young children)
• Marasmus (severe energy deficiency in young children)

Protein Excess Intake

• Impairment in kidney functions, especially in patients with diabetes
• Link between cancer colon and increased consumption of red meat
• High protein foods are usually high in fats leading to hyperlipidaemia

Carbohydrates

• Types: Simple carbohydrates (sugars) – monosaccharides (glucose, fructose, galactose), disaccharides (sucrose, maltose, lactose) and Complex carbohydrates (starch, glycogen, fiber)

Carbohydrate Functions

• Main source of energy for red blood cells and brain (glucose)
• Sparing protein as a source of energy, preventing ketosis
• Used as flavoring and sweetening agents in food industry
• Fibers promote healthy intestinal function, prevents hypercholesterolemia and heart diseases

Insoluble Fiber

• Cellulose and hemicellulose
• Maintains peristaltic movement
• Removes waste products from the intestinal tract
• Found mainly in fruits, vegetables, and wheat bran

Soluble Fiber

• Gum, pectin, and some hemicellulose
• Fermented by bacteria in the colon to produce gases and volatile fatty acids
• Slows gastric emptying and chyme movement through the intestine
• Delays glucose absorption
• Lowers elevated blood cholesterol levels
• Found mainly in oats, fruits, and legumes

Dietary Sources of Carbohydrates

• Plant sources: cereal grains (wheat, etc.), refined products
• Animal sources: only glucose and lactose in milk

Recommended Carbohydrate Intake

• 60% of total energy, 50% complex carbohydrates and 10% sugars
• Minimum intake of 100 g to supply energy to brain and red blood cells, and to minimize body protein breakdown for gluconeogenesis
• Daily fiber intake: 20-35 g or 10-13 g/1000 kcal.

Carbohydrate Deficiency

• Rare condition, can occur with severe dieting or anorexia
• Restricted carbohydrate intake or impairment in its metabolism
• Fat is used for energy production, with potential risk of incomplete combustion and ketosis development

Carbohydrate Excess Intake

• Acute rapid effect: osmotic diarrhea, gastrointestinal tract disturbances, hyperglycemia
• Excess fibers without increased water intake can cause hard stool and intestinal blockage
• Can reduce availability of minerals (calcium, zinc, iron)
• Long-term effects: predisposition to obesity, dental caries, stress on patients with respiratory insufficiency

Lipids (Fats)

• Types: Fats and oils in the form of triglycerides (glycerol core linked to three fatty acids)
• The nature of the fat (solid or liquid) depends on the type of fatty acids linked to the glycerol core

Fatty Acids

• Saturated: Mainly in animal fats (solid at room temperature) and tropical oils (coconut, palm)
• Unsaturated: Present in plant oils (liquid at room temperature), can be:
  • Monounsaturated: olive and canola oils
  • Polyunsaturated: corn, soybeans, safflower oils
• Essential fatty acids: Alpha-linolenic acid and linoleic acid (1-2% of total caloric intake, about 1 tablespoon of plant oil daily)

Dietary Sources of Lipids

• Visible fat: fats in animal products (butter, ghee), vegetable oils, and margarine
• Invisible fat: hidden in whole milk, pastries, cookies, cakes, cheese, and crackers

Lipid Functions

• Source of energy
• Source of essential fatty acids
• Supply fat-soluble vitamins
• Protect and support organs
• Prolongs stomach emptying time, giving a sense of satisfaction after meals
• Provides flavor and texture to food

Recommended Lipid Intake

• About 30% of total calories
• Maximum of 10% of total calories from saturated fats
• Limit cholesterol to about 300 mg/day
• Maintain at least 15% of total energy requirements from fat

Lipid Excess Intake

• Digestive disorders
• Obesity
• The risk of hyperlipidemia and its role in the development of atherosclerosis
• Increased risk of cancer (e.g., colon, rectum, prostate, endometrium)

Lipid Deficiency

• Not a common condition
• Can occur with severe dieting or anorexia nervosa
• Very low-fat diets can cause:
  • Disturbance in blood glucose levels, especially in diabetic patients
  • Deficiency of fat-soluble vitamins