BIO103 Lecture 10 11
FOOD AND
NUTRITION
&
The Digestive
System
Lecture No. 10
FOOD AND NUTRITION
Food
Food is any edible material that supports growth, repair and maintenance of the body.
Foods are substances containing nutrients
Nutrients are needed for:
• Cell repair
• Cell growth
• Energy
• Protection
Food
Classification of foods:
A. According to the source of origin
1. Animal foods
2. Plant foods
B. According to the calorigenicity
1. Calorigenic foods
2. Non-Calorigenic foods
C. According to the main function
1. Energy yielding foods
2. Body building foods
3. Protective foods
Factors associated with Food
The important factors in relation to Food are:
1.
2.
3.
4.
5.
6.
7.
Energy Value
Quality and Quantity of Primary Foods
Variation in the diet
Digestibility
Cooking
Psychological factors
Cost
Nutrients
Nutrients are specific dietary constituents. They can be classified into:
Macronutrients
• Carbohydrate
• Protein
• Fat
• Trace elements
• Dietary fibre
• Water
Micronutrients
• Vitamins
• Minerals
Role of Proteins in the Diet
Replacement of cells
Growth
Large molecules
Smaller molecules called Amino Acids
Source: meats, eggs, beans
Role of Carbohydrates
Primary energy source
Molecules of C, H, O
• Sugars ~ simple carbohydrates
• Starches ~ complex carbohydrates
• Fiber
Sources: Rice, potatoes, sugar etc.
Role of Fats
Provide energy/stores energy
Absorb vitamins
Make up cell membranes
Sources: oil, cheese, butter and other milk product.
Vitamins
Organic (contain carbon)
Growth
Regulate body functions
Prevent disease
No food has all vitamins
Water soluble
Fat soluble
Sources: Vitamins are organic molecules.
They are water and fat soluble and found in vegetables, fruits, egg, milk etc.
Minerals
Inorganic (no carbon)
Control chemical reactions
Build cells
Conduct nerve impulses
Carry oxygen
Sources of Minerals
Calcium: Best sources of calcium are milk
,cheese, eggs, green vegetables, oranges, nuts, beans,
NUTRITION
&
The Digestive
System
Lecture No. 10
FOOD AND NUTRITION
Food
Food is any edible material that supports growth, repair and maintenance of the body.
Foods are substances containing nutrients
Nutrients are needed for:
• Cell repair
• Cell growth
• Energy
• Protection
Food
Classification of foods:
A. According to the source of origin
1. Animal foods
2. Plant foods
B. According to the calorigenicity
1. Calorigenic foods
2. Non-Calorigenic foods
C. According to the main function
1. Energy yielding foods
2. Body building foods
3. Protective foods
Factors associated with Food
The important factors in relation to Food are:
1.
2.
3.
4.
5.
6.
7.
Energy Value
Quality and Quantity of Primary Foods
Variation in the diet
Digestibility
Cooking
Psychological factors
Cost
Nutrients
Nutrients are specific dietary constituents. They can be classified into:
Macronutrients
• Carbohydrate
• Protein
• Fat
• Trace elements
• Dietary fibre
• Water
Micronutrients
• Vitamins
• Minerals
Role of Proteins in the Diet
Replacement of cells
Growth
Large molecules
Smaller molecules called Amino Acids
Source: meats, eggs, beans
Role of Carbohydrates
Primary energy source
Molecules of C, H, O
• Sugars ~ simple carbohydrates
• Starches ~ complex carbohydrates
• Fiber
Sources: Rice, potatoes, sugar etc.
Role of Fats
Provide energy/stores energy
Absorb vitamins
Make up cell membranes
Sources: oil, cheese, butter and other milk product.
Vitamins
Organic (contain carbon)
Growth
Regulate body functions
Prevent disease
No food has all vitamins
Water soluble
Fat soluble
Sources: Vitamins are organic molecules.
They are water and fat soluble and found in vegetables, fruits, egg, milk etc.
Minerals
Inorganic (no carbon)
Control chemical reactions
Build cells
Conduct nerve impulses
Carry oxygen
Sources of Minerals
Calcium: Best sources of calcium are milk
,cheese, eggs, green vegetables, oranges, nuts, beans,