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  1. Introduction to Science | Week 1
    1 Quiz
  2. Family Health | Week 2
    1 Quiz
  3. Family Health (Sanitation) | Week 3
    1 Quiz
  4. Family Health (Nutrition) | Week 4
    1 Quiz
  5. Drug and Substance Abuse | Week 5
    1 Quiz
  6. Environmental Pollution: Air Pollution | Week 6
  7. Soil pollution | Week 7
  8. Water Pollution | Week 8
    1 Quiz
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Based on the nutrients in food, food substances are classified into:

  1. Protein
  2. Carbohydrates
  3. Fats and oil (lipids)
  4. Vitamins
  5. Minerals
  6. Water

Generally, all foods are categorized into:

1. Energy-giving food – Carbohydrates and Fats and Oil.

2. Bodybuilding food – Protein

3. Health preserving food – Vitamins and Minerals

Below is a list of different classifications of nutrients, their sources, functions and composition.

ProteinMeat, milk, fish, poultry, beans, eggs, cheese
Supports growth and maintains healthy body cellsCarbon, hydrogen, oxygen, nitrogen, sulphur and phosphorus
CarbohydratesCereal, potatoes yam, bread, maize, sugar
Provides main source of energy for the energyCarbon, hydrogen, oxygen
Fats and oilVegetable oil, butter, palm-oil, margarine Fats and OilsProvides energy for the body, it also keeps the body warmCarbon, hydrogen, oxygen
VitaminsLiver, carrots, oranges, grapes, milk, cheese, fruits
Protects the body against diseases, promotes chemical reaction in the bodyVarying in components e.g vitamin A, Vitamin E
MineralsLiver, meat, poultry, fish
Regulates the body’s metabolismPotassium, iron, calcium
Most food we eat contain water e.g fruits
Helps with body process such as digestion, makes up 60% of the human adult bodyHydrogen, oxygen

Vitamins: Promote chemical reactions in the body

The various types of vitamins, sources, functions, effects of deficiency are seen below.  

VitaminsSourcesFunctionsEffects of deficiency 
1A (Retinol)Liver, eggs, milk, fish, liver oil, tomatoes, mangoes For healthy skin and normal vision Dry skin, night blindness 
2B complexYeast, palm wine, beans, eggs, tomatoes, groundnutFor normal growth, for normal working of heart and nervous system Reduced growth, beriberi 
3C (Ascorbic acid)Citrus fruits e.g oranges, tomatoes, guava, pawpaw, green vegetables Maintenance of connective tissue bones, help to resist infectionsSlow healing of wounds, scurvy 
4D(Calciferol) Milk, egg yolk, liver, fish liver oilFacilitates absorption of calcium and phosphorous in the intestine, for hardening of bones Rickets (poor bone and teeth formation)
5E (Tocopherol)Leafy vegetables, oils, e;g palm oil, eggs Required for the proper function of many organs in the body. It is also an antioxidant. 
6.KGreen vegetables Synthesis of blood clotting factors Slow clotting of blood leading to severe bleeding 

Minerals regulate the metabolism of the body. Their sources, types, and deficiency symptoms are written below:

Minerals SourcesFunctionsDeficiency symptoms 
1SodiumSalt, meat, egg, milkPermeability, for normal cell membrane Dehydration, kidney failure 
2Chlorine SaltMaintains correct osmotic pressure of body fluidsMuscle cramps
3PotassiumAll natural foodsPermeability, for normal cell membrane  Loss of bone minerals, muscle paralysis 
4CalciumDiary products e.g milk, cheese, eggs, vegetables 
Bone formation and blood clotting softening of bones Rickets 
5.Phosphorous Dairy products, meat, beans, plantainBone formation and general metabolism 
6.MagnesiumLeafy vegetables, nuts, seafoods A major component of bonesTeeth muscle, muscle contraction 
7IronLiver, egg, meat, green vegetable Formation of haemoglobin in red blood cells Anaemia 
8.IodineSeafood, iodized table salts The body needs iodine to make thyroid hormones. These hormones control the body’s metabolism and many other important functions.Goiter, cretinism
9.Fluorine MilkHardening of bones and teethDental caries 

An excessive loss of water from the body is called dehydration measured with a calorimeter.

Factors that Determine Nutrients needs of an Individual:

  1. Age
  2. Weight
  3. Sex
  4. The amount of physical exercise

Specific health conditions such as pregnancy, breastfeeding, illness, or drug use, make unusual demands on the body and increases its need for nutrients.