Classes of Food, their Composition and Functions

Classes of Food

Food is classified into six classes according to the nutrients they give the body. Nutrients refers to a group of chemical compounds found in food which are essential for nourishment and maintenance of life. The various classes of food contain nutrients crucial for keeping the body energized, healthy, strong, and immune to diseases.

The six classes of food are: 

1. Carbohydrate

2. Protein

3. Fats and oils

4. Vitamins

5. Mineral salt

6. Water

Please on read more on nutrition and classes of food here.

Classes of Food and their Compositions

• Carbohydrates: They are made up of carbon (C), hydrogen (H) and oxygen (O). Their chemical formula generally follow a ratio of one carbon to two hydrogens and one oxygen (1:2:1); that is "CH₂O". Carbohydrates are classified into monosaccharides, disaccharides and polysaccharides. Please read more on types of carbohydrates here.

• Proteins: They are made up of carbon, hydrogen, oxygen, nitrogen, and sulphur atoms. However, it is noteworthy to state that phosphorus is not a basic structural part of a standard protein molecule (amino acids), but it can be subsequently attached to proteins through chemical changes in the cell.

• Fats and Oils (Lipids): They are composed of carbon, hydrogen and oxygen atoms (CHO). They do not have a definite or simple whole-number ratio of carbon, hydrogen, and oxygen atoms like carbohydrates. Fats and oils  combines three fatty acid chains with a glycerol, giving rise to molecules called triglycerides.

• Vitamins: They are organic compounds primarily composed of carbon (C), hydrogen (H), and oxygen (O) atoms. However, most vitamins also nitrogen (N) or sulfur (S) atoms, while vitamin B12 uniquely contains a metallic cobalt (Co) atom.

• Mineral Salts: They are electrovalent or ionic compounds comprising of positively charged metallic atoms (cations) and negatively charged non-metal atoms (anions) locked in a repeating crystal grid. The ions in mineral salts include  These include Na⁺, K⁺, Ca²⁺, Mg²⁺, Fe²⁺, Fe³⁺, Zn²⁺, Cl^-, SO₄^2-, CO₃^2-, F^-, PO₄^3-, S^2-, HCO^-, etc. Please read more on the sources, functions and deficiencies of mineral salts here.

• Water: It is made up of hydrogen and oxygen in the ratio 2:1. The two hydrogen atoms and one oxygen atoms are linked together with strong covalents bonds to create a bent shape, characterizing water with its unique life-giving capability.

You can read on ersonal cleanliness in family health here.

Sources and Functions of Classes of Food

Carbohydrates 

Sources of carbohydrates include yam, maize, rice, millet, wheat, sugarcane, plantain, cassava, etc.

Functions of Carbohydrates

• They are excellent sources of energy for the body.

• The serve as energy storage for the body.

• The contain dietary fiber which can facilitate bowel movement.

• They are required for proper metabolism of fats.

• They are essential in the formation of mucus, which serves as important lubricant in the body.

• Excess glucose is stored as glycogen in the liver through a process termed glycogenesis; and are released to the muscles for later use between meals.

You can read on disaccharides and oligosaccharides here.

Protein

Sources of protein include egg, beans, soya beans, cowpea, fish, milk, groundnut, etc.

Functions of Protein

• They are important for growth and body building.

• Repair of worn out tissues and development of new cells.

• They are required for creating enzymes and hormones needed for normal functioning of metabolic activities. Please read an introduction to homeostasis here.

• The are required in building antibodies that help fight antigens, pathogens (bacteria, viruses, protozoas, etc).

• They transport oxygen through an iron-rich protein found inside red blood cells. This protein is termed hemoglobin.

• Proteins like beans slows digestion, thus keeping one filled for a longer duration.

Please read on cell organelles in basic science here.

Fats and Oils

Sources of fats and oils include groundnut oil, palm oil, butter, margarine, cheese, corn oil, olive oil, melon oil, coconut oil, and fatty meat like pork.

Functions of Fats and Oils

• They act as energy reserve in the body.

• It insulates the body by preventing excess loss of heat. This process keeps the body warm.

• It protects delicate intermnal organs in the body by cushioning them from shock.

• They act as energy source by providing backup energy when carbohydrates run low.

• The are crucial in forming the outer walls of cell membranes.

Please read on the concept of cell here.

Vitamins

Sources of vitamins include milk, fruits, fresh vegetables, eggs, grains, etc.

Functions of Vitamins

• They protect the body against deficiency diseases.

• Vitamin A helps.us to see in the dark, thus preventing night blindness. It also keeps the skin healthy.

• Vitamin B is important for production of new red blood cells and healthy nerves.

• Vitamin C protects the gum, prevents scurvy, protects the body from germs, promotes cut healing, and builds stronger skin and bones.

• Vitamin D (often called the sunshine vitamin) can be derived from morning sunlight, and it helps in the absorption of calcium, consequently building strong bones and teeth.

• Vitamin E can function to protect the cell, and also enhance reproduction.

• Vitamins K assists in blood clotting; that is, it stops bleeding when we cut ourselves.

You can read on characteristics of living things in basic science here.

Water

Sources of water include springs, rain, tap water, well, rivers, sea, etc.

Functions of Water

• It is crucial in the digestion and absorption of food.

• It regulates the body temperature by cooling the body during strenuous exercises.

• It acts as a vital component of the blood plasma, which serves as a medium of transport.

• It is needed for various metabolic reactions in the body.

• It acts as a lubricant for joints, and a cushion for the brain and spinal cord. The synovial fluid also acts as a lubricant for joints.

• It is required by the kidneys to eliminate urea. It also support the movement of food through the intestine.

• It keeps the skin healthy and hydrated.

Please read on the continuation of this topic (balanced diet) here.

Please read basic science scheme of work for jss1 first term here.