Chapter 7) Human nutrition

Essential nutrients

Proteins, Carbohydrates, Fats & oils, Vitamins & mineral ions, Fiber, Water.

Proteins

Function: Growth and repair

Made of: Amino acids

Digested into: Amino acids

Ex: eggs, milk, milk products, meat, fish, legumes

Carbohydrates

Function: Energy

Made of: Carbon, hydrogen, and oxygen

Digested into: Glucose

Ex: rice, bread, potatoes

Fats & oils.

Function: Energy storage, insulation, protection

Made of: Fatty acids and glycerol

Digested into: Fatty acids and glycerol

Ex: Nuts, Avocado, milk products, oily fish

Vitamins and mineral ions

Function: Vitamins; Maintain health and prevent deficiency diseases

Function: Minerals; Important for body functions (e.g. calcium for bones, iron for hemoglobin)

Made of: cannot be produced by the body

Ex: Vitamin C is best supplied by eating raw fruit & vegetables

Lack of: Can cause different deficiency diseases (such as scurvy or rickets.)

Fibre

Function: Preventing constipation and gut mobility

Made of: of the cell walls of plants.

Ex: leafy vegetables

Water

Necessary for all life processes

Vitamin C

Role: For healthy skin, teeth, and keeps lining of blood vessels healthy.

Food source: Citrus fruit, green vegetables, potatoes

Deficiency disease: Scurvy (bleeding gums, wounds do not heal properly)

Vitamin D

Role: Strong bones and teeth

Food source: Fish, eggs, liver, cheese and milk

Deficiency disease: Rickets (softening of the bones)

Calcium

Role: Strong bones and teeth, and involved in the clotting of blood

Food source: Milk and eggs

Deficiency disease: Rickets (softening of the bone)

Iron

Role: Needed to make haemoglobin in red blood cells

Food source: Red meats, liver and kidneys, leafy green vegetables

Deficiency disease: Anaemia (reduction in number of red blood cells , person becomes tired and short of breath)

Balanced diets

Contains all nutrients in the right proportions to stay healthy

Digestive system

1. Ingestion: Taking substances into the body through the mouth

2. Digestion: Breakdown of food

3. Absorption: Movement of nutrients from the intestines into the blood

4. Assimilation: Uptake and use of nutrients by cells

5. Egestion: Removal of undigested food from the body as faeces

All take place in Alimentary canal

Alimentary canal

Continuous tube through the body, from the mouth where food is ingested, through the oesophagus, stomach, small intestine, and large intestine, to the anus where faeces are egested

Function of the mouth?

Ingestion, chewing, starts starch digestion.

Function of the oesophagus?

Moves food using peristalsis.

Function of the stomach?

Digests protein and kills bacteria with acid.

Function of the liver?

Produces bile.

Function of the gall bladder?

Stores bile.

Function of the pancreas?

Produces digestive enzymes.

Function of the small intestine?

Digestion and absorption.

Function of the large intestine?

Absorbs water.

Peristalsis

involuntary, wave-like contraction and relaxation of muscles that propels contents through hollow organs, primarily in the digestive tract.

Physical digestion

Involves the mechanical breakdown of food into smaller pieces without altering its chemical structure

Chemical digestion

Involves enzymatic reactions that break down food into simpler nutrients, altering its chemical composition

Bile

greenish-yellow fluid produced by the liver that plays a crucial role in the digestion and absorption of fats.

Absorption

Movement of nutrients into the blood

Lipase

Function: Breaks lipids into fatty acids and glycerol

Where its produced: Pancreas

Amylase

Function: Breaks starch into maltose

Where its produced: Salivary glands and pancreas

Protease

Function: Breaks proteins into amino acids

Where its produced: Stomach and pancreas