Diet

A balanced diet is a diet that contains all the essential nutrients in the correct proportions and right quantities needed to maintain health, growth, and development.
A balanced diet must include:
- enough energy (provided by carbohydrates, fats, and proteins)
- essential amino acids from proteins
- essential fatty acids from fats
- micronutrients (vitamins and minerals)
- water to replace water lost in urine, sweat, breath and feces
- fibre for moving food from the mouth to the anus along the gut.
- If eaten in the correct proportions, these components make up a balanced diet which is a healthy diet.

Principal dietary sources and importance

From rice, pasta, bread, potatoes, cereals.
Primary source of energy. Broken down during respiration to release energy for cellular processes.

From meat, fish, eggs, beans, pulses, tofu, dairy.
Growth and tisue repair. Essential for manufacturing enzymes, anttibodies, and certain hormones.

From citrus fruits (e.g. oranges, lemons), strawberries, green vegetables.
Essential for maintaining healthy skin and gums, critical for collagen production and wound healing.

From oily fish, eggs, liver, dairy products, sunlight.
Needed for the absorption of calcium in the small intestine to build strong bones and teeth.

Calcium comes from milk, cheese, yogurt, green leafy vegetables (e.g. broccoli).
Calcium is essential for structural strength of bones and teeth, muscle contraction, and blood clotting.
Iron comes from red meat, liver, spinach, egg yolks, dark chocolate.
Iron is an essential component of hemoglobin in red blood cells, which binds and transports oxygen around the body.

From wholemeal bread, brown rice, oats, fruit, vegetable skins.
Adds bulk to food in the alimentary canal, providing muscles with something to push against to stimulate peristalsis and prevent constipation.

From drinking water, juices, milk, water-rich fruits (e.g. melon, tomatoes).
Acts as a solvent for metabolic/chemical reactions, serves as a transport medium (plasma, urine) and aids in temperature regulation (sweating).

Scurvy is caused by a severe deficiency of Vitamin C.
Key symptoms of scurvy are:
- severe joint pain
- bleeding gums
- loose teeth
- wounds that fail to heal properly because of the breakdown of collagen fibers.

Rickets is caused by a severe deficiency of Vitamin D.
Key symptoms of rickets are:
- soft, weak bones that bend or bow outward under the body’s weight that lead to skeletal deformities
- dental problems