Health and Human Development - Nutrients and their impact on health:
Growth and repair of body tissues. Proteins form the structure of the soft
and hard tissues that make up most parts of the body. Hard tissue includes
bones and teeth. Soft tissue includes skin, muscles, organs, tendons,
membranes, enzymes, hormones and antibodies. All these tissues are
constantly being produced.
Proteins control fluid, electrolyte and acid-base balance in the body.
Proteins also provide some energy. The 'Better Health Commission Targets
for 2000 and Beyond' suggest no more than 12%-15% of energy should come
Severe deficiencies are rare in developed countries and when occasionally
seen, would be related to child abuse or extreme cases of anorexia nervosa.
Lower than recommended intakes of protein in young children slow the growth
rate of all parts of the body, including the brain.
In countries with a long history of war or famine, where crops frequently
fail, protein deficiency diseases are commonly seen in young children.
Marasmus is a combined protein-energy deficiency resulting from starvation.
Kwashiorkor  results from a lack of protein in the diet, usually
occurring in young children after weaning.
More common in industrialised countries. When more protein is eaten then
required, the amino acids that make up the protein molecule are deaminated;
meaning the nitrogen-containing amine group is separated.
Deamination  produces ammonia, which the cells release into the blood
stream. The liver then takes this up.
Liver cells convert the ammonia to urea and release this into the blood to
be filtered out by the kidneys and excreted in the urine. The carbon
section that remains can be converted to energy if required, or stored as
Complete proteins are found in meat, chicken, fish, eggs, cheese, and
milk. The proteins of bread, cereals and vegetables, although incomplete,
are readily available when combined with other foods.
View the video to learn more about the use of meats in the diet.
Previous | Next