Why protein is important in our daily diet


The two main types of protein are complete protein and incomplete protein. Complete proteins come from animal products and contain all essential amino acids. Incomplete proteins are low in certain essential amino acids and come from non-animal products.


Animal sources of complete proteins include meat, poultry, fish, eggs, milk and milk products. Other sources of incomplete proteins include vegetables, legumes, tofu, nuts, seeds, grains and fruits.

Digestion Of Protein:

Digestion of protein starts in stomach because of the protein-spitting enzyme. The process is continued to duodenum and small intestine. They are broken down to amino acids and small peptide chains and absorbed. Digestion of protein is impaired when there is deficiency of enzymes or there is anatomical defect in digestive tract.

Protein deficiency (causes)

  • Low intake or loss of appetite.
  • Poor digestion and absorption.
  • Reduced synthesis when the amino acids are not converted to albumin.
  • Excessive loss in diseases likes nephrites, cirrhosis of liver with ascites (collection of fluid in abdominal cavity), gastroenteropathy and profuse expectoration in bronchiectasis (localised dilatation of bronchus due to infection) or lung abscess.

Protein deficiency (effects)

  • Weakness.
  • Anaemia.
  • Protein energy malnutrition – kwashiorkor and marasmus.
  • Delayed wound and fracture healing.
  • Decreased resistance to infection because antibody formation is decreased.
  • Sprue syndrome.