Nutritional Importance of Proteins

MARYAM JAMILAH BINTI ABDUL HAMID082013100002

IMS BANGALORE

Introduction

Recommended protein allowances (WHO)

Proteins from animal sources• Have a high quality since they contain all

essential amino acids in proportions similar to those required for synthesis of human tissue proteins

• Gelatin prepared from animal collagen deficient in certain essential amino acids; poor quality

Proteins from plant sources• Have lower quality than animal proteins• May be combined in such a way as to improve

quality

Biological value of some dietary proteinsSource BV

Egg 100Beef 100Milk 85

Soya bean protein 67

Potato

30

67

Whole wheat bread Ability to provide the all essential amino acids required for tissue maintenance Measured on a relative scale with egg albumin scored at 100

Learning Outcome

• Essential amino acid• Maintain nitrogen balance• Mutual supplementation

Essential amino acid

• H VITTAL LMP• Building blocks for body tissues, bones, muscles,

cartilage, skin, and blood.• During starvation, provide energy (10-15%)• Enough carbohydrate intake, act as protein sparing

effect• It is a component of every cell in your body. In fact,

hair and nails are mostly made of protein• Your body uses it to build and repair tissue.• You need it to make enzymes, hormones, and other

body chemicals

Maintain nitrogen balance

•Nitrogen loss is 3.5 g of N/day 22 g of protein (65 kg person)•For protein turnover (0.75-0.8 g/kg of good quality protein)•For growth

POSITIVE NITROGEN BALANCE

• Occurs when nitrogen intake exceeds nitrogen excretion

• Observed during situations in which tissue growth occurs

Eg: childhood, pregnancy, during recovery from an illness

NEGATIVE NITROGEN BALANCE

• Occurs when nitrogen losses exceed nitrogen intake

Occurs due to

• Inadequate dietary protein, lack of essential amino acid

• Trauma, burns, illness, surgery

Mutual Supplementation

Proteins from different plant sources may be combined in such a way that deficiency of an

essential amino acid in one protein is compensated by the adequate amount of the

same in another protein

• Eg: Wheat protein (lysine-deficient, methionine-rich) with kidney bean protein (methionine-deficient, lysine-rich)

• Results in a protein mixture of improved biological value, equivalent to animal protein

REFERENCES

• Vasudevan, D., S, S., & Vaidyanathan, K. (2013).Textbook of biochemistry for medical students.New Delhi: Jaypee Brothers Medical Publishers (P) Ltd.

• http://www.detourbar.com/protein-basics/the-importance-of-protein-in-your-diet/

Thank you