DR VISHNU KUMAR PROFESSOR AND HOD BIOCHEMISTRY, MADHAV PRASAD TRIPATHI GOVERNMENT MEDICAL COLLEGE, SIDDHARTH NAGAR, UTTAR PRADESH.

1. NUTRITION
BI 8.1 TO 8.5
Dr. Vishnu Kumar
Professor & Head, Department of
Biochemistry, MPTMC, Siddharthnagar
vkawasthi@hotmail.com
madhwapur1976@gmail.com

2. Learning Objectives
• Introduction
• Proximate Principles of nutrition
 Respiratory quotient
 Basal Metabolic Rate
 Specific Dynamic action
• Nutritive indices of proteins
• Nutritional Importance of Protein

3. Nutrition is the science of food and the nutrients
and other substances contained in food.
It is the study of their actions, interactions and
balance in relation to health and disease.

4. There are five classes of nutrients that contribute
to an adequate diet. Each plays a special role.
These may be divided into :
• Macronutrients
• Micronutreints

5. Macronutrients
• Carbohydrates
• Fat
• Protein
Micronutrients
• Vitamins
• Mineral elements
Macrominerals
Microminerals

6. Food- provide energy (calories) & body building
materials.
Calorie- heat required to raise temp. of 1g of
water through 1°C.(kCal=1000cal)
Calorific value (kCal/g)
Carbohydrate 4
Fat 9
Protein 4.2
Alcohol 7

7. • Protein ,fats & carbohydrates are some times
referred as proximate principle. They form the
main bulk of food.
• They are oxidized in body to yield energy, which
the body needs.
• Though the protein provides energy their primary
function is to provide essential and nonessential
amino acids for building of proteins.
• Fats, concentrated form of energy, provide
essential fatty acids.

8. In Indian dietary intake, they contribute to total
energy in the following proportion-
Proteins 7 to 15%
Fats 35 to 45%
Carbohydrates 50 to 70%

9. Respiratory Quotient
(RQ)
Defined as the ratio of volume of CO2 produced
to the oxygen consumed.
RQ = CO2 produced
O2 consumed
Carbohydrates = 1
Fat = 0.7
Protein = 0.8

10. Factors affecting energy expenditure:
• Basal metabolic rate
• Thermogenic effect (specific dynamic
actions) of food
• Physical activity
• Environmental temperature

11. Basal metabolic rate (BMR)
Energy required by the person who is
a) At complete physical and mental rest.
b) Awaken state.
c) Post-absorptive condition.
d) Ideal room temp (26°C).
e) Stress free environment.
Men (34-37 kCal/m²body surface area / hr)
Women (30-35 kCal/m²body surface area / hr)

12. • BMR is the energy required by an awake
individual during physical, emotional and
digestive rest.
• It is the minimum amount of energy
required to maintain life or sustain vital
functions like the working of the heart,
circulation, respiration etc.

13. Measurment of Basal Metabolism
Basal metabolism can be measured by:
• Calorimeter directly by measuring the heat
dissipated under basal condition or
• Indirectly by measuring oxygen
consumption and carbon dioxide evolved
per unit time.

14. BMR measurement

15. Factors affecting BMR
1.Age (Children > adults )
2. Sex ( Male > female )
3. Body surface area (Built > lean )
4. Temperature (Cold > hot)
5. Ethnic ( Western > asian)
6 .Exercise ↑
7. Starvation ↓
8. Fever ↑
9. Hormone Thyroid ↑

16. KNOW YOUR BMR
Women: BMR = 655 + ( 9.6 x w ) + ( 1.8 x h ) - ( 4.7 x a)
Men: BMR = 66 + ( 13.7 x w) + ( 5 x h ) - ( 6.8 x a)
Unit: kcal/day
w = weight in kg
h = height in cm
a = age in years.

17. Specific Dynamic Action (SDA)
• This is the energy expended in the digestion ,
absorption, storage and subsequent processing of
food.
• This is called the thermogenic effect of food as
these process require energy and generate heat.
• SDA can be considered as the activation energy
needed for a chemical reaction. This energy has to
be supplied initially.

18. • The consumption of protein produces the
greatest increase in energy loss compared to fat
or carbohydrate.
• Proteins 30%
• Fat 15%
• Carbohydrates 5%
• Mixed diet 10%
In some people a high degree of diet induced
thermogenesis may be a factor which allows
them to maintain a normal body weight even
after overeating.

19. Physical Activity
• Represents 20 – 40% of the total energy
expenditure.
• Because of great variation in amount of
physical activity among individuals , this
component of energy expenditure is the
most important reason for the difference in
caloric intake required to maintain energy
balance.

20. Environmental Temperature
• Temp. will affect the metabolic rate.
• Low temp. increases energy expenditure by
inducing shivering and nonshivering
thermogenesis.
• Shivering provides a regulated means of
producing heat by increasing muscle activity in
response to cold stress.
• Nonshivering thermogenesis can also produce heat
in response to cold stress. The site is brown
adipose tissues.

21. Nutritional importance of proteins
• Proteins are vital to any living organism
• Important constituents of tissues and cells
• Supply the body building material & make
good the loss that occur due to wear and
tear.
• Forms the defense system of body

22. Nitrogen Balance
Catabolism of amino acids leads to a net loss of
nitrogen from the body. This loss must be
compensated by diet in order to maintain a
constant amount of body protein.
Nitrogen balance studies evaluate the relationship
between the nitrogen intake and nitrogen
excretion.

23. Intake of nitrogen = excretion of nitrogen (Healthy)
Intake of nitrogen > excretion of nitrogen (+NB)
Intake of nitrogen < excretion of nitrogen (- NB)
Proteins are major source of nitrogen (16%)
Positive Nitrogen Balance Negative nitrogen balance
• growing period, starvation
• pregnancy acute & chronic illness
• convalescence protein deficiency

24. Nutritional indices of proteins
• Biological value of proteins (BV)
• Net protein utilization (NPU)
• Net dietary protein value (NDPV)
• Protein efficiency ratio (PER)
• Chemical score.

25. Biological value of proteins (BV)
Defined as the percentage of absorbed nitrogen retained
by the body and is calculated by-
BV = Retained nitrogen X 100
Absorbed nitrogen
Egg BV = 97 very good protein
Milk 84
Meat 80
Fish 85
Rice 64
Groundnut 54

26. Net protein utilization (NPU)
NPU = Retained nitrogen X 100
Intake of nitrogen
• Better index than BV to denote nutritional quality
of proteins.
Milk 75
Meat 76
Fish 72
Rice 57
Groundnut 45

27. • Biological measures of NPU gives a more
complete expression (both absorption and
retention) of protein quality than chemical score.
• In calculating protein quality , 1g of protein is
assumed to be equivalent to 6.26g of nitrogen.
• Protein requirement varies with the NPU of
dietary protein. If NPU is low the protein
requirement is high and vice versa.
• The NPU of the protein of Indian diet varies
between 50-60.

28. NDPV & PER
NDPV - Intake of nitrogen x 6.25 x NPU
Protein Efficiency Ratio – The nutritive value of
food protein can be determined with lab animals
like rat.
Gain in weight in gm / Protein ingested in gm

29. Chemical Score is a measure of the conc. of each
EAA in the test protein expressed as a percentage
of that amino acid in the reference protein.
This mode of assessment does not take into account
the digestibility of dietary protein.
The chemical score for starches is between 50- 60
and for animal food is 70 -80.
Chemical score - mg of EAA / gm of protein
mg of amino acid / 1g of protein X 100
mg of amino acid / 1g of egg protein

30. Nutritive value of food proteins
Protein BV NPU PER Chemical score
Egg 90 91 4.5 100
Milk 84 75 3.0 65
Fish 85 72 3.0 60
Meat 80 76 2.8 70
Rice 64 57 2.0 60
Wheat 58 47 1.7 42
Bengal gram 58 47 1.7 44
Groundnut 54 45 1.7 44
Soya bean 64 54 2.0 57

31. Limiting amino acid
• One or more essential amino acids which is deficient in
the protein which limits the weight gain.
• Problem can be solved by mutual
supplementation of proteins in the diet.

32. Protein limiting Amino acid Mutual supplied
protein
Rice Lysine, threonine pulse proteins
Wheat Lysine, threonine pulse proteins
Gelatin Tryptophan milk protein
Zein Tryptophan, Lysine fish protein
Tapioca Phenylalanine fish protein
Bengal gram Cysteine, methionine cereals

33. EAT TO LIVE
AND NOT
LIVE TO EAT
THANK YOU