Nutrition and health-for MBBS and BDS students

1. NUTRITION
DR. V.P. ACHARYA

2. Top 6 food scams that makes the world fat
and unhealthy
•Fat-free foods
•Healthy whole grains
•Organic processed food
•Sports and recovery drinks
•Foods with added protein
•Natural

3. Definitions
• Nutrition : Science of food and its
relationship to health
• Diet: a particular selection of food, especially
as designed or prescribed to improve a
person's physical condition or to prevent or
treat a disease: a diet low in sugar.
• Dietetics: Practical application of the
principles of nutrition
• Nutrients: Organic & inorganic complexes
contained in the food

4. • Macronutrients: Carbohydrates,
lipids, proteins
• Micronutrients: Vitamins &
minerals
• DRI: Dietary reference intake
By US and Canadian experts

5. Dietary reference intake- estimates the amount of
nutrient required to maintain normal growth as
well as prevent deficiencies
Estimated
average
requireme
nt
Recomme
nded
dietary
allowance
Adequate
intake
Tolerable
upper
intake
level

6. DRI- 4 dietary standards for different age
groups, gender and physiologic stage
1. Estimated average requirements
(EAR): Average daily nutrient intake
level estimated to meet requirements
of ½ the healthy individuals in a
particular life stage and gender group.
Estimates actual requirements in groups
and individuals

7. 2. The recommended dietary allowance:
Average daily dietary intake level that is
sufficient to meet the nutrient
requirements of nearly all (97-98)
individuals in a life stage and gender
group.
RDA = EAR + 2 SDEAR

8. 3. Adequate intake: When sufficient
scientific evidence is not available for
calculating EAR & DRA.
Based on estimates of nutrient intake by a
group
Ex: Infants on mother’s milk for first 4-6
months

9. 4. Tolerable upper intake level:
Highest average daily nutrient intake
level that is likely to pose no risk of
adverse health effects to almost all
population.

10. Respiratory coefficient
R.Q. =
R.Q. of carbohydrates = 1
Fat = 0.7
Protein = 0.8
Mixed diet = 0.7 - 1
consumedO2ofVolume
produced2COofVolume

11. CALORIFIC VALUE
One calorie is the heat required to raise the
temperature of 1g water through 10c
Medical science- Kcal (depicted by C)
1Kcal = 4.2 K joules
Bomb calorimeter- measures calorific value of
food
Overall efficiency of conversion of energy to ATP
is 40%

12. Bomb calorimeter

13. Energy yield from nutrients
Nutrient Calorific value in
KCal / g
Carbohydrates 4
Fats 9
Proteins 4
Alcohol 7

14. BMR
• Basal metabolic rate
• The energy required by an awake individual
during physical, emotional and digestive rest
• Measurement- Benedict Roth basal
metabolism apparatus - direct calorimetry
• Indirect calorimetry- by measuring O2
consumed and CO2 released

15. RMR- Resting metabolic rate
• 10% higher than BMR
• 24-Hr RMR – REE (Resting energy expenditure)
↓
1800 Kcal for men (70 Kg)
1300 Kcal for women (50Kg)

16. Factors affecting BMR
1. Age – Period of active growth
peak at 5 years
Old age - ↓
2. Gender- M> F
3. Temperature- cold temperature ↑ es e.g.
Eskimos
4. Exercise- ↑ es
5. Starvation- ↓es

17. 6. Fever – Per degree centigrade 12%
↑ in BMR
7. Thyroid hormones – ↑ BMR

18. Normal levels of BMR
• Adult men – 34-37 Kcal/ Sq.m/ Hour
• Women- 30-35 Kcal / Sq.m/ Hour
• For easier calculations-
24 Kcal/ Kg body wt/ day
• Rough estimate- 1Cal/Kg/hr for men
0.9.Cal/ Kg/ Hr for women

19. SDA
• Specific dynamic action
• Thermogenic effect of food
• Increased heat production following food
intake
• Due to the expenditure of energy for digestion
and absorption of food
• Activation energy needed for a chemical
reaction
• Significance: Helps in calculating total energy
requirement

20. Nutrient SDA
Carbohydrates 5%
Proteins 30%
Fat 15%
Mixed diet 10%

21. Physical activity
Type of physical activity Extra calories to be added
Sedentary +30% of BMR
Moderate +40% of BMR
Heavy +50% of BMR
Pregnancy +300 Kcal/day
Lactation +500 Kcal/day

22. SO WHAT’S YOUR CALORIE
REQUIREMENT?
?
?
RMR + Physical activity + Thermic effect of food (SDA)

24. DIET

25. PROXIMATE PRINCIPLES
• CARBOHYDRATES
• PROTEINS
• FAT

26. CARBOHYDRATES
• Calories derived from carbohydrates- 7
Kcal/gm
• 60-65% Cal
• Available Vs unavailable carbs- starch, sugars
Vs Cellulose, pectin, lignin
• Where do we found carbohydrates??
• Sucrose- the big culprit
• Dietary fibre

27. Beauty….You are my way to the Divine

28. LIPIDS- Are they all bad??
• Visible Vs invisible fat
• Visible fat should be 15-20% of total calorie
intake- 20 g/day- 25-30% should be PUFA
(~3g)
• Fat consumption has increased from 3Kg to 13
Kg /Yr over last 50 years!!!
• ω6 Vs ω3 FA
• Trans FA

30. Proteins- only source for essential AA
• Protein sparing effect- when carbohydrates
are present, they are not used for energy
• 0.75-0.8 g/kg/day- Rough estimate 1g/Kg/day
• 10-15% of energy supplied by protein

31. Nitrogen balance- I= U+ F+ S
• Factors affecting nitrogen balance
Growth +
Hormones- GH, Insulin ,androgen (+) &
Cortocosteroids (-)
Pregnancy +
Convalescence +
Acute illness -
Chronic illness -
Protein deficiency -

32. Mutual supplementation of
proximate principles
• Pulses- Rich in Lys but deficient in Methionine
• Cereals- Lack in Lysine but rich in Methionine
• Combination of Chapati/ Rice + Dal is aideal

33. Malnutrition
• Over-nutrition- Obesity
• Under-nutrition- PEM (Protein energy
malnurition)
• India faces the dual burden

34. PEM
Parameters Kwashiorkor Marasmus
Cause Late weaning and starchy
diet
Early weaning and
repeated infection
Age <1 year 1-5 years
Growth retarded Marked
Attitude Lethargic & apathetic;
sugar baby
Irritable
Appearance Plump due to edema Chip-munk facies
Appetite Anorexia Eager to eat

35. Kwashiorkor Vs Marasmus
Parameters Kwashiorkor Marasmus
Skin Crazy pavement dermatitis Dry and atrophic
Hair Flag sign No specific change
S. Albumin <2 g/dl 2-3 g/dl
S. Cortisol ↓ ↑

37. Obesity
• Measured in terms of BMI,
WHR, waist circumference
etc
• Multifactorial
• Genetics come last

38. Obesity affects almost all organs!!!

39. Designing a balanced diet chart-
Eating right

41. Glycemic index
• Glycemic response of a specific meal as compared
to a reference meal (Usually 50gm glucose)