Nutritional Biochemistry

1. Course: B.Sc. Biochemistry
Sub: introduction to biochemistry
UNIT-3.2
1

2. INTRODUCTION
Nutrition may be defined as the science of
food and its relationship to health. It is
concerned primarily with the part played
by nutrients in body growth, development
and maintenance .
The word nutrient or “food factor” is used
for specific dietary constituents such as
proteins, vitamins and minerals. Dietetics
is the practical application of the
principles of nutrition; it includes the
planning of meals for the well and the sick.
Good nutrition means “maintaining a
nutritional status that enables us to grow
well and enjoy good health.”
2

3. Protein, carbohydrate and fat
had been recognized early in
the 19th century as energy-
yielding foods and much
attention was paid to their
metabolism and contribution
to energy requirements.
3

4. CLASSIFICATION OF FOODS
 Classification by origin:
- Foods of animal origin
- Foods of vegetable origin
 Classification by chemical composition:
- Proteins
 Fats
 Carbohydrates
 Vitamins
 Minerals
4

5. CLASSIFICATION BY PREDOMINANT
FUNCTION
Body building foods:
-meat, milk, poultry, fish, eggs, pulses etc
Energy giving foods:
-cereals, sugars, fats, oils etc.
Protective foods:
-vegetables, fruits, milk, etc
5

6. NUTRIENTS
Organic and inorganic complexes
contained in food are called nutrients.
They are broadly divided in to:
Macronutrients:
-proteins
-fats
-carbohydrates
Micronutrients:
-vitamins
-minerals
6

7. 7

8. PROTEINS
PROTEINS ARE COMPLEX ORGANIC
NITROGENOUS COMPOUNDS.
THEY ALSO CONTAIN SULFUR AND I SOME
CASES PHOSPHOROUS AND IRON.
PROTEINS ARE MADE OF MONOMERS
CALLED AMINO ACIDS.
THERE ARE ABOUT 20 DIFFERENT
AMINOACIDS WHICH R FOUND IN HUMAN
BODY.
OF THIS 8 AA ARE TERMED “ESSENTIAL” AS
THEY ARE NOT SYNTHESIZED IN HUMAN
BODY AND MUST BE OBTAINED FROM
DIETARY PROTIENS.
8

9. Functions of Proteins
Body building
Repair and maintenance of body
tissues
Maintenance of osmotic pressure
Synthesis of bioactive substances
and other vital molecules
9

10. Evaluation of proteins
The parameters used for net
protein evaluation are:
Biological value
Digestibility coefficient
Protein efficiency ratio
Net protein utilization (NPU)
10

11. Assessment of Protein nutrition
status
Protein nutrition status is measured by Serum
Albumin Concentration.
It should be more than 3.5 g/dl.
Less than 3.5 g/dl shows mild malnutrition.
Less than 3.0 g/dl shows severe malnutrition.
11

12. FATMost of the body fat (99 per cent) in
the adipose tissue is in the form of
triglycerides, in normal human
subjects, adipose tissue constitutes
between 10 and 15 per cent of body
weight. One kilogram of adipose
tissue corresponds to 7700 kcal of
energy.
12

13. Essential fatty acids are those that
cannot be synthesized by humans
Dietary sources of EFA
Linoleic acid
Sunflower oil Corn oil Soya bean oil Sesame
oil Groundnut oil Mustard oil Palm oil
Coconut oil
Arachidonic acid
Meat, eggs, milk
 Linolenic acid
Soya bean oil, Leafy greens
13

14. Functions of fatsThey are high energy foods, providing as much
as 9 kcal for every gram.
Fats serve as vehicles for fat-soluble vitamins
Fats in the body support viscera such as heart,
kidney and intestine; and fat beneath the skin
provides insulation against cold.
14

15. The “non-calorie” roles of fat
vegetable fats are rich sources of essential fatty
acids which are needed by the body for growth,
structural integrity of the cell membrane and
decreased platelet adhesiveness.
Diets rich in EFA have been reported to reduce
serum cholesterol and low-density lipoproteins.
Polyunsaturated fatty acids are precursors of
prostaglandins.
15

16. Fat requirements
In developed countries dietary fats provide 30 to
40 per cent of total energy intake. The WHO
Expert committee on Prevention of Coronary
Heart Disease has recommended only 20 to 30
per cent of total dietary energy to be provided by
fats. At least 50 per cent of fat intake should
consist of vegetable oils rich in essential fatty
acids.
16

17. CARBOHYDRATE
Carbohydrate is the main source
of energy, providing 4 Kcals per
one gram Carbohydrate is also
essential for the oxidation of fats
and for the synthesis of certain
non-essential amino acids
17

18. Sources of carbohydrates
There are three main sources of carbohydrate, viz.
starches, sugar and cellulose.
The carbohydrate reserve (glycogen) of a human
adult is about 500g. This reserve is rapidly
exhausted when a man is fasting. If the dietary
carbohydrates do not meet the energy needs of the
body, protein and glycerol from dietary and
endogenous sources are used by the body to
maintain glucose homeostasis.
18

19. Dietary fibre
Dietary fibre which is mainly non-starch
polysaccharide is a physiological important
component of the diet. It is found in vegetables,
fruits and grains. It may be divided broadly into
cellulose and non-cellulose polysaccharides
which include hemi-cellulose pectin, storage
polysaccharides like inulin, and the plant gums
and mucilage. These are all degraded to a greater
of lesser extend by the micro flora in the human
colon
19

20. VITAMINS
Vitamins are a class of organic compounds
categorized as essential nutrients. They are
required by the body in a very small amounts.
They fall in the category of micronutrients.
Vitamins are divided in to two groups: fat soluble
vitamins- A, D, E and K and water soluble
vitamins: vitamins of the B-group and vitamin C.
20

21. VITAMIN A
Vitamin A» covers both a pre-
formed vitamin, retinol, and a pro-
vitamin, beta carotene, some of
which is converted to retinol in the
intestinal mucosa.
The international unit (IU) of
vitamin A is equivalent to 0,2
microgram of retinol (or 0,55
microgram of retinal palmitate).
21

22. Functions of Vitamin AIt is indispensable for normal vision.
It contributes to the production of retinal
pigments which are needed fro vision lights.
It is necessary for maintaining the integrity and
the normal functioning of glandular and epithelial
issue which lines intestinal , respiratory and
urinary tracts as well as the skin and eyes.
It supports growth, especially skeletal growth
It is antiintencive.
It may protect against some epithelial cancers such
as bronchial cancers.
22

23. Deficiency of vitamin A
 The signs of vitamin A deficiency are
predominantly ocular. They are:
 Nightblindness
 Conjunctival xerosis
 Bigot's spots
 Corneal xerosis
 Keratomalacia
23

24. VITAMIN D
The nutritionally important
forms of Vitamin D in man are
Calciferol (Vitamin D2) and
Cholecalciferol (Vitamin D3).
24

25. Functions of vitamin D and its
metabolites
Intestine: Promotes intestinal absorption of
calcium and phosphorus
Bone: Stimulates normal mineralization,
Enhances bone reabsorption, Affects collagen
maturation
Kidney: Increases tubular reabsorption of
phosphate
25

26. Deficiency of vitamin D
Deficiency of vitamin D leads to:
Rickets
Osteomalacia
26

27. THIAMINEThiamine (vitamin B1) is a water
soluble vitamin. It is essential for
the utilization of carbohydrates.
Thiamine pyrophosphate (TPP), the
coenzyme of cocarboxylase plays a
part in activating transkelolase, an
enzyme involved in the direct
oxidative pathway for glucose.
27

28. Deficiency of thiamine
The two principal deficiency diseases are beriberi
and Wernick's encephalopathy.
Beriberi may occur in three main forms:
 peripheral neuritis,
 cardiac beriberi
infantile beriberi, seen in infants between 2 and 4
months of life. The affected baby is usually breast-
fed by a thiamine-deficient mother who
commonly shows signs of peripheral neuropathy.
Wernick’s encephalopathy is characterized by
ophthalmoplegia, polyneuritis, ataxia and mental
deterioration
28

29. VITAMIN B6
Pyridoxine (vitamin B6) exists in three forms
pyridoxine, piridoxal and pyridoxamine. It plays an
important role in the metabolism of amino acids,
fats and carbohydrate.
The requirement of adults vary directly with
protein intake. Adults may need 2 mg/day, during
pregnancy and lactation, 2.5 mg/day. Balanced diets
usually contain pyridoxine, therefore deficiency is
rare.
29

30. VITAMIN B12
Vitamin B12 is a complex organo-metallic
compound with a cobalt atom. The preparation
which is therapeutically used is cyanocobalamine.
 Vitamin B 12 cooperates with foliate in the
synthesis of DNA.
Vitamin B 12 has a separate biochemical role,
unrelated to folate, in synthesis of fatty acids in
myelin
30

31. Vitamin B12 deficiency
Vitamin B12 deficiency is associated with
megaloblastic anaemia (per nicous anaemia),
demyelinating neurological lesions in the spinal
cord and infertility (in animal species). Dietary
deficiency of B12 may arise the subjects who are
strict vegetarians and eat no animal product. At
the present time there is little evidence that
vitamin B12 deficiency anaemia represents an
important public health problem.
31

32. VITAMIN C
Vitamin C (ascorbic acid) is a water-soluble
vitamin. It is the most sensitive of all vitamins to
heat. Man, monkey and guinea pig are perhaps
the only species known to require vitamin C in
their diet
Vitamin C has an important role to play in tissue
oxidation it is needed for the formation of
collagen, which accounts for 25 per cent of total
body protein
32

33. Deficiency of vitamin C
Deficiency of vitamin C results in
scurvy, the signs of which are swollen
and bleeding gums, subcutaneous
bruising or bleeding into the skin or
joints, delayed wound healing, anaemia
and weakness. Scurvy which was once an
important deficiency disease is no
longer a disease of world importance.
33

34. NUTRITIONAL PROFILES OF PRINCIPAL
FOODS
The principal food includes:
Cereals
Millets
Pulses
34

35. Cereals
Cereals (e.g. rice, wheat) constitute the bulk of
the daily diet. Rice is the staple food of more
than half the human race. Next to rice, wheat is
the most important cereal. Maize ranks next to
rice and wheat in world consumption. Maize is
also used as food for cattle and poultry because it
is rich in fat, besides being cheaper than rice or
wheat.
35

36. Assessment of protein in cereals
Protein quality:
The quality of a protein is assessed by comparison to the “
reference protein” which is usually egg protein . Two
methods of assessment of protein quality need be
mentioned:
(i) Amino acid score: It is measure of the concentration of
each essential amino acid in the reference protein.
Number of mg of one amino acid per g of protein
Amino acid score= ……….......................................... x 100
Number of mg of the same amino acid per g of egg
protein.
Net protein, utilization (NPU):
Nitrogen retained by the body
NPU=.......................................................................x 100
Nitrogen intake
In calculating protein quality, 1 gram of protein is
assumed to be equivalent to 6.25 g of N.
36

37. Calculating protein quantity of cereals
 Protein quantity:
 The protein content of many Indian foods has
been determined and published in food
composition tables. One way of evaluating foods
as source of protein is to determine what per cent
of their energy value is supplied by their protein
content. This is known as Protein – Energy Ratio
(PE ratio or percentage).
 PE per cent = Energy from protein x 100
Total energy in diet
37

38. Fat requirements from cereals
The daily requirement of fat is not known
with certainty. During infancy, fats
contribute to a little over 50 per cent of the
total energy intake. This scales down to
about 20 per cent in adulthood. The ICMR
Expert Group (1981) has recommended an
intake of 20 per cent of the total energy
intake as fat , of which at least 50 per cent of
fat intake should consist of vegetable oils
rich in essential fatty acids. The requirement
of essential fatty acids ranges from 3 per cent
intake to 6 per cent of energy intake in young
children. 38

39. Carbohydrate requirements from
cereals
The recommended intake of carbohydrate in
balanced diets is placed so as to contribute
between 50 and 70 per cent of total energy
intake. Most Indian diets contain amounts
more than this providing as much as 90 per
cent of total energy intake in some cases,
which makes the diet imbalanced.
39

40. Other recommended intakes
from cereals
Fat soluble vitamins
The recommended dietary allowance of vitamin
E is placed at 10 mg of alpha tocopherol
equivalents for adult males and 8 mg for adult
females.
Water soluble vitamins
The requirements of thiamine , riboflavin and
niacin are closely related to energy intake and
utilization, and are started in terms of 1000 kcal
intake of energy as below:
Thiamine 0.5 mg/1000kcal
Riboflavin 0.6 mg/1000kcal
Niacin 6.6 mg/1000kcal
40

41. Healthy diet (Balanced Diet)
A healthy diet is one that helps maintain or improve general
health. A healthy diet provides the body with essential
nutrition: fluid, adequate essential amino acids from protein,
essential fatty acids, vitamins, minerals, and adequate calories.
The requirements for a healthy diet can be met from a variety
of plant-based and animal-based foods.
A healthy diet supports energy needs and provides for human
nutrition without exposure to toxicity or excessive weight gain
from consuming excessive amounts. Where lack of calories is
not an issue, a properly balanced diet (in addition to exercise)
is also thought to be important for lowering health risks, such
as obesity, heart disease, type 2 diabetes, hypertension and
cancer.
41

42. MALNUTRITION: INTRODUCTION
Malnutrition essentially means “bad nourishment”. It
concerns not enough as well as too much food, the wrong
types of food, or the inability to use nutrients properly to
maintain health.
The World Health Organization cites malnutrition as the
greatest single threat to the world's public health.
Malnutrition in all its forms is a considerable public health
concern and is associated with increases risk of disease and
early death.
42

43. MALNUTRITION: : INTRODUCTION
 In 2006, more than 36 million people died of hunger or
diseases due to deficiencies in micronutrients; accounted for
58% of the total mortality in the same year.
Under nutrition contributes to almost 35% of the estimated 7.6
million deaths under-5 deaths; consequently affecting the
future health and socioeconomic development and productive
potential of the society.
The malnourished are unable to live a normal life, are less
likely to fulfill their potential as human beings and cannot
contribute fully to the development of their own countries.
43

44. MALNUTRITION
The World Health Organization defines malnutrition as "the
cellular imbalance between supply of nutrients & energy and
the body's demand for them to ensure growth, maintenance,
and specific functions”.
Malnutrition comprises both;
1. Under nutrition
2. Over nutrition
44

45. TYPES OF MALNUTRITION
• Under nutrition is depletion of energy (calories) resulting
form insufficient food intake over an extended period of time.
• In extreme cases under-nutrition is called Starvation. While
Famine is severe food shortage of a whole community.
Specific Deficiency is the pathological state resulting form a
deficiency of an individual nutrient such as vitamin A
deficiency, iodine deficiency.
45

46. TYPES OF MALNUTRITION
Over nutrition:
Many tend to think malnutrition only in terms of hunger,
however, overeating is also a contributing factor.
• “Over nutrition is the pathological state resulting from the
consumption of excessive quantity of food over an extended
period of time”.
• Overweight and obesity are very common conditions in
developed society and are becoming more common in
developing societies and those in transition.
46

47. NUTRITIONAL DEFICIENCY DISEASES
On global scale the five principal nutritional deficiency
diseases are:
1. Kwashiorkor
2. Marasmus
3. Xerophthalmia
4. Nutritional anemia
5. Endemic goiter
47

48. MALNUTRITION IN CHILDREN: PROTEIN-ENERGY
MALNUTRITION
In children, protein–energy malnutrition is defined by
“measurements that fall below 2 standard deviations under
the normal weight for age (underweight), height for age
(stunting) and weight for height (wasting)”.
Protein– energy malnutrition usually manifests early, in
children between 6 months and 2 years of age and is
associated with early weaning, delayed introduction of
complementary foods, a low-protein diet and severe or
frequent infections.
48

49. UNDERNUTRITION
ACUTE
UNDERNUTRITIO
N
CHRONIC
UNDERNUTRITIO
N
• Marasmus
• kwashiorkor
• Marasmic-
kwashiorkor
• Wasting
TYPES OF UNDERNUTRITION
• Stunting
• Underweight

50. 1

51. 2
PROTEIN-ENERGY MALNUTRITION

52. MANIFESTATIONS OF UNERNUTRITION
Under nutrition results in the loss of body weight. The loss of weight
is a manifestation of energy depletion.
Malnutrition from any cause retards normal growth. Malnourished
children grow up with worse health and lower educational
achievements.
Decrease in immunity increases the susceptibility to infections such
as T.B, which add to the morbidity and mortality.
Malnutrition is also associated with lowered vitality of the people
leading to lowered productivity and reduced life expectancy.
52

53. MANIFESTATIONS OF OVERNUTRITION
In the more developed countries of the world, over nutrition is
encountered much more frequently than under nutrition.
The health hazards from over nutrition are:
1. Obesity,
2. Diabetes,
3. Hypertension,
4. Cardiovascular diseases,
5. Renal diseases,
6. Disorders of liver and gall bladder.
53

54. GLOBAL BURDEN OF MALNUTRITION
Despite the fact that the world already produces enough food
to feed everyone — 6 billion people — and could feed the
double — 12 billion people.
There were 925 million undernourished people in the world in
2010, an increase of 80 million since 1990.
Nearly 17% of people in the developing world are
undernourished.
54

55. Percentage Population Undernourished World Map
3

56. GLOBAL BURDEN OF MALNUTRITION
1 out of 3 people in developing countries are affected by
vitamin and mineral deficiencies and therefore more subject to
infection, birth defects and impaired physical and psycho-
intellectual development.
Under nutrition, an important part of the complex, affects
millions of people, mainly in Africa, Asia and Latin America.
56

57. SCOPE OF THE PROBLEM
Directly or indirectly the concurrent vicious life cycle of
malnutrition contributes to almost 35% of the estimated 7.6
million deaths under-5 deaths; consequently affecting the
future health and socioeconomic development and productive
potential of the society.
South Asia is the worst affected region with half of the world’s
malnourished children are to be found in just 3 countries
Bangladesh, India and Pakistan.
57

58. GLOBAL BURDEN OF MALNUTRITION
This is one side of picture. 2 out of 3 overweight and obese
people now live in developed countries, the vast majority in
emerging markets and transition economies.
By 2010, more obese people will live in developing countries
than in the developed world.
Under-and over-nutrition problems and diet-related chronic
diseases account for more than half of the world's diseases and
hundreds of millions of dollars in public expenditure.
58

59. PEOPLE AT RISK
Protein-energy malnutrition (PEM) occurs more commonly in
three situations:
1. In young children in poor communities, usually in developing
countries.
2. In adults, even in affluent countries, due to severe illness
(hospital malnutrition).
3. In people of all ages in a famine.
59

60. PEOPLE AT RISK
Although the under nutrition affects all age groups; however
the most vulnerable groups are pregnant women, lactating
women and young children, mainly because they have a
relatively greater nutritional requirements and are more
susceptible to the harmful consequences of deficiencies.
Under nutrition affects all age groups, but it is especially
common among the poor and those with inadequate access to
health education and to clean water and good sanitation.
60

61. 61

62. Malnutrition is primarily due to:
1. An inadequate intake of food (food gap) both in quantity and
quality.
2. Infections, particularly diarrhea, measles, intestinal worms and
respiratory infections.
In fact it is a vicious circle – Infections make malnutrition
worse and poor nutrition increases the severity of infectious
diseases.
62
INFECTION AND MALNUTRITION

63. Inadequate dietary intake
Weight loss
Growth flattering
Decreased immunity
Mucosal damage
Appetite loss
Nutrient loss
Malabsorption
Altered metabolism
Disease: increase in incidence,
duration, severity
MALNUTRITION CYCLE
4

64. DETERMINANATS OF MALNUTRITION 6

65. 5

66. PREVENTION OF MALNUTRITION
Since malnutrition is the outcome of several factors, it requires
a coordinated approach of many disciplines at various levels;
1. Family
2. Community
3. National
4. International

67. ACTION AT FAMILY LEVEL
The principal target of nutritional improvement in the
community is family.
The instrument for combating malnutrition at the family level
is “Nutrition Education”.
The community health workers can play an important role in
nutrition education to the families in their respective areas.

68. ACTION AT FAMILY LEVEL
Nutrition education should educated family on :
1. Selection of right kind of local foods.
2. Planning of nutritionally adequate diets within limits of their
purchasing power.
3. Identification and correction of harmful food taboos & dietary
prejudice.
4. Promotion of breast feeding and adequate infant & child
feeding .
5. Consider the nutritional needs of expectant & nursing mothers
and children in the family.
6. Planning a kitchen garden or keeping poultry.

69. ACTION AT COMMUNITY LEVEL
The solutions to malnutrition can be assisted by governments,
but in the end communities will often have the leading role in
reducing malnutrition and promoting social development.
People's participation is essential. It is necessary to recognize
that the poor will be the principal actors in their own
development and to foster policies and programs that empower
the underprivileged.
Empowerment and participation of women are particularly
important, because women have the most important role in
food security (and often in food production), in child care and
in family health.

70. ACTION AT NATIONAL LEVEL
The burden of improving the nutritional status of the people,
by and large, is the responsibility of the State.
Prevalent malnutrition in a country is clear evidence of poor
development.
Several approaches and strategies at the national level,
suggested by FAO/WHO are as follow:
1. Rural development
2. Increase agricultural production, distribution and storage
3. Stabilization of population
4. Nutrition related health services

71. ACTION AT THE INTERNATIONAL LEVEL
Food and nutrition are global problems, and international
cooperation can play an important role in reducing the
nutrition problems worldwide.
The multilateral World Food Program was established in 1963
as a mean of providing enough safe food to those in need and
to come to the aid of victims in acute emergencies caused by
floods, earth quick, droughts, wars, etc.
In September 2000, the United Nations Millennium
Declaration was endorsed by 190 countries and was translated
into eight Millennium Development Goals (MDGs) to be
achieved by 2015.

72. MILLENNIUM DEVELOPMENT GOAL 1
Health Targets Health Indicators
Goal 1:
Eradicate extreme poverty and
hunger
Target 1:
Halve, between 1990 and 2015, the
proportion of people who live
below poverty line
The proportion of people whose income is
less than one dollar a day.
Target 2:
Halve, between 1990 and 2015, the
proportion of people who suffer
from hunger
Prevalence of underweight children under
five years of age
Proportion of population below minimum
level of dietary energy consumption

73. CONCLUSION
Under nutrition and malnutrition are widespread problem of
poverty and deprivation that affects millions of people, perhaps
the majority, in developing countries.
The poor, the hungry and the malnourished are unable to live a
normal life, are less likely to fulfill their potential as human
beings and cannot contribute fully to the development of their
own countries.
Political actions, more than political will, to implement well
conceived policies and programs at the national level, while
simultaneously acting internationally, can serve to greatly
reduce nutrition problems worldwide.

74. References/Sources IMAGES:
1.https://lh3.ggpht.com/h0t_UzhGrE6Okvz2WVtE7D3WQBOSvC_WskadQP9lSRhPwNdCDS
YqUG_SzQTa3uJ8rLVs3Xo=s170
2. https://lh3.ggpht.com/TXwGzdPZNs8h6hK1S8R02sZ9rJtdxmVjvizlyeE3Fjml1-
50o8K9hZl4AFabdBVV9QfRG08=s170
3. https://lh4.ggpht.com/ttG8-
MkySs5iUbH5Bb_XSuWvuyqtTgZ1vYIi2Cue5O187OLhOtCI5yFJWyOPdm8zqgkKpuI=s110
4. https://lh6.ggpht.com/5Gr-nyJeWp0SjL7DSL-fmkj7RIS_sCqOE-
yDF4TgEj5_nKEQ5Bu8v1T1NVpx3EbO6f5VWQ=s114
5. https://lh4.ggpht.com/o6NkH3-jWx8yEv8B5mIftQzeX6dGVjjOF-
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Books/ Web resources
 Fundamentals of biochemistry by JL Jain and Jain
 www.who.int/maternal_child_adolescent/topics/child/malnutrition/en
 http://en.wikipedia.org/wiki/Healthy_diet
 www.nhs.uk/Conditions/vitamins-minerals/Pages/vitamins-minerals.aspx