HUMAN NUTRITION AND HEALTH CARE LECTURE ONE.

Food can be defined as anything edible that can be solid, semisolid or liquid
which when swallowed, digested and assimilated in the body, proves useful
to it. These substances not only keep the person alive, but also provide
energy used for growth and development, regulate the body processes and
protect the body from diseases.
NUTRITION & HEALTH

NUTRITION?
• • The study of foods and how our bodies use them. Concerned
with how food is produced, processed, handled, sold, prepared,
shared and eaten. What happens to food in the body,
masticated, digested, absorbed to provide the body with
essential nutrients for growth and development.
• OR
• • Science that deals with chemical substances known as
nutrients for maintenance of health. • ‘Branch of science that
studies the process by which living organisms take in and use
food for the maintenance of life, growth, reproduction, the
functioning of organs and tissues, and the production of energy

Nutrients are organic or inorganic substances present or contained in food
which is required or necessary for growth and maintenance of function of
body.” E.g.: Proteins, Vitamins etc.
Or
Nutrients have been defined as “chemical substances found in food that cannot
be synthesized at all or in sufficient amounts in the body, and are necessary for
life, growth and tissue repair”.
Or
Nutrient “or “food factor” are organic and inorganic complexes contained in
food, which are responsible for the functions of foods and protect the body
from disorders.

Balanced Diet A balanced diet is one which includes a variety of foods in
adequate amounts and correct proportions to meet the day’s requirements of
all essential nutrients such as proteins, fats, carbohydrates, vitamins,
minerals, water, and fibre.

1. Food is a basic and foundational part of our lives. Food plays a vital role
for human existence just as the air we breathe and the water we drink.
The food we eat is utilized in the body and assimilated substances are
used for growth and maintenance of the tissue.
2. People who eat right foods rich in nutrients enjoy their lives more, live
longer, and are at a reduced risk of disease.
3. Good nutrition is critical in preventing not only deficiency diseases, but
also chronic diseases. Nutrition is vital to our bodies as water is to
plants. An unhealthy diet increases the risk of many diet related diseases.
THE RELATIONSHIP BETWEEN NUTRITION AND HEALTH

NUTRIENTS AND THEIR FUNCTION
• To maintain health and function properly, the body must
be provided with nutrients. Nutrients are chemical
substances that are necessary for life.
• • They are divided into six classes:
• Carbohydrates (CHO)
• Fats (lipids)
• Proteins
• Vitamins
• Minerals
• Water

Cereals, grains and products
Pulses and legumes
Milk and meat products Fruits and vegetables

b) ACCORDING TO THEIR FUNCTION IN THE BODY
Energy giving foods:
• The carbohydrates, fats and the protein are considered as calorie nutrients, so that the body can
perform the necessary functions. Rice, chapatti, bread, potato, sugar, oil, butter and ghee are
examples of energy giving foods.
Body building foods:
• Foods such as proteins, fats and carbohydrates are also called as body-building food. They are the
nutrients that form body tissues. Fish, meat, chicken, eggs, pulses, nuts and milk are some body
building foods.
Protective foods:
• Vitamins and minerals are the nutrients that function to regulate body processes. They protect us
from various diseases. Fruits and vegetables are some examples. Therefore we must eat these
regularly.

Micronutrients
Macronutrients
Water

 Carbohydrates are the chief sources of energy (Providing 4 Kcals/gm).
 Carbohydrates consist of carbon, hydrogen, and oxygen.
 The general empirical structure for carbohydrates is (CH2O)n. (1:2:1)
 The building blocks of all carbohydrates are simple sugars called
monosaccharide.
Classification of Carbohydrates
• Monosaccharide: these are the simplest form of carbohydrates containing
simple sugar molecule. Example: Glucose, Fructose and Galactose.
• Disaccharide: These carbohydrates composed of two units of
Monosaccharide’s. Example: Sucrose, Lactose and Maltose.
• Polysaccharide: These are the complex sugars containing numerous units of
monosaccharide molecules. Example: Glycogen, Cellulose and Pectins.
Carbohydrates

Daily requirements
Carbohydrate intake should be in the range of 300-500gm (50%- 70%) out of the total energy
intake for adults and 40-60% for children but an individual requires at least 50-100 grams of
digestible carbohydrate each day.
Consuming excess carbohydrates is a major cause of obesity as the major part of
any surplus carbohydrates becomes adipose tissue. • Excess can cause tooth decay
and may irritate the lining of the stomach causing flatus. • A deficiency of
carbohydrates usually results in loss of weight and possible metabolism.

Functions of Carbohydrates
a) Living organisms use carbohydrates as accessible energy to fuel cellular
reactions.
b) They are the most abundant dietary source of energy (4kcal/gram) for all living
beings.
c) Stored carbohydrates act as an energy source instead of proteins.
d) Carbohydrates are essential for the metabolism of fat.
e) Carbohydrates aid in the regulation of nerve tissue and is the energy source for
the brain.
f) They help promote digestive health
g) They help preserve muscles.

PROTEIN
They are composed of carbon, hydrogen, oxygen and nitrogen
but in different proportions. Some contain sulphur,
phosphorus, iron and iodine. Each gram of protein provides
4kcals.
• Proteins coagulate (thicken) when heated or when acid is
added to them. Meat, eggs and cheese coked too a high
temperature becomes tough.
• When lemon juice is added to milk the protein in the milk
coagulates and the milk appears curdled

FUNCTIONS OF PROTEINS
1) Protein helps in synthesis of enzymes, immunoglobulin, plasma proteins and hormones in
the body.
2) Protein helps in growth and repair of body tissues
3) Proteins are secondary sources of energy during deficiency of carbohydrates and fats.
(Provides 4 Kcals/gm).
4) Proteins help in forming haemoglobin.
5) Proteins help in antibody formation.

Sources of protein
• AINIMALSOURCES----- meat, fish, poultry, eggs and
dairy.
• • PLANT SOURCES--------grains, nuts, sunflower seeds,
sesame seeds. Legumes such as soybeans, navy means,
pinto beans, split beans and peanuts.
• METABOLISM AND ELIMINATION All essential amino
acids must be present to build and repair the cells as
needed. Surplus amino acids are sent to the liver where
they are dismantled by splitting off the nitrogen.

LIPIDS. Fats and Oils
• Fats are oily substances that not soluble in water, Each gram of fats
provides (9kcals)
• Most foods high in fat are more expensive than those high in
carbohydrates.
• Composition of Fats Composed of carbon, hydrogen and oxygen in
different proportions Functions Provides the body with heat and
energy.
• Function and structure of body tissues Carriers of essential fatty
acids and vitamins Feeling of Satiety.

Classification of fats
• UNSATURATED FATS-------Unsaturated fats raise high-density lipoprotein
(HDL or "good") cholesterol
• Mono unsaturated and Poly unsaturated Fats…Healthy fats found in
vegetable oil, olive oil, avocado and some types of nuts and seeds.
• SATURATEDFAT Low-density lipoprotein (LDL or "bad") cholesterol

levels, may increase your risk of cardiovascular disease. Eg . butter and
other animal fat.
• Trans fats are a form of saturated fat associated with a number of
negative health effects.
• Dietary requirements 20-35% of the total calories should come from
fats Not more than 10% of calories should come from saturated fats

 Supplies energy (9 kcals/ gm).
 Improve the palatability of food (flavor and taste)
 Supports body organs like liver and kidneys
 Provides insulation and thermoregulation against cold
 Provides essential fatty acids which helps in growth, promotion and
maintenance of skin integrity.
 Helps in formation of hormones in the body.
 Helps in transportation of fat soluble vitamins.
FUNCTIONS

• Vitamins are organic compounds that people need in small
quantities. Most vitamins need to come from food because the body
either does not produce them or produces very little.
• Different vitamins play different roles in the body, and a person
requires a different amount of each vitamin to stay healthy.

FAT SOLUBLE VITAMINS
Vitamin-A
• The chemical name is Retinol.
• Found in foods of both plant and animal origin.
• Function: It is essential for eye health.
Deficiency
Deficiency Syndrome
 Decreased resistance to infection
 Dry scaly skin
 Night blindness (Inability to see in dim light)
 Bitot’s spots- Greyish, rough and raised patches on conjunctiva
 Keratomalacia- Softening of the cornea.
• Daily requirements: 0.4-1 mg Sources. Green leafy vegetables and yellow orange
fruits and vegetables like mango, papaya, pumpkins and carrots are good sources
of β-carotene.

Vitamin-D
 Vitamin D is synthesized by sunlight.
 Vitamin D is essential for bone growth.
Daily requirements: 400 IU Sources
 Generated in the skin by action of ultra violet rays of sunlight
 Food sources are milk, butter, cheese, egg, fish and fish liver oils, and foods
which have been fortified by addition of vitamin D.
Functions
 Increases intestinal absorption of calcium and phosphates.
 Mineralization of bones.
 Vitamin D is also essential for the dental health. It prevents tooth
decay and loss, strengthen the gums and reduces risk of any oral
infection.

Rickets characterized by reduced
growth and softening of bones. This
disease is generally seen in children
due to lack of vitamin D. Children
develop very thin, deformed bones
Osteomalacia, similar to rickets but is
usually seen in elderly people suffering
from vitamin D deficiency.
This disease reduces the absorption of
calcium in the body leading to soft and
deformed bone structure, bending of the
spinal cord and legs and increased risk
of fractures.
Osteomalacia
Rickets:

Osteoporosis, being most common
in elderly where the bone density
reduces, making it more porous in
nature and causing increased risk of
broken bone and fractures.
Osteoporosis

Vitamin E
• Vitamin E is an antioxidant and formed up of chemical substance
called Tocopherols.
Daily requirements:
• 15UI per day.
Sources
• Milk, oils, eggs, leafy vegetables, papaya, grains, nuts.
Functions
• Antioxidant (Prevents the formation of oxidative free radical)
• Co factor in electron transport
• Prevents or delays the ageing.

Vitamin K
• It is called as Antihemorrhagic vitamin. It is required for the
fromation of Prothrombin in the liver the 2nd
factor of coagulation.
• Due to deficiency of Vit. K the prothrombin content in blood may lead
to bleeding disorder.
Daily requirements
• WHO suggested RDA of 55 μg per day for adults.
Sources
• Green leafy vegetables, cereals, fruits.

FORMULAR FOR CALCULATING MINIMUM
CALORIC REQUIREMENTS
• To calculate one’s minimum caloric requirements, first determine
the BMR. The BMR= 1 kcal of the body weight per hour. The BMR,
plus 50% of the total is equal to the persons caloric requirement
• Change body weight from pounds to kg by dividing the body weight
by 2.2
• Multiply the number of kg of the body weight by 24 hours per day.
Multiply the answer in step 2 by .50 (50%)

• Add the answer in steps 2 and 3. The sum is the minimum caloric
requirement

EXAMPLE
• Abena weighs 49 kg. Calculate her minimum
caloric requirement.
• Steps:
• 1. Multiply 49 by 24 hours =1176kcals
• 2. Multiply 1176kcals by .50 =588kcals
• 3. Add 1176 + 588 = 1764 kcals. This is
Abena’s minimum daily caloric requirement

HUMAN NUTRITION AND HEALTH CARE LECTURE ONE.

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