NUTRITION
MODULE 1: KEY CONCEPTS IN NUTRITION
Nutrition is the study of nutrients in food, how the body uses them, and the relationship
between diet, health, and disease. Nutrients provide nourishment. Proteins, carbohydrates, fat,
vitamins, minerals, fiber, and water are all nutrients. Nutrition is about eating a healthy and
balanced diet. Food and drink provide the energy and nutrients you need to be healthy.
Food energy is defined as the energy released from carbohydrates, fats, proteins, and
other organic compounds. Fats have the greatest amount of food energy. Food energy is
measured in calories, also known as kilocalories (kcals). The calorie content of a food was
measured in a calorimeter.
Nutrients are compounds in foods essential to life and health, providing us with energy,
the building blocks for repair and growth and substances necessary to regulate chemical
processes. There are six major nutrients: Carbohydrates, Lipids, Proteins, Vitamins, Minerals,
Water.
The nutrient density of a food is the ratio of beneficial ingredients to the food's energy
content for the amount that is commonly consumed. Information about nutrient density, which
refers to the content of micronutrients relative to energy in food or diets, can help identify foods
that have a low calorie to nutrient ratio. It thus allows the consumption of diets that cover
nutritional needs without increasing the risk of becoming obese.
, Nutritional needs of the body: There are 6 essential nutrients that the body needs to
function properly. Nutrients are compounds in foods essential to life and health, providing us with
energy, the building blocks for repair and growth and substances necessary to regulate chemical
processes.
Six major nutrients:
Carbohydrates, Lipids, Proteins, Vitamins, Minerals, Water.
Proteins: meat, dairy, legumes, nuts, seafood and eggs
Carbohydrates: pasta, rice, cereals, breads, potatoes, milk, fruit, sugar
Lipids (most commonly called fats): oils, butter, margarine, nuts, seeds, avocados and olives,
meat and seafood
Vitamins: common vitamins include the water soluble B group vitamins and vitamin C and the fat
soluble vitamins A, D, E and K
• Fruits and vegetables are generally good sources of Vitamin C and A and folic acid (a B group
vitamin)
• Grains and cereals are generally good sources of the B group vitamins and fibre
• Full-fat dairy and egg yolks are generally sources of the fat soluble vitamins A, D and E
• Milk and vegetable or soya bean oil are generally good sources of vitamin K, which can also be
synthesised by gut bacteria
Minerals: (sodium, calcium, iron, iodine, magnesium, etc.): all foods contain some form of
minerals.
• Milk and dairy products are a good source of calcium and magnesium
• Red meat is a good source of iron and zinc
• Seafood and vegetables (depending on the soil in which they are produced) are generally good
sources of iodine
Water: As a beverage and a component of many foods, especially vegetables and fruits.
Classification of foods: Man must eat to live and what he eats will affect to a high degree
his ability to keep well, to work and to live long. Food performs many vital functions in the body.
Foods are classified according to their functions in the body.
1. Energy Yielding Foods: This group includes foods rich in carbohydrate, fat and protein. They
may be broadly divided into two groups.
Cereals, pulses, roots and tubers: Cereals provide in addition to energy large amounts of proteins,
minerals and vitamins in the diet. Pulses also give protein and B vitamins besides giving energy to
the body.
Fats, Oils and pure carbohydrates like sugars: Sugars provide only energy and fats provide
concentrated source of energy.
2. Body Building Foods: Foods rich in protein are called body building foods. They are classified
into two groups.
,Milk, egg, meat & fish. They are rich in proteins of high biological value. These proteins have all
the essential amino acids in correct proportion for the synthesis of body tissues. Pulses, nuts and
oilseeds: They are rich in protein but may not contain all the essential amino acids required by the
human body.
3. Protective Foods: Foods rich in protein, vitamins and minerals have regulatory functions in the
body like maintaining the heartbeat, water balance, temperature, etc. Protective foods are
broadly classified into two groups. Foods rich in vitamins and minerals and proteins of high
biological value (eg) milk, egg, and fish. Foods rich in certain vitamins and minerals only (eg)
green leafy vegetables and fruits.
FACTORS INFLUENCING FOOD SELECTION
1. FLAVOR: An attribute of a food that includes its appearance, smell, taste, feel in the mouth,
texture, temperature, and even the sounds made when it is chewed. The most important
consideration when choosing something to eat is the taste of the food. Flavor is a combination
of all five senses: taste, smell, touch, sight, and sound.
2. DEMOGRAPHICS: Demographic factors that influence food choices include age, gender,
educational level, income, and cultural background. Women and older adults tend to consider
nutrition more often than do men or young adults when choosing what to eat. Older adults are
probably more nutrition-minded because they have more health problems, such as heart
disease and high blood pressure, and are more likely to have to change their diet for health
reasons. Older adults also have more concerns with poor dental health, swallowing problems,
and digestive problems. People with higher incomes and educational levels tend to think about
nutrition more often when choosing what to eat.
3. CULTURE AND RELIGION: Culture can be defined as the behaviors and beliefs of a certain
social, ethnic, or age group. A culture strongly influences the eating habits
of its members. Each culture has norms about which foods are edible, which foods have high
or low status, how often foods are consumed, what foods are eaten together, when foods are
eaten, and what foods are served at special events and celebrations (such as weddings).
4. RELIGION affects their day-to-day food choices. For example, many Jewish people abide by
the Jewish dietary laws, called the Kashrut. They do not eat pork, nor do they eat meat and
dairy products together. Muslims also have their own dietary laws. Like Jews, they will not eat
pork. Their religion also prohibits drinking alcoholic beverages. For other people, religion
influences what they eat mostly during religious holidays and celebrations. Religious holidays
such as Passover are observed with appropriate foods.
5. HEALTH: We know that obesity and overweight can increase your risk of cancer, heart
disease, diabetes, and other health problems. Knowledge of nutrition and a positive attitude
toward nutrition may translate into nutritious eating practices Many circumstances and beliefs
prevent change, such as a lack of time or money to eat right. But some people manage to change
their eating habits, especially if they feel that the advantages (such as losing weight or
preventing cancer) outweigh the disadvantages.
6. SOCIAL AND EMOTIONAL INFLUENCES: People have historically eaten meals together,
making meals important social occasions. Our food choices are influenced by the social
situations we find ourselves in, whether in the comfort of our own home or eating out in a
, restaurant. For example, social influences are involved when several members of a group of
college friends are vegetarian. Peer pressure no doubt influences many food choices among
children and young adults. Even as adults, we tend to eat the same foods that our friends and
neighbors eat.
7. EMOTIONS are closely tied to some of our food selections. As a child, you may have been
given something sweet to eat, such as cake or candy, whenever you were unhappy or upset. As
an adult, you may gravitate to those kinds of foods, called comfort foods, when under stress.
Carbohydrates, such as in cake or candy, tend have calming effects. Eating in response to
emotions can lead to overeating and overweight.
8. FOOD INDUSTRY AND THE MEDIA: The food industry very much influences what you
choose to eat. Food companies decide what foods to produce and where to sell them. They also
use advertising, product labeling and displays, information provided by their consumer services
departments, and websites to sell their products. On a daily basis, the media (television,
newspapers, magazines, radio, and the like) portray food in many ways: paid advertisements,
articles on food in magazines and newspapers, and foods eaten on television shows.
9. ENVIRONMENTAL CONCERNS: Some people have environmental concerns, such as the
use of chemical pesticides, and so they often, or always, choose organically grown foods (which
are grown without such chemicals. Many vegetarians won‘t eat meat or chicken because
livestock and poultry require so much land, energy, water, and plant food, which they consider
wasteful.
NUTRIENTS AND NON-NUTRIENTS
The foods we eat contain nutrients. Nutrients are substances required by the body to perform its
basic functions. Nutrients must be obtained from diet, since the human body does not synthesize
them, or does not synthesize them in large enough amounts for human health. Nutrients are used
for many body functions such as: growing, moving your muscles, repairing tissues and much
more! There are six classes of essential nutrients required for the body to function and maintain
overall health. These six classes of essential nutrients are: carbohydrates, lipids (fats), proteins,
water, vitamins, and minerals. Foods also contain non-nutrients. Some non-nutrients appear to
be very important for human health, like fiber and antioxidants, some non-nutrients may be
harmful to human health such as: preservatives, colorings, flavorings and pesticide residues.
MACRONUTRIENTS: Nutrients that are needed in large amounts are called macronutrients.
There are three major classes of macronutrients: carbohydrates, lipids, and proteins. All three of
these nutrients are needed in relatively large amounts and they contain Calories which can be
"burned" in your body to create energy for your body cells. The energy from these macronutrients
comes from their chemical bonds. This chemical energy is converted into cellular energy that is
then utilized to perform work, allowing our bodies to conduct their basic functions. A unit of
measurement of food energy is the Calorie.
Carbohydrates are molecules composed of carbon, hydrogen, and oxygen. The major food
sources of carbohydrates are grains, milk, fruits, and starchy vegetables like potatoes. Non-
starchy vegetables also contain carbohydrates, but in lesser quantities. Carbohydrates
provides energy and serves as building blocks for bigger macromolecules, carbohydrates are
