Proteins

Proteins are essential nutrients for the human body. They are one of the building blocks of body tissue and can also serve as a fuel source. As a fuel proteins provide as much energy density as carbohydrates.

Why is protein an important nutrient?

Ø  It is an important component of every cell in the body.

Ø  Body uses protein to build and repair tissues.

Ø  Protein is essential for good health.

Ø  Body also uses protein to make enzymes, hormones, antibodies and other body chemicals.

Ø  Protein is an important building block of bones, muscles, cartilage, skin and blood.

Nutritional value of protein

Protein is essential for growth and repair of the body and maintenance of good health. Protein also provides energy.  1 gm of protein provides 4 Kcal. The Reference Nutrient Intake (RNI)is set at 0.75 gm of protein per kg body weight/day for adults. The amount of protein we need changes during a lifetime.

Do we need protein?

Ø  Every cell in the human body contain protein

Ø  The basic structure of protein is a chain of amino acids

Ø  We need protein in our diet to help our body to repair cells and make new ones

Ø  Protein is also important for growth and development in children,, teenagers and pregnant women.

Examples -à collagen, insulin and antibodies.

Proteins are made up of smaller building blocks called amino acids joined together in chains. There are 20 different amino acids.

Dietary Intake of Protein

The DRI (Dietary Reference Intake) is 0.8 gm of protein per kg of body weight or 0.36 gms per pound. This amounts to 56 gms/day -à for average sedentary man

46gms/day -à for average sedentary women.

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Carbohydrates

Carbohydrates

The sugars, starches and fibers found I fruits, grains, vegetables and milk products are called carbohydrates because, at the chemical level, they contain carbon, hydrogen and oxygen. They are the main type of nutrients have most important source of energy for our body.

Digestive System -à changes carbohydrates into glucose (blood sugar) -à Body uses this sugar to give energy -à to cells, tissues and organs of our body-àstores any extra sugar in liver and muscles for future use.

Carbohydrates are classified into two types depending on chemical structure.

Simple carbohydrates & Complex carbohydrates

Simple carbohydrates	Complex carbohydrates
Sugar found in fruit, vegetables, milk and milk products	Include whole grain breads, cereals
Includes sugar added during food processing and refining	Starchy vegetables and legumes are good sources of fiber.
Raw sugar, brown sugar, corn sugar, corn syrup and high-fructose
Glucose fructose, sucrose and fruit juice concentrate

Benefits of carbohydrates :

1)      Main source of energy

2)      Help to fuel our brain, kidneys heart muscles and central nervous system

3)      Fiber -à helps in digestion, gives safety level, controls blood cholesterol level.

 Functions of carbohydrates :

            Provide energy

           Store energy

           Build macromolecules

           Spare protein and fat for other uses

            Glucose energy is stored as glycogen in muscles and liver.

Whole carbohydrates -à vegetables, whole fruit, legumes, potatoes, and whole grains.

Refined carbohydrates-à sugar, sweetened beverages, fruit juices, pastries, white bread, white pasta, white rice and others.

Classification

          Monosaccharide or simple sugar

          Disaccharide
         Oligosaccharides

         Polysaccharides

How much energy should come from carbohydrates :

About 50 to 60 percent of our total daily calories should come from carbohydrate.

1 gm of carbohydrate -à gives 4kcal

Carbohydrates -à makes up 45 to 65 percent of our total daily calories.

Eg. If a person consumes 2000Kcal/day -à 900 to 1300 Kcal/day (should be from carbohydrates) i.e. between 225 – 325 gms of carbohydrates/day.

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