Proteins Importance in Nutrition

Proteins (Importance in Nutrition)

Proteins are organic macromolecules made up of linear chains of amino acids. However, while a protein’s basic structure is a linear amino acid chain, the final structure of a protein is not linear. Instead, the protein’s amino acid sequence—and the physical and chemical properties of the amino acids and of the entire protein molecule - influences how it folds into a three dimensional shape. The amino acid sequence of a protein is determined by the base pair sequence in the gene which codes for the protein. There are twenty ‘standard’ amino acids (along with one or two non-standard proteins which are not coded for by DNA in the usual sense).

What is Protein?

Largest constituent of body weight after water 20% of our body weight.  Found throught the body. In muscle, bone, skin, hair, and virtually every other body part or tissue. Makes up the enzymes that power many chemical Reactions and the hemoglobin. At least 10,000 different proteins make you what   you are and keep you that way.

Proteins as Enzymes

The function of proteins as enzymes is perhaps their best-known function. Enzymes are catalysts—they initiate a reaction between themselves and another protein, working on the molecule to change it in some way. The enzyme, however, is itself unchanged at the end of the reaction. Enzymes are responsible for catalyzing reactions in processes such as metabolism, DNA replication, and digestion. In fact, enzymes are known to be involved in some 4,000 bodily reactions.

Proteins in Cellular Signaling and Molecular Transport Cells signal one another for an enormous variety of reasons, the most basic of which is simply to coordinate cellular activities. Signaling is how cells communicate with one another, allowing such essential processes as the contraction of the heart muscle to take place.

           

Proteins are important in these processes due to their ability to bind other molecules—a protein produced by one cell may bind to a molecule produced by another, thus providing a chemical signal which allows the cells to provide information about their state. Proteins are also involved in molecular transport.

A prime example of this is the protein called hemoglobin, which binds iron molecules and transports them in the blood from the lungs to organs and tissues throughout the body.

Functions of Proteins

Ø  Protein has a range of essential functions in the body, including the following:

Ø  Required for building and repair of body tissues (including muscle)

Ø  Enzymes, hormones, and many immune molecules are proteins

Ø  Essential body processes such as water balancing, nutrient transport, and muscle contractions require protein to function.

Ø  Protein is a source of energy.

Ø  Protein helps keep skin, hair, and nails healthy.

Ø  Protein, like most other essential nutrients, is absolutely crucial for overall good health.

Ø  About half of the protein consumed daily is converted into enzymes, the specialized "worker proteins" that regulate the speed of biological reactions in your body and permit it to perform functions such as digesting food and assembling or dividing molecules to make new cells and chemical substances. To perform these functions, enzymes often need specific vitamins and minerals.

So what does protein do?

To make all the proteins that the body needs, 22 different amino acids are required. Nine are considered to be essential, meaning they are not synthesized by the body and must be obtained from food. Our bodies can produce the other 13 from fats, carbohydrates, and other amino acids. So, these are referred to as non-essential amino acids.

Protein Needs Various Stages

Daily Protein requirement of an adult 1gm/kg body wt, but in following conditions need of protein increases:  Growth needs of children -1.5 gm/kg body wt. Development of maternal tissues and the fetus during pregnancy and lactation – 1.75gm/kg body wt.

Infections, immobilization, surgery, burns, and other injuries. Emotional stress increases protein breakdown. Frequent intestinal infection A poor state of Nutrition.

Food Sources of Proteins

Animal (food) products are rich sources of protein. Meat, milk and milk products, egg, poultry, and fish, contain balanced level of amino acids. Protein can also be obtained from plant (vegetable) food items such as legumes (soybean and soybean products, peas, beans etc.), and nuts.

Food Sources of Proteins
Milk and milk products
Milk(Cows)	3.2g/100
Milk(Buffalos)	4.3 g/100
Curd(Cow’s milk)	3.1 g/100
Paneer (Cottage cheese)	18.3 g/100
Khoa(Cow’s milk)	20.0 g/100
Pulses
Soyabean	43.2 g/100
Others	17.1 – 25.1 g/100
Flesh Foods
Egg	13.3 g/100
Fish(Rohu)	16.6 g/100
(Hilsa)	21.8 g/100
Goat’s meat	21.4 g/100
Fowl	25.9 g/100
Nuts
Groundnut	25.3 g/100
Cashew nut	21.2 g/100

Usage of Proteins

It is possible to consume too much protein. The amount of protein needed for good health varies.

Ø  An average healthy adult man or woman needs about 0.8 grams of protein per every kilogram (2.2 pounds) of body weight.

Ø  As you grow older, new proteins are synthesized less efficiently, and muscle mass (protein tissue) diminishes while fat content stays the same or rises. This is why muscle seems to "turn to fat" in old age.

Ø  Infants, adolescents, pregnant women, individuals with injuries, and athletes may often require more protein on a daily basis.

RDA of Protiens

Ø  Children - Age - 4-6 - 30/24 gms

Ø  Children - Age - 7-10 - 36/24 gms

Ø  Males - Age - 15-18 - 54/59 gms

Ø  Males - Age - 19-24 - 54/58 gms

Ø  Males - Age - 25-50 - 56/63 gms

Ø  Males - Age - 50-++ - 56/63 gms

Ø  Females - Age - 15-18 - 48/44 gms

Ø  Females - Age - 19-24 - 46/46 gms

Ø  Females - Age - 25-50 - 46/50 gms