Proteins are the building blocks of life. Each and every cells in the human body contains protein. The basic structure of protein is a chain of amino acids. Human body needs protein to repair and maintain itself. Each gram of protein contains 4 calories.
Body absorbs amino acids from the small intestine which is then carried throughout the body by blood.
Functions of protein
Repair and maintenance
Protein is essential for maintenance of body tissue, including development and repair. Hair, skin, eyes, muscles and organs are all made up of protein.
Protein is major source of energy. When more protein are consumed than the body needs for tissue maintenance and other necessary functions, the body use it for energy.
Transportation and storage of molecules
Protein is a major element in transportation of certain molecules. For example, hemoglobin is a protein that transports oxygen throughout the body. In addition, protein is sometimes used to store certain molecules. Ferritin is an example of a protein that combines with iron for storage in the liver.
Protein forms antibodies that help prevent infection, illness, and diseases. These proteins identify and assist in destroying antigens such as bacteria and viruses.
Sources of protein
Eggs are one of the least expensive forms of proteins. The American Heart Association says a normal healthy adults can safely enjoy an egg a day. A medium egg contains around 6 grams of protein. An omelette is a good way to start the day. Most of the protein is in the egg white. Although they are good source of protein and are low in saturated fats, eggs are high in cholesterol. Try recipes with egg whites only.
Milk, yogurt and cheese
Dairy foods, such as milk, cheese and yogurt are not only great sources of protein but also are rich in calcium. Go for skim or low fat dairy to keep bones and teeth strong.
Seafoods are excellent source of protein as they are usually low in fat.
Tofu and other soy foods
Soy is one of the top vegetarian protein sources.
Nuts and seeds
Unless allergic to them, nuts and seeds are a must have in diet. They are full of protein, healthy fats and fiber.
When it comes to animal protein, opt for lean protein from white meat poultry such as, chicken and turkey.
Beans and lentils
These vegetarian proteins are extremely healthy and should be eaten frequently. They not only provide protein but also are filled with fiber, folate and iron.
Daily requirement of protein
The Recommended Dietary Allowance ( RDA) for protein is 0.8 grams of protein per kilogram of body weight.