February 07, 2014

Proteins

     Proteins are the building blocks of life. The body needs protein to repair and maintain itself. The basic structure of protein is a chain of amino acids. Every cell in the human body contains protein. It is a major part of the skin, muscles, organs, and glands. Protein is also found in all body fluids, except bile and urine.


    When proteins are digested, amino acids are left. The human body needs a number of amino acids to break down food. Amino acids need to be eaten in large enough amounts for optimal health.


Amino acids are classified into three groups

  • Essential
  • Nonessential
  • Conditional

Essential amino acids cannot be made by the body, and must be supplied by food. They do not need to be eaten at one meal. The balance over the whole day is more important. The nine essential amino acids are:

  • Histidine
  • Isoleucine
  • Leucine
  • Lycine
  • Methionine
  • Phenylalanine
  • Threonine
  • Tryptophan
  • Valine

Nonessential amino acids are made by the body from essential amino acids or in the normal breakdown of proteins. They include:

  • Alanine
  • Asparagine
  • Aspartic acid
  • Glutamic acid

Conditional amino acids are usually not essential, except in times of illness and stress. They include:

  • Arginine
  • Cysteine
  • Glutamine
  • Glycine
  • Ornithine
  • Proline
  • Serine
  • Tyrosine

Functions

  • Protein is very critical in the regulation of human metabolism. 
  • It is used to form muscle, connective tissue, blood clotting factors, blood transport proteins, lipoproteins, visual pigments and the protein matrix inside the bones.
  • Protein is also used to maintain the body fluid balance by producing albumin and globulin. 
  • Dietary protein also contributes to the acid-base balance by producing buffers that help regulate the amount of free hydrogen ions in the blood. 
  • The immune system is also composed of proteins. Antibodies are proteins. Without enough dietary protein, the immune system will lack the cells needed to function properly.
  • Dietary protein can also be used as an energy source. If a diet does not contain enough carbohydrate to supply needed glucose, protein can be used to synthesize glucose. 

Good Foods

  • Meat, poultry, fish and shellfish - Reduce your saturated fat and cholesterol intake by choosing lean meat and skinless, white-meat poultry instead of fatty meats or dark-meat poultry with the skin. Fatty fish and shellfish provide heart-healthy omega-three fatty acids.
  • Eggs and Milk - All animal-derived proteins are high-quality, so eggs or dairy can be possible choices if you want a meatless meal. All of the protein in eggs is found in the fat-free whites. Milk, yogurt and cheese are high in protein, and they provide calcium, an essential mineral for bone strength. Choose reduced-fat dairy products because they are lower in calories and saturated fat.
  • Soy protein - It can be a healthy choice, for vegan, or strict vegetarian, because it is a rare plant-based source of each of the essential amino acids. Firm or soft tofu, soy milk, soy yogurt, vegetarian burgers or other meat substitutes and soybeans are all high in protein. Soy provides heart-healthy unsaturated fats, or you can choose reduced-fat products, such as light tofu or non-fat soy milk, to keep your fat and calories lower.
  • Bananas, mixed berries and melon are some super foods
  • Mixed Nuts - Almonds and Pistachios are high up there in protein while comparably lower in saturated fat than their nutty peers.
  • Pumpkin Seeds - Just ½ cup of pumpkin seeds has about 14 grams of protein — the perfect pre-workout snack!
  • Nut Butter  - Almond, peanut, or cashew 
  • Protein shakes
  • Protein Bar - Their classic varieties are a great source of protein with all-nut base 
  • Oatmeal 
  • Edamame - One cup of the pods offers about 17 grams of protein. 
  • Hummus 
  • Protein Pancakes - Top with fresh berries or sliced banana.
  • Chocolate Milk - Low-fat chocolate milk is actually a great source of high-quality protein 
  • Greek yogurt 
  • Lentils - Lentils are great protein-packed legumes that are easy to turn into super, shelf-stable salads. One cup has a whopping 22 grams of protein in just 300 calories 
  • Black-Bean 
  • Rice Crispies 
  • Other sources - Legumes, such as beans, peas and lentils, whole grains, nuts, seeds and vegetables are cholesterol-free, low in saturated fat and high in dietary fibre. 



Risks of High Protein Diet

  • Some high-protein diets restrict carbohydrate intake so much that they can result in nutritional deficiencies or insufficient fiber, which can cause health problems such as constipation and diverticulitis.
  • Some high-protein diets promote foods such as red meat and full-fat dairy products, which may increase your risk of heart disease.
  • A high-protein diet may worsen kidney function in people with kidney disease because your body may have trouble eliminating all the waste products of protein metabolism.

Recommended Daily Intake

  • Women 19 years and above – 46gram
  • Men 19 years and above – 56gram

Protein Deficiency

     Two deficiency diseases that affect children are caused by a grossly inadequate supply of protein, energy or both.

  • Marasmus, a condition resulting from severe malnutrition, affects very young children who lack both energy and protein foods as well as vitamins and minerals. The infant with marasmus appears emaciated but does not have edema; hair is dull and dry, and the skin is thin and wrinkled.

  • Kwashiorkor results when there is a sudden or recent lack of protein-containing food, this disease results in edema, painful skin lesions, and changes in the pigmentation of skin and hair.

     When people are unable to obtain adequate supply of protein for an extended period, muscle wasting occurs. And arms and legs become very thin. At the same time, albumin deficiency causes edema. Resulting in an extremely swollen appearance.
The edema decreases when sufficient protein is eaten. Patients with edema become lethargic and depressed. These signs are seen grossly  neglected children or in the elderly poor or incapacitated. Children who lack sufficient protein do not grow to their potential size.
Infants born to mothers eating insufficient protein during pregnancy ca have permanently impaired mental capacities.

References




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