Discuss the role protein plays in cell formation and growth. Specifically, what

Question

Discuss the role protein plays in cell formation and growth. Specifically, what body tissues or cells are made from the proteins we either eat or form in our own body? Consider that a gram of protein has the same caloric value as a gram of carbohydrate, yet those four calories are used very differently by the body. What is “protein sparing” and why is it so important to good health. Are low carb-high protein diets successful for promoting weight loss? Are there risks associated with these diets? If so, what are they, from a nutritional standpoint?

Explanation / Answer

Proteins are large, complex molecules that play many critical roles in the body. They do most of the work in cells and are required for the structure, function, and regulation of the body’s tissues and organs.

Proteins are made up of hundreds or thousands of smaller units called amino acids, which are attached to one another in long chains. There are 20 different types of amino acids that can be combined to make a protein. The sequence of amino acids determines each protein’s unique 3-dimensional structure and its specific function.

Protein deficiency and malnutrition (PEM) can lead to variety of ailments including mental retardation and kwashiorkor. Symptoms of kwashiorkor include apathy, diarrhea, inactivity, failure to grow, flaky skin, fatty liver, and edema of the belly and legs. This edema is explained by the action of lipoxygenase on arachidonic acid to form leukotrienes and the normal functioning of proteins in fluid balance and lipoprotein transport.

PEM is fairly common worldwide in both children and adults and accounts for 6 million deaths annually. In the industrialized world, PEM is predominantly seen in hospitals, is associated with disease, or is often found in the elderly.

proteins are phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, and histidine.[There has been debate as to whether there are 8 or 9 essential amino acids. The consensus seems to lean towards 9 since Histidine is not synthesized in adults.]There are five dispensable amino acids which humans are able to synthesize in the body. These five are alanine, aspartic acid, asparagine, glutamic acid and serine. There are six conditionally essential amino acids whose synthesis can be limited under special pathophysiological conditions, such as prematurity in the infant or individuals in severe catabolic distress. These six are arginine, cysteine, glycine, glutamine, proline and tyrosine.

Some protein sources contain amino acids in a more or less 'complete' sense.

  Protein sparing (amino acid sparing) is the process by which the body derives energy from sources other than protein. Such sources can include fatty tissues, dietary fats and carbohydrates. Protein sparing conserves muscle tissue.

  Although popular and effective for weight loss, low-carbohydrate, high-protein,high-fat (Atkins) diets have been associated with adverse changes in blood and renal biomarkers. High-protein diets low in fat may represent an equally appealingdiet plan but promote a more healthful weight loss.

Extreme protein intake (in excess of 200 g per day), coupled with inadequate intake of other calorie sources (fat or carbohydrates), can cause a form of metabolic disturbance and death commonly known as rabbit starvation.Even when consuming other calorie sources, consuming more than 285 g of protein per day (for an 80 kg person) may be unsafe.

Relatively little evidence has been gathered regarding the effect of more moderate long-term high intake of protein on the development of chronic diseases.Increased load on the kidney is a result of an increase in reabsorption of NaCl. This causes a decrease in the sensitivity of tubuloglomerular feedback, which, in turn, results in an increased glomerular filtration rate. This increases pressure in glomerularcapillaries. When added to any additional renal disease, it may cause permanent kidney damage.

Protein deficiency and malnutrition (PEM) can lead to variety of ailments including mental retardation and kwashiorkor.Symptoms of kwashiorkor include apathy, diarrhea, inactivity, failure to grow, flaky skin, fatty liver, and edema of the belly and legs. This edema is explained by the action of lipoxygenase on arachidonic acid to form leukotrienes and the normal functioning of proteins in fluid balance and lipoprotein transport.

PEM is fairly common worldwide in both children and adults and accounts for 6 million deaths annually. In the industrialized world, PEM is predominantly seen in hospitals, is associated with disease, or is often found in the elderly.

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