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Senior Member
Join Date: Apr 2007
Posts: 531
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A member on the Mind and Muscle forums suggested I post some brief info about the books
Protein Essentials ffice ffice" />
Introduction
Unit One will cover various aspects regarding protein, amino acid definitions, and functions, including the classifications of amino acids, protein structure, and protein digestion and absorption. It will also cover protein requirements for athletes and protein timing from different viewpoints (athletes, coaches, researchers, RDs ). While this unit will be fairly scientific, it will provide a good starting point for anyone really interested in protein and its effects on the body.
In Unit Two, various proteins, amino acids, amino acid derivatives, and their sources will be discussed. The advantages, disadvantages, and recommendations for the more popular proteins, amino acids, and amino acid derivatives will be provided, and the unit will close with a discussion concerning protein controversies. There will also be some research abstracts provided that relate to some of the controversies mentioned.
Unit Three is dedicated entirely to research abstracts. I will also give my opinion on some of the abstracts.
Protein and athletes needs (excerpt from Protein Essentials)
In a recent review paper by Tipton and Wolfe (2004), various aspects concerning athletes and protein were comprehensively examined. The main aim of the review was to update the literature since 1991 and critically examine the available information on protein nutrition for athletes. Below are some of the key points made in the review.
Key points in the Tipton and Wolfe review, "Protein and amino acids for athletes"
"Generally, coaches and athletes are not interested in scientific arguments. They are interested in knowing whether a particular athlete's performance will be enhanced by consuming more or less protein. None of the methods utilized in studies have directly measured protein intake and its direct effect on athletic performance. At this time, there is no clear consensus on the importance of elevated protein for the athletic population. There is also controversy surrounding protein requirements for athletes, as it is hard to assign an exact meaning to this term. Athletes from different sports have different needs. We must also consider individual differences. Just because two athletes play the same sport does not mean that they will have the same response to a specific protein intake. .....
Carbohydrate as energy (excerpts from The Carbodydrate Files)
Dietary carbohydrates have been given an energy value of 4 kcal/g (17 kJ/ g), although where carbohydrates are expressed as monosaccharides, the value of 3.75 kcal/g (15.7 kJ/ g) is used. It is now clear, however, that a number of carbohydrates are only partly or not at all digested in the small intestine and are fermented in the large intestine to short chain fatty acids. These include non-digestible oligo-saccharide, resistant starch and non-starch polysaccharides. Fermentation is metabolically less efficient than absorption in the small intestine and these carbohydrates provide the body with less energy. In light of recent research the energy value of all carbohydrates in the diet should be re-evaluated. While the energy derived from carbohydrate delivered to the colon will vary according to the extent of colonic fermentation, there may be cause for assigning a single energy value to all such carbohydrates. Published studies suggest that a caloric value of about 2 kcal/g (8 kJ/g) would be a reasonable average figure for carbohydrates which reach the colon. While individual carbohydrates will have different values, in the range of 1-2 kcal/g, these differences are negligible.
GluconeogenesisGluconeogenesis, ultimately, is the generation of glucose from noncarbohydrate sources like lactate, glycerol, and amino acids. Many 3 and 4-carbon substrates can enter the gluconeogenesis pathway. Lactate from anaerobic exercise in skeletal muscle is easily converted to pyruvate; this happens as part of the Cori cycle. The vast majority of gluconeogenesis takes place in the liver and, to a smaller extent, in the kidney. The rate of gluconeogenesis is ultimately controlled by the action of a key enzyme fructose 1,6-bisphosphatase ( Fructose-1,6-bisphosphatase is an enzyme involved in gluconeogenesis that converts fructose-1,6-bisphosphate into fructose-6-phosphate). Most factors that regulate the activity of the gluconeogenesis pathway do so by inhibiting the activity of key enzymes. However, both acetyl CoA and citrate activate gluconeogenesis enzymes (pyruvate carboxylase and fructose 1,6-bisphosphatase, respectively). Oxaloacetate (an intermediate in the citric acid cycle) can also be used for gluconeogenesis. Amino acids, after their amino group has been removed, feed into parts of the citric acid cycle, and can thus generate glucose in this pathway.
thanks,
Coach Hale |
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