Currently, a number of laboratory methods have been developed to assess the content of almost any nutrient in the body, according to Pannochka, an Internet publication for girls and women from 14 to 35 years old.. net Most of them are not used in routine clinical practice.
If anthropometric measurements allow us to judge primarily the peripheral reserves of proteins, then biochemical indicators reflect the state of the visceral pool.
Determination of transport proteins synthesized by the liver is a sensitive test in relation to the protein status of the patient. However, the information content of biochemical markers is significantly influenced by many factors, primarily the life span of these proteins.. Only short-lived markers are able to quickly reflect the dynamics of changes in protein-synthetic processes in the body.
Total protein, as a total indicator depending on a large number of different terms, is low-sensitive and can give false negative results with an increase in the globulin fraction and dehydration.
Albumin, which is a reliable prognostic marker, is of primary importance in assessing nutritional status.. Albumin is synthesized by the liver in an amount of 10-12 g per day, its life span is 18-20 days. About 40% (120 g) circulates in the vascular bed, and most is in the interstitial fluid. The main role of albumin is to create oncotic pressure and participate in the transport function. The informative value of albumin as a marker of the visceral protein pool is influenced by a rather long lifetime and the possibility of interstitial albumin movement into the intravascular pool..
The representative of the B-globulin fraction, transferrin, which is involved in the transport of iron, lives up to 7-8 days, and therefore also cannot be considered an indicator that quickly responds to changes in nutrition. In addition, the content of transferrin can increase with iron deficiency, which usually accompanies protein deficiency, which also affects its reliability..
More accurate indicators of the state of the visceral protein pool are considered to be short-lived transport proteins: prealbumin (lifespan 2 days) and retinol-binding protein (lifespan 10-12 hours). They promptly reflect changes in the intake of proteins, but, on the other hand, their values \u200b\u200bcan change noticeably due to intercurrent diseases, which reduces the significance of these indicators as markers of protein deficiency..
In principle, almost any protein synthesized in the body can be considered as a nutritional marker. So, recently, great importance is attached to the insulin-dependent growth factor.
Creatinine and 3-methylhistidine excreted in the urine are indicators of catabolism in muscle tissue: creatinine is a breakdown product of high-energy creatine phosphate, and 3-methylhistidine is a byproduct of protein metabolism in skeletal muscle.
Their excretion is proportional to the available muscle mass, however, these markers are significantly influenced by the degree of muscle activity, changes in diet and impaired renal function.. Usually the percentage of creatinine excreted in 24 hours to the level of its optimal excretion is determined.. As an indicator of muscle tissue, you can use the creatinine / height ratio (creatinine-growth index). Its average rate for men is 10 mg / cm, for women - 5.8 mg / cm.
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