Deficiencies, nutritional detecting

Limitations of Self-Selection A New Method of Detecting Nutritional Deficiencies... 

Lipids may also be involved in the calcification of the dentine matrix, because sudanophilic materials have been detected in ontoblasts, at the dentine-predentine junction and in the peritubular dentine matrix311. A series of nutritional studies have shown that dentine lipids are in a dynamic state312-315. A diet deficient in essential fatty acids produced degenerative effects on dentinogenesis and resulted in the production of teeth more susceptible to dental caries315. ... 

In addition to steatorrhea and nutritional deficiencies, patients with pancreatic exocrine insufficiency also develop symptoms such as postprandial pain, cramps, bloating, and distention. These are caused by profound alterations of upper gastrointestinal secretory and motor functions in response to increased nutrient delivery to the distal small intestine, particularly the ileum. In the first 5-10 years of chronic pancreatitis, overt malabsorption is usually neither detected nor a major clinical problem, although enzyme output may decrease by 60%-90%. Still, there is evidence that, even in the early stages of chronic pancreatitis, the site of maximal nutrient digestion and absorption is shifted from the duodenum to the more distal small intestine. 

The early 1960 s saw the introduction of flame atomic absorption spectrometry (AAS) to clinical laboratories and this provided a sensitive yet simple analytical technique for the estimation of some trace elements in biological fluids. Trace elements is now perhaps an inaccurate description for those metals previously detectable in only small amounts when using older and less sensitive analytical techniques. Many such elements can now be estimated with precision and this has proved a great stimulus to trace-element research in clinical medicine. The number of trace elements known to be essential to man has doubled in the last twenty years [1]. Specific and treatable diseases are now known to be associated with excess or deficiency of trace elements and even in advanced societies dietary intake of some elements may be less than ideal [2]. Thus, monitoring of biological fluids for trace element levels in both health and disease can contribute towards major advances in nutritional management. 

A number of methods have been developed to permit assessment of folate and vitamin B12 nutritional status and to differentiate between deficiency of the vitamins as a cause of megaloblastic anemia. Obviously, detection of antibodies to intrinsic factor or gastric parietal cells will confirm autoimmune pernicious anemia rather than nutritional deficiency of either vitamin. 

The importance of zinc to growth and development in all forms of life was first established through zinc deficiency studies of microorganisms followed by those in plants and animals see Nutritional Aspects of Metals Trace Elements) The involvement of zinc in a wide variety of metabolic processes including carbohydrate, lipid, protein, and nucleic acid synthesis and degradation paralleled the technical advances in analytical methods that could detect the presence of zinc in minute amounts coupled with advances in the methodology for protein isolation and purification. 

The median urinary iodine (MUI) concentration provided a measure of the current nutritional status of iodine. MUI was performed in spot urine samples obtained from all mothers and their neonates 5 days after delivery, by using the Sandell—Kolthoff reactions. Decreased MUI excretion of both neonates with hypothyroidism and their mothers was classified as mild-to-moderate iodine deficiency according to the WHO criteria. The mean total thyroid volume (TTvol) of the neonates and their mothers was increased on ultrasonography, whereas no palpable thyroid tissue was detected on physical examination (Table 65.3). 

In addition to the nutritional and physiological effects of Maillard browned protein as described in the previous section, it has been shown that the reduced nutritional value of the brown products does not seem to be limited to the loss of amino acids, since supplementation of the diet with those amino acids could not completely restore its biological value (15). This suggests the possible formation of some inhibitory or anti-nutritional compounds during the Maillard reaction, the presence of which cannot be detected with short-term nutritional feeding assays. Moreover, the short-term feeding effects reported in the literature (30) seem to be due in part to nutritional deficiency and not specifically the browning compounds. 

The essentiality of molybdenum for humans was determined after identification of sulfite oxidase as a molybdenum enzyme [10], the detection of a genetic deficiency of the molybdenum cofactor in a child [11,12], and the occurrence of molybdenum deficiency symptoms after molybdenum-free parenteral nutrition [13]. Apart from the genetic deficiency and the molybdenum-free parenteral nutrition, however, molybdenum deficiency does not occur in animals and humans since the general availability of molybdenum meets the requirements of animals and humans [14]. 

Pongpanich, B., Srikrikkrich, N., Dhanamitta, S., and Valyasevi, A., 1974. Biochemical detection of thiamin deficiency in infants and children in Thailand. The American Journal of Clinincal Nutrition. 27 1399-1402. 

In thiamine deficiency, pyruvate accumulates in the blood and tissues and there is a change in the lactate-pyruvate ratio. These findings have been used in detecting thiamine deficiency in man. MIorwitt has proposed as a test of thiamine nutrition the simultaneous measurement of lactic acid, pyruvic acid, and glucose in the blood 5 min. after mild exercise and 60 min. after ingestion of glucose. The carbohydate index (C.I.) is determined from the formula... 

Specific instances have been cited in which the antibody response served as a sensitive index of nutritional status. These observations have suggested a further exploration of the potentialities of the immune response as a measurement of performance in the evaluation of nutritional state. This technique may find a useful application in the detection of borderline clinical deficiencies. 

The classical way of assessing vitamin K nutritional status was by determination of prothrombin time. Can you suggest a more sensitive way of detecting marginal vitamin K deficiency ... 

Minerals are deposited in hair as it grows and, in theory, the hair reflects the mineral status of an individual at the time of hair growth. Scientific analytical methods, such as atomic absorption spectometry, neutron activation analysis, and x ray fluorescence spectometry, are sensitive enough to detect the levels of minerals in hair samples. Because hair samples are easily and painlessly obtainable, and because hair samples are stable and store easily, there is considerable interest in the use of hair as a diagnostic tool for mineral deficiencies and/or toxicities. However, like many other diagnostic tests, hair analysis is only a tool to complement other tests and observations. It is not a panacea. For the reasons which follow, an individual s nutritional status cannot be assessed solely on the basis of a hair analysis ... 

Sometimes, as in the case for all temporary poisoning or nutritional deficiency, the clinical symptoms are the direct expression of the biochemical lesion no specific anatomical lesion may be detected. Table 1 shows how the biochemical lesions may be classified according to their origin. 

During lipid peroxidation, n-3 fatty acids decompose to produce ethane, whereas -6 fatty acids produce pentane, which can be detected in exhaled breath. A higher breath pentane formation rate therefore indicates more peroxidation of 71-6 fatty acids. Breath pentane and plasma vitamin E levels were measured in 10 normal subjects, and in 5 patients receiving parenteral nutrition diets who wwe deficient in vitamin E. Half of die normal subjects then received 1000 lU of, , , -a-tocopheryl acetate for 10 days, and breath pentane and plasma vitamin E levels were re-measured. Data taken from Lemoyne et al. (1987). lU, international units of, , i -a-tocopherol equivalents. 

At present, niacin status is most commonly assessed by the assay of some of the breakdown products of niacin coenzymes in the urine. Of these, -methyl nicotinamide (NMN) is the easiest to measure, because of a convenient conversion in vitro to a fluorescent product, which can then be quantitated without the need for separation. However, more definitive and reliable information can be obtained by the measurement of urinary NMN in conjunction with one or more of the urinary pyridone turnover products (N -methyl-2-pyridone-5-carboxamide and N -methyl-4-pyridone-3-carboxamide), which can be detected and quantitated by UV absorption following high-pressure liquid chromatography. The Interdepartmental Committee on Nutrition for National Defense (USA) selected the criterion of niacin deficiency in humans as an NMN excretion rate of <5.8 tmol (0.8 mg) NMN per day in 24h urine samples. 

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