Hormonal Parenteral nutrition

Deficiency syndromes of Zn, Cu, Cr, Se and Mo have occurred in patients on total parenteral nutrition (TPN). There is still much research to be done in assessing the nutritional status of many elements and understanding their metabolism, so that normal dietary intake may be supplemented for health benefits. Table 2 is a summary of the amounts required, the functions and the nutritional (usually dietary) imbalances in humans, where known, of the essential trace elements.31-33 (Note that this summary does not attempt to include imbalances related to environmental toxicology and occupational hazards.) Several trace elements have important functions in the immune system. Some are associated with nucleic acid. Others have structural roles, such as Si in cartilage, F and Zn in bone. They may be parts of vitamins, such as Co in vitamin B12, or hormones, such as iodine in thyroid hormones, Zn and Cr have a role in the synthesis and action of insulin.31-33... 

Equally, demonstrating that a compound has a physiological function as a coenzyme or hormone does not classify that compound as a vitamin. It is necessary to demonstrate that endogenous synthesis of the compound is inadequate to meet physiological requirements in the absence of a dietary source of the compound. Table 1.3 lists compounds that have clearly defined functions, but are not considered vitamins because they are not dietary essentials endogenous synthesis normally meets requirements. However, there is some evidence that premature infants and patients maintained on long-term total parenteral nutrition may be unable to meet their requirements for carnitine (Section 14.1.2), choline (Section 14.2.2), and taurine (Section 14.5.3) unless they are provided in the diet, and these are sometimes regarded as... 

Selenium, as selenocysteine, is incorporated into glutathione peroxidase (antioxidant), iodothyronine deiodinase (thyroid hormone regulation), and selenoprotein P (vitamin C metabolism). Prematurity, acute illness, chronic GI losses, and long-term selenium-free parenteral nutrition are associated with low serum selenium concentrations and decreased glutathione peroxidase activity. " The... 

Deficiency of iodine, a component of thyroid hormones, may result in goiter formation (see Chap. 73). However, not everyone with an iodine-deficient diet will develop a goiter. Thyroxine (T4) and triiodothyronine (T3) can be used to assess iodine status (see Table 135-8). Intravenous iodine supplements typically are not necessary except during long-term parenteral nutrition with minimal enteral intake. Iodine needs generally are met by cutaneous absorption of iodine from germicides (e.g., povidone-iodine) used in catheter care or consumption of iodized salt. " Use of povidone-iodine wiU likely decrease with the increased use of chlorhexidine for catheter care, and the need for iodine supplementation must be individualized. Iodine excess is rarely a clinical concern when thyroid function is normal. 

Endocrine Hypothyroidism and altered metabolism of thyroid hormones have been reported as adverse events in neonates and children, resulting from the use of antiseptics containing povidone-iodine [SED-15, 1896 SEDA-30, 279 SEDA-31, 411 SEDA-32, 440]. Because of concerns about possible iodine excess, chlorhexidine-based antiseptics have replaced povidone-iodine in some clinical settings. However, this may not be advantageous for infants and children who are receiving total parenteral nutrition (TPN) as iodine is not routinely added to TPN solutions. Previously, iodine deficiency was considered unlikely in patients receiving TPN, because of adsorption from iodine-containing skin disinfectants and other adventitious sources [67 68 ]. 

Intestinal operations Food intake Mucosal damage Miscellaneous Resection, bypass, transposition Fasting, refeeding, hyperphagia, parenteral nutrition Irradiation, cytotoxics, chemical carcinogens Hormones, lactation, hypothermia... 

Overall, nutrition therapy is a component of medical treatment that includes oral, enteral, and parenteral nutrition (PN). However, a meta-analysis provided no evidence that nutritional support has a significant effect on anthropometric measures, lung function, or exercise capacity in patients with stable COPD (25,26). By contrast, repeated administration of ghrelin, a novel growth hormone- releasing peptide that is reduced in COPD (27), may improve body composition, muscle wasting, and functional capacity in cachectic patients with COPD, thus possibly reversing some of the systemic aspects of COPD (28). 

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