Immunonutrients, which improve immune function, have been shown to benefit patients at times of surgery or during critical illness. They improve immunity when given in large doses with resulting shorter hospital stays. Some examples are arginine, omega-3 fatty acids, glutamine, nucleotides (components of DNA and RNA), beta-carotene, and branched-chain amino acids.
Glutamine amino acid is abundant in the body, but easily depleted under severe physical stress. It provides fuel for rapidly dividing cells and is converted to the strong antioxidant glutathione. Glutamine helps maintain gut barrier function which prevents infections from moving from the intestine into the rest of the body. Severe illnesses such as trauma, sepsis, surgery, chemotherapy, and radiotherapy deplete glutamine stores.
In general, intensive care unit patients have low glutamine blood levels on admission. It has been found that glutamine treatment reduces their infection and inflammation risk, but their lengths of admission were not reduced. Glutamine reduced infection rates of surgical patients and reduced their stay in the hospital, but did not alter mortality.
Good levels of glutathione are needed in severe health problems, such as HIV, hepatitis C, and cirrhosis. Glutathione is produced from glycine, glutamic acid and cysteine amino acids. Glutamine can be easily converted to glutamic acid for production of glutathione in various disorders, such as diabetes. Glutamine plays an important role in maintaining the lining of the intestine and doses of glutamine at .3 g/kg body weight per day improved health of the intestine. Glutamine is poorly soluble in water. A combination of alanine and glutamine may work better than glutamine alone.
Glutamine can be converted to citrulline, which can be converted to arginine. Arginine is the precursor for nitric oxide (NO) which is important for regulating circulation.
There is debate whether chemotherapy patients should receive glutamine since glutamine is fuel for rapidly growing cells, like cancer cells. Intestinal permeability was slightly improved in Crohn’s disease with glutamine; however oral glutamine had no effect on inflammation in that disease. I.V. glutamine has been found to have dramatic results in premature infants. They require less I.V. feeding, have less time on the ventilator, and takes less time to start on normal feedings.
CONCLUSION: Overall, glutamine supplementation reduces infections, inflammation, hospital stays and mortality. It also improves gut barrier function and immunity.
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