HIV and Malnutrition: Effects on Immune System
Dietary intake also varies inversely with level of virus, suggesting that viral replication directly or indirectly suppresses appetite [ 7 ]. Thymolymphatic deficiency and depression of cell-mediated immunity in protein-calorie malnutrition. To summarize this evidence 67 , there is evidence that intestinal epithelial integrity is improved by vitamin A 68 , but not of improved antimicrobial properties in breast milk, and no evidence of improved barrier function in the vagina. Received Sep 1; Accepted Nov Studies confirm that the initial finding of thymolymphatic atrophy resolves with renutrition 53 , and in parallel, T-lymphocyte function as examined by cell proliferation and the tuberculin test improves 28 , 45 ,
In T-cells, the supplementation of selenium suppresses HIV replication and decreases the production of cytokines that cause inflammation. Supplementation with selenium in deficient HIV-positive people has been shown to improve selenium status. Selenium deficiency correlates with viral progression and death in HIV infection more than any other micronutrient. She is also a doctoral candidate, studying nutritional sciences with a minor in microbiology and immunology.
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It is not a substitute for professional care. If you have or suspect you may have a health problem, consult your health care provider. People with HIV often take micronutrient supplements, but the research has not yet proven what the most useful dosages are for these individuals. Certain nutrients may directly influence the immune system's ability to fight infection.
For example, cells that are supplemented with vitamin D appear to prevent Mycobacterium avium complex MAC from growing in macrophages from HIV-positive patients. This article will briefly review selected micronutrients and their known functions in the complex immune system. Malnutrition and Immune Function It has long been known that malnourished individuals are at higher risk for infectious disease due to an inadequate immune response. Infection then leads to inflammation and worsening nutritional status, which further compromises the immune system.
This has been called the "vicious cycle. Protein-calorie malnutrition has a significant negative effect on various components of the immune system. Studies have shown decreased function of the organs thymus, spleen, lymph nodes of the immune system in malnourished humans. The branch of the immune system that produces antibodies is depressed in malnutrition, specifically with a decreased number of circulating B-cells and antibody responses.
Other mechanisms that kill infectious organisms are also depressed in malnutrition. The functions of cytokines, chemicals that act as cell messengers, are altered in malnourished individuals.
Vitamin A deficiency can interfere with how epithelial cells function, which is vital in maintaining tissue structure. Deficiency of single nutrients also results in altered immune responses: Of the micronutrients, zinc; selenium; iron; copper; vitamins A, C, E, and B-6; and folic acid have important influences on immune responses.
Overnutrition and obesity also reduce immunity. Low-birth-weight infants have a prolonged impairment of cell-mediated immunity that can be partly restored by providing extra amounts of dietary zinc.
In the elderly, impaired immunity can be enhanced by modest amounts of a combination of micronutrients. These findings have considerable practical and public health significance. Oxford University Press is a department of the University of Oxford. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide.
Sign In or Create an Account. Immune cell activation and systemic proinflammatory mediator levels are increased in malnutrition. Malnutrition impairs immune priming by DC and monocytes, and impairs effector memory T cell function.
Immune dysfunction can directly drive pathological processes in malnutrition, including malabsorption, increased metabolic demand, dysregulation of the growth hormone and HPA axes, and greater susceptibility to infection. Malnutrition, which encompasses under- and overnutrition, is responsible for an enormous morbidity and mortality burden globally. Malnutrition results from disordered nutrient assimilation but is also characterized by recurrent infections and chronic inflammation, implying an underlying immune defect.
Defects emerge before birth via modifications in the immunoepigenome of malnourished parents, and these may contribute to intergenerational cycles of malnutrition. This review summarizes key recent studies from experimental animals, in vitro models, and human cohorts, and proposes that immune dysfunction is both a cause and a consequence of malnutrition.