Showing posts with label system. Show all posts
Showing posts with label system. Show all posts

Zinc immune system function - Disease resistance in human body

Jan 2014  › › Zinc immune system function and disease resistance in human body
Zinc, an essential trace mineral, exerts its ubiquitous effects on the function of the immune system in human body and modulates its disease resistance.
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The basic cellular functions of Zinc in human body are in gene expression, deoxyribonucleic acid (DNA) replication, ribonucleic acid (RNA) transcription, cell membranes stability, and cell activation, division, proliferation and apoptosis.

Zinc and disease resistance in human body

  Many research studies have documented that zinc has a pivotal role in the function in immune system of human body. It has been found to increase the infection resistance in human body. Its deficiency has been associated with recurrent episodes of diarrhea in children. Administration of zinc lozenges has been found to decrease the severity and duration of common cold. In many incidences of infections, lower plasma concentrations of this trace mineral have been recorded.

However it is to be noted that there is a delicate zinc mediated regulation of the function of immune system in human body and any increased or decreased plasma levels of the trace mineral can disturb the function of the system. Reduction in taste acuity, growth retardation, retardation of reproductive growth, skin diseases, immune depression and slowed healing of wound are some of the clinical symptoms of marginally low plasma levels (<60 mcg/dL) of zinc on the human body systems. Very low plasma levels (<30 mcg/dL) are characterized by mental impairment, diseases, severe immune depression and alopecia.

Excess zinc and immune depression

On the negative side, excess supplementation of zinc is associated with disease resistance depression and a myriad of health issues and diseases. As the pathogens also require this mineral for their cellular functions, excess of this trace mineral may in fact increase the progression of diseases as found in some AID patients. However multifarious factors affect the availability of zinc for both the host human body as well as the pathogen and this aspect of immune system requires further research input.

Zinc and innate immune system

The nonspecific protective mechanism is affected by zinc deficiency with the effects like damages to epidermis, damages to pulmonary tract and gastrointestinal tract lining. As a consequence, diseases of skin, gastrointestinal and respiratory systems crop up. The functions of neutrophils or polymorphonuclear leukocytes (PMNs) are affected. The function of Natural killer cells and the complementary activities get compromised.

Zinc and specific immunity

Zinc deficiency causes reduction in the number of T and B lymphocytes present in the spleen tissue as well as in the peripheral blood. T and B lymphocytes function is depressed and their presence is reduced. In animal studies gestational deficiency of this trace mineral has been found to have epigenetic effects by which some immunodeficiency get passed on even to third generation offspring.
Hematopoiesis in human body
immune system development


Thymus is the organ for T lymphocyte development and zinc deficiency leads to thymic involution and thymic atrophy, causing reduction of T lymphocytes. With the reduction of T lymphocytes, many protective mechanisms in human body like antigen recognition, cell proliferation, cytolysis, delayed hypersensitivity and cytotoxic activities are suppressed. Bone marrow is the center for the development of B lymphocytes. In case of deficiency the development of B lymphocytes is blocked and results in compromise of production of antibody molecules, especially immunoglobulin G in human body. The function of macrophage in phagocytosis of disease microbes is deregulated.

The intra and extracellular reactions of zinc in human body clearly demonstrate its central role in defence from diseases and priming up immune system.
Image credit: Wikipedia
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Selenium for HIV and AIDS - Selenium immune system

› › Selenium and HIV/AIDS - immune system

Selenium is found to boost the immune system and decrease progression of HIV/AIDS.

As per the World Health Organization (WHO) global summary of the acquired immunodeficiency syndrome epidemic, December 2008, number of people living with Human immunodeficiency virus in 2008 was 33.4 million, people newly infected with this virus in 2008 was 2.7 million and AIDS death in 2008 was 2.0 million.

In the treatment of this pandemic affecting immune system the focus is now shifting towards nutrient supplements like selenium in addition to antiretroviral therapy so as to improve the quality of life of the affected. It is found that dietary selenium supplement can reduce the viral load and help in increasing the CD4+ T Cell Count and boosting immune system.

Selenium as antioxidant boosts immune system of HIV infected

Selenium as an essential trace mineral is required for the formation of selenoprotein enzymes, which are vital for the immune system. These selenoenzymes by neutralizing the free radicals (by-products of metabolism) save the body cells from oxidative damages. Glutathione (GSH) is the unique tripeptide essential for the functional physiology of immune system. The raised glutathione levels make the immune system to go into antiviral , anti HIV mode and the T cell function is enhanced. Antioxidants (includes selenium) are known to inhibit viral replication, boost immune system and also help in inhibiting apoptosis.

HIV/AIDS prevalence is low in regions with selenium rich soil

Viral infection and full-blown syndrome in sub-Saharan Africa has reached pandemic proportions with nearly 25% of the population being affected (Botswana 25%, Zimbabwe 25% and Zambia 19%) with HIV-1 infection as high as 36% in some parts. All these regions have one thing in common; the soil is poor in selenium. However in West Africa, Senegal has the lowest prevalence of only 1.77% in the population.

Senegal is fortunately situated on the sedimentary bed rocks of desiccated sea of Cretaceous and early Eocene period with soil rich in selenium, magnesium, phosphorus and calcium. Similarly Bolivia, which is rich in selenium (a major exporter of the mineral), has very low prevalence (0.2%) of of this viral infection when compared to the surrounding countries. Finland, whose soil is deficient in selenium, has made it mandatory to add selenium to fertilizers in 1984 and has 0.3% prevalence of Aids while the surrounding countries have double the prevalence.

Even after considering the lifestyle, unprotected promiscuous activity and AIDS awareness and education in these regions, the selenium availability in soil stands out as the main factor directly affecting the relative incidence of HIV. Selenium status in those infected with this virus and those with AIDS is a significant predictor of survival.

Selenium boosting immune system makes HIV/AIDS less virulent and slows its replication

It is well established that the infected persons slowly become selenium deficient and their infection protection mechanism collapses. This is due to encoding the entire glutathione peroxidase (a selenoenzyme) by the HIV as it replicates. It sources the selenoenzyme component amino acids and selenium from the cells and plasma of the patient, affecting his immune system.

In a 18 month study jointly undertaken by the Duke University and Tamil Nadu State AIDS Control Society (TNSACS) in the South Indian State of Tamil Nadu, 10,500 people with HIV/AIDS were given antiretroviral therapy (ART) along with micro and macro nutrients. The study found that the micronutrient interfered with protein required for viral replication and reviving the disease resistance, improved the condition of the affected patients.

In another experiment conducted by K. Sandeep Prabhu and others it was found that HIV replication was inhibited at least ten fold when Selenium (sodium salt of selenium) was added to the cell culture. When the virus depletes all the mineral of the host cell, it replicates and attacks other healthy cells for more selenium.

The greater the uptake of selenium by HIV, greater is the its deficiency and compromise of the AIDS affected person's immune system. Selenium supplementation keeps the virus within the affected cell and cater to its need of this mineral. This helps the immune system to be well prepared and highly functional warding off any opportunistic infections.

Treatment of HIV/AIDS with Selenium, tryptophan, glutamine and cysteine

Dr. Harold Foster (died august 15, 2009), formerly faculty member in the Department of Geography, University of Victoria, treated AIDS patients in Africa with amino acids tryptophan, glutamine, cysteine and trace mineral selenium; which are the basic components of the selenoprotein enzyme glutathione peroxidase.

Affected patients are found to be extremely deficient in all the four nutrients required for the synthesis of glutathione peroxidase. When treated with these nutrients it was observed that patients were able to return to work within a month and their immune system revived. This virus competes for the glutathione peroxidase nutrients for its replication and depletes these nutrients in the infected individual.

With the current antiretroviral therapy for HIV/AIDS targeting the replication of the virus, the intake of these amino acids along with selenium further boosts the immune system of the affected person helping him to lead a near normal life.

Selenium and HIV/AIDS (current topic).
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