HIV/Aids: to the soil we shall return

The problem with HIV is that it infects and depletes immune cells that are crucial in protecting the body from other disease-causing microbes. HIV induced immune suppression leaves the body vulnerable to attack by other microbes that normally do not cause disease in healthy persons. Acquired immunodeficiency syndrome (AIDS) is a condition in which the immune system becomes severely weakened and loses its ability to fight infections. The other problem with HIV is that it changes its surface coat and hence escapes attack from the body’s immune cells. Imagine that HIV has an endless wardrobe of coats. Whenever new viral particles are formed, they acquire new surface coats each time. This confuses the body’s immune cells. Immune cells fail to recognise HIV with new surface coats due to lack of immunological memory, putting HIV one step ahead of the immune system. It’s like cops that fail to recognise robbers’ camouflage dress ‘ they recognise the robbers only after the robbery. Several factors determine the risk of HIV infection. Exposure to HIV in the anal cavity is more risky than through cells lining the vaginal cavity; both risks are higher than exposure to HIV through the mouth. The size of the HIV inoculum during exposure is also important in determining the risk of HIV infection and occurrence of illness after exposure. Persons with higher viral loads pose a higher risk than those with lower viral loads. Mother-to-child transmission is also enhanced in mothers with high viral loads. There are reports that the virulence of HIV is decreasing. Thus HIV is weakening and may not be killing its hosts as rapidly as it used to do a few years ago. This is typical of a parasite that wants to perpetuate itself: it kills slowly. Antiretroviral therapy lowers the viral load and may have contributed to the decrease in the strength of HIV. But the best medicine is food. Foods with medicinal functions are part of a growing trend in food product marketing now called “nutraceuticals” or functional foods. Selenium, a rare element found naturally in the earth’s crust, plays a crucial role in the human body as part of a system of enzymes that enhance the ability of normal cells to eliminate free radicals and foreign compounds, such as carcinogens in automobile exhaust and cigarette smoke. But selenium is toxic in large doses. This problem has been overcome by a natural selenium biofortification process in mushrooms. African mushrooms contain selenium in correct amounts, and selenium-enriched mushrooms are now being used to boost the immune system and slow the progression of HIV+ persons towards AIDS. HIV+ persons should be encouraged to eat mushrooms. Mushrooms are known to have medicinal properties. The literature contains more than 341 researched articles linking mushrooms to good health. HIV+ people who took selenium supplements experienced fewer opportunist infections, better intestinal function, improved appetite, and improved heart function. Geographical areas where soils have high levels of selenium have been linked to low incidence of disease. In China, selenium deficient regions are known as the “disease belt”. Here, the daily average intake of selenium is less than 10 micrograms. This contrasts with parts of the USA and Canada where daily selenium intake is 170 micrograms. A three year study of an entire town in Jiangsu Province where 20, 847 residents were given table salt fortified with selenium showed that hepatitis infection decreased to 4.52 per 1, 000 compared to 10.48 per 1, 000 in communities using regular table salt. Soil degradation is now being linked to the geographical distribution of HIV/AIDS in Africa. The epicentre of the HIV/AIDS pandemic is in Southern Africa, where the countries’ soils are depleted of selenium. For example, previous reports put Namibia’s HIV prevalence rate at 21.3%, after South Africa (21.5%), Lesotho (28.9%), Zimbabwe (33.7%), Botswana (37.3%) and Swaziland (38.8%). But Senegal in West Africa has the lowest numbers of HIV prevalence at 1.77% in the general population, and 0.5% in antenatal clinic attendees. What might explain this geographical distribution of HIV? To the soil we shall return-only this time, for answers! Geologically, Senegal is situated in the desiccated or dried up Cretaceous and early Eocene sea, and the land is formed from sedimentary rocks from dissolved minerals in the evaporating seawater. Consequently, calcium phosphates are one of the country’s mined mineral products used for fertilizers, and are derived from the selenium rich phosphorite. Geographical disease pattern analogies suggest that HIV/AIDS is rife in regions with selenium depleted soils. Adults and children with advanced AIDS syndrome display both highly depleted selenium plasma stores and reduced CD4 Cell counts. The fall in selenium levels triggers the reduction in CD4 cells, which in turn causes further decline in serum selenium. This phenomenon is now being called “the selenium CD4 T-cell tailspin”. HIV depresses selenium levels in the host. This allows the virus to replicate indefinitely by continuously depriving the host of glutathione, an inhibitor of reverse transcriptase. As levels of selenium decline, so do CD4 cells which allow opportunistic pathogens to invade the immune system and further deplete levels of selenium and CD4 cells in a positive feedback loop whereby if one variable declines, it causes further depression in the other. This downward spiral compromises the ability of the immune system to defend the body from infection, which plays a significant role in AIDS mortality. Although the cause of progression of HIV to AIDS is still unknown, the role of nutrition and supplementation in the prevention and treatment of the disease cannot be ignored. Luc Montagnier, the co-discoverer of HIV, stated that AIDS is characterised by a persistent oxidative imbalance and a decrease of glutathione. Glutathione is an antioxidant that effectively neutralizes free radicals, dangerous destructive oxygen atoms that injure the body’s healthy molecules, cells and tissues. When glutathione levels in the cells fall below 80%, the cell dies from acute oxidative stress. Oxidative stress of cells in the immune system compromises their role in immune function and immune response. Specifically, the CD4 T-cell counts fall leading to immunodeficiency. Selenium is required for the enzyme glutathione peroxidase, a major protective enzyme against oxidative stress. Evidence suggests that HIV-1 infected patients are under chronic oxidative stress, which contributes to several aspects of HIV pathogenesis. Selenium is a critical nutrient in determining the course of HIV/AIDS because of its role in immune function and antioxidant protection. Research suggests that HIV hijacks the host’s supply of selenium for its own antioxidant protection, thereby inducing or exacerbating a selenium deficiency with increasing disease progression. Selenium deficiency is associated with much faster disease progression in HIV-infected adults. In addition, selenium-deficient HIV-positive adults are 20 times more likely to die from HIV-related complications than those with adequate selenium status. Major factors have contributed to selenium depletion in the soil. Acid rain is caused by large quantities of sulphur and nitrogen that convert into sulphuric and nitric acids in the atmosphere and changes the capacity of soil to bind elements at pH neutral or slightly alkaline. The altered pH balance increases bioavailability of certain elements and decreases that of others including selenium. Heavy metals in rainfall also contain mercury, which can combine with selenium to produce the insoluble mercury selenide. Soil acidification therefore lowers the abundance of selenium in the global food chain, which may have contributed to the rapid increase of cancers and HIV/AIDS in Southern Africa. Climate change may also be involved in tipping the immune progression towards AIDS. Overexposure to ultraviolet light decreases CD4+ helper T-cells and increases suppressor T-cells making the individual more susceptible to diseases. Pollution from chlorofluorocarbons contributes to the thinning of the ozone layer, which causes an excess of ultraviolet B radiation to reach the earth. In countries that lie under ‘holes in the ozone layer’, “the selenium CD4 T-cell tailspin” hypothesis may explain the high incidence of HIV/AIDS. While this requires further research, the question one could ask is: shall we see UV-proof clothes as a protective measure against HIV/AIDS? l Kazhila Chinsembu is a lecturer in the Department of Biology, University of Namibia. Email: kchinsembu@unam.na

May 2006
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