Selenium prevents and reduces infection

Abstract Selenium is an essential trace element in human health and disease. It is currently a subject of intense interest. Selenium has important health effects related to the immune response. It appears to be a key nutrient in counteracting the development of virulence and inhibiting HIV progression to AIDS. In the context of health effects, low selenium status in some parts of the world, notably in Africa, is giving cause for concern. Selenium and immunity Selenium enters the food chain through plants, which take it up from the soil. Deficiency has been identified in parts of the world notable for their low soil selenium content. The lowest plasma levels are reported in some areas of China and they are associated with the Keshan disease leading to cardiomyopathy and arthritis. Investigations to date, based on animal and human models, have delivered increasing evidence of Se involvement in the functioning of the immune system. The effect of selenium on the antioxidant glutathione peroxidases and its role in the endothelial immune system is known since many years (J Spallholz, Antioxidant Nutrients and Immune Function, Plenum Press, NY, 1990). When selenium is deficient, we can assume that glutathione levels will be dramatically lower. Glutathione boosts the white blood cell production to fight infection, particularly the T-cells, which are called lymphocytes. Recently, the importance of selenium in the progression of some viral diseases (e.g. AIDS) has been revealed (P Zagrodzki, Post Hig Med Dosw 2004, 58 , 140-149). Selenium is normally found in significant amounts in immune tissues such as liver, speen and lymph nods. Selenium modulates activation of CD4+ cells. Reduced CD4+ cellcounts are a marker for immunodeficiency. Retroviruses like HIV depress selenium levels in their hosts and reduce the glutathione level. This entails a reduction in CD4+ cellcounts. Mice fed selenium diets for 8 weeks saw an increase in CD4+ Tcells proportional to the dose in the diet (KF Hoffmann et al., J of Nutrit. 2010, 1155-1161). The geographical link between selenium deficient regions and HIV/AIDS infection. Figures from Harvard University (ISIS Report 20/07/04) put infection rates as follows : Zimbabwe 25.84%, Botswana 25.10%, Zambia 19.07%, South Africa 12.91%, Ivory Coast 10.06%, Tanzania 9.42%, Ethiopia 9.31% and Congo 4.31%. But Senegal in West Africa has the lowest numbers of AIDS prevalence at 1.77 % in the general population along with with the highest levels of selenium in soils. The soil is of Cretaceous origin and contains the selenium rich phosphorite. In West Cameroon In wild plants used as spices the content of selenium is also very high (AA Bouba et al., Food Nutrit Sc, 2012, 3, 423-432). A study in Zambia (Dr Alida Melse-Boonstra, Lusaka, May 2007) found that in this country soil data were at an average of 0.10 ppm for selenium which is below the reported range of worlwide values for this element of 0.5 -1.27 ppm). In Malawi a widespread selenium deficiency was noticed (R Hurst et al., 2013, Scientific Reports, nature.com, , 3, 1425). In Djibouti the daily intake is 27 microgr and in Ghana 264 microgr. Other benefits of dietary selenium A Belgian study has shown that deficiency of selenium might be an underestimated factor for the development of high blood pressure (TS Nawrot et al., Eur Heart J. 2007, 28, 628-633). In Uganda endemic goiter persistance is related to low serum selenium. In the US cancer mortality rates (lung, rectum, bladder, breast…) had a consistent inverse correlation with soil selenium content in different counties (LC Clark et al., Arch Environ Health 1991, 46, 37-42). Small selenium dietary supplements are adviseable but attention must be paid that selenium has a very narrow hormetic curve and that overdose may cause toxicity. The safe upper limit is estimated to be 400 microgr per day. But this depends evidently on the health status of the person and medical advise is recommended. The easiest way for people living in countries with low selenium in soils to raise their plasma selenium level is regular consumption of staple foods rich in selenium like peanuts, chickpeas, lentils, white beans. Plants from the Artemisia family also accumulate many minerals, including selenium, 10 times more than fruits and vegetables (U.S. Geological Survey Bulletin 2117). The same accumulator effect has been shown in China for Artemisia argyi (Ping Liu Xin et al., Adv Mat Res 2013, 1, 634-638) and the US for Artemisia ludoviciana (A Mehdawi et al., Current Biology, 2011, 21, 1440-48). The metal is present in the form of selenium polysaccharide. This may explain why several of our partners in Congo, Uganda, Tanzania and India have found that the regular consumption of Artemisia annua or Artemisia afra infusion increases the CD4+ count. Pierre Lutgen 25 Jan 2015