{"id":302,"date":"2017-02-01T09:49:50","date_gmt":"2017-02-01T09:49:50","guid":{"rendered":"http:\/\/seleniumfacts.com\/?p=302"},"modified":"2017-02-02T02:09:12","modified_gmt":"2017-02-02T02:09:12","slug":"basic-guide-selenium","status":"publish","type":"post","link":"https:\/\/seleniumfacts.com\/index.php\/basic-guide-selenium","title":{"rendered":"A basic guide to selenium"},"content":{"rendered":"
Selenium is a by-product of the mining and refining of copper. There are no sites in the world for the mining of selenium alone. Given its relative scarcity and its many uses — industrial and agricultural as well as nutritional — selenium for supplements will surely be more expensive in the future, and there may well be shortages of it in the future. Accordingly, it is important for us to use it wisely and to conserve it.<\/strong><\/figcaption><\/figure>\n

Selenium is an important micronutrient.\u00a0 It is essential for life for both people and animals.\u00a0 The body cannot synthesize selenium and is dependent upon the selenium that it can get from food.\u00a0 In many regions of the world, there is too little selenium in the soil and in the food, and supplementation is necessary for optimal health.
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Regions with selenium-poor soil<\/strong>
\nIn many regions of the world, the content of selenium in the soil is quite low.\u00a0 In large parts of Asia, China in particular, and in much of Europe and the Middle East, there are low levels of selenium in the soil.<\/p>\n

Plants accumulate inorganic selenium from the soil and convert it to organic selenium. In that way, the selenium enters the food chain. For example, cows eat grass containing selenium, and the some of the selenium enters the meat and the milk of the cows.\u00a0 People eat the meat and drink the milk.\u00a0 Too little selenium in the soil means too little selenium in the food.<\/p>\n

The Finnish experiment with selenium additives to fertilizer<\/strong>
\nIn 1985, the Finnish government decided that selenium should be added to all agricultural fertilizer.\u00a0 The background to this decision was an intense debate in which advocates of selenium additives presented data about the low levels of selenium in Finnish citizens.\u00a0 The selenium status of Finnish citizens had reached such a low level that public health authorities in Finland were worried about the dangers of selenium deficiency.<\/p>\n

The success of the selenium fertilizer project in Finland
\n<\/strong>Twenty years later in\u00a0 2005, the Finnish authorities issued a report summing up the first 20 years of the selenium fertilizer project.\u00a0 The new data showed that adding selenium to agricultural fertilizer has been a safe and effective<\/a> solution to the problem of low selenium status in the Finnish people.\u00a0 Actually, the measurements of the selenium in blood samples, in milk samples, and in meat samples all showed a positive trend, except in organic farming areas where the use of artificial fertilizers was not permitted.<\/p>\n

Not enough selenium to copy the Finnish experiment<\/strong>
\nDespite the success of the Finnish experiment, none of the other countries in the rest of Europe has taken a similar decision.\u00a0 One important reason is that selenium is a rare trace element, and there is relatively little selenium produced every year.\u00a0 Of the amount that is produced, the preponderance goes to industrial purposes.<\/p>\n

There is, simply put, not enough selenium available to fertilize cultivated fields and pasture lands with it everywhere in the selenium-poor countries of the world to the extent that the Finns have done.\u00a0 Selenium is so relatively rare that we humans need to administer its uses carefully and should begin to stockpile it for the use of future generations [Haug].<\/p>\n

Recommended dietary intake for selenium<\/strong>
\nToday, in the United States and Canada and many countries in Europe, the recommended dietary intake for selenium is set at 55 micrograms per day.\u00a0 This is the daily intake level at which it is thought that the activity of the selenium-dependent antioxidant enzyme glutathione peroxidase can be optimized.<\/p>\n

Since the establishment of this intake level, selenium researchers have suggested that greater intakes may be needed for selenium-dependent protection against cancer and other chronic diseases. The putative beneficial range is plasma selenium status between 120 and 170 nanograms per milliliter [Hurst 2010].\u00a0 The evidence from Hurst’s research seems to indicate that we need approximately 105 micrograms per day to reach the lower limit of that range and approximately 155 micrograms per day to reach the upper limit of that range.\u00a0 Both intakes are well under the tolerable upper limit for daily intakes established by the European Food Safety Authority in February, 2006: 300 micrograms of selenium per day.<\/p>\n

Special groups at risk of getting too little selenium<\/strong>
\nEven at the recommended level of 55 micrograms of selenium per day, there can be special groups of people at risk of getting too little selenium<\/a> in their diets.\u00a0 For example, vegetarians and vegans are likely to be at risk because meat, fish, and dairy products are important sources of dietary selenium.<\/p>\n

Another group that may be at risk is the group of people who are sensitive to gluten and who therefore avoid grain products.\u00a0 Grains are just below fish and meat from mammals on the list of important dietary sources of selenium.<\/p>\n

Elderly people who eat less may be at risk.\u00a0 Smokers may need extra selenium.\u00a0 Body size and exercise levels may influence the amount of selenium needed on a daily basis.<\/p>\n

Selenium and selenocysteine and selenoproteins<\/strong>
\nSelenoproteins are proteins in the body that contain selenocysteine, the 21st amino acid.\u00a0 Selenocysteine is itself dependent upon the availability of selenium<\/a> for its synthesis.\u00a0 Researchers have identified 25 selenoproteins that play a role in human health.\u00a0 These selenoproteins have several biological functions:<\/p>\n