Selenium and liver cancer: the Qidong study results

China is a country with many selenium-poor regions. The people living in these regions have paid the price with high rates of heart disease, bone disease, and various forms of cancer. Selenium supplementation has proven beneficial in China.

Some 50 years ago now, Chinese researchers began to understand the health risks associated with low selenium status.  Cross-sectional studies showed an association between low selenium concentrations in cereal grains, the low selenium status of local citizens, and the incidence of Keshan disease, a heart disease with high death rates.  The administration of selenium supplements in intervention studies resulted in significant reductions in the incidence of Keshan disease [Chen 2012].  Selenium status is one of the main factors contributing to the development of Keshan disease.

Selenium and Kashin-Beck disease
Not long afterwards, Chinese researchers realized that Kashin-Beck disease, a disease of the bone, is prevalent in regions of China and Tibet that are poor in selenium.  The researchers saw that a deficiency of selenium and iodine was a common factor Kashin-Beck disease regions [Yao 2011].

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Selenium and cancer prevention: The Linxian Study

In the 1990s and before, the diets of the people in the Linxian province in China were poor in important micronutrients. Selenium status among the residents was notably low. Cancer rates were high. Supplementation with selenium and other antioxidants reduced cancer incidence and mortality.

The Nutrition Intervention Trials conducted in the Linxian province in China yielded some of the first promising results linking selenium supplementation to the reduction of cancer incidence and mortality.  The Linxian province at the time was characterized by a selenium-poor diet.

The treatment group that received selenium supplements was the group that showed significant health benefits of the supplementation:

  • Significantly lower total mortality
  • Significantly lower cancer mortality
  • Significantly lower stomach cancer mortality

The reduced mortality rates began to become apparent already after 1 – 2 years of supplementation.  The patterns for reductions in cancer incidence generally approximated the patterns for cancer mortality [Blot].

The Linxian study results were exciting because they were published in the Journal of the National Cancer Institute and because they appeared before the results of the Nutritional Prevention of Cancer study in the United States [Clark].

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We must not waste selenium

Selenium exists only in scarce quantities. Adequate dietary and supplemental intakes are vital for human health.  We need to use it carefully, and we need to begin to stockpile it for the use of future generations.

Selenium is a trace element.  It exists only in rare quantities in the world.  It is produced primarily as a by-product of the process of mining copper.  It is not recyclable.  It is very unevenly distributed in the soils of the earth.

Consequently, the availability of selenium in grasses and grains and, at the next stage of the food chain, in animals, varies considerably from region to region in the world. The human dietary intakes of selenium vary accordingly around the world.

Selenium a vital nutrient for humans
Selenium is a necessary micronutrient that our bodies do not produce.  We get our selenium primarily from our diets.  Selenium is important for good immune system function, good thyroid function, good reproductive function, and good protection of our cells’ DNA.

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