Nutrition :: Selenium – an essential mineral for the body
Selenium, a mineral found in the soil, is taken up into plants and animals and is necessary for proper body functioning.
The majority of the United States has soils that are very low in selenium, requiring the supplementation of all animal feeds to prevent deficiency related diseases.
In the Upper Midwest, there are pockets of soil that are exceptionally high in selenium, so plant and animal products from this area are higher in selenium than those in other areas.
The U.S. population consumes most of its selenium from wheat products, beef, chicken and several types of fish.
The major selenium-containing proteins are involved in maintaining antioxidant status and working in conjunction with vitamins E and C. Selenium also is essential for the enzymes that activate thyroid hormones and for proper motility of sperm mitochondria.
The most interesting discovery in the last 30 years of selenium research was the finding that forms of selenium could reduce tumor formation and growth in rats. This further was investigated in a human clinical cancer prevention trial, which showed that there was a reduction in the risk of prostate, colorectal, and lung cancers with selenium supplementation of 200 micrograms per day.