Organic selenium - Selenium absorption and metabolism

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Organic selenium is the best form of this trace mineral with better absorption and metabolism.

This essential trace mineral exists in its organic and inorganic forms.
Its natural form shows higher degree of absorption and metabolism than the inorganic form.
It is the integral part of the selenoprotein and antioxidant enzyme, glutathione peroxidase (GPx), and is vital for reducing the destruction of cells in free radical peroxidative reactions.

What is organic selenium?

Though it rarely exists in its elemental form, its inorganic salts are present in soil.
Its selenite and selenate salts are obtained as by-product of copper mining.
Plants take up these salts by absorption and transform them into amino acids like selenomethione and selenocysteine.
Selenium utilization in plants is similar to that of sulphur and the trace minerals are found together.
From the sulphate salts in the soil, plants make the amino acid methionine and from selenite and selenate salts they make L-selenomethionine.
Till the advent of enriched yeast production, the sources of this trace mineral were from plant foods and inorganic supplements like sodium selenite (Na2SeO3) and sodium selenate (Na2SeO4).

Types of organic selenium forms

L-selenomethionine: Great proportion of seleno amino acids from food sources exist in this form.
This type of selenium has good rate of utilization in the body.
D-selenomethionine: This is an isomer of L-selenomethionine and found in small quantities in food.
L-selenocysteine: Formed due to substitution Se instead of sulfur in the amino acid cysteine.
This form is found in small quantities in food.
D-selenocysteine: Very small quantity of this isomer is found in food.
Selenium yeast: Properly fed-batch fermented yeast contains high concentration of L-selenomethionine and small quantities of L-selenocysteine.
L-Se-methylselenocysteine: This compound is found in Brassica (broccoli, cauliflower) and Allium (onion, garlic) plant families.
This is now synthesized from chemicals and found to be non-toxic.
It is found to be effective in the treatment of cancers.

Comparison of organic selenium and inorganic salts for their absorption and metabolism

The absorption of inorganic selenate salts is fast but they are excreted with same speed without much utility to the body.
The metabolism of selenite salts poor and only up to 50% is utilised.
However it is retained in the body for some time.
The utilization rates of selenomethionine in the intestinal tract are high (19% better than selenite) as it is recognized as an amino acid by the body.
This form is well retained and utilized in the body.

Superiority of selenomethionine from organic selenium sources over synthetic products

Christine D Thomson, Alexandra Chisholm, Sarah K McLachlan and Jennifer M Campbell from the Department of Human Nutrition, University of Otago, Dunedin, New Zealand conducted a study on comparative absorption, metabolism and bioavailability of selenium from natural sources and synthetic sources.
It was proven beyond doubt in this experiment that the food form of selenomethionine absorption and metabolism is much better than the synthetic chemical form.
In order to have sufficient regulated supply of this trace mineral in our body, it is best advised to obtain Selenium from food sources, wherein the absorption and metabolism are better.
Related topics on selenium foods and supplements:
Sulfide lotion and shampoo.
Dietary supplements - dosage.
Brazil nuts.
Selenium health benefits.
Selenium food sources.
Sodium selenite - Sodium selenate.
Selenium yeast.
Organic selenium - absorption and metabolism (current topic).

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