Plants vs. Yeast
"Consumption of selenium enriched plants or yeast-based nutritional supplements has been reported to provide anticarcinogenic benefits which are selenium compound dependent. Plants and yeast convert inorganic selenium in the soil or growth media into organoselenium compounds, probably following a route similar to the sulfur assimilatory pathway."
Plants such as broccoli and garlic are similar to yeast in that they all belong to the Plant Kingdom. Yeast's are of the Eumycota Division of the Plant Kingdom. In the simplest terms, yeast are fungi which are single celled plants.
Selenium is a trace mineral that enters the soil naturally through the weathering of selenium rich rocks such as: sandstone, siltstones, phosphorite, limestone, iron, coal, copper deposits, and crude oil deposits. Selenium does not occur in sedimentary rocks from the pre-Cretaceous period (volcanic ash, granites, and old metamorphic rocks)
Soil bacteria and fungi oxidize elemental selenium into selenite/selenate, which are highly soluble in alkaline soils, thus facilitating their uptake by plants.
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How plants uptake minerals (selenium)
Minerals present in the soil enter plants via the roots. Since roots are continuously growing they are constantly coming in contact with additional mineral salts that can be absorbed into the plant with water. Plant roots not only absorb free mineral salts; they assist in liberating the minerals from other soil compounds, thus increasing the amount which can be absorbed. The accumulation of minerals at appreciable rates is confined to cells which are still growing and having cell division. Several other conditions that effect the absorption of selenium or minerals are:
- Adequate supply of the mineral
- Availability of water
- Soil pH
- An adequate supply of oxygen
- Proper temperature
- A supply of sugars or hydrolyzable polysaccharides within the plant cells
Should any of these conditions not be "ideal", it will limit the rate and amount of mineral absorbed by the plant. back to top
How yeast take up minerals (selenium)
Bakers yeast is grown in a liquid growth medium within a large fermenter. All necessary minerals are present in the fermentation medium from the molasses or supplementation at a linear feed rate during the fermentation. In the case of producing selenized yeast, the sodium selenite salt is added to the medium/mother culture at specific times. Through the process of growth and cell division, minerals are absorbed and utilized by the yeast.
Commercial fermenters are equipped to control: pH, temperature, and oxygen thus allowing the "controlled" growth of the yeast. This fermentation control yields a finished product that is very consistent in mineral uptake from batch to batch; whereas in plants there can be a wide degree of uptake due to the lack of "control" parameters.
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Summary
In summary, both higher plants and yeast require similar conditions to uptake selenium salts from their surrounding environment. In both cases, the plant or the yeast must be actively dividing and growing. In a controlled fermentation of yeast, the surrounding environment can be maintained to assure the natural optimal growth parameters and to guarantee the uptake of selenium in a natural process. This can not be said for plants growing in "Nature".
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Cypress' Leadership in the Field
Lon C. Baugh, Ph.D., Director of Fermentation at Cypress Systems, co-developed the product used in the Nutritional Prevention of Cancer Study conducted by Dr. Larry C. Clark of the University of Arizona, Arizona Cancer Center. Cypress continues to utilize this original production protocol and identifies its current product as SelenoExcell™ High Selenium Yeast. |
