Selenium Update

[Guest guest]

Hi,

previously I said that L-Selenomethionine was the only form of Selenium

that was bio-available. Actually certain forms of selenium yeast are also bio-

available, but it some forms of selenium yeast are not bio-available, that is

why I

suggested only L-selenomethionine. If inorganic selenium is simply mixed with

yeast

that will not be bio-available, but if the yeast is grown in a medium of

selenium

then it is bio-available.

Sodium Selenite is not bio-available and might actualy cause problems compared

to

L-seleonomethoinine which is good and highly bio-available.

Edited articles on Selenium......

Basic Selenium Information

by Mark F. McCarty, Ph.D.

Selenomethionine is the principal form of selenium found in foods. Brewers

yeast, which can be cultivated in selenium-enriched media, is capable of

being trained to convert selenium predominantly to selenomethionine. Yeast

preparations can be produced to contain substantial amounts of

selenomethionine suitable for selenium supplements. Selenomethionine is

virtually 100% absorbed and well retained as compared to inorganic

selenium, which is rapidly excreted.

Some manufacturers only mechanically mix inorganic selenium compounds,

such as sodium selenite or selenium dioxide, with ordinary yeasts. These

yeast products contain virtually no selenomethionine. The selenite in

these yeasts is significantly less bioavailable than selenomethionine. In

addition, vitamin C reduces selenite to elemental selenium. Studies have

shown that such yeast products produce only negligible increases in blood

selenium concentrations.

Recently, genuine high selenium yeast was proven effective in producing

consistent elevations of blood selenium concentrations in a large scale

human intervention trial, supported by the National Cancer Institute. In

contrast, there have been no comparable studies conducted with any of the

non-food form, artificially selenized yeasts.

© 2000 Selenium Forum

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New Discoveries Expand Our Knowledge About Selenium's

Importance

by A. Passwater, Ph. D.

Dr. Rotruck and his colleagues at the University of Wisconsin

demonstrated that selenium was incorporated into molecules of an enzyme

called glutathione peroxidase (GPX). This vital enzyme protects red blood

cells, cell membranes and sub-cellular components against undesirable

reactions with soluble peroxides.

Phospholipid Hydroperoxide Glutathione Peroxidase (PHGPX) protects

membranes against peroxides already bound to membrane surfaces. [2] PHGPX

blocks formation of the extremely harmful alkoxyl radical and inhibits

peroxidative chain branching. This activity is even of more importance in

the prevention of cancer, heart disease and accelerated aging.

First there were animal studies that showed that selenium protected

against chemicals and ultraviolet energy that cause cancer. [4-7]

Forms of Selenium Supplements:

The most efficacious and safest forms to supplement our diet with selenium

is not the inorganic salt form, but the organic forms, selenium yeast and

selenomethionine.

Selenium Yeast:

Selenium yeast was found to out-perform inorganic selenium in increasing

the amount of selenium in the milk of lactating mothers and the blood of

their infants. The researchers concluded, " Selenium yeast was safe and

more effective than selenite. " [27]

In another test, 150 micrograms daily of selenium as selenium yeast was

effective in raising blood selenium levels of healthy adults, whereas the

same amount of inorganic yeast failed to raise blood selenium levels. [28]

Dr. Gerhard Schrauzer of the University of California-San Diego concludes

" since a ten-fold lower oral dosage of organic selenium produced a

two-fold greater increase in selenium levels in the blood,

organically-bound selenium is at least twenty-fold more effective in

providing the body with the trace element. " [29]

Selenomethionine: The form of selenomethionine that the body can use is L-

selenomethionine. L-selenomethionine is better absorbed and better

incorporated into body components than any other known form of selenium.

Experiments comparing inorganic selenium with DL-selenomethionine found

that DL-selenomethionine was not as effective as the inorganic selenium

[45].

I have been using various forms of selenium in my animal studies for

thirty years and find that the selenium-containing amino acids

(selenomethionine and selenocysteine) and the methylated selenides are far

superior to the inorganic forms of selenium (selenite and selenate) in

terms of overall health, longevity and freedom from cancer.

In studies in New Zealand, it was found that selenomethionine was at least

75 percent bioavailable, compared to 59 percent for sodium selenite. Blood

selenium levels rose more quickly and didn't plateau as early with

selenomethionine than with sodium selenite. [30-32]

In a Finnish study, again selenomethionine raised blood selenium levels

higher and remained in the blood longer than inorganic selenium. [33] In a

later Finnish study, it was found that as much as 3,500 micrograms of

inorganic selenium had to be given to raise their blood selenium levels to

match that of typical Americans. The long- term safety of such a high dose

of inorganic selenium is not known.

In 1984, a MIT study determined that organic forms of selenium are able to

increase the body pool size about 70 percent more effectively than

inorganic selenite. [34]

Dr. P. Whanger of Oregon State University has spent several years studying

the effectiveness of several forms of selenium supplements. His latest

research was published in the MArch issue of the American Journal of

Clinical Nutrition. Some of his ***findings include, " The selenium

concentrations in all blood*** fractions increased at a faster rate (two-

to three- fold) in women taking selenomethionine than in those taking

selenate...About 95 percent of the selenium was associated with hemoglobin

in women taking selenomethionine - interestingly, most of the GPX activity

was also associated with hemoglobin [35]

Selenomethionine can furnish the required form of selenium for all four,

whereas inorganic selenium has to be converted into selenomethionine or

selenocysteine to be incorporated into two of the classes of

selenoproteins. Also, selenomethionine can be catabolized into selenium

ions to form the selenium ion-specific selenoproteins. It is easier for

selenomethionine to provide selenium ions than it is for inorganic

selenium to be converted into selenomethionine.

The transport protein for selenium ions is selenoprotein-P.

Inorganic selenium:

As discussed earlier, inorganic selenium forms (selenate and selenite) are

not as well absorbed as organic selenium-containing amino acids

(selenomethionine and selenocysteine).

Inorganic selenium, at low doses, is better than no selenium at all.

However, larger doses of inorganic selenium has an oxidative effect that

increases undesirable lipofuscin production. [36] The selenium in

inorganic selenite is in the plus four valance state which is very

oxidative. The selenium of selenomethionine is in the minus two valance

state. The lipofuscin accumulation in the liver can be accounted for by

the fact that in order for selenium to go from the inorganic plus four

valance state to the plus minus valance state, six electrons must be

obtained from liver cells. The safety of inorganic selenium is about

one-third that of selenomethionine. [37]

Inorganic sources of selenium do not find their way to muscle protein to

an appreciable extent. If laboratory animals are fed selenomethionine,

selenium soon increases in all organs, muscles, GPX and hemoglobin. When

inorganic selenium is fed to animals, it accumulates in the liver, kidneys

and GPX.

Inorganic selenium reacts spontaneously with sulphydryl groups to form

selenotrisulfides. This can severely disrupt the structure of proteins.

Inorganic selenium reacts with the sulfhydryl groups of glutathione to

form selenopersulfide and free selenide. Inorganic selenium, due to its

free-radical promoting oxidative nature, is mutagenic and has caused

cataracts at high doses in mice. [44] In contrast, selenium-containing

amino acids are stable, less toxic, and do not have mutagenic or oxidizing

activity.

Synergism With Vitamins C and E:

Vitamin C increases the absorption of selenomethionine and organic

selenium- containing yeasts. [38,39] If vitamin C mixes with inorganic

selenium in the food, the inorganic selenium is reduced to insoluble and

biologically inert metallic selenium.

Vitamin E is a partner with selenium in protecting body components against

oxidative free radicals. Both vitamin E and selenium have their own

specific modes of stopping free radicals, plus they have common modes. The

two are " synergistic " which means that the activity of both together is

greater than the sums of the activity of each by itself. It's a case of

nutritionally adding one plus one and getting more than three. Vitamin E

and selenium are a powerful combination and the body needs both together.

In my three-part 1986 series on selenium safety, I discussed that many

natural diets contained more than 600 micrograms of selenium daily.

[40-42] In Northern Greenland, many residents consume about 1,300

micrograms of selenium daily. And, in China, some residents were found who

took 1,000 micrograms of selenium daily when they found out that it

protected them from certain selenium-deficiency diseases (including Keshan

disease) endemic to their area. They developed thickened fingernails and a

garlic- like breath. Now we have a report that a woman took 2,400,000

micrograms of selenium daily for seventy-five days with only mild and

reversible side effects. [43] This is 12,000 times the recommended upper

limit for supplementation for healthy people.

Keep in mind that everything -- even oxygen and water -- is toxic at some

level. It is the dose that makes the poison. The amount of selenium

supplement that is safe and effective is the old recommended daily range

of 50 to 200 micrograms daily. Yet, we continue to read the foolishness

that the cancer-protecting dose is toxic. That nonsense is a disservice to

everyone.

REFERENCES:

1. Rotruck, J. T., et al., Science 179:588-90 (1973)

2. Ursini, F., et al., Biochim. Biophys. Acta 839:62-70

(1985)

3. Sunde, A., Molecular Biology of Selenoproteins,

in Annual Review of Nutrition (1990), eds. Olson,

E., et al., Annual Reviews, Inc., Palo Alto, Ca. (1990).

4. Passwater, A., Amer. Lab. 5(6) 10-22 (1973)

5. .... Advan. in Cancer Res. 29:419 (1979)

6. .... Prevent. Med. 9:362 (1980)

7. .... Cancer Res 41:4386 (1981)

8. .... Arch. Environ. Health 31:231 (1976)

9. .... Bioinorg. Chem. 7:23 (1977)

10. .... Lancet II 130 (1983)

11. .... Amer. J. Epidem. 120:342 (1984)

12. .... Nutr. Cancer 6:13 (1985)

13. .... Fed. Proceed. 44:2584 (1985)

14. .... Brit. Med. J. 290:417 (1985)

15. .... Biolog. Tr. Element Res. 7:21 (1985)

16. .... Lancet II 175 (1982)

17. .... Clin. Chem. 30:1171 (1984)

18. Aaseth, J., et al.; Selenium in Biology and Medicine

(May, 1980)

19. Tarp, U., et al., Scandinavian J. Rheumatol.

7:237-40 (1985)

20. Berry, J., et al., Nature 349:438-40 (Jan 31,

1991)

21. Passwater, A., Amer. Lab. 3(4) 36-40 (1971)

22. Passwater, A., Amer. Lab. 3(5) 21-6 (1971)

23. Passwater, A., The New Supernutrition,

Pocket Books, NY (1991)

24. Birkmayer, J., Eur. Pat. Appl. EP 345,247 (Dec. 6,

1989).

25. Passwater, A., Selenium as Food and

Medicine, Keats Publ., New Canaan, CT (1980)

26. Passwater, A., Selenium Update, Keats Publ.,

New Canaan, CT (1987)

27. Kumpulainen, J., et al., Amer. J. Clin. Nutr. 42

829-35 (1985)

28. Schrauzer, G., Trace Substances in Environmental

Health 13:64 (1979)

29. Schrauzer, G., Bioinorganic Chem. 8:303-18 (1978)

30. Thomson, C. D., et al., Br. J. Nutr. 39:579-87

(1978)

31. Thomson, C. D., et al., Amer. J. Clin. Nutr.

36:24-31 (1982)

32. , M. F., et al., Br. J. Nutr. 39:589-600

(1978)

33. Levander, O. A., et al., Fed. Proc. 42:927 (March

1983)

34. Janghorbani, M., et al., Amer. J. Clin. Nutr.

40:208-18 (1984)

35. , J. A., et al., Amer. J. Clin. Nutr.

53:748-54 (1991)

37. Foo Pan and Traver, H. Arch. Biochem. Biophys.

119:429-34 (1967)

36. Csallany, A. S. and Menken, B. Z., J. Amer. Coll.

Toxic. 5(1) 79-85 (1986)

37. , L. C. and Combs, G. F., J. Nutr. 116:170

(Jan. 1986)

38. Mutanen, M. and Mykkanen, H. M., Human Nutrition;

Clinical Nutrition 39C 221-226 (1985)

39.

40. Selenium: Old Horror Tales Disproved, Whole Foods

9(11) 11-12 (Nov. 1986).

41. Selenium: The Upper Limit of Safety, Whole Foods

9(10) 11-14 (Oct. 1986).

42. Selenium Safety, Part I, Whole Foods 9(9) 7-11 (Sep.

1986). 43. Here's Health p6 (April 1990)

44. Whiting, R. F. In: Selenium in Biology and Medicine,

Spallholz, J. E., , J. L. and Ganther, H. E., Eds.

AVI Publishing, Westport, p325 (1981)

45. , H. J., et al., Cancer Res. 44(7) 2803-06

(July 1984)

All rights, including electronic and print media, to

this article are copyrighted by A. Passwater,

Ph.D. and Whole Foods magazine (WFC Inc.).