Breastcancerchoices.org  
.
Scrutinizing the evidence for breast
cancer procedures and treatments
Supplement Strategies - Selenium
  

               ..        

            July 9, 2009


    The mineral, selenium, is a powerful antioxidant.  Additionally,
    research has found other mechanisms of action of interest to
    breast cancer patients.

    Linking Selenium Deficiency to Breast Cancer

  • Update: In 80 breast cancer patients who had a mastectomy,
    their blood levels of selenium were lower than in healthy
    patients.  In the patients, there was a significantly higher
    concentration of selenium in cancerous tissue, as opposed
    to adjacent healthy tissue.  The higher concentration of
    selenium in cancerous tissue may be attributable in part to
    selenium's defense mechanism (selenium activates the
    antioxidant glutathione) against the carcinogenic process.
    (See Charalabopoulos K et al., Selenium in Serum and
    Neoplastic Tissue in Breast Cancer: Correlation with CEA,
    bjcancer 2006.)

  • Selenium helps to convert T(4) - thyroxine, the prohormone
    with 4 molecules of iodine into T(3) - triiodothyrone, the
    cellularly active thyroid hormone, with three molecules of
    iodine.  Thyroid hormones help the entire body - raising the
    metabolic rate and balancing physiological functions.

  • Selenium is an antioxidant, a part of glutathione peroxidase,
    which prevents fats from being oxidized.  During the
    production of thyroid hormones, selenium helps to degrade
    excess hydrogen peroxide that can damage the cells.

    Selenium Reverses Chromosome Breaks

    UPDATE:  Selenium has several anticancer properties, including
    protection against oxidation and enhancing nucleotide excision
    repair.

    Women who carry a mutation of the BRCA1  gene were found to
    have more chromosome breaks ( which can lead to breast cancer
    ) than women who did not carry the mutation.  When women with
    the BRCA1 mutation were given selenium for three months, the
    number of their chromosome breaks were reduced to normal.

    (See Kowalska E et al., Increased Rates of Chromosomes
    Breakage in BRCA1 Carriers are Normalized by Oral Selenium
    Supplementation, Cancer Epidemiology Biomarkers and
    Prevention 2005. See also Alternative Medicine Magazine, March
    2006.)

    Double-Blind, Placebo-Controlled Cancer Study

    Although there have been many studies on selenium, we include
    it on the list of beneficial supplements for cancer principally
    because of the following double-blind, placebo-controlled study
    published in JAMA.

    Selenium supplements can reduce cancer rates, new study shows

    Jan. 7, 1997 Press release

    ITHACA, N.Y. -- Men and women taking selenium supplements for
    10 years had 41 percent less total cancer than those taking a
    placebo, a new study by Cornell University and the University of
    Arizona shows. "Although more than a hundred of animal and
    dozens of epidemiological studies have linked high selenium
    status and cancer risk, this is the first double-blind, placebo-
    controlled cancer prevention study with humans that directly
    supports the thesis that a nutritional supplement of selenium, as a
    single agent, can reduce the risk of cancer," said Gerald F. Combs
    Jr., a nutritional biochemist and Cornell professor of nutritional
    sciences.

    Combs and a group of co-authors reported their findings in the
    Jan. 1, 1997 issue of The Journal of the American Medical
    Association. The senior author is epidemiologist Larry Clark, who
    was at Cornell at the onset of the study and is now at the
    Department of Family and Community Medicine at the University of
    Arizona School of Medicine.

    In 1983, the researchers recruited 1,312 randomized patients with
    histories of skin cancer at seven dermatology clinics located in
    low-selenium areas of the United States (Augusta and Macon, Ga.,
    Columbia, S.C., Wilson and Greenville, S.C., Miami, and Newington,
    Conn., where consumers ingest an average of about 100
    micrograms of selenium a day). The patients were given either a
    placebo or a 200-microgram daily supplement of selenium (twice
    the average amount these Americans consume in their diet,
    thereby tripling their selenium intake).

    Skin cancer patients were chosen because they have a 25 percent
    annual chance of a recurrence, and skin cancer is easy to
    diagnose and can be quickly treated. The researchers set out to
    determine whether they could reduce the average recurrence
    rate with selenium supplements.

    Ironically, 10 years later, the results were not significant for skin
    cancer. However, they were "compelling" for overall cancer
    incidence and mortality rates, Combs stressed. Of the selenium
    group, 69 developed some type of cancer compared with 116 of
    the placebo group; 28 of the selenium patients died of cancer
    compared with 58 from the placebo group.

    "Overall, the selenium group experienced 18 percent less
    mortality than the placebo group, and almost all of that difference
    was due to some form of cancer," said Combs, who credits Cornell
    with having the longest history of research in selenium nutrition
    research in the world. "This is the first time anyone has shown
    that any single nutrient can result in such a reduction in cancer
    risk. The fact that we saw a pattern in lower incidence and
    mortality rates across all the clinics gives us even greater
    confidence in these findings."

    Prostate, esophageal, colorectal and lung cancer rates were
    among the most dramatic: patients in the selenium group had 71
    percent, 67 percent, 62 and 46 percent reductions in cancer rates,
    respectively, than the placebo group.

    The current Dietary Guidelines now recommend that men
    consume 70 micrograms of selenium a day and women 55
    micrograms; Americans typically get between 100 to 160
    micrograms a day in their diets, Combs said.

    Selenium blood levels vary widely in populations. Even Americans
    with the lowest selenium intake of 60 to 80 micrograms per day --
    those living along the Southeastern seaboard and in the Pacific
    Northwest -- ingest two to five times more than citizens of New
    Zealand and 10 to 20 times more than people living in some areas
    of China. Selenium blood levels vary among populations largely
    because of wide differences in soil, agronomic practices, food
    availability and preferences and methods of food preparation.

    Although a 1995 Harvard University study of more than 62,000
    nurses reported no anti-cancer benefits of selenium, Combs said
    that the researchers measured selenium in the toenail clippings
    of the nurses. "This method presumes that the concentration of
    selenium in nails accurately correlates with metabolic selenium
    status in the body," Combs pointed out. "There is no evidence for
    that."

    The University of Arizona-Cornell research team reported in 1991
    that low selenium levels in the blood were linked to increased risk
    of neoplastic polyps in the colon, a precursor to colorectal cancer.
    And in other studies at Cornell, colleagues of Combs' reported in
    1995 that animals fed diets high in selenium had 50 percent fewer
    tumors than those fed diets of average selenium content.

    Combs is not recommending the use of oral supplements of
    selenium; however, he does emphasize the importance of
    consuming low-fat diets that are adequate in selenium and are
    balanced with respect to other essential nutrients. The most
    important dietary sources of selenium are meats, fish and cereals;
    dairy products and eggs contribute significant amounts. Some
    nuts can also be high in selenium if they were grown in high-
    selenium areas.

    Of the 40 nutrients currently recognized as essential for human
    nutrition, selenium was the last to be recognized in 1957. A key
    component for at least two essential enzymes, selenium provides
    the body with antioxidant protection in concert with vitamin E and
    is required for normal thyroid hormone metabolism.

    The study was funded in part by grants from the American Institute
    of Cancer Research, the American Cancer Society and the National
    Institutes of Health.

Editor's note: the usual recommended selenium dose is
    200 mcg. Selenium works synergistically with iodine and
    Vitamin E.



    This website is intended as information only. The editors of this site are not medically-trained.
    Please consult your licensed health care practitioner before implementing any health strategy.
    The information provided on this site is designed to support, not replace, the relationship that
    exists between a patient/site visitor and his/her existing physician. This site accepts no
    advertising. The contents of this site copyrighted 2004- 2010 by Breast Cancer Choices, Inc.
    Contact us with comments or for reprint permission at admin@breastcancerchoices.org
    Web page updated January 18,  2010.
.
.