Much ado about nothing

February 12, 2019

One could justifiably use the above-mentioned Shakespeare title about a newly published article (1) that supposedly shows that antioxidant supplements reduce the effectiveness of chemotherapy and radiation therapy in postmenopausal women.

Please note that this assertion is by no means proven; there is much research that points in both directions.

The above-mentioned journal article does not contribute to clarification of the issue, not least because of the weak design of the study.

The data in the study came from interviews of postmenopausal women in two regions in Germany. The researchers used data from the “Mamma Carcinoma Risk Factor Investigation,” a study that was first published more than 10 years ago to report on the risk factors associated with postmenopausal hormone therapy.

Despite the known weaknesses of the interview study, the Danish TV2 reported the results of the study as a great sensation and with a headline that announced:

“New research: Dietary supplements can spread breast cancer.
German researchers have learned that antioxidant supplements can worsen breast cancer in women. The Danish Cancer Society is concerned.
For many years, there have been discussions as to whether antioxidant supplements are good for human health or not. And now a German study makes it clear that they are definitely dangerous for women with breast cancer.”

No, no, and no again.

There is no evidence for the dramatic TV2 news statements.

The German study does not make anything clear.

And the journal article authors’ own conclusion is much more cautious than the TV2 news report.

The journal article authors write:

“Our data do not support an overall association of postdiagnosis supplement use with prognosis in postmenopausal breast cancer survivors. Our results, together with other clinical and experimental evidence, suggest that during breast cancer treatment, antioxidants should potentiall be used with caution.”

In their journal article, the authors do not even advise against the use of antioxidants during chemotherapy and radiation therapy. They just urge caution.

Normally, German research results are shrugged off in Denmark, and interview-format studies get the same treatment. But, this time, the German interview study could be used to advance specific points of view, and so it was.

There are many things in this German study that grab the attention of the alert reader, and a close reading of the study reveals that the authors are biased, not least in their selection of earlier research on the topic.

An interview study, with no blinding of at all, is certainly not the most valid form of research and cannot be compared with prospective randomized controlled trials (RCT’s).

In the German study, the researchers asked some 2000 breast cancer patients whether they took antioxidant supplements before and/or after the time of their diagnosis with breast cancer and/or during their chemotherapy and radiation therapy.

The women in the study were to answer yes if they had just taken one or another supplement three days a week for a year at a given point in time. A “current user” was any woman who used supplement postdiagnosis within the 6 months before the first follow-up interview.

The term “supplement” and the term “antioxidant” are used quite sloppily but with a noticeable consistency. Whenever the researchers discuss the study, the usage, or the statistics, they use the term “supplements.” Whenever they discuss the chemotherapy or the radiation therapy, however, they use the term “antioxidants” without specifying what the term “antioxidants” covers.

In other words, the researchers have had to extend the definition of antioxidants with other supplements in order to achieve sufficient statistical power and thereby just barely sneak over the line into statistical significance.

About this, the authors write in their article:

“The main exposures of interest included postdiagnosis use (no postdiagnosis use, postdiagnosis use, current use) of any type of supplement; specific supplements, such as magnesium and calcium; and supplement group, such as antioxidants, in which there was adequate statistical power to conduct analyses. Only a few women reported postdiagnosis use of multivitamins, vitamins A, C, E, zinc, and selenium, and therefore they were collectively evaluated together as antioxidants in all of our analyses.”

Above and beyond the fact that the researchers have jumbled everything together in a big group that they call “antioxidants,” there is also a total lack of information about daily dosages, single dosages, and preparation types.

This study has a weak design and has unclear results. Therefore, the authors are careful to settle for a cautious conclusion, which speaks for itself.

The misinformation occurs when the Danish media then trumpet the study conclusion as the definitive truth.

Any serious researcher would avoid making such bombastic statements.


  1. Jung AY et al. Antioxidant supplementation and breast cancer prognosis in postmenopausal women undergoing chemotherapy and radiation therapy. Am J Clin Nutr 2019;109:69–78.
  2. Flesch-Janys D, Slanger T, Mutschelknauss E, Kropp S, Obi N, Vettorazzi E, Braendle W, Bastert G, Hentschel S, Berger J. Risk of different histological types of postmenopausal breast cancer by type and regimen of menopausal hormone therapy. Int J Cancer 2008;123(4):933–41.

Perhaps selenium can prevent hereditary breast cancer

May 30, 2005

Women with a genetic tendency towards breast cancer have unstable chromosomes. Studies now show that these chromosomes can be stabilized by taking selenium supplements.
About every twenty cases of breast cancer are due to inheritance. Most often, the cause is an innate mutation in the so-called BRCA1 gene, which, under normal circumstances, repairs damage to chromosomes.

If you carry this mutation, you already have a high risk of breast cancer: Approximately 60% will get the disease before they reach 50, and approximately 85% will get it before they reach 70. At the same time, the risk of ovarian cancer is no less than 60%.

It is a despairing situation to be born with this mutation, which presents the affected with difficult decisions. Some prefer to prevent the cancer by having their breasts and ovaries removed at a young age, while others wait and see if they are among the unlucky ones. Those affected must at least think about having the children they want at a young age if they want to retain the opportunity to breastfeed. There is no certainty as to when the disease will strike.

Now, however, a highly interesting Polish study suggests that the risk can be significantly reduced with a simple supplement of selenium. The supplement drastically reduces the frequency of chromosomal damage in women with the congenital defect. This can, if the results hold, buy the vulnerable women time and reduce their risk of instability in the protective chromosomes.

The experiment was carried out at the Pomeranian Academy of Medicine in Szczecin. It was about measuring the amount of mutations – so-called chromosome breaks – on white blood cells, which in the laboratory were exposed to “chemical radiation” in the form of the chemotherapy drug bleomycin.

Two experiments were performed. In one, chromosome breaks were compared in 26 women with and 26 women without the congenital defect. In the first, 0.59 fractures per cell were measured, while women without the defect had only 0.39.

35 other women, all of whom were carriers of the mutation, now participated in the second trial. Half of them received a daily supplement of approx. 280 mcg selenium a day, after which they had blood samples taken after 1-3 months, so that their blood cells could also be exposed to bleomycin. The result was almost exactly as in the first experiment: In the blood cells of the women who did not receive selenium, 0.63 chromosome breaks occurred per cell, while those who received the selenium had only 0.40 fractures per. cell.

In other words, women with the inherited mutation could increase the stability of their chromosomes to normal with something as simple as a daily selenium supplement. The question then is how this is to be interpreted. Does this mean that they also had their cancer risk reduced?

There are many indications of this, but one cannot be sure. Researchers have concluded that hereditary breast cancer is due in part to unstable chromosomes. Others have found that breast cancer patients have clearly more chromosomal abnormalities in their white blood cells than healthy ones. In addition, several experiments have shown a correlation between the susceptibility to cancer in general and the level of chromosome rupture.

In addition, a study of 3,812 workers who were exposed to mutation-promoting substances showed that those who had the most chromosomal abnormalities were also most likely to get cancer later on. The clues are many.

Selenium has an antioxidant effect and has been shown to be strongly anti-cancer in several trials. As the soil in Poland (just like Denmark) is very low in selenium, the researchers believe that a similar experiment in other countries could give a different result.

The participants received the equivalent of approx. three regular selenium tablets with organic selenium a day. It is a dose that certainly does not exceed what is allowed.

By: Vitality Council

Kowalska E. et al. Increased rates of chromosome breakage in BRCA1 carriers are normalised by oral selenium supplementation. Cancer Epidem Biomarkers Prev 2005;14(5):1302-6.