Websites that promote bioidentical hormones for treating menopausal symptoms or for maintaining a youthful glow typically claim that their products are safe because they are more “natural” than those made in a regular pharmacy.
I’ve long argued that just because these products are “bioidentical” doesn’t mean you can assume they are safer or even safe at all. And that’s why I want to tell you about a paper published in Cancer Prevention Research by scientists affiliated with the European Prospective Investigation into Cancer and Nutrition (EPIC) study that caught my attention.
EPIC is long-term prospective study looking at the relationships between diet, nutrition, metabolic factors and cancer in 366,521 women and 153,455 men in 10 European countries. In this paper, the investigators looked at whether there was an association between a woman’s own natural hormone levels (estrogen and testosterone) and her risk of developing breast cancer.
The study analyzed blood samples from 554 women taking part in the EPIC study who had developed breast cancer (172 had ER-negative tumors and 382 had ER-positive tumors) and 821 women who had not. The blood samples were taken when the women enrolled in EPIC. At that time, all of the women were about 60 years old, had been postmenopausal for about 10 years, and were not using hormone replacement therapy (HRT). In addition, none had ever had cancer.
Epidemiologic studies have found that risk factors associated with estrogen exposure, such as early age at menarche, late age at menopause, using HRT, and weight gain after menopause, increase a woman’s risk of developing hormone-sensitive breast cancer. The researchers took these factors into account in their analysis so that they could focus specifically on the relationship between hormone levels and breast cancer. They also took into account smoking status, alcohol consumption, physical activity level, and education level, as each has been associated with breast cancer risk.
The study found that the women who had developed breast cancer had hormone levels that were naturally higher than the women who did not develop breast cancer. Even more interesting: this study showed that high hormone levels were associated with an increased risk of developing either a tumor fueled by estrogen (ER+ and/or PR+) or one that was not (ER- and/or PR-).
As the authors note, we are still trying to understand the precise relationship between hormones and breast cancer. It may be that high hormone levels can cause a breast tumor to develop. Or it may be that high hormone levels promote the growth of a tumor that is already established. Or it could both. There’s much more we need to still learn.
Importantly, this study’s findings give us yet another opportunity to point out that menopause is programmed in for a reason. We need high levels of hormones to reproduce; then, we shift down to lower levels for the second part of life. There is no reason to “replace” hormones to prolong reproductive levels and there are obvious downsides from trying to do so.
I hope anyone who is considering using bioidentical hormones will think about this: Virtually everyone would agree including those who promote bioidentical hormones that nothing is more “natural” than the hormones a woman produces in her own body. And here we have a study (and it’s not the first) to show that a women’s own hormones can increase her risk of developing breast cancer.
That certainly makes me and I hope it makes you stop and think about how easy it is to assume that anything “natural” is “safe!”