Could Aromatase Inhibitors Actually Increase One’s Risk for Breast Cancer?

In Alternative Cancer Therapies, Alternatives Cancer Treatment, Alternatives to Anti-Hormone Therapy For Breast Cancer, Alternatives to Hormone Therapy for Breast Cancer, Alternatives to Tamoxifen, aromatase inhibitors, Breast Cancer, Cancer, Estrogen, Estrogen and Breast Cancer, Hormone Balance, Hot Flashes and Night Sweats, Soy and Breast Cancer Risk, Uncategorized on October 21, 2019 at 4:05 pm

Most oncologists recommend estrogen blockers or aromatase inhibitors for those with hormone-sensitive cancers. However, new research shows that decreased estrogen levels can promote insulin resistance, which may actually increase the risk of cancer of the breast, endometrium, and ovaries. 

To recap from my previous post, What You Need to Know About Sugar and Breast Cancer, insulin resistance leads to increased insulin in the body. High insulin triggers breast cancer cells to divide and grow.

After menopause many women face a dramatic increase in insulin resistance (and start noticing belly fat that wasn’t there before). Declining estrogen is considered to be the reason.[i] If decreased estrogen promotes insulin resistance, could intentionally reducing estrogen increase one’s risk of breast cancer? Can aromatase inhibitors actually promote breast cancer? Research shows they just might.

Decreased Estrogen Levels Promote Insulin Resistance

Studies (both clinical and animal) have shown a strong correlation between circulating estrogen deficiency and insulin resistance. At Texas A&M, a team lead by Dr. Shaodong Guo identified that decreased serum estrogen levels promote insulin resistance and that even a slight decrease in circulatory estrogen levels is associated with resistance and may increase the risk of cancer of the breast, endometrium, and ovaries. The researchers found that “for premenopausal women, even a slight decrease in their circulatory estrogen levels associated with insulin resistance may increase the risk for cancers, particularly in the organs having high estrogen demand (breast, endometrium and ovary). On the other hand, postmenopausal state with profound estrogen deficiency confers high risk for cancers in different organs with either high or moderate estrogen demand.”[ii]

According to the Guo, the lead investigator for the Texas A&M study, estrogen deficiency or impaired estrogen signaling is associated with insulin resistance. “Studies have shown the reduction of estrogen in postmenopausal women accelerates the development of insulin resistance and Type 2 diabetes.” He further explains that estrogen replacement therapy in postmenopausal women can reduce insulin resistance. “Clinical trials of estrogen replacement therapy in postmenopausal women have demonstrated a lowered insulin resistance as well as reductions in plasma glucose levels.”

2015 research published in the Journal or Diabetes Research also concluded that the loss of circulating estrogen E2 and impairment of its cellular activity can lead to an abrupt reduction in metabolic rate and that E2 replacement is preventive. “It is very clear that E2 has tremendous potential as a therapeutic against diabetes and its associated complications, but it has to be administered in a safer form and personalized to individual needs”. [iii]  While the link between synthetic HRT (hormone replacement therapy) and breast cancer has been established and therefore may not be an option, it  just doesn’t make sense to intentionally lower our own already-declining natural estrogen.

Many women choose bio-identical hormones, but to be clear, bios are not ‘natural’, they are chemically constructed in a lab. According to Dr Mache Seibel, M.D., author of The Estrogen Window, you have to be careful with compounded bio-identicals. He says that studies show that despite the fact that the prescription may be filled correctly, typically progesterone tends to be 60-80% lower than ordered and estrogen 80-200% higher than ordered which can result in increased estrogen dominance and could raise your risk of hormone-driven cancer. He also points out the serious risks of declining estrogen, which include increasing your risk of heart disease by 30% and dementia 70%. 

Why You Need Estrogen 

We need estrogen for aiding in the prevention of heart disease and for strong, healthy bones. In fact, estrogen is essential to the health of all parts of your body, from your eyes to your heart to your brain to everywhere else.  Estrogen also improves body fat distribution and B-cell function, and reduces inflammation. And of course, estrogen increases insulin sensitivity (and thus is protective against diabetes and metabolic syndrome predisposing one to obesity) and conversely, low estrogen levels can lead to increased insulin resistance or impaired insulin activity.

Given that studies show that the reduction of estrogen in postmenopausal women accelerates the development of insulin resistance and thus could promote breast cancer, it is hard to believe that aromatase inhibitors are always a good idea. Perhaps ‘prescribing’ phytoestrogens such as flax and sesame seeds, herbs, and even perhaps whole soy, would be a better tactic. Phytoestrogens are plant-based weak estrogens which bind to estrogen receptors in the body (just like tamoxifen) and through competitive inhibition, can prevent the receptor-binding of more potent estrogens (including xenoestrogen such as BPA). Phytoestrogens also promote hormone balance and homeostasis. One can also take steps to raise progesterone to balance natural estrogens by taking supplements such as zinc and vitamin E, lowering stress, and using an over-the-counter progesterone cream. I will further address the role of phytoestrogens and hormone-driven cancers in my next post.

Natural Aromatase Inhibitors

Some natural substances and formulas that reduce aromatase activity (should you need to reduce aromatase activity or improve estrogen metabolism or hormone balance) include Calcium d Glucarate, which helps clear excess estrogen and chemical estrogens from the body, and a product known as Aromastat, which contains a blend of herbal ingredients that work together to help keep your natural hormones balanced.  Aromastat contains chamomile (apigenin), chrystin, daidzein, genistein, indole-3-carbinol, and glycitein (it does contain soy isolates, so if avoiding, look for these ingredients individually, although in the case of genistein, I prefer you eat organic whole soy). For more information on natural alternatives to tamoxifen and aromatase inhibitors, please read my previous posts on the subject or visit my Shop page.

This information is for educational and thought-provoking purposes only and is not a recommendation to forgo medical advice and treatment.  This post is not intended to treat, cure, prevent, or diagnose any disease or condition. The information provided is from my research and not to be taken as scientific evidence.

In your good health,


~~If you don’t know your options, you don’t have any~~

ej portrait 150resElyn Jacobs is a holistic cancer strategist and speaker specializing in the prevention and treatment of cancer. She is a Contributing Editor for The Truth About Cancer and is on the Medical Advisory Board for BeatCancer.Org and the Advisory Board to the Radical Remission Project. Elyn has written for numerous journals and publications. She was the former Executive Director of the Emerald Heart Cancer Foundation and the creator and host of the Survive and Live Well Radio Show. To contact Elyn, visit www.elynjacobs.com. Elyn offers consults via Skype, phone, or in-person. Elyn does not provide online advice.








Elyn Jacobs does not provide medical advice. The information provided is for general information only. No online site should be used as a substitute for personal medical attention.

This information is for educational purposes only and is not a recommendation to forgo medical advice and treatment.  This post is not intended to treat, cure, prevent, or diagnose any disease or condition. This post does not represent medical advice nor should it be considered to be medical advice or a replacement for medical advice.  I encourage you to discuss this information with your integrative oncologist, naturopathic doctor, or conventional oncologist. The information provided is from my research and not to be taken as scientific evidence.

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  1. Elyn, How do I best get my wife tested and treated for Estrogen imbalance. Best, Doug

  2. Female/Male Saliva Profile III – Test Kit For 8 Hormone Level Imbalances https://amzn.to/31thN6w

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