Boron Safety for Breast Cancer Survivors Taking Aromatase Inhibitors

General Nutrition / Health / Osteoporosis / January 12, 2015

Author: Lara Pizzorno, MDIV, MA, LMT

Lara Pizzorno is the author of “Your Bones: How You Can Prevent Osteoporosis and Have Strong Bones for Life – Naturally” and a member of the American Medical Writers Association with 29 years of experience specializing in bone health . Lara is the Editor of Longevity Medicine Review ( as well as a Senior Medical Editor for SaluGenecists Inc., and Integrative Medicine Advisors, LLC  

Lara Pizzorno is the author of “Your Bones: How You Can Prevent Osteoporosis and Have Strong Bones for Life – Naturally” and a member of the American Medical Writers Association with 29 years of experience specializing in bone health.

Recently we asked Lara if she would help us provide a series of short, ongoing videos to help you (our customers and readers) stay up to date on the latest facts and science related to bone health and overcoming osteoporosis naturally.

In this latest video, Lara talks about whether boron is safe for breast cancer survivors who are taking aromatase inhibitors.  Watch the video below (or read the transcript provided) and let us know what you think in the comments. 🙂



Hello, I’m Lara Pizzorno the author of “Your Bones” and I’m here today to share some information with you that I hope will help you have healthier bones.

In this last few videos we’ve been talking about the importance of a trace mineral called boron for healthy bones. In this video I wanted to discuss with you whether boron is safe for breast cancer survivors who are taking aromatase inhibitors such as Arimidex.

This topic came up for me because a few months ago now because a woman wrote me to ask if taking boron was a good idea for her. She had recently been successfully treated for stage 1 her 2 positive breast cancer which is an estrogen positive form of breast cancer and had prescribed a drug called Arimidex which she was to take for the next 5 years to block her body’s ability to produce estrogen, in the hopes that it would protect her against developing and recurrence of her breast cancer. The drug she was prescribed called Arimidex is used in both the treatment and to help recurrence of estrogen positive breast, ovarian and also prostate cancers. It’s one of a class of drugs called aromatase inhibitors and prevents the production of estrogen by binding to and shutting down an enzyme called aromatase. This is the enzyme that is responsible for synthesizing estrogen from its precursors which are other steroid hormones called androgens. And these include DHEA and testosterone and would normally be the targets of aromatase. Arimidex inhibits estrogen synthesis by out- competing androgens’ ability to bind with aromatase. Arimidex and the other aromatase inhibitors are so effective at preventing the production of estrogen that if you are taking one of these drugs you will be producing virtually no estrogen. So boron will have no estrogen to convert to its magnesium absorbing form of 17-beta estradiol. And this means that taking boron is not going to have any negative effect on breast, prostate or ovarian cancer treatment if you are taking an aromatase inhibitor. But it also means that estrogen’s beneficial effects, its beneficial effects on our ability to absorb magnesium, and in our production of osteoblasts and in our activation of vitamin D are going to be lost. For these reasons, aromatase inhibitors cause substantial bone loss and increase risk of osteoporosis and fractures. Not only when used in postmenopausal women with breast or ovarian cancer but also given as androgen deprivation therapy for men with prostate cancer.

If you’ve read “Your Bones” then you know that men produce a small amount of estrogen, but that it plays a very important role in their ability to maintain healthy bones. So by preventing men from producing the small amount of estrogen, the aromatase inhibitors also cause bone loss in men and increase their risk of osteoporosis.

Well, it turns out that boron is now being used to increase and restore effectiveness of another drug that is used to treat or prevent estrogen positive cancers called tamoxifen. Even in breast cancer patients whose cancer cells who are supposedly resistant to tamoxifen, boron is changing this.

And why might this be important for your bones if you have or are recovering from an estrogen positive type of cancer?

Well, tamoxifen causes far less bone loss than the aromatase inhibitors, so it is worth looking into if you might be able to use tamoxifen rather than one of the aromatase inhibitors. Tamoxifen has long been considered the first line therapy for estrogen positive breast cancers. Most all of the estrogen positive breast cancers respond positively to tamoxifen treatment but about 8% of patients with these cancers are resistant to tamoxifen. Why? Because these patients have a slow CYP2D6 enzyme, this is the enzyme in the liver that is responsible for converting tamoxifen into its most potent forms. Two potent metabolites called 4-hydroxy tamoxifen or 4-OHT, that’s what you’ll see in the research literature and endoxifen, both of which inhibit estrogen dependent cell proliferation. There are test that can now be run to determine if you are among these 8% of people who are resistant to tamoxifen treatment and if you are not, tamoxifen will be a much less bone destructive treatment for you than one of the aromatase inhibitors. So this is something you might want to discuss with your doctor.

Boron in addition is now being used to develop different forms of tamoxifen that are already in these two more potent forms the 4-OHT and endoxifen forms. So even people who are resistant to tamoxifen because they have a slow CYP2D6 enzyme can benefit from tamoxifen and discuss using it rather than an aromatase inhibitor their physicians.

If you need to be on an aromatase inhibitor, the good news is that not only will taking boron NOT interfere with the cancer protective effect of aromatase inhibitor therapy, but boron will lessen some of its harmful effects on your bones. Boron is still going to help you convert vitamin D into the form in which it helps absorb calcium most effectively and the latest research which I have discussed in an earlier video clip in this series on boron is  showing us that boron plays a number of protective roles for us including greatly lessening chronic inflammation, which would otherwise excessively activate osteoclasts.

So boron can still help you maintain the health of your bones even if you need to be on an aromatase inhibitor. In our next video we will talk about how much boron you need to take and whether you can rely on dietary sources for this trace mineral or whether you should consider a bone health supplement that will provide boron for you. Thanks for tuning in, I hope this was helpful.


Limburg C, Maxwell C, Mautner B. Prevention and treatment of bone loss in patients with nonmetastatic breast or prostate cancer who receive hormonal ablation therapy. Clin J Oncol Nurs. 2014 Apr;18(2):223-30. doi: 10.1188/14.CJON.223-230. PMID: 24675258

Decensi A, Sun Z, Guerrieri-Gonzaga A, et al. Bone mineral density and circulating biomarkers in the BIG 1-98 trial comparing adjuvant letrozole, tamoxifen and their sequences. Breast Cancer Res Treat. 2014 Apr;144(2):321-9. doi: 10.1007/s10549-014-2849-2. Epub 2014 Feb 1. PMID: 24487691

Jiang Q, Zhong Q, Zhang Q, et al. Boron-Based 4-Hydroxytamoxifen Bioisosteres for Treatment of de Novo Tamoxifen Resistant Breast Cancer. ACS Med Chem Lett. 2012 Apr 6;3(5):392-396. PMID: 23864928


Hello, I am a ER positive breast cancer survivor of 7 yrs. I did take tamoxifen for 4 1/2 yrs. I was recently in a car crash and broke my clavicle. I read that it is best to take high levels of calcium and boron to help the bone heal correctly and quickly. If I am not on an estrogen blocker, is taking 60 mg of boron too risky? I am 48 years old. I have not had a period in 8 months, so I’m starting to go into menopause which of course lowers my estrogen. I am also on 25 mg/day of Spironolactone for adult acne which lowers my androgen levels.

I am at higher risk for osteoporosis due to heredity. I have never broken a bone until now. How do I keep my bones strong and healthy when it seems to conflict with ER/PR breast cancer?

Thank you for any information you can give me.

Lara Pizzorno
Lara Pizzorno

Hello Michelle,

First of all, having a clavicle break as a result of a car accident does not necessarily indicate fragile bones. BUT, if you have not done so already, you should have your DXA run – NOW, so you can see where you are.

You need boron. At the amount required for its beneficial effects—minimum of 3 milligrams/d–boron is not readily available in the diet – unless you REALLY love raisins and would enjoy eating at least 3 ounces of them daily (185 calories) – or you could consume 6 tablespoons of peanut butter instead, but this will add about 570 calories per day.

Boron should not be a problem for you; in fact, several boronic compounds are utilized in cancer treatments.
Boron is strongly recommended for anyone at risk for or has osteopenia; osteoporosis; osteoarthritis; or breast, prostate, or lung cancer.
Boron exerts so many beneficial effects, I am only noting the most pertinent ones here for you – for the full discussion on boron, you can read my most recently published article “Nothing boring about boron” via PubMed: Here’s the citation:
Pizzorno L. Nothing Boring About Boron. Integr Med (Encinitas). 2015 Aug;14(4):35-48. PMID: 26770156 [PubMed] PMCID: PMC4712861 [Available on 2016-08-01]

· does not increase estrogen production – it beneficially affects how estrogen is used.
· is critical for both the growth and maintenance of bone
· improves your body’s ability to utilize vitamin D and safely use estrogen and testosterone
· greatly improves wound healing
· boosts magnesium absorption
· reduces levels of inflammatory biomarkers, including high-sensitivity C-reactive protein (hs-CRP) and tumor necrosis factor α (TNF-α) (both of which are strongly implicated in cancer development and progression)
· raises levels of key antioxidant enzymes, such as superoxide dismutase (SOD), catalase, and glutathione peroxidase (again highly protective vs cancer)
· protects against pesticide-induced oxidative stress and heavy-metal toxicity (two more cancer promoters)

To respond best for YOU, I need to know more.

Are you taking any bone support supplements? If you have read anything else I’ve written, you know that calcium alone – or just with vitamin D or just with boron – or just with any one other nutrient – is not going to provide the support your bones need for healthy rebuilding. Your bones require calcium, numerous trace minerals in addition to boron, magnesium, D3, K2, K1, vitamin C, B vitamins – and more for effective healthy remodeling / rebuilding. If you are not already taking AlgaeCal Plus, I cannot recommend it strongly enough – it will provide all but the B vitamins, and at the dosages and in the forms that are most effective. Plus, the trace minerals provided by AlgaeCal are no longer found in even remotely decent amounts in conventionally grown foods. We all need to supplement to get them.
What are your vitamin D levels (your blood level of 25(OH)D indicates your vitamin D status and should be between 50-80 ng/mL for optimal health).
Are you taking supplemental vitamin K2? If so, what form and how much?
Do you eat lots of leafy greens? You really need the K1 they provide now as you are beginning to transition through menopause, and as your estrogen levels drop, your pro-inflammatory cytokine levels will shoot up. K1 helps control the resulting increase in inflammation, and chronic inflammation promotes cancer as well as osteoporosis. Leafy greens are also high in magnesium, and if you are going to continue to take Spironolactone (see below, I hope you will reconsider and find an alternative solution), you really need the magnesium as your progesterone is also being zapped (plus, progesterone levels drop in peri-menopause anyway, so I expect yours are really low/non-existent.)
What is your diet like overall?
What is your weight?
Do you exercise?
How is your digestive system?

Apologies for the seeming digressions here, but as you are entering a phase of your life in which what you do now will greatly impact your experience of life from here on out, I am wanting to get the full picture to see if we can optimize your transition through menopause.

In sum, boron will be very helpful for you. The drug you are using for your acne, spironolactone, will not – big time, will not! You may already know that estrogen is produced in women’s bodies from testosterone via the activity of the aromatase enzyme. Spironolactone blocks androgens (i.e., testosterone and DHEA), and will nuke your dwindlling estrogen supply. In addition, it blocks progesterone, which keeps us calm and happy, and is required for osteoblast production and activity. You need both estrogen (highly anti-inflammatory, helps prevent excessive osteoclast production; and involved in magnesium absorption into bone) and progesterone (involved in osteoblast production and activity) to maintain bone. In addition, spironolactone is a diuretic – it will increase the rate and amount of your loss of all the trace minerals your bones require. Mineral deficiencies, especially of zinc, and hormonal imbalances cause adult acne – these can and should be corrected to restore your health, and beautiful skin. If your current physician is not capable of assisting you, I can provide you with a referral to a qualified functional medicine practitioner if you will let me know where you live.

If you are concerned about your estrogen levels, I urge you to have a full hormone evaluation run – the most comprehensive and accurate test is the 24 Hour Urine Comprehensive Hormone Profile that is run by Meridian Valley Labs. (I have no financial connections to this lab, but we use this test for our patients and for ourselves at least once a year). This lab checks all the estrogens, their metabolites and the balance among them (which is called your Estrogen Quotient), so you can see exactly where you are and if you are at any risk –and then fix this naturally via dietary changes and retest in a couple of months. It also checks adrenal hormones, progesterone, DHEA, thyroid hormones – and more. If you want to read up about this test, I’ve written a review article re hormone testing that includes a summary of it. This article is written for doctors, but you will get the gist of it. It can be accessed free on-line on Longevity Medicine Review at

You are at a crucial time in your life and deserve to be gloriously healthy for many many years to come. I very much hope this helps and that you will let me know more if I can further assist you,

Deborah DiCarlo
Deborah DiCarlo

I recently went thru surgery for breast cancer (Oct, 2015) and am now taking anastrozole 1 mg -for the next 5 yrs. My oncologist advised this as well as taking calcium and vitamin D3 to counteract the drug. After consult today (July 26/16) she told me I have osteoporosis in the spine and has recommended I start treatment of Zoledronic Acid. After reading the info she gave me and doing some research on the internet, I’m not sure I want to go thru with this. I have heard/read the info regarding AlgaeCal and am very interested in switching to this more ‘natural’ source of calcium and D3. How will AlgaeCal interact with this treatment? I look forward to hearing from you. Thank you.


Hi Deborah,

Zoledronic Acid belongs to a class of drugs known as bisphosphonates. Most doctors will recommend a high-quality calcium and vitamin D supplement along with their prescribed treatment – as it looks like your doctor has. If you choose to take a bisphosphonate, AlgaeCal should not be taken at the same time of day (separate at least 3 hours apart) as they will compete for absorption.

We have customers who take AlgaeCal in addition to bisphosphonates, but we cannot guarantee increases in bone density on bisphosphonates because they result in poor quality bone, which may affect your ability to build bone.

To see customers who have taken AlgaeCal and bisphosphonates and customers who have just chosen to take AlgaeCal, you can do so here:

If you would also like to chat more in depth about your options, please call us at 1-800-820-018 4Monday through Friday: 7am to 4pm (PST) and Saturday & Sunday: 8am to 2pm (PST). We’re here to answer any further questions you may have 🙂

– Monica from AlgaeCal

Add your voice to this discussion...

Your email address will not be published. Required fields are marked *

crave your fish oil