SABCS 2020: Supplement Use After Breast Cancer
At the 2020 San Antonio Breast Cancer Symposium, results were presented from a study on dietary supplement use by breast cancer survivors and how these supplements may interact with tamoxifen and the aromatase inhibitors. Maura is the lead researcher on the study.
Listen to the episode to hear Maura discuss:
why telling your doctor and/or a registered dietitian with oncology expertise about any and all the supplements you take is so important
why people may be getting more of a particular supplement than they realize
her advice for women who’ve been treated for breast cancer and are considering taking supplements
Maura Harrigan is an oncology research registered dietitian and project manager at the Yale School of Medicine. She also serves as a registered dietitian nutritionist in the Survivorship Clinic at the Yale Cancer Center.
— Last updated on June 29, 2022, 2:46 PM
This content made possible by Lilly Oncology.
Jamie DePolo: Hello! As always, thanks for listening.
Maura Harrigan is an oncology research registered dietitian and project manager at the Yale School of Medicine. She also serves as a registered dietitian nutritionist in the Survivorship Clinic at the Yale Cancer Center.
At the 2020 San Antonio Breast Cancer Symposium, results were presented from a study on dietary supplement use by breast cancer survivors and how these supplements may interact with tamoxifen and the aromatase inhibitors. Maura is the lead researcher on this study and joins us today to talk about the results. Maura, welcome to the podcast.
Maura Harrigan: Thank you so much, it’s a pleasure to be here.
Jamie DePolo: So, to start, just in case everyone is not familiar, could you give us an overview of the study? I believe that looking at supplement use is kind of one part of a larger study. Is that right?
Maura Harrigan: Yes. So, the collection of dietary supplement use is kind of an ancillary look of the study. And the study is called the LEAN study — Lifestyle, Exercise, And Nutrition — which is a healthy lifestyle intervention for women who’ve completed treatment for breast cancer. And it was actually intended to be a weight loss intervention because, as we’ve found, women who undergo treatment for breast cancer often gain weight during treatment, and then that weight gain puts them at increased risk for recurrence. So, that’s kind of the premise of the study, and it was designed and based upon the diabetes prevention program and adapted to the breast cancer population.
So, it’s this very effective healthy eating and exercise intervention for weight management. And as part of our data collection — in addition to the FFQ we call it, Food Frequency Questionnaire, which is a validated food collection document — we also designed a medication and supplement questionnaire with the study. So, we were asking women to report their supplement usage at baseline. And it just was eye opening, to be honest.
Jamie DePolo: Okay. So, let’s talk about these results. I think — if I’m remembering correctly — it was about 80% of the women were using a supplement. At least one?
Maura Harrigan: Yes. Yes. It’s phenomenal usage. Now, just to put it in context, 50% of American adults use supplements. This is a robust market. And cancer survivors are even greater users of it.
So, it averages about 70% of cancer survivors use dietary supplements. And in our finding this snapshot, as I like to call it, 80% of our women enrolled in the study were using dietary supplements. And let me just define “dietary supplements” at the get-go: it includes vitamins, minerals, and herbal preparations. This is a legal definition that was put into law by the DSHEA Act of 1994 — just throwing that out there — and I highlight that legal decision because it set in motion the robust market there is for dietary supplements that is non-regulated.
Jamie DePolo: Right. I was going to ask you to say that.
Maura Harrigan: And it’s like the wild, wild west.
Jamie DePolo: Yeah, because none of these supplements have to be approved by the FDA. There’s a kind of a voluntary thing, I know, with a particular CO — who, the name of which escapes me right at the moment — but it’s not just looking at something. You’re not even really assured that what it says on the label is what’s in the package or what’s in the pill or the tincture.
Maura Harrigan: That’s exactly right. So, that DSHEA Act classified supplements. Not only defined them but classified them as a food, not a medication, so that they’re not regulated by the FDA. The only time the FDA steps in is if there’s a reported event — medical event, from usage — and then the FDA will step in and investigate it, but it has to be reported by the consumer. So, there's no safety requirements by the manufacturer before they put these on the market.
So, it's just fraught. And, as you said, there’s issues with the content and the labeling, and the actual content of the supplement. There are lots of issues with that. So — and people don't realize this — so these supplements are really like pharmacologic agents, but people don't view them that way. And that's why capturing this data in the study and then kind of making the link, because they’re not benign. And not to say all supplements are not needed, they are, but they need to be sifted through. And that's why people need to report their usage to their doctor. And it's really helpful to have a dietitian. And also, we have an oncology pharmacist who works with us.
And we sift through these supplements and we cross check them against the treatments people are receiving — particularly the hormonal treatments, as we did here with the aromatase inhibitors and tamoxifen, and there are interactions that occur that people are unaware of. So, that's why we're trying to bring this to everyone's attention. That this matters, and it often flies under the radar of clinicians. And I say the issue is kind of like our own version of “Don't Ask, Don't Tell.” Patients don't tell, and healthcare teams don't ask. So, we need to correct that, but there’re challenges with it.
So, as we found — we asked, we drew up a list of herbal preparations and vitamins and minerals. And there was a pretty extensive list, about 50 different preparations, just to help jog people's memory — because this is self-report, which has its own problems. And what I found was that two-thirds of the herbal preparations that we listed no one was using, and then they wrote in another like 25 formulations that they were using. So, it’s a very fluid usage, and each snapshot comes out differently. So, that's another thing for people to realize. It's a rapidly changing market, and fluid usage, and subject to problems of self-report. So, you have to kind of dig and kind of get at it.
Now just, like a sidebar — just a COVID sidebar here, a COVID update: In my work now, I do telehealth. I love it! Because in terms of supplements, I have the people go to their medicine cabinets. I have them open up their kitchen cabinets. They take out the bottles. They’re showing me the labels. This is like a home visit, and this is to me — I've had much better reporting and accuracy, and reporting of supplement use, and also my interaction with them is much more effective. So, that’s something I'm going to keep going forward.
Jamie DePolo: Sure, that's very interesting because, yeah, you can then actually see like if somebody says, “Well, I'm taking…”— I’ll just use an example, like zinc — but maybe the zinc tablet has other things in it, and you wouldn’t know until they actually showed you that bottle.
Maura Harrigan: So, you bring up, really, a very good point there, is that people don’t realize that there may be multiple formulations in a bottle. And they maybe they have three bottles lined up, and in those three bottles, vitamin A may be present in all three. So, we call that stacking — stacking of nutrients — and it's very easy to then take in too much, because there is such a thing as too much. So, it can exceed the tolerated upper limit which are all defined for these micronutrients.
So, that’s something that I check, is stacking of nutrients. Are you overdosing particularly with what we call the fat-soluble vitamins, which are A, D, E and K, which the body stores in the liver, does not excrete what it doesn’t need. So, that's where you can get into your liver toxicities and interactions with medications, as opposed to the water-soluble vitamins, which you excrete out what you don't need in your urine. And I often say to people, “You have very nutrient-dense, expensive urine right now.”
Jamie DePolo: I like that. That's good
Maura Harrigan: That usually gets them to rethink what they're doing.
Jamie DePolo: Sure. So, I'm curious, with the study, I mean clearly 80% is a very high number of people taking supplements. So, I kind of have two things going on in my mind right now. One, I think maybe because some of these — especially supplements as opposed to vitamins — may be marketed as “natural” or “this is found in nature.” So, they don't think about it as it could possibly harm them. And two, did the study look at all why the women were taking supplements? My suspicion will be that they're trying to be as healthy as they can be. They’re recovering from cancer. They may still be taking treatment, like hormonal therapy, and they're thinking, “Oh, I'm going to be the healthiest I can be, so I'm going to do this.”
Maura Harrigan: Yes, we did ask them to report their reasons why taking, and they were targeted. Some, we know, to support bone health. So, they would be calcium and vitamin D. But the majority were reporting that they were taking it to prevent cancer recurrence. And what’s very clear from the American Cancer Society, World Cancer Research Fund, American Institute for Cancer Research, all these standards of practice are: Do not use dietary supplements to protect against cancer. Very clear.
That message is not getting to people. So, they’re taking it with good intentions. And I want to point that out because — and when you're counseling people about it you have to be mindful of their good intention, because you have to honor that. You have to acknowledge that they’re really trying, and they're doing this on their own, and they're just working with information that's out there, and a lot of that information out there is not evidence-based and a lot of misinformation. So, they're dealing the best they can. So, you have to honor that, you can't just dismiss what they're doing. So, you have to approach it by acknowledging that they're really trying, and they're interested in making an effort. I always say, “My job is to make sure that you're not taking anything that's interfering with something else that's being prescribed for you.” And when you put it in that context, they’re open to hearing what you have to say.
Now, many people have very strong beliefs in taking supplements, and that belief is important. That belief matters, and that belief counts. So, you just can't just dismiss it. So, there is a little art to this counseling. I always describe it as a “negotiation,” where you go in to sift through and say, “Okay, this is not harmful. This you need. This one, though, could interfere with your other treatments.” And then they're more apt to hear that and more apt to make a good change.
Jamie DePolo: Okay, now, kind of following up on that — I believe vitamin D was the most common supplement taken, in this snapshot, in your study. So as you talk about the different information out there, there are studies that show “Maybe vitamin D can reduce cancer risk.” So, of course, if I have been diagnosed, “Well, why wouldn't it reduce the risk of recurrence?” I can see that extrapolation happening in a lot of people's minds. Other studies have shown that if you have low vitamin D levels, certain treatments may not be as effective.
So, there's all this sort of conflicting stuff out there. And, as you say, it can be very hard to wade through because you're seeing this news story and that news story and they conflict. But, “Well, ultimately this one said it was good, so I'm going to try it because what harm can it do, because it's natural?” So, how do you counsel people on all that? It's got to be so hard.
Maura Harrigan: It is challenging. It is challenging. And the research on vitamin D is not conclusive yet. And the media reports on studies, and they don't always put in the context of, “This is an ongoing sorting-out of information.” And so that makes it hard for a layperson to kind of realize, “Well, this is just one aspect of the research and there's still more questions.”
But, what I like to say to people is…it's interesting, they come to me, their first nutrition question to me is, “What supplements should I be taking?” Not, “What foods should I be eating?” And I find that's where people's heads are at in terms of nutrition. And so I try to explain to them is that the micronutrients that are in supplement form do not act the same way as micronutrients in whole foods. Your body does not handle them in the same manner. In fact, the nutrients that are in whole foods are much more available to your body, and the body handles supplements like it's a medication.
So, there's really no replacing the power of Mother Nature, who packages all her nutrients in a matrix of foodstuffs — with fiber, with phytonutrients, with probiotics, and anti-inflammatory agents. So, they're all packaged together. So, when I start talking about food that way, they start shifting. They’re like, “Oh, food does have all these things that I'm looking for.” And the bottom line is most people do not eat well. They’re not eating a rich diet of nutrient-dense fruits and vegetables. So, steering them that way — that you can do a lot, even better, with what we call a predominantly plant-based diet and steer that direction.
And most people have a lot of room for improvement there, and they recognize that, but they often don't think that's enough. And it's my job to show them that, “Oh, yes, it is. In fact, it's even better.” Now, there's not to say that there are places for supplements, but honestly most of it is to correct deficiencies. That's how it came into being. Supplements were identified through deficiencies. So, correcting a deficiency is really important, but that doesn’t mean more is better.
Jamie DePolo: Right. Well, that's the good old U.S. slogan: “If one is good, 10 is better.”
Maura Harrigan: Right. Exactly.
Jamie DePolo: This is just my personal opinion: Sometimes I feel that people find it easier or would rather, “Let me just take a pill. I don't want to just switch my diet. I don't want to do some exercise. Just let me take a pill and be done with it.” And so, how do you overcome that mindset?
Maura Harrigan: Again, it's a challenge, and a lot of the medical system that they’re a part of treats things with a pill. So, they're just assuming that's the power of prescribed medication. So, they’re in that mindset.
I come at it a different way with people — particularly with cancer survivors, people in active treatment. I will say, “You’re surrounded by a team of experts. You have your medical oncologist who's doing your chemotherapy. You have your surgeon. You have your radiologist. And they're all experts in their field, and you're getting the state-of-the-art of all of this for your care. But your contribution to your care is how you nourish your body and how you move your body. And by nourishing your body and exercising your body, you make your body more resilient and more receptive to these treatments. So, this is your contribution to your care. You're part of the team and only you can do this.”
And that resonates with a lot of people in a positive way because they'll see that as, “Oh, wow, I have some control here because all these other treatments, I just show up where I'm told — when and where — and I do it.” But, the control over their own body, their own nourishment, and their own exercise, a lot of people find that empowering — and the bonus is they feel better when they do these things, and they tolerate their treatments better.
So, it's very empowering to people and for many people, the cancer diagnosis is the teachable moment for them to address these issues that they maybe not had been successfully addressing before their diagnosis. And in my work, and in the LEAN study, and in Survivorship Clinic, I have found that people — and this is a beautiful thing to witness — people will say they've adopted healthy eating, they've adopted regular exercise since their diagnosis. They feel better, and then they'll say, “I know this sounds crazy — I've never been healthier. I've never felt better, and I've been through a cancer diagnosis.” And it's through the power of good nutrition and exercise. And it changes their view of their body, their health, it gives them a positive outlook going forward — and that's a beautiful thing to witness and to give people the tools to do that. And it gives them, again, that empowerment, that sense of control, hope, and just feeling energized — truly energized — and fueled, and nourished.
Jamie DePolo: Sure. No. Yeah. That makes sense.
So, I kind of want to go back to vitamin D and maybe some of the supplements that you found. So, in this particular snapshot of the study, vitamin D now can interact with tamoxifen, letrozole, and exemestane, if I am remembering correctly. So, what are those interactions and — I guess sort of as a side question to that — I have a couple friends who are physicians; they're not oncologists but they are physicians. And they have told me, “Well, you know how much education we get about nutrition in med school? We get 3 hours.” So, my other question is: If they do go to their physician, or their oncologist, is that even the correct person to talk [to?] I mean, obviously, they need to tell their doctor about what they're taking — everything that they're taking — but is the doctor going to immediately be able to sort of help them sort out, or should the doctor refer them to a dietitian?
Maura Harrigan: Well, of course, being a dietitian…
Jamie DePolo: …Of course…
Maura Harrigan: …I'm a little biased here, but I would say please, please refer to a dietitian. We have a deep bench of knowledge about this. This is our training. Also, there's board certification in oncology nutrition for dietitians. So, there's advanced practice certification. It’s called — the credential is CSO: Certified Specialist in Oncology.
So, it is very deep training and also the counseling skills that are needed. So, yes, my goal is to integrate this level of nutrition counseling into all oncology care. Right now, it seems to be the standard of practice is it's all by consult. You have to request a nutrition consult, and then a very qualified dietitian steps in. But I want it where it's just part of the standard of care. That this is something that everyone gets: An evaluation of how you're eating, what your supplement use is, and then even how to manage your side effects that can impact your ability to eat and nourish your body — we call those nutrition impact symptoms, that are very well understood by dietitians. So, we have work-arounds for everything. We can really be an ally through treatment — from diagnosis on through treatment and into survivorship to really help people manage the treatments and be more resilient.
So, that is important. And I want to say, when we look for these interactions, we're using a very well-developed database called the Natural Medicines Database, which does an excellent job of identifying potential interactions. And they’re graded on three levels: Minor to moderate to major. And then working with an oncology pharmacist is really helpful, too.
So, that's what we do. We go in, and we go into the Natural Medicines Database, and we identify any potential interaction and what level it is. And if it's a minor interaction, we’re not really that concerned with it. The moderate ones we're cautious with. The major ones, that’s where we step in and say, “Yeah, you can't take this with that.”
So, that's where we get our information from. Now, the interactions work with different metabolic pathways. And you can explain this to varying degrees with people depending on their interest, but I like to say it's like merging traffic. You know, you have cars going into the same lane on the highway — well, that is how I explain if you're taking a dietary supplement that interacts with the medication: it's like merging traffic in your body. And that merge can work different ways. It can either potentiate the dose of that medication, or it can diminish that dose. So, it's variable.
And the metabolic pathways are different versions of the CYP pathways. But there is also a pharmacodynamic interaction, where a supplement can have what we call “estrogenic activity.” So, in hormonally sensitive breast cancers that's an issue, too.
So, there are many levels of these interactions, it's very complex. And that's why it's so important to tease through these supplements and sift through, cross check, because you want to know that when you're taking a prescribed medication, you are getting the intended dose. You don't want something to interfere with that dose, and I think everyone would agree with that. So, when you explain it that way, they're like, “Oh, okay.”
Another way to kind of do a work-around with people is you can ask them to suspend it during active treatment, and then revisit it once they're done. So, you're asking them just to take a hiatus. Particularly, if they have a very strong belief in it. So, that's another way to kind of manage these interactions and say, “How about just for now? While you're receiving this treatment, let's suspend it. And then when you finish, let's talk again — we'll revisit it.”
Jamie DePolo: So, do we know exactly what the interaction is between vitamin D and these particular hormonal therapies?
Maura Harrigan: Well, first I want to just couch this by saying these are potential interactions.
Jamie DePolo: Okay.
Maura Harrigan: And again, you always have to look more holistically at what's going on. But we looked on the Natural Medicines Database. They were identified as moderate interactions. So, cautious. And it was through the CYP3A4 pathway. The effect on the dosages, I cannot answer at this point, but they can be either increased or decreased and that, again, I would defer to the pharmacist for that question.
Jamie DePolo: Okay, that's fine. But in either case, I guess people should know that it could affect how much of the medicine is in their bodies and, as you said earlier, people want to make sure they're getting the correct dose. Not too much. Not too little. So, they need to be aware of this potential interaction.
Maura Harrigan: Absolutely. Particularly with these hormonal therapies, because people are going to be on them for 10 years. And if you're going to be on a medication for that long, you want to make sure it's working, and it's at the correct dose. You don't want to interfere with that. So, that's where these evaluations are important.
Jamie DePolo: Okay. Now, I guess, I’m curious: How common is it for cancer centers to have somebody like you that people have access to? And, I guess, what would be your advice to women who are either in treatment, maybe they’re on a hormonal therapy, maybe they've just finished treatment? And should everyone request a consult with a nutritionist?
I mean, I know you said you would love it to be just part of the standard of care, but it doesn't sound like we're quite there yet. So, in your mind, would your advice be to somebody, “Hey, yeah, request that consult. Let's talk about your diet. Let's talk about your exercise levels. Let's talk about all the supplements you're taking, even if you don't think of them right away,” and get that conversation going? Because, as you said, it doesn't sound like a doctor is going to automatically refer somebody to a dietitian.
Maura Harrigan: I always encourage people to be their own advocate in their care and being proactive, so this is part of that. You seek these services out. They are available, but you have to find them.
Jamie DePolo: I see.
Maura Harrigan: So, in my ideal world, that will change. That these services would be brought to you, but that's not the case right now. So, I am fortunate to work at Smilow Yale Cancer Center — Smilow Hospital — and we have one of the first Survivorship Clinics in the country. It's been in place for about 14 years now, and out of that clinic, we've also started a supplement clinic. So, we’re piloting that now with oncology pharmacists and [an] integrated medicine doctor. So, we're doing innovative stuff, and we really want to make this all the standard of care. That's really our end game.
Jamie DePolo: Okay, well let me ask you this, too. Given the advent of telemedicine in this time of COVID, now, say somebody lives very remotely — maybe has to drive an hour to a treatment center. Does the more frequent use of telemedicine make some of these services more available to people who are maybe a little bit more remote? They don't live in a big town, they can't just go someplace in 20 minutes and have a consult with a dietitian. I mean, is that feasible? Could somebody, say, from Montana request a consult with you via telemedicine?
Maura Harrigan: Well, first, I think telemedicine is fabulous for this purpose. For nutrition, all my work in the survivorship clinic is now telehealth — and it's my kitchen to your kitchen, and we really do great work. It's much more effective than being in a consult room in the hospital, honestly. So, nutrition counseling is very suited to telehealth. So, it is effective. I know that there are restrictions as to how far your telehealth net can go.
Jamie DePolo: Okay. Like insurance-wise and everything?
Maura Harrigan: Like across state lines. So, I know there's that restriction, but the potential is there. And yes, there could be [a] tremendous amount of outreach — getting this level of expertise from these academic centers out into their remote communities. It's so needed, and the technology is there. So, we can make that happen. And again, nutrition lends itself to it. An evaluation of supplements lends itself to that. Other disciplines, not so much. Physical therapy is a little difficult to do that way, but nutrition and supplement evaluation, very suited to it.
Jamie DePolo: Okay. That's very interesting because, I guess, even if somebody did live remote, there’s probably at least one big city in their state. So, they could potentially search out a cancer center, maybe that's in a bigger city that might have a few more resources, and connect with a dietitian that way. So, that's something that people could consider.
Maura Harrigan: Yes.
Jamie DePolo: Okay, because the whole goal of Breastcancer.org and our podcast is we really like to give people action items. So, I guess, that would be: If somebody is a breast cancer survivor looking to improve nutrition, that may be an avenue that they could do it, if they don't feel like they have anything close to them.
Maura Harrigan: Yes. So, you can contact the academic medical centers and ask for a board-certified oncology dietician, and that's a way to get to the source.
Jamie DePolo: Okay, perfect.
Now, to wrap up. I don't know if you have any more recommendations, but if you did — say for women being treated for breast cancer — what would your advice to them be about supplement use?
Maura Harrigan: Be judicious. More is not better. But take a good look at how you’re eating first. And food is visual, right? So, I often say — and I know this sounds simplistic, but it’s very effective — I say, think of the rainbow colors, right? Purple, blue, green, red, yellow, orange, white. Think of those colors. Have something like that at every meal, and in your week capture those colors. And it can be frozen, it could be canned — it does not have to be fresh, it does not have to be organic, right? So, it’s very economical. It’s a very simple way of looking at really eating a nutrient-dense diet, and the power is in the colors. It doesn’t matter if it’s a fruit or a vegetable. What matters is the color.
And this is food as medicine — the healing power are in the colors that Mother Nature gives to us. And that’s a very simple way to greatly increase the nutrient density of your eating and to access all the powerful phytonutrients, probiotics, fiber, anti-inflammatory agents, that Mother Nature has packaged for us in these delicious foods.
So, I always emphasize that — and that comes before using supplements. Then, if we identify gaps in your eating or identify deficiencies through blood tests, then we can target supplements to correct those deficiencies.
Jamie DePolo: Okay. I like it. Eat a rainbow.
Maura Harrigan: It’s my most effective teaching tool.
Jamie DePolo: I like that. It’s easy. It’s simple to remember.
Maura, thank you so much. This has been really informative, and I think you gave our listeners a lot of great points on what to think about when they’re eating and also when they’re using supplements. So, thank you so much.
Maura Harrigan: My pleasure. Thank you for having me.