168 | Can You Starve Cancer? What the Evidence Says

We fear this so much that people are still drinking alcohol. People are still eating processed meat we know that causes cancer. And so sometimes I find that our focus is not in the right place.

Welcome back to the Exam Room Nutrition Podcast. I'm your host, Colleen Sloan. I'm a PA and dietitian. And September is a big month for cancer awareness, with several different cancers being recognized throughout the month. So I thought, what better way to kick it off than by bringing on an oncology dietitian to help us unpack some of the biggest cancer nutrition myths floating around social media? Just in the past month, I've seen claims on social media that apricot kernels can kill cancer cells, that fasting around chemotherapy may improve treatment, and even that restricting certain amino acids could help slow cancer growth. And some of that messaging sounds really convincing. But is it actually supported by the literature? And that's exactly what I wanted to unpack with today's guest, Ginger Holton. You may recognize her as the host of Organ's Good Clean Nutrition Podcast. But she's also a registered dietitian and certified specialist in oncology nutrition who works directly with patients, navigating these exact questions. Getting a cancer diagnosis is scary enough. Our nutrition advice should help patients feel more confident about what they can eat, not more afraid of food. And Ginger helps us do just that. So grab your coffee or drive safe and enjoy my conversation with Ginger. All right, Ginger, I am so excited to chat with you today. I love talking to fellow podcasters. So welcome to the show. Thank you. I'm really excited for this today. I want to talk about cancer and cancer nutrition and a lot of myths that we're hearing online and social media these days. But first, you know, getting a cancer diagnosis is really scary. And many patients might ask their clinician, what do I have to stop eating? So, how do we answer that question?

You know, for some reason, whenever somebody gets a diagnosis, they get so much advice, and everything online is what to cut out. Cut out meat, don't eat any dairy, sugar causes cancer. You cannot eat soy. Processed food is terrible. Like the list goes on and on, and it's just so restrictive and fear-based. Um, you'll see that online, and then everyone is giving you that advice, also. Like your hairdresser, your friend, your friend's mom. It's really overwhelming. But like you said, getting a diagnosis is really scary. Getting into treatment is intense and time consuming and overwhelming. And nutrition brings this sense of peace. And I think that's where this comes from. It's a sense of control.

Speaking of that, I just saw a video on social media that had like over 3 million views. And it claimed that apricot seeds are, quote, God's chemo. And the person on stage was just going on and on about the nutrient that it can target and kill cancer cells, but it leaves the healthy cells alone. And so I actually want to start with that claim. Is there any truth to something like this? And then what are the risks of listening to claims like this?

Uh yeah, I actually have a personal story about what you're talking about. It's apricot kernels slash lay trial slash B17. Those are the names that this falls under. A long time ago, I was working at an integrative cancer center and I was in a big nutrition consult, and there was a man that had cancer sitting in front of me, and he was holding like a pile of these apricot kernels in his hand, just eating them. And he offered them to me, and I wouldn't eat it. Um, and I was like, I'm all good, like you do you. Uh, the enzymes in our body break down those compounds into cyanide, and you can actually get poisoned from them. That includes vomiting, nerve damage, liver damage. There's even some evidence of coma and death, and we're talking at high levels, but cyanide, these are these are toxic chemicals. Um, this theory actually came from like the 1960s and 70s. That's when the apricot kernels caught fire. But then, like, if you look at other cancer diets, Gerson diet, that's 1920s, Budwig 1950s, SEXT, that was in the 1920s. So there's these really interesting quote-unquote cancer cures that are really ancient now, right? But people are still so attracted to them. Cause wouldn't it be incredible to eat apricot kernels and kill cancer? Like, I have so much compassion for somebody that wants that.

I agree. And this messaging is all over social media. And what I get fearful of is that someone might try turn down traditional therapy, whether it be radiation or chemotherapy, in hopes that this food or this nutrient is going to cure their cancer. What are the harms or risks that you're seeing if people are choosing to go that route?

You know, I actually won't take clients on to my caseload because I work independently virtually with people that are in chemo and treatment or just got a new diagnosis and I'm consulting with them. I won't take them on if they're not doing traditional treatment because I will never tell you that I can cure cancer with nutrition. And a lot of times that is the expectation and it's dangerous. Um, so I have no judgment whether people want to pursue chemo or not. There's a lot of different personal beliefs and religious beliefs and family culture that goes into those decisions, but it's not safe for me if somebody thinks that I'm gonna cure their cancer with broccoli sprouts or apricot kernels.

Yeah. Well, you practice evidence-based medicine. And we know that nutrition has a place, nutrition has a role, nutrition should be a priority, but it's not that promise that this food is going to cure cancer. We want to support you along this journey. But again, like you said, we're not making just expectations that might not be met.

You're so right. I mean, even the power of nutrition to get you through treatment better, less side effects, that's worth so much. That alone can be life-changing.

Ginger, I love that you mentioned treatment. And we're not really going to get into it today. We're going to get back to some of those myths. But I actually did a podcast episode with an oncology PA and an oncology dietitian. And we sort of had this back and forth conversation. And um, it's episode 57. It's called Cancer Survivorship and Nutrition. So it really digs into nutrition during and after treatment. So after this episode, go listen to that one. I think you'll really enjoy it. But Ginger, let's get into some of these myths. We've already talked a little bit about the apricot kernels. And I want to talk about a big one that we're seeing online, and it's been present for quite a long time. And that's this myth that sugar feeds cancer. And that if you, you know, stop eating sugar, you can kill your cancer cells or starve the cancer cells. So, what's going on with this myth? And what do we tell our patients?

So much of the confusion out there comes from trying to simplify nutrition, which, as you know, we can't really do that. So, cancer cells do utilize sugar as a quick energy source, and there's a name for that. It's called the Warburg effect, but that is so oversimplified because in general, cancer cells are growing faster than regular cells. They're hungry. They're gonna sequester whatever they can get. All of your cells need energy, including blood sugar glucose. And so, quote unquote starving cancer, it doesn't work that way, just if you know about the metabolism. But I think it is confusing because one of the key AICR cancer prevention recommendations is limit the consumption of sugar-sweetened beverages. And I think people misinterpret that as oh, sugar feeds cancer. But actually, that important recommendation comes from the fact that they're trying to reduce obesity risk because overweight and obesity is linked to certain cancers. I think there's just a lot of misinterpreting going on.

Yeah, I agree with you. And there's a lot of nuance that's missed. And, you know, ask any dietitian. We all do recommend limiting added sugars. I don't know any of us that are gonna recommend that you're just eating 150 grams of added sugar every single day. That's no one is recommending that. But we're also not telling you to avoid sugar at all costs because there can be some moderation that is allowed there. Now, another one that's gotten misunderstood for a long time and honestly years. Now that I'm thinking about it, I did a research paper in college. I won't date myself, but this was a while ago about soy and its connection with some of these hormone-sensitive cancers and its effect on estrogen. So I'm curious, what do you think about soy and its effect on cancer?

Yeah, Colleen, this one needs to go away. It just needs to go away. Um, this was the fear about soy came from a headline that came out from animal studies a really long time ago. I just, it's so funny to me that some of these myths are still circulating. And it's so challenging that the antioxidants in soy are called phytoestrogens. There's phytoestrogens in a lot of different plants that we eat, but soy, for some reason, people just think that it's gonna act like estrogen in our body. But if you look at the modern human research, if you look at every recommendation from the major cancer organizations, what we're seeing is soy is not only safe, but maybe even beneficial and cancer protective. So if you're getting any dated advice from your oncologist or what have you, come to your dietitian and we can help myth bust because it's actually still widely circulating and it's very damaging to my patients.

Yeah, and correct me if I'm wrong, like the soy that we're talking about, like in edamame and tofu, that's what's cancer protective. It's gonna be that added soy um isoflavanol, is that right? That is the ingredient that's more in like a protein bar and these types of shelf sable ingredients. Is there a difference between the two?

Well, when you're extracting anything, right, it's gonna be more concentrated. And so there are some recommendations. Like we don't recommend supplementing with soy to try and get the benefits. The recommendation really is eat the whole food. Tempe, tofu, edamame. I love soy milk for my clients. It's so high in protein. It's really great if it's fortified with calcium. So we do need to be eating those whole foods as part of a cancer risk reduction routine.

Yeah. All right, let's talk about meats. Um, this is another big one that comes up, and there's a lot of opinions, and it kind of swings both ways. But, you know, we have a lot of data and information about meat. So I'm I'm lumping all of them together into one, but if you can break it down, because some meat have been categorized or classified as carcinogens and some aren't. So if you can kind of give us a meat 101, which ones should we be limiting and which ones, you know, raise cancer risk and which ones might be um health promoting?

There's so much confusion with meat. So it's pretty clear that processed meat, that means anything that's been salted, cured, smoked, fermented, having preservatives added. And I hate to say it everyone, but bacon, sausage, hot dog, salami jerky, canned meats, those we know should be limited because they could be cancer promoting for very specific cancers. Like we know this. So I do recommend that my patients limit or avoid those foods. And the foods that I say avoid or limit is very, very rare and very few, and the research has to be amazing. People also get confused that, oh, I can't eat any red meat. And that's actually not true. The recommendation is not zero, it's 12 to 18 ounces of cooked weight per week. That's about three servings. And so red meat and pork, beef and pork, lamb, that kind of thing can fit in. And importantly, chicken and fish are not included in that. So there's no limitations on chicken or fish. So you can have some red meat. We should limit processed meat. Chicken, fish, plant-based proteins, including soy, are very safe and probably helpful.

Now, speaking of carcinogens, I'm seeing this kind of pop up again. Um, and sugar alternatives, sugar substitutes kind of always seems to wax and wane in their popularity and in the spotlight. But right now, aspartame is kind of all over my social media feed. And, you know, the World Health Organization back in 2023 classified aspartame as possibly carcinogenic. But it's interesting because other regulatory agencies continue to consider it a safe alternative to added sugars. And there are recommended limits. So this gets confusing for people online seeing stories of like, oh my gosh, aspartame is causing cancer and they link to a study. So can you unpack this contradiction in the literature and what should we be telling our patients?

This truly is confusing. And you're right, the research has been bopping around for a really long time. So right now, where we've landed is aspartame is in group 2B, which means possibly carcinogenic to humans. And both animal and human studies have gone back and forth. But the basic conclusion is that the link between intake and cancer in humans is not convincing. But it's really important to understand the limit. So the acceptable daily intake per the FDA is 50 milligrams per kilogram a day. So to put that into perspective, a 150-pound adult would drink uh 10 to 14 cans of diet soda to reach that amount. Some people do that for sure. But obviously, as a dietitian, I would never recommend that. If I had a patient that was drinking like two or three diet sodas a day, I would probably at that point be working with them to reduce, not because of the aspartame, but because of so many other reasons and we need more fiber and water and other types of food. But you know what's interesting here is we fear this so much, the class 2B, the possibly carcinogenic, but people are still drinking alcohol, and that's actually a group one carcinogen. People are still eating processed meat. We know that causes cancer. And so sometimes I find that our focus is not in the right place. And I think aspartame's a great example of that.

Yeah. Now you mentioned alcohol. This one's actually pretty interesting to me because, like you said, there is absolutely a well-established relationship between alcohol and cancer risk. We know this. But the messaging, even lately, has felt pretty inconsistent. And I noticed this with the new dietary guidelines. It kind of took some of the restriction or the limitations of the language we used to have, as now it just kind of says limit to alcohol. But recently, the Surgeon General warned that light or moderate consumption may increase the risk of certain cancers. That's even like one alcoholic drink a day. So again, there seems to be inconsistencies, but yet our literature really shows that alcohol is carcinogenic. So how do we kind of tackle that discrepancy?

I wish that the current dietary guidelines would have come out about alcohol in a more evidence-based way. Because if we're being evidence-based, alcohol causes certain cancers: breast, colorectal, liver, laryngeal, pharyngeal, oral cavity, and esophageal, like these are known links. So alcohol is cancer causing, and we have to be honest about that. And Colleen, you know that it hurts my heart to like say that about a specific food because I really want all foods to fit. But if we're being really serious and we're following the research, it's just true that we should limit or eliminate alcohol to reduce your risk of certain cancers.

I'm with you. And you know, I think it's so ironic that on social media, people love to toss the word of toxic and poison around when talking about other foods like seed oils or aspartame, right? They label it as a poison. And I'm like, but nobody calls alcohol what it is, and it truly is a toxin. It is poison to our bodies. So I just find that so ironic.

We are missing the bigger point there. Um I stopped drinking alcohol a couple of years ago because I realized that I need to be in alignment with my own evidence-based practice and I need to practice what I preach, and I care a lot about cancer prevention. And so I just really try to set that example for my patients. It is hard, it is possible, and it does make a difference in your cancer risk.

Thank you for that, Ginger. That's awesome. All right, let's talk about fasting around chemotherapy. This is another thing that's getting a lot of attention. And just fasting in general has really become quite popular, intermittent fasting, time-based fasting for weight management, but now it's kind of trickled into the cancer world. So, what does the research suggest? And then when do you think this is not an appropriate dietary pattern for patients?

This is a really interesting area where the research is kind of compelling. Like if you look at the research, it's like, oh, interesting. Like this could help me tolerate treatment better, um, get, you know, kill cancer better. But a lot of people do not have any idea what treatment is actually like. For example, chemo days can literally be 10 to 12 hours long, sometimes longer. You might be nauseous, your stomach is bubbling, you might be dizzy. Steroids make you ravenous, maybe moody. The chemo days are really tough. And if you're trying to fast, that can be so much harder. Also, a lot of my clients and a lot of folks that are diagnosed are already underweight. And so if we're going one, two, three days without eating, the fasting can actually work against you. And then many of my clients, maybe like three to five days post-treatment, they can hardly eat anything anyway. They feel terrible, they're really fatigued, they are really nauseous. So it's not safe for most people to be going multiple days, especially if they have cancer, without eating. And that's where the challenges with the rubber hits the road is with actually putting this into practice.

I I think you're right. And I'm actually glad that a lot of people don't understand what it is like to go through cancer, uh chemo treatment. I would never wish that on anyone. I think those people are incredibly strong and brave, and it's so hard that now making them follow a restrictive diet when on days where they feel just absolutely awful is is almost like it's insensitive, you know? And I don't really think that we're doing them any benefit on those really, really especially hard days. And I think it's interesting also for you to point out that individuals likely are coming in malnourished into treatment, and we really do need to focus on optimizing their nutrition, not eliminating other nutrients that could help them.

You know, sometimes I get people where it could be an interesting fit, but this is where it's got to be personalized. Let's say your treatment is stable. Maybe you're in maintenance mode, you got a solid body weight, good muscle mass, you've been treating, you know, doing treatment really well, maybe for a long time. Perhaps that kind of person I might be open to talking about a little bit of fasting, but that's not the case that I see 90% of the time. And most of my patients, even if they want to try it, they end up giving it up within hours because it's really hard on them. It's not realistic.

Yeah, I love your approach, Ginger. And I'm like that too, but I I maybe come off aggressive or just overly passionate. But I agree with you that it depends, right? That's a dietitian's favorite answer. But it's interesting that social media makes blanket statements that they're saying all patients who are going through chemotherapy treatment should follow this certain dietary pattern. And that's where I think it's inappropriate and potentially harmful. So that's really where working with a dietitian who can determine if this is appropriate and safe for you is really, really important. Now, talking about starving our cancer cells, I think another interesting thing that's coming down the pipes is restricting specific amino acids. And I'm curious, what is the research showing? Is this ready for clinical practice? Like, are you recommending this or are we kind of getting too excited?

I've had several patients who have brought this up and a couple who have tried it. Uh, one sent me a YouTube video the other day. And when you watch this YouTube video, you're like, oh my gosh, there's human studies, it cures cancer. So I was watching this YouTube video with my normal dietitian like skepticism. And I was like, where is this study? So I grabbed it, I was able to find it and I read it, and it was done on some inpatient, like a small number of inpatient folks going through cancer treatment in China. And you can't really restrict amino acids because all food, like protein, is made up of a collection of 20 different amino acids. So, in order to really do this, they had to drink special specialized shakes, like they're drinking this liquid diet. So most of them dropped out because they were nauseous or they were becoming malnourished. Um, they did see some interesting results in the people that were able to stay in, but we're talking about like a handful of people, and most people couldn't tolerate it. And I think sometimes we make it so simplified, like, oh, just to restrict amino acids. But it's it's not that simple. You probably have to like drink a very specific drink, and then you can't eat anything else. So most people get so frustrated, it's confusing, it's overwhelming. They're cutting out protein when they should be adding protein. So I'm watching this research. I think it's really interesting. I'd love to see more. It'd be amazing if it worked. But uh, cancer is really smart. Different cancers rely on different amino acids, and tumors can also adapt by making their own amino acids anyway. And so I think we're trying to out outsmart cancer in a way that is massively oversimplified right now.

That's interesting. And yeah, I mean, I think it's important as clinicians to follow the research and change our recommendations as appropriate. And who knows, maybe in some years we find out, find a new diet and a new plan that works really well. But for now, I agree with you. Protein is really important in uh treatment. And so I think that would just make it even harder for these patients to eat and to enjoy foods as well. Now they're gonna be stressing out about amino acids, and I think that could be really challenging. Let's talk about supplements. Uh, they are marketed to strengthen your immune system, reduce side effects, even to like fight cancer or kill cancer. But supplements also are risky for some patients. So I'm curious if there are risks and what they are about supplements and if there are certain supplements that you actually do recommend.

I To be fair, really love supplements. And I hate it when a patient's doctor tells me no supplements, none. And I do get that sometimes, and I find it completely dismissive. Protein powder is a supplement. L-glutamine that saves my patients from mouth sores is a supplement. A multivitamin is a supplement. Vitamin D, calcium. These are safe, effective supplements that are extremely appropriate for a person's cancer journey if they need those nutrients. So I push really, really hard and talk to the oncologist to get my patients the supplements that they need. But the risks I would say, first of all, is over-supplementing. I've met people that are taking a hundred pills a day, then they can't even eat food. And there also are supplements that interact with your chemo. Uh, vitamin C and magnesium can make diarrhea worse. Many supplements at high dose can increase bleeding risk. And so I'm really pro-supplement, and we have to be extremely careful. And you have to work with a dietitian and your oncologist and a pharmacist to make sure that you're doing it safely.

Oh, I'm glad that you mentioned that. I actually talked about this with another cancer dietitian friend of mine, episode 75. And we talked about uh if your patients are consuming too many supplements and don't even know, because that terminology, supplement, we know what we're talking about. And I love how you kind of listed different things that fall under that category of a supplement, but a patient might think, like, oh, if it's not a pill, it's not a supplement. So their greens powder and their probiotic powder and all these other things they're having, they don't consider a supplement. And like you had mentioned, they could be over-supplementing. So, really, really important to ask your questions in a way that your patient understands and gets you all the information you need because the worst thing you can do is add on something else to a stack that they're already overconsuming.

What I do first is I say, okay, give me everything. And then I go through piece by piece and I'm also I'm looking for doubles, right? And so sometimes somebody's really constipated and I'm like, oh my goodness, you're getting 20 milligrams of iron here, here, here, here, here, you know, um, and that's compounding some of your side effects. So not all of us have a deep background in supplementation. And so if you don't, there is help out there and there are experts that you can refer to. I think it's not in everyone's wheelhouse, but it's very important in cancer care.

Yeah, I agree with you. I love that you look for doubles because that's usually where it's popping up, right? Like this supplement has this much vitamin D. You're also taking a vitamin D supplement, your calcium has vitamin D in it. So that's yeah, it takes an astute clinician to be able to pull that out. So I love that you do that. All right. Well, with so much attention on individual foods and like anti-cancer diets, I think like we've talked about, you know, the the through line has been we're missing sort of the point and the most important things that we should be talking about with our patients. So we're just seeing clinicians who might not be in oncology, where should we focus our education and our energy for our patients?

We need to be really up on myth busting. But if we come in and we're just negative, you know, like today I'm like, well, we can't, no alcohol, no processed meat, like, you know, uh these specialty diets aren't gonna help, uh, apricot kernels are gonna poison you. If we come in it like that, I think it really makes people feel, well, there's nothing I can do. And what we really want to do is make our clients feel empowered. You can eat more fiber, you can eat more fruits and veggies. We should increase protein. And a lot of where dietitians and PAs come in is strategy and support. I never work with a patient once. I work with a patient for six months or more throughout their cancer journey, and that has proven really effective for me.

Yeah, I agree with you. And we sort of look out of touch if we either don't know about the myth or just like dismiss it. I really like to say, oh, what do you know about it? Because even sometimes there's things I haven't seen on social media yet. And they can educate me and we pull the study together and really unpack it. Because I think if you just say, like, oh, no, that's wrong, they don't know what they're talking about. Now you kind of look like you don't know like what you're talking about, and you're not open to helping them feel better or getting them well. You sort of look like the enemy. So I really love that you mentioned we need to be up to speed on that, but at the same time, walking that journey with the patient to help understand where you're coming from and why you are promoting the basics that have been around a long time, even though they don't look flashy or they don't like sound like they're gonna work. I think sort of meeting them in the middle and giving that education is really, really important.

I love to pull up the AI CR recommendations. They have this very fun graphic of the 10 things like increase physical activity, drink less sugar-sweetened beverages, um, don't take supplements to prevent cancer. I show it to my patients when I'm working with them and we talk about what they're doing well and where they might need to focus. And so that is a way to meet them where they're at and help them feel empowered.

I love that. Well, I hope I never have to work with you, but if I did, you are a wonderful dietitian and I love how you work with your patients. You have such compassion for them, meeting them where they are and really helping them succeed and thrive in their journey. So, Ginger, if people want to connect with you online, where can they do that?

Yeah, I'm the host of Orgain's Good Clean Nutrition Podcast. So, similar to you, I tackle nutrition trends and evidence-based information. And then I also run a private practice in Seattle, but I work all over the country. Ginger Holton Nutrition Practice and Ginger Holton Nutrition on Instagram.

Definitely check out their podcast. They've won multiple awards. It's an incredible podcast full of incredible experts, unpacking a lot of really great things. I learned so much from you and your experts. So thank you for sharing that. I will link down to all of that below. Ginger, thank you so much for your time. I appreciate you being here. Thank you so much for having me. And thank you for carving out some time for nutrition today. I will see you next week.