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Cancer Mythbusters: Superfoods and Cancer

  • What is a superfood? And can it really fight cancer? Dana-Farber nutritionist Stacy Kennedy, sorts through the truth and the hype around superfoods and their purported healing powers, and looks at the more general topic of what we should and shouldn't eat to help lower cancer risk.

    Read the transcript:

    MEGAN: I'm Megan Riesz and this is Cancer Mythbusters, a podcast from Dana-Farber Cancer Institute about the many myths and misconceptions in the world of cancer. Every episode we'll take a look at a myth and debunk it with the help of our world-leading clinicians and researchers.a

    What should we eat and what shouldn't we eat? What keeps cancer patients healthy and what can help fend off cancer in the first place? These are big questions, and it can be hard to tell the difference between a nutritional myth and a nutritional fact.

    What is a fact is that good nutrition is important, especially for cancer patients – that means a balanced, minimally processed plant-heavy diet, which can benefit your overall health and energy levels and support your immune system, as well as help you manage symptoms during treatment and promote survivorship.

    The term "superfood," a relatively new term, refers to foods that claim to have exceptional health benefits. What's the deal with these foods? When it comes to a cancer patient's diet, are these foods better than others?

    Today I'm joined by Stacy Kennedy, a nutritionist at Dana-Farber, who will help me answer these questions.

    Thanks for joining me, Stacy.

    STACY: It's great to be here. Thanks so much.

    MEGAN: What are superfoods? Let's start there.

    STACY: So superfoods have really become a term that is synonymous with ultra-healthy, nutrient-packed, plant-based foods and supplements. So these are foods or beverages or ingredients that are essentially advertised as having exceptional powers, essentially for fighting common health conditions, helping with everything from weight loss to energy, vitality, hormonal balance, and there are news ones coming out all the time — but I think the question is, are these foods really super or are they healthy foods with really awesome marketing?

    MEGAN: Do superfoods have a role in cancer prevention?

    STACY: So I think this is a really key area to look at in detail in the sense that if we peel away this term "superfood" and we look at what they actually are, many of them are fruits, vegetables, nuts or seeds or other plant-based foods, maybe herbs or like an herb you would grow in your garden that come from all over the world, and when we think about health behaviors that might help to reduce the risk of developing certain cancers or strengthen the immune system or help promote survivorship, one of the cornerstones is having a diet rich in fruits and vegetables, other plant-based foods and being physically active, things like that.

    So superfoods per se do not have enough scientific evidence and research to support many of the claims that we hear or that we think we hear, so a specific superfood having a role in reducing the risk or promoting survivorship for a particular kind of cancer, we're really not here yet in terms of the science, but if we peel that term away and we start to see these items as new opportunity for international fruits and vegetables, then maybe we can start a build a case about how they can help us achieve that well-balanced diet that is recommended by the American Cancer Society, National Cancer Institute, etc.

    MEGAN: How can superfoods help patients who are currently in cancer treatment?

    STACY: Sure, so I think that's a great question and, again, it really is a matter of trying to ignore the hype and speak with your dietician, your nutritionist, your physician, your nurse about the role that some of these foods you're hearing about might have for you — are they safe? Might there be effective? Why or why not? — and having those conversations, but we can take a look at a few popular examples.

    So, one example…some of the foods are things that we've certainly heard of and they're pretty mainstream in the marketplace, right? Like you might see chia seeds or goji berries or acai berry, and with that we can start to think about, 'Okay, well, what is this really?'

    So if we look at, say, the acai berry or the goji berry, these are essentially fruits that have potent phytonutrients, so plant-based compounds that give them those vibrant colors, from other parts of the world, so, in a way, similar to our blueberry or to our cranberry here in New England, and so, we can look at eating foods as being helpful in terms of giving us certain vitamins, certain minerals, fiber and etc., water even, and so in that way they might be helpful.

    In terms of other examples, I would mention a couple of others — so cacao is often touted as a really potent superfood, and so, cacao would be essentially like the essence of chocolate, and so whether or not this is something that will emerge as having a role in cancer prevention, right now there's very limited-to-know research, but if you love chocolate and we do know it's important to avoid excess weight and have a healthy balanced diet, you could use something like that in your smoothie, in your oatmeal to help add some flavor and some nutrients without adding a lot of other additives that you might not want.

    MEGAN: What would you say overall about the relationship between certain foods and nutrients, and their ability to prevent cancer?

    STACY: So this is always an interesting question, because when we look at reports and studies on individual, say, superfoods, in our example here, so even there's this new berry called maqui berries that are coming out. When you look at any kind of research, the research is extremely preliminary.

    So in looking up studies on popular superfoods, what you find are journals and the studies are either in cells, so kind of test tube studies under a microscope or possibly in animal models, but there are not well done studies today looking at these individual superfoods in humans living their everyday life and looking at relationship with cancer.

    So just because on a slide under a microscope in a cell you might be able to manipulate things and potentially see an effect on how that cell grows or doesn't grow, it's a very big leap and really not scientifically evidence-based to then assume that that food will have that same effect in the human body and start to see results. There's a lot more research that needs to happen first.

    So we want to think of superfoods as just another opportunity for a healthy part of your balanced diet to add to the 50 percent of your plate that we encourage to come from vegetables and fruits and plant foods. These could be an option, an option for that.

    MEGAN: Can you reiterate some other lifestyle and dietary measure that people can take to lower their cancer risk?

    STACY: Sure, absolutely. So in terms of nutrition, maintaining a healthy weight is extremely important, but going about that in a healthy way — so eating a balance diet, which is predominantly plant-based, but might also include things like fish or other sources of lean protein in a balance so that when you look at your plate you want half to be vegetables or fruits. You want a quarter to be a protein and a quarter to be your wholegrain or starch.

    Sometimes foods take up more than one category, so like a sweet potato kind of counts as a starch, but it's also a vegetable — so looking for a variety of plant-based foods. Those colorful examples really can help build the foundation of a healthy diet for helping reduce the risk of certain cancers or promote survivorship.

    Physical activity is very important as well, not only for its role in weight management, but its role in helping to support the immune system, and then we look at things like vitamin and supplements kind of on an as-needed basis.

    Then there's another challenge with superfoods — even though they're called "food" many are sold either also as a supplement or even sometimes we can only get them in supplemental form, and so that's something for patients to actually be cautious of during treatment.

    So, for example, eating turmeric, like adding the spice to your quinoa when you're cooking it or into your stir-fry with a little black pepper or into a soup, that's a great way to get some of the antioxidant and the anti-inflammatory and other benefits seen in that root. However, for some patients taking a supplement might be risky in terms of an overconcentration of antioxidants during treatment, for example, radiation therapy. So even though superfoods are called food just "buyer beware" to kind of be careful for where it crosses the line between a supplement versus a food.

    Superfoods aren't going anywhere. In fact, I was reading and seeing that the term is really increasing in its market share. So there has been one report that says there has been a 36 percent increase in the number of foods and beverages that are proclaiming to be a superfood, and there are some interesting ones on tap for 2018. I saw watermelon seeds, chaga mushrooms, tiger nuts, there are all these things. Algaes, spirulina — that's been on for a while, and a lot of these, like I mentioned, have a role in a healthy diet, including seaweed or algae in a soup is…it can be very healthy, but I think some of the take-home messages are really start to look at these as a new flavor opportunity, a new way to boost your intake of healthy plant-based foods. Try not to really focus too much on some of the guarantees and promises, because unfortunately the research just doesn't back that up yet, but it doesn't mean that we need to necessarily avoid them, but they may be just kind of another fun and new and different plant-based food to kind of try out and test.

    MEGAN: Thanks again for being here, Stacy.

    STACY: Great. Thank you so much.

    MEGAN: So, myth busted. Ultimately, it's important not to look at superfoods as miracle foods, but as a "piece of the pie." When you strip away the term "superfood", what remains is a group of foods that haven't been proven to prevent cancer all on their own. However, these nuts, fruits, vegetables, seeds and other foods can make up components of a well-balanced diet.

    A healthy diet can not only help with things like weight management, but it may also reduce your risk for developing certain cancers whilst supporting your immune system, helping you feel well during treatment, and promoting healthier survivorship.

    To learn more about nutrition, visit dana-farber.org/nutrition.

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  • Health & Wellness
  • Nutrition & Diet