GryphonCAST Episode 6 Transcript
Speakers: Mchael Lim, Lior Boguslavski, and Alison Duncan
Michael Lim
Cardiovascular Disease or CVD, is a leading cause of death in both Canada and the US. Among the many factors that increase the risk of CVD, some such as genetics are unfortunately unchangeable. However, other factors like high cholesterol can be modified through what we eat. One such food; beans. Beans are nutrient dense source of fibre and protein are known to decrease the CVD risk. We know beans are healthy for us. But do we know how much we should eat to reap those benefits? What about what types of beans? Open your ears and mind and let's chat about that. Welcome to GryphonCAST, a podcast where we casually chat about science coming out of the College of Biological Science at the University of Guelph and how that work can affect lives around the world. I'm your host, Michael Lim. With me today is co-host Lior Boguslavski and special guest and Professor Dr. Alison Duncan. We chatted about Dr. Duncan's recent published work looking at how the consumption of beans lead to decreases in LDL or bad cholesterol in adults who have high cholesterol. We'll also discuss what her work might mean for implementing dietary strategies to reduce CVD risk. Welcome, Dr. Duncan.
Alison Duncan
Thank you, Michael. Thank you, Lior.
Michael Lim
So, as we get started to kind of introduce yourself to your audience. How would you describe your research or I guess the work in general done in your lab?
Alison Duncan
I would say that my research is really focused on generating evidence to support a role for whole foods in the prevention of different chronic diseases. So being at Guelph, I'm particularly interested in looking at that continuum between agriculture, food and health. So, some examples are that I've studied the human health effects of soybeans, lentils and beans. I'm also interested in better understanding how different population segments consume and understand these foods. So for example, I studied how older adults perceive beans. And I'm also interested in translating the knowledge and all that interesting research to people who can use it.
Lior Boguslavski
That sounds really interesting, very great work. Why did you decide to research this topic and did you expect to be doing this type of work?
Alison Duncan
Um-hum, well, I did expect to be doing this kind of work because I essentially love doing nutrition research. And I decided to do this because I recognized a gap in the literature. And I wanted to do a human clinical trial looking at health effects of consuming something as readily available to us as canned beans
Michael Lim
Was there any kind of eureka moment? Where you were out shopping one day, saw beans on the shelf and like "Oh, perfect study option right there".
Alison Duncan
Well, I eat canned beans almost every day so I don't know if there was any one moment. I think that my moment was really in high school when I realized I wanted to study nutrition. Because nutrition is really been a focus of my entire career since first year undergraduate and I've just always been interested in it. But I think this study in particular, I really wanted to do a human study that intervened with canned beans and produced evidence that could be used for people that can use it.
Lior Boguslavski
Well, that leads perfectly into what we're going to be discussing today. So, you recently published a study called "Canned Beans Decrease Serum Total and LDL Cholesterol in Adults with Elevated LDL Cholesterol in a 4-wk Multicenter, Randomized, Crossover Study". Can you briefly describe why you think that bean diet literature is so extensive and why beans were the chosen health food in this study in particular?
Alison Duncan
Sure. I think that first and foremost, beans are, they're an incredibly nutrient dense food. They're very, very nutritious and in combination with how affordable they are. They're a very appealing candidate to study and examine how they might affect human health. So, they do get a lot of attention. But there's still some gaps in what we need to know. There's still lots to be done. And so for this particular study, I chose the canned beans because we needed more research here. We needed to address different questions and this study addressed two main kind of gaps. One was, it looked up two daily amounts of beans on the same study, and also it looked at multiple five different varieties of beans in the same study.
Michael Lim
So, come speaking on different sizes of beans. In your study, you selected different bean sizes, being a half a cup of beans or whole cup of beans, and these in turn were then compared by using a whole cup of rice or rather a whole cup of white rice. Is there a particular reason why you decided to use a half cup and a whole cup for those versus a whole cup of rice, is that standard for this kind of work?
Alison Duncan
Those are good questions. I think when doing a nutrition study that's especially on foods a lot of attention is paid to what you're actually going to study. So of course, the beans were a big focus for this study. What types of beans? How much beans? And so, in terms of the amounts of the beans, it was really decided based on what had been studied before to show effects on the things we're looking at. And also what's reasonable for people to consume. And also two amounts that were distinct, yet not really too far apart. So the half and one cup is kind of something a lot of people can relate to. And then, in terms of the rice, you know, it's a tricky thing to decide what you should do for control in a food study. We can't give like non-beans. So, white rice was kind of a choice based on a couple of ideas. That is, it's something you know, everyone can relate to. It's a familiar food. It also hasn't been shown to effect the measures that we're looking at. So it was kind of, you know, a little placebo version but not really but it was a control food that made sense to choose.
Michael Lim
I guess we have to eat something, can't eat nothing compared to that [cross-talk] in a multi-week study.
Alison Duncan
Exactly, I mean, that is an option Michael, we could have done that, we could have done a diet with and without beans. And that could have been an option. It's just that the idea of having something and it's, it's kind of appealing for logistical being in the study component.
Michael Lim
Also, let's jump back a little bit. You're talking about how there's a gap in terms of studying canned beans. Is there a lot of literature in terms of looking at, I guess fresh beans or dried beans compared to canned beans?
Alison Duncan
Yeah, that's a good question. And so by the end I know you guys are gonna know a lot about beans so you can get them. [crosstalk] You can also [crosstalk] have them for dinner tonight. And you can also get them in a dried form, in the bag, and then you can soak them and prepare them. And so the studies that are available in the literature they're not extensive to tell you the truth. But there are some on dried but there's also a lot on different forms like in a chili or in some kind of food product like it's kind of across the board. That's what I was kind of appealed towards just a plain old canned beans. You know everyone can get those. They're on sale. They're affordable. And you can relate to them.
Lior Boguslavski
Well, based on the results of your study you found that consuming beans found that there's a decreased total cholesterol and LDL cholesterol by consuming these beans. Well, do you think that increasing the amount of beans in an individual's diet would help the cholesterol levels even more? So say, one and a quarter cup or one and a half cup as opposed to one cup?
Alison Duncan
Yeah, that's a good question Lior. I think that was kind of the hypothesis we had by examining the half versus one cup that we might see that kind of increase in magnitude of effect. That's what we examined. And we didn't see that from a statistical standpoint, but the numbers kind of reveal that from the half cup to the one cup. So, to answer your question directly, I mean, I'm not sure I would want to research that? I think, you know, a cup is a lot. It's probably enough. And the thing about nutrition and examining these types of things in literature, is we're doing it on a pretty short term. Yet people's lives are pretty long term. So, I would be not really wanting people to consume like a lot more than a cup. That's a lot! And even if they don't consume that much as long as you know, they're incorporating beans into their diet on a regular basis. I'm not so worried about you know exactly cup kind of thing. It's more that you're including it in your diets, your diets have beans in it and that's a good thing.
Lior Boguslavski
Would you be interested in perhaps pursuing a study where it's beans in combination with another health food in terms of lowering cholesterol? Would that be an interest as well or strictly just beans?
Alison Duncan
No, I mean, I think that's of course an interest and that's the whole idea to have a healthy diet that's based on variety and based on incorporating many different foods that have been demonstrated to improve our health. So, that is what should be done. In we can't be eating beans all day only. So, there's many other things to be eating. In terms of researching that, that is very interesting. It has a lot of challenges, but it's not impossible. And in fact, in Canada, we have one of our leading nutritional scientists from University of Toronto, Dr. David Jenkins. He studied what's called the portfolio diet, which is exactly that. It's combining a whole bunch, a whole medley of foods that have demonstrated health benefits. Like beans, and soy beans, and nuts, and plant sterols. And so, and it showed incredible effects. So that whole aspect of variety, it has a lot of power.
Michael Lim
Even just beyond the food types, like for your study, you had five different types of beans. I imagine it makes it lot easier to eat a cup of beans a day when they're all mixed up instead of just one of a cup of one single type of bean and even then the dietary and the nutritional benefits are pretty similar across the beans, right?
Alison Duncan
Yeah, I mean, in our study, we looked at five varieties of beans kind of all on a rotated basis. So, we did not do a direct comparison of the bean varieties to each other. More, it's more that our studies show that consuming a variety of beans was efficacious. It was able to decrease cholesterol.
Michael Lim
From speaking of cholesterol compared to other diets, and we touched a little bit on this a little bit earlier in terms of white rice, but is white rice always used as a baseline comparing to people's diets, or why do you think that is? And do you think comparing to a more nutrient dense food like say, brown rice or maybe even hummus might be a better comparison?
Alison Duncan
Yeah, I mean, it's so challenging to figure out the best comparison because we're dealing with foods we're not dealing with a pill where you could just give a sugar pill kind of thing. And so, it has the elements of considering your control food to be something that people will be familiar with, and it'd be not a big deal for them to consume. It would also be something that's not expected to affect your outcomes. So, for example, brown rice, it might affect your outcomes because it has more fibre. So that wouldn't be as great of a choice. So, it definitely is a challenge and white rice seems to be the best choice in this case.
Lior Boguslavski
So, your study excluded a variety of participants based on different criteria such as being diabetic, having high blood pressure, or regularly consuming large amounts of alcohol. Do you think the health effects seen by increasing bean consumption would be greater in populations like these?
Alison Duncan
I think that's a good question. I think that it could be because some of those factors also increase heart disease risk, and so maybe those individuals might have more to gain from consuming beans. However, the primary reason for us excluding those factors wasn't really related to that it was more related to trying to avoid situations that would affect our study measures that weren't the beans. And so, when we are looking at a research study and intervening with something if we see changes in our measurements of our study, we want it to be because of what we intervened with ... the beans. We don't want it to be because the person's blood pressure changed or because they had diabetes, or they had another thing happening. That is in our study, we wanted everyone to have their habitual routine and we screened them to not have factors that could affect our study outcomes.
Lior Boguslavski
So, the results of the study can still be applied to these populations of people then who would benefit from beans even though they were not participants in the study?
Alison Duncan
I think that in the strictest sense of the word, the application of the results are most fine tuned to the types of participants you studied. However, in many cases, they can be more generalizable to a wider population. And I think, yes, it could be it. I think it is. It is, this is generalizable to a wider population because let's face it, you know, there's not a lot of downsides about eating beans. You can get over the flatulence, and you can get used to it. So, I think that it has generalizability to those individuals.
Michael Lim
Another part I decided I was kind of curious about is that it lasted for four weeks for our audience who hasn't read paper. So, is there a reason why it's only in the middle of the study around the two week mark, you had a 3 day food record where participants were essentially writing down what they were eating so you get kind of nutrient profile in the middle of the study. Instead looking at say, the beginning or the end? Do you think there'd be differences across the three windows of time?
Alison Duncan
Yeah, that's a good question. I think that it's relevant to note that the food records as part of the study weren't really completed for us to look at effects on the food records. Moreover, they were completed to just get an idea of what participants were eating during the study. And so it was really kind of like a background collection of data. And so we felt that midway was the best because it was kind of like, okay, very into the time that the intervention period, and this was kind of like they're going to used to it and this is what it was like. And so, that's kind of why we did that. The other element is completing food records is a lot of work actually on the participant. It was sufficient to do that.
Michael Lim
Out of curiosity, do you think that the study of participants would have had substituting food for beans even after the study ended so they heard the results of your study. It's time for beans forever. Goodbye, rice.
Alison Duncan
Yeah. Yeah, that's a really good question. And I mean, that's our hope that the experience for those particular people would be long lasting. Having said that, this was a crossover study, wherein every participant did every treatment period. So, everyone was at four weeks at one cup, four weeks a half cup, and four weeks at white rice in a random order. And then there was a four week break in between. So, during that four week break, we didn't want them to keep eating beans. So, what I'm hoping is that they really wanted to when they stopped the study and then at the end of the entire study, they went back to their beans.
Lior Boguslavski
Well later in your study you touch upon the types of beans you chose being particularly popular in you know, by being purchased from Canadians. One type, pinto beans, did not fit into that category, even though they're widely used in bean diet research. Why did you think pinto beans are so popular in this work?
Alison Duncan
Yeah, that's a good question. And in choosing those five varieties that we did examine, we did a lot of exploration and consideration and we had like a document committed to that that we're working on for a few months and we were consulting with Ontario bean growers and sales of beans and the research. And you're right that pinto kind of stands out a little bit, but not a lot when you compare it to the research. And I think that basically, you know, we're not dealing with just Canada we're dealing with other countries and other cultures and pinto beans is more common there. So, it made sense to include it about that comparability aspect.
Michael Lim
Speaking of the five types of beans, out of curiosity, of those five, do you have a favorite?
Alison Duncan
Yeah, it's hard to say for me to rank my favorite beans because they're all so amazing. The one thing I know that I will mention just kind of a little note is I did learn a lot about the history of the Navy bean because it's not navy it's actually white [ laughing] for it has meaning from the Navy. Black beans are great if you're wanting to include them and say brownies I like that a lot. And I also eat black beans a lot. I'd say that you know, because of the availability, the dark red, I think I'm just I just eat more of that I think, but I find that they're actually sold out more now and are just around is fine. too. So I have been eating a lot more of white kidney because it seems like people are buying more canned beans or the supply chain is an issue. So, I've been having white kidney beans a lot lately.
Michael Lim
So you want to take credit and say it's your study motivated people.
Alison Duncan
I've been leaving like reports on my study at the grocery store.
Michael Lim
Why you should buy beans, flyers everywhere.
Alison Duncan
Yeah, exactly. They should have it in the flyers is a little side note.
Lior Boguslavski
For those people who are interested in incorporating more beans into their diet but perhaps don't like the taste of beans or don't like traditional bean recipes. Like chili's for instance. Do you have any specific recipes or types of ways that you incorporate beans into your diet even if you don't feel like you know, eating a side of beans for example, with dinner?
Alison Duncan
Oh gosh, there's an endless supply of resources in that regard. I'd say here in Ontario, the Ontario bean growers has tons of resources for lots of really cool recipes and that are different and incorporate beans in a way that you don't realize it. Also Pulse Canada. They have ... so beans are a type of pulse, and they have a lot of really amazing recipes. Also in our lab, we've created different resources like we created a bean toolkit that has a lot of cool recipes. So really, the possibilities are endless, especially if you have like a masher or a food processor or any sort of like device I usually just use the mashing because I don't want to wash all the appliances. [crosstalk] There's like, it's endless.
Michael Lim
So, in the end, we kind of have given away the spoiler many times already so far, but your study showed that consuming one cup of beans, not half a cup, decreased the total amount of cholesterol and LDL cholesterol in adults therefore lowering their CVD risk. So, what do you think are some of the major benefits provided to your field? What about the fact that these canned pulses can produce these results? Do you think there's more research in the area needs to be done or more types of beans?
Alison Duncan
Yeah, I mean, so you're right in the in summarizing the results, and I think that it advances the field because it just adds to the literature and its publication in a very high quality nutrition journal enables it to be exposed to academics worldwide so that it can help inform the progression of nutrition research. I think in terms of next research steps, it's really there's so much to be done. Nutritional research has a lot to be done always. And in this area, there's examining other populations of groups. There's examining other risk factors for heart disease. There's examining other diseases. There's always a lot of research to be done. Lots of job security there.
Lior Boguslavski
In general, I think most people might underestimate the impact that lifestyle changes like diet can have on our health and disease risk. Is this something that motivates you personally and in your research?
Alison Duncan
It's interesting because that question, I thought about that a lot. And I think well, first of all, what motivates me to do nutritional research is that I essentially, I really love the fact that we all have a choice about what we eat and drink each day. I think that's really interesting. And I want to be a part of creating information that guides those choices. But with respect to you know, people underestimating it. I feel like maybe you know, people aren't underestimating it they're not just they're just maybe not approaching it with the same matter of intensity and timing as they might be if they already have a health issue. So, for nutrition, we're kind of more a lot of the time not all the time, but a lot of the time we're talking about more long term for future. So, this is in contrast to like if you have something happened to you and you take a medicine right away you're going to like this is intense I'm going to do this and it's going to work vs nutrition is kind of long into the future and it takes a while to get the benefits and you might not immediately see them you have lots of time. And so, I think that those are factors that come into play.
Lior Boguslavski
And what was the most surprising part of this research?
Alison Duncan
I can't really say that, like I had any surprises, which I'm glad about because it meant that we pre-conceived challenges because that's a lot of research. But I will note that it's you know, the pandemic was a surprise. It disrupted this study like you know, human clinical trials, probably for a few years to come are going to have a footnote about COVID-19 pandemic disruption.
Michael Lim
So, kind of looking to that answer if you go back in time and change one thing other than stopping COVID from the spread around the world. What would it be and why?
Alison Duncan
Yeah, I can't think of anything that I would change. I feel like we put so much effort into this study and thinking about every possible challenge and mitigating it so I feel confident and we did all that we could. In terms of what we're doing next. We actually still have samples that are being analyzed by our collaborators at the Guelph Research and Development Centreby Dr. Dan Ramdath’s lab and they're looking at the fecal samples that we had the participants collect. They're looking at measuring different things in the fecal samples to examine potential mechanisms by which the cholesterol was lowered. So, that's like what's happening next for this work.
Michael Lim
And now we're gonna take questions from social media. So, we already want to ask our first question.
Lior Boguslavski
Do you have a recommended way to introduce beans into a diet? Is there an upper limit for how many servings of beans can be consumed within a week?
Alison Duncan
Okay, so I mean, it's encouraging people are asking about the upper limit. I think that you know, you're probably, you're probably going to meet your limit just by natural like, I don't, I'm not aware of like toxicity like six cans or something like there's no probably thing to just consume some beans at this point. And in terms of introducing them, what I would recommend is in moderation slowly because you can have side effects and beans that are related to flatulence and gastrointestinal reaction. That will go away once you're used to them. So, I would just recommend checking out some recipes or ... really all I do is I just eat them [crosstalk] but I just have like a little tiny little container and I just put like I just fill it with beans and canned beans that I've drained and rinsed. And they're quite filling pretty much every day I have beans and tortilla with some grated cheese and warm it up and I'm completely full.
Michael Lim
Our next question asks: Beans are well known for their quote unquote, adverse gastrointestinal outcomes, or I guess, you know, much less. Is there a way to prepare beans that reduce that and does that affect the health benefits of the beans provided?
Alison Duncan
Yeah, so in this study, actually, we monitor those symptoms over time with the half cup in the one cup. And we're working on analyzing those data to publish them. But in terms of that, that's correct. That can happen and I think it varies by person. In terms of what your background I already was, but definitely graduated amounts is the best way to handle it. There is not evidence that I'm aware of that that would alter the health effects of the beans. And so, I think it's more revealing like the beans are kind of doing their job. [laughter] more like that they were working [Micheal Lim] so the flatulence was good. It means that it's working. [Alison Duncan] Accept that it's part of our society. I mean, if you're, if you're a child, that's like comic relief, right there.
Michael Lim
Spread some joy in your home.
Alison Duncan
That's right. And they do "Oh, they have called beans the musical, the music... [Michael Lim] "Oh, yes. The musical fruit. [laughter, Alison Duncan] It's not a fruit though that's why I said I don't know why? [laughter] The musical bean.
Lior Boguslavski
So, going off of that, are there no notable health differences between fresh dried and canned beans? And can anything be done in terms of how they're cooked to reduce these differences if there are any, and does it depend on the type of bean or brand as well?
Alison Duncan
Yeah, that's lots of questions. So basically, there have been some demonstrated very minor nutritional differences between dried and canned primarily related to the folate content, but the significance of it is not a rationale to choose the dry beans over the canned beans. Canned beans also can be higher in sodium but that can be mitigated by buying low sodium versions. And also, draining and rinsing. Ontario bean growers actually has resources on how to best strain and rinse but the longer the better is essentially the way to go. And it hasn't really shown to alter the health effects.
Michael Lim
Otherwise, as long as you eat the beans, it doesn't matter how you do it. Doesn't matter what type. Just get the beans in you. Do you have any final comments to make about your work and if we are only to take away one thing from our chat today? What do you hope that it is?
Alison Duncan
Well, I think final comments I just want to show how grateful I am or like say how grateful I am to everyone involved. The University of Guelph, the graduate students, the collaborators, the funders and the participants. I think that's my final comments. And then in terms of what I want people to take away. I think, just the general idea that we have a lot to learn from nutrition research that can change our lives for the better. That would be my message. If I start saying names of people that I'm grateful to. We'd have to extend for a long time but for this study I'm grateful to so many people. Kati Doma’s a PhD student on this work and you know her and I email back and forth I'd say my email when I go to email during this time of this study, it will be caught in my husband's name that came up and I think Kati won out on that. And Karen Dolinar is a MSc student and so we worked really closely and had a lot of fun. And of course this was a multicenter study and we had a group of researchers led by Dr. Tom Wolever, at INQUIS, a research center in Toronto, so all of the people there and I already mentioned Dan Ramdath and Dion Lepp works with him. There's - there's so many people.
Michael Lim
Lior, do you have any final dying questions you really want to get out of Dr. Duncan?
Lior Boguslavski
I think the bean literature's just so fascinating. Do you see yourself continuing to do research in the long term, like for, you know, the bean literature or do you see yourself branching into other health foods and other nutrition sort of areas besides beans like letting beans rest for a second?
Alison Duncan
Oh, I can never let beans rest. So, I'm definitely interested in in all of the above of what you just said. All of the above.
Michael Lim
On that positive note, that brings us to the end of today's podcast. A big thanks again to our guest, Dr. Alison Duncan, for joining us today. Gryphon CAST is brought to you by your hosts, Lior Boguslavski and me, Michael Lim. Editing assistance from Ian Smith. If you're hoping to learn more about different science topics, please check out Scribe Research highlights. That's S-C-R-I-B-E scribe research highlights on the University of Guelph website at uoguelph.ca or you can follow us on social media at @UofGCBS. You can find us on Instagram, Twitter, and Facebook. Music in the podcast comes from uppbeat.io. They'll be details in the show notes and until next time please stay curious.