What follows is an edited transcript of my conversation with Dr. Chana Davis. (She joined me on episode 47 of my podcast.)
Dr. Chana Davis is a scientist with a PhD in genetics from Stanford University and 10 years of experience in cancer research and personalized medicine. She is a plant-based Vancouver mom of three who is passionate about sleuthing out and sharing science-based, plant-smart advice.
In this conversation, we discuss all things next generation plant-based burgers. What we mean by “next generation” is burgers like the Beyond Burger and the Impossible Burger, which are made to resemble meat in a lot of different ways. So, we're not talking about a good old bean burger here!
We're going to discuss whether these next generation vegan burgers are healthy (and the definition of healthy) and how they compare to beef in the environmental impact department. We'll discuss glyphosate, which is an ingredient in Roundup, within the context of these burgers, and how the Beyond and Impossible Burgers differ from each other.
Meat analogues like these are excellent sources of plant-based protein, but there's still a myth that surrounds this: that plant proteins are somehow incomplete proteins. So Chana is going to do some amazing bullshit-busting around this issue.
Also on the menu is the natural versus synthetic fallacy. Just because something is “natural” doesn't mean it's healthy. Some of the most toxic substances on the planet are completely natural and not manmade. Similarly, “organic” does not mean pesticide free. So you'll hear about the pesticides used in organic farming and their regulation – or lack thereof. Let's get to the interview.
Chana, are these next generation plant-based burgers healthy? I'm also interested in your definition of “healthy”, as it’s a very ill-defined term.
Chana: Oh boy, that is a big question. So what's in a Beyond Burger? A Beyond Burger is basically a blend. I kind of think of it as a vegan protein smoothie made from pea protein with a bunch of coconut oil, and canola oil, and then a few other flavours thrown in. Nutrient-wise, it has pros and cons.
It has a lot of good things going for it because it uses a pea protein isolate, so it has a lot of protein. It also matches the iron of meat, so it’s a great iron source. Beyond and Impossible designed their burgers so that you can't make the argument that they don’t provide enough iron.
Interestingly with Beyond, the iron number looks higher than beef per serving, but because it's non heme iron, it's not going to be absorbed as well. So in the end it sort of ends up being the same. I've talked to Pat [founder of Impossible Foods] about Impossible and I just assumed Beyond went through the same process: their goal is to recapitulate the entire sensory experience of meat. Its juiciness, its mouth feel, the way it cooks, all of that. But they also wanted to match some of the nutritional properties which they know consumers are looking for. They know consumers like meat because it's high protein. They know they like it because it's also an iron source.
To match the sensory experience, they had to add a lot of fat. They had to use saturated fats because saturated fats have different characteristics when cooked, and to get the same texture. So both companies use coconut oil in order to get their saturated fats. The Beyond Burger is actually a mix of coconut oil and canola oil, whereas the Impossible contains only coconut oil.
I know that Pat actually has it as a goal to dial back the saturated fats on the Impossible Burger a little bit, but they're constantly iterating and our current version is quite high in saturated fats. So nutritionally it's got some of the good things that beef has. It's got the protein and it's got the iron, but it also has some of the bad things that beef has, like saturated fat. They also share the downside of beef in that they're low in fiber, and it's because they used protein isolates and not the whole plants in order to get that protein super concentrated.
One other difference people often mention is that both the Beyond and Impossible burger have more sodium than some beef patties. But does that matter? We need to put all these numbers in context, and see what they mean for your health.
The plant-based burgers are a little bit higher in sodium, but we need to put that in perspective. So for the Beyond Burger, compared to different beef patties that you would buy at Costco, the Beyond Burger has about 300 milligrams more sodium. So what does 300 mean? You would actually have to eat five or six to be in the danger zone for sodium. The reality is, sodium wise, when you eat a burger, much more of the sodium is going to come from the fixings of the burger. So if you're just eating the burger patty it’s not an issue, but if you're eating the whole combo meal, then you're in trouble, but you're in trouble regardless of which path do you choose. So I think the patty is a smaller part of the sodium equation, so that doesn't really concern me.
Regarding fat content, Beyond Burgers and Impossible Burgers are quite high in saturated fat. They are not that different than ground beef with the raw numbers of saturated fat. So does that matter? The answer is we don't really know.
For one thing, the plant-based burgers are using coconut oil as a source of saturated fats rather than beef fat, and those are different types of saturated fats. They're both saturated, but there are different chain lengths. So in coconut oil you tend to have medium chain triglycerides – you’ve probably heard of MCT. The saturated chain links are different and we don't really know for sure what the implications of that are. Some studies will tell you that the coconut oils don't have the same downsides as the saturated fats derived from beef, but the reality is that all of the data is not totally conclusive. What I think people can agree on, in terms of saturated fats and health, is that in general it is a good thing to replace saturated fats in your diet with unsaturated fats, with polyunsaturated fats being actually the best replacement. So I think that both burger companies currently don't really have a huge fat advantage over beef. Maybe because of the coconut oil, but we don't really know enough for sure to say how meaningful that it's going to be.
So there's more research we need in that area.
Chana: Yes, more research is needed.
Let’s make sure are listeners are keeping in mind that nobody is eating just Beyond Burger patties and nothing else. That would be a problem! We’re looking at these patties in detail, but what we’re not doing is looking at what else we’re eating and how it fits in. What if everything else you’re eating is perfectly whole, plant-based foods and you have a Beyond Burger occasionally? Versus what if all you’re eating is Beyond Burgers for dinner every single day? Just a reminder of the importance of context.
My overarching conclusion on health is that these burgers are probably marginally better than beef, but not hugely better. You are actually best off eating a bean burger or eating a bowl of beans because they have fiber. I don't consider these patties a health food, but I also don't consider them to be toxic. It actually matters a lot more what the rest of your meal looks like. This is just one piece of the meal. Again, if you eat it kind of like a steak alongside a large salad, I'm fine with that meal. I've got no problem with that. But if it's going to make you go to A&W every day, and get that plus fries, then that's not a good thing.
It also depends on what you would be eating otherwise. So for someone who would normally be eating an A&W burger with beef and they're going to substitute in a Beyond patty, that's great. But for someone who is plant-based whole foods to start stopping by A&W because they carry Beyond Burgers, that's going to be a net negative.
That's a good way of putting it. So Ethan Brown, the founder of Beyond Meat, was saying in an article I read that the vast majority (93%) of customers eating Beyond burgers are not vegan. They’re switching up their protein sources mainly for the health and environmental reasons. So as we just discussed, the health reasons could go either way. There are so many variables here that could play into whether it's going to be a net positive or net negative for any individual. Can we touch on the environmental side to this? We’ve talked about the nutrition, but what about the environmental context?
That one is a no-brainer. I have the Beyond stats in front of me right now. So a Beyond Burger compared to a beef patty: 99% less water, 93% less land use, 90% fewer greenhouse gas emissions, and 46% less energy overall per patty. Wow. That's a pretty big difference. That is huge. I don't have the Impossible stats in front of me, but they are very similar.
Interesting. So it seems like the environmental reasons are actually a lot clearer than the health ones?
Yes. And in fact, that reflects the motivations. I know Pat personally. I don't know Ethan Brown personally, but I know Pat’s goal is to save the planet. He wants to save the planet and save the animals. I think from his perspective, as long as they’re health neutral, it's all good. It’s just a bonus to be able to benefit your health at the same time. I think the marketing team at Impossible would love to raise the health banner more than Pat is probably comfortable doing. Again, if you look at the Impossible website their mission is very clear. Pat wants to eliminate animal farming from the planet to make it a healthier planet and to reduce suffering.
What a good mission. A vegan superhero in action right there.
Yeah. I just love the way he expresses this. He says, “Animals are an extremely inefficient technology of turning plant matter into meat.” I think it'll be interesting to see how the definition of meat gets challenged, just the same way the differences with cheese and milk are being challenged.
That's a good point. So something that comes up a lot is the GMO versus non-GMO argument. The Beyond Burgers are not GMO, they don't have any genetically modified ingredients. For the Impossible burger that's different, right? And they are not organic. Something that has been coming up in my discussions with people is herbicide use, glyphosate in particular because these burgers are made with pea protein and a lot of those types of pulses and legumes are treated with glyphosate. It's a desiccant too, as well as herbicide. So what's your take on the safety of glyphosate?
Well, I have spent a lot of time looking at glyphosate safety, and particularly in the context of pea protein. I've also looked at some studies on glyphosate exposure and people who are eating organic versus people who are eating conventional. When you look at the urine of people who are eating conventional and that of people who are eating organic, you do see higher levels of glyphosate in circulation in the urine of people who are eating conventional. This is not surprising because you shouldn't be using glyphosate on organic crops, right?
But does the difference matter? Are the people that are eating conventional getting levels of glyphosate that are worrisome? It's very important that we understand at what level this becomes worrisome. With any chemical including water, including alcohol, including Tylenol, there is a level that is worrisome and we can put a number on that.
The differences in glyphosate levels are quite small. So this is an interesting exercise in the way you can frame things differently. So there's this one study that I'm talking about here in the conventional people, they had about two micrograms per liter of glyphosate in their urine, and the organic people had one microgram per liter. So you can either say it’s one microgram per liter higher, which I can tell you is not very much, or you can say it's double. So I think some people are going to tell you it’s double. Some people are going to tell you it's a tiny bit higher and that tiny bit is way, way, way below the safety limit.
So, what is the safety limit? There are three different safety limits: Chronic dietary toxicity, acute dietary toxicity (one massive dose), and chronic non-dietary toxicity for operators or people who work in the field.
For chronic dietary toxicity, the acceptable exposure is 0.5 milligrams per kilogram of your body weight. Let's look at this for the average person eating conventionally-grown food. Their levels were two microgram per liter of blood. So if you multiply that by five liters, you get 10 micrograms in their body. Say they weigh 70 kilograms, that means they had 0.1 micrograms per kilogram. But the limit is 0.5 milligrams. So milligrams means a thousand fold more than a microgram. So it's a 1,000 fold difference, taking into account a factor of 5x to account for exposure versus absorption.
Karina: So 1,000-fold less than the safety limit. Interesting. This is important information.
It’s really useful to have some actual numbers. So for chronic dietary toxicity, it’s 0.5 milligrams per kilogram of your weight. Acute dietary toxicity uses actually the same number of 0.5 milligrams per kilogram of body weight. But for the operators and workers, they recommend 0.1 milligrams per kilogram of body weight (from coming into contact with the product).
So I looked at a review paper that looked at urine studies on both consumers of conventional produce as well as workers in the field. There was one individual, one farmer, who really stood out above the rest. He was about 10-fold higher than everyone else. His number was 8% of the recommended maximum for chronic glyphosate exposure, so less than 10%, and he was about 10-fold higher than everyone else. So that was the one outlier. I definitely wouldn't bathe in this stuff, but I would not have any issues about eating it on a regular basis.
Do you know Desiree Nielsen? She’s a plant-based dietitian in BC, in Vancouver. She made a really good point that I think we should bring up more often: in most of the studies on the benefits of fruits and vegetables that we vegans like to celebrate, participants are eating conventionally-grown vegetables. There’s rarely a large population study of only organic vegetable eaters. So just bear that in mind. Most studies on the benefits of fruit and vegetable intake (including soy), are from conventionally grown foods
So how does glyphosate compare in toxicity to other substances? We might get into the idea of “natural” versus “synthetic”, but we know that organic produce can be grown with chemicals that are often higher in toxicity than others.
I've sort of stayed away from this debate because people get so religious about organic food. I don't want to get sucked in, but because I wrote an article about the safety of soy and had people responding by saying, “I totally agree, but only non-GM soy, right?”, I need to answer that.
So there's a number that's commonly used called the LD 50, and it's the lethal dose at which 50% of test subjects will die. So typically we're talking rats, but then you try and extrapolate from rats and mice to humans. So when we're assessing the toxicity of a given chemical, we can rank things from practically nontoxic to highly toxic.
The most toxic things only take a teeny tiny dose to kill you, and the most toxic thing on the list is botulism toxin. And so the LD 50 for botulism toxin is 0.001 milligrams per kilogram of your body weight, so you don't want to get near that stuff.
Next on the list is hydrogen cyanide which can be found in fruit pits, in trace amounts. But this is a natural substance. The next one on the list is aflatoxin from soil, fungus and moldy foods. The next, mycotoxin and then nicotine. All of the things on this list that are the most toxic are natural, right? One thing that drives me bananas is this belief that “natural” equals “safe” and that “manmade” equals “unsafe”.
So, what does organic mean? It does not mean pesticide free.
A lot of people just assume that organic means no pesticides. What organic actually means is that you can only use pesticides that are natural. We just discussed that some of the most potent chemicals on the planet are natural. Does the fact that organic uses only natural pesticides make you feel more comfortable? In fact, they’re actually less well-regulated because they’re natural.
Copper sulfate is an example of a natural fungicide that is extremely toxic, and in fact way more toxic than glyphosate. So where’s glyphosate on the list? Glyphosate actually ranks fairly nontoxic and is similar to ethanol. So the lethal dose is considered 5,600 milligrams per kilogram for the LD 50 and ethanol would be 7,000.
I've heard some people mention associations between glyphosate and things like cancer and Non-Hodgkin’s lymphoma and such. But then I also found a study that looked at 90,000 farm workers and their spouses in the States, over 20 years, and there was no association between glyphosate and Non-Hodgkin’s lymphoma or cancer.
Someone on social media mentioned this to me yesterday. The fact that jurors had ruled in favor of someone in this lawsuit. What happened if you put scientists on the jury? What would they have said? It's hard to say. I don't think they would actually be unanimous on that one. I think the data on Non-Hodgkin's lymphoma and glyphosate are not cut and dry. We don't really have the details yet.
One of the really interesting articles that I could share if you're interested involves an international regulatory body. I believe it was the European international regulatory body. All of the international assessments of glyphosate have come out in its favor as it being acceptable. The only national international report that I'm aware of that was sort of a red flag on glyphosate was a report in 2015 or 2016 that declared glyphosate as a potential carcinogen. Then this European report gets into a big discussion about why that body reached a different conclusion than the others have.
A lot of it comes down to the specific role of that body, that chemical governance body. They are much more focused on the question of “is there any toxic dose at all?” And not really at all on “are we seeing that toxic dose in the real world?” The reality is they are a rather conservative body. That group of experts reached one conclusion, whereas 10 years later with more data and an actual panel of experts in that field, others reached a different conclusion. A lot of why they reached different conclusions comes down to interpretation of the human data sets.
And I think a lot of what they think happened is that when you have human data sets that are observational, whether or not you believe the results are going to be influenced by your prior preconceptions going into it. And I think this group, they went into it already believing that it was carcinogenic. So they already believed they saw that in the data, whereas the other group went into it assuming it was not carcinogenic, and therefore they didn't see that in the data.
Unfortunately, there's a lack of controlled trials on this of course. So when you're looking at observational trials as I'm sure you know, you can usually see what you want to see. So a lot of it comes down to that, but again, I tend to agree with the more recent international regulatory bodies which have deemed it safe, and they're incorporating not only more data, but they're also incorporating the consideration of our actual exposures.
That's a really interesting point. I actually saw a study, unfortunately was an animal study, but they were looking into the differences between the effects of glyphosate its own versus the effects of Roundup, which is what it's in. Roundup contains a whole bunch of other ingredients. So there was this one study where the researchers actually found opposite effects when comparing glyphosate on its own versus Roundup, which is very interesting because like you just said, we have to look at it in the real world. It's kind of like the nutrition research, right? Looking at a Beyond Burger by itself versus your whole context of what else you're eating. It's a very similar kind of approach I think. So is there anything else that we've missed on the organic versus conventional topic?
On the organic discussion, the message I like to convey to people is let's separate all the different dimensions of this decision and treat them and evaluate them as objectively as we can. Health impact for you, health impact to the soil and the ecosystem, sustainability and ability to feed the planet. All of those are different dimensions and I think when we have these debates about this, we need to focus on one aspect at once.
I also think we need to look at it one product at a time. There's usually a go-to organic solution and a go-to non-organic solution. So you can say, “well what are the pros and cons of that individual crop?” It would be worth understanding what exactly are the organic farmers doing right versus what is the non-organic farmer doing. But the reality is the non-organic farmers are going to actually be more heavily regulated in terms of the safety profile of the herbicides they’re using.
That's super important to keep in mind. Now there's one more thing I wanted to touch on. So all of these burger products that we've been talking about, they are pretty decent sources of plant based protein. But there's still this myth that surrounds this: that plant proteins are somehow inferior or incomplete proteins. So I would love it if you could do some bullshit-busting around this for us.
It would be my pleasure! The origins of that myth come from the fact that meat tends to be more protein dense. The reality is you can meet your whole days’ worth of amino acid requirements from meat in less than a day's worth of food. You could meet it in two large steaks or something. I think I did the math - maybe it's like six eggs or something. You could meet your whole days’ worth of amino acid requirements. Plant eaters tend to spread their protein out throughout the day and not get it in massive chunks. So whereas a plant-based eater is going to get a little bit from each part of their day, it’s still going to add up and get them there.
But meats tend to be averaging maybe double on each amino acid that you need. Plants are giving you 100% to 150% and meats are giving you say 200% to 300%.
One quote that I like from my own article is that “calling plant based proteins incomplete is like calling milk an incomplete source of calcium because it takes more than one glass to meet your daily requirement.” The confusion is that you think you need to get your daily requirement in one meal. You need to get your daily requirement in one day and you will get there with plants as long as you eat enough total protein.
The reason you're going to get enough is because every plant uses the same 20 amino acids that animals do. They’re not missing any amino acids. The kernel of truth in it is that if you eat only rice, which many poor countries do, and you eat a lot of rice as your main nutrition, rice is low in lysine. It's not missing lysine, it's low in lysine. So if you wanted to make sure you have gotten enough lysine, you would have to eat a lot of rice. You would have to eat a little over 2000 calories’ worth of rice to get enough. Let's just say I'm on a rice-only diet. You can still get enough of every amino acid, you just have to eat a lot of it. But if that's all you're eating, you will be eating enough. It's just that if it's a low protein food, you're not going to get that total protein. If you only eat one food it can get dicey. If you’re eating balanced food, you’ll be fine.
Absolutely. And of course, as we talked about on the show before, protein needs are very different. There's no one RDA for people because it's based on your lifestyle and if you train or not, and what kind of training you do and all this kind of stuff. But I think the main point is, as long as you're hitting the protein that you need, you're good.
So to put some numbers on it, I believe that the lysine in rice is maybe 75% of what it would ideally be like. So each amino acid has a recommended daily intake per gram of protein. So you want to know for a gram protein, how much is there of each one? So I think many of them are going to be over 100% of what you need per gram of protein. In rice, the lysine is under what you would ideally have. But again if you eat enough of it, you'll still get there.
It is true that rice and beans do complement each other in that beans happen to be high in lysine, which is what rice is low in. And so adding a little beans means that you can overshoot your amino acids more easily. And similarly, the amino acid that's lowest in beans happens to be really high in grains. So they kind of are Yin and Yang, but you know, as much as that's true, I feel that perpetuating this notion of “you have to eat rice and beans together in order to get a complete protein”, it just makes it sound more complicated than it actually is. I mean, you're going to want to eat more than one food anyways. It makes veganism sound much more complicated than necessary. The general message of eating a variety of foods is going to solve all your problems.
If you only eat one food, you've got a lot of problems besides perfect balance. This is why the word “incomplete” is such a misnomer, because it makes people think that it's missing something. It’s just different levels, but it's not certainly not missing.
There's one more thing I just realized, circling back to Impossible versus Beyond. I wanted to mention a couple of differences between them. You mentioned that Beyond Burgers do not contain any genetically modified organisms. That is true. Impossible Burger is not GM free because they use genetic engineering to produce the heme binding protein, called leghemoglobin, and the reason they did that is that Pat's goal is to basically replace ground beef across the planet.
If your goal is to produce these at that kind of scale and you want to have as little planetary impact as possible, you need to do things in an efficient way. So he wants to get one specific protein out of soy. So all plants actually have heme in them, but very low amounts.
So they made that decision just to be practical. They wanted to not have to use tons and tons of soil, but they wanted to get this special protein as a plant-based source of heme. I think it's a very pragmatic decision. Also, Impossible did make a decision to match the zinc levels in beef and they also put in B12. They just want to make sure that people are getting what they need. Beyond has not added zinc and B12 but there's no reason they won't do that in the future.
I bet they will. Those are easy enough to get in the rest of your food too, so it doesn't all have to be one package. With B12 if, you have fortified milks, you're probably good. In terms of veganism though, this one is interesting. I'm happy to be able to speak a little bit on Pat's behalf on this one because I know this is a sort of an agonizing thing for him, because this heme protein and eating it in such high concentrations is novel. It’s in our food supply, we all eat it, but we don't eat it in those concentrations. The FDA was a bit hard on Impossible about giving them permission for their heme protein.
They wanted it to be recognized as a safe ingredient, but the FDA made them jump through quite a few hoops in order to get that safe label on their genetically modified heme ingredient. What they required them to do is animal testing. So they had to design some experiments, which I think they did in rats, and that was the only way to get approval. They just had no choice. Pat actually has a letter on the Impossible website that’s titled “The agonizing trade off we had to make”. I was in his lab for six years and he had a lot of focus in his lab on eliminating animal testing.
He had multiple people working on developing new techniques that would replace animal testing. He was very passionate about that and he was forced to use animal testing as the only way to get this ingredient approved (this heme is their secret sauce and the reason their burgers cook the way they do). I think it was very tough decision, but they had to go for the big picture.
Right, fair enough. That must have been really gut-wrenching and challenging for someone like that – a very principled individual. That's good to know. I think it's very interesting that you have this relationship with him; you've been in his lab and you can speak on his behalf about what he wants to do and what his mission is.
Chana, thank you so much for taking the time to be on our show today. Our conversation was awesome. I loved it. What’s the best way for our listeners to find you and your work online?
I would recommend either Instagram or Facebook for daily updates. I try to post something almost every day, Monday to Friday. And I also have a website where you can sign up for my weekly newsletter and which I provide some nutritional rambling on whatever topic I've been researching, as well as a recipe of the week.
Research references mentioned and used in this interview are available here.
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