Episode Transcript
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Welcome to Nutrition For Mortals, the podcast that says life is too damn short to spend your time and attention worrying about your food choices.
So let's take a deep breath and then join us, two registered dietitians and friends, as we explore the world of nutrition with a special focus on cultivating a healthy and peaceful relationship with food.
My name is Matt Priven and I am joined, as always, by my co-host and the best dietitian on planet Earth, Jen Baum.
Hey, Matt.
And just a quick reminder, if you would like to support the show, we do have a Patreon where we do an extra bonus episode every month.
As always, a portion of our Patreon goes to support The Hunger Project, which is a fabulous organization.
And we're also real live dietitians in practice.
And so if you or anyone you know has ever been interested in or thought about working with a dietitian, you can always reach out to us.
And you can find us at oceansidenutrition.com.
So let's get into it, Jen.
Yeah, and so Matt, why don't you set up today's episode a little bit for our listeners?
Okay, so today we're gonna be continuing our chat about personalized nutrition.
Is nutrition something we can generalize about when giving recommendations?
Or is everyone a special unique snowflake that needs their own magic combination of nutrients delivered in endlessly complex combinations in different ways?
And so, you know, many businesses are betting on the latter or they're at least trying to sell this idea to us.
So we're taking a look at the state of the science with personalized nutrition.
And in our last episode, we talked about personalizing your nutrition around the population of microorganisms that make up your gut microbiome.
And we talked about some of the direct to consumer products that are being marketed currently, how much faith we should have in them.
And today, we're gonna turn our attention to genetics.
So should we be using the information about our genes to inform how we eat?
Yeah, and this was another episode where I got to have the listener experience.
You had a fabulous one-on-one interview with our special guest, Dr. Lara Hyde.
And so everybody knows Dr. Lara Hyde is a nutritional biochemist with a PhD in biochemical and molecular nutrition.
She's an adjunct instructor at the Tufts Friedman School of Nutrition Science and Policy and creator of the wonderful YouTube channel, Nourishable.
So I got to have a chat with Lara today about what's called Nutrigenetics.
And so we talk about what's the state of the science, what are companies offering to us, what promises are being made.
Lara shares her own experience with testing out these products, shares her thoughts.
And we even get a little philosophical talking about free will versus determinism when we ponder these implications of how a knowledge of our genetic predisposition can change our experience of life.
So we really get into it.
I'm excited to share this conversation with you.
Yeah, I was sad to miss this one, but I am super excited to listen along.
Well, let's jump in.
Dr. Lara Hyde, welcome back to the show.
It's wonderful to be back.
So there are a lot of promises being made these days about how genetics can inform your eating decisions.
And we're gonna talk all about it today.
Now, this is an area often called nutrigenetics.
So let's start with Lara, what the heck is nutrigenetics?
Great question.
It is a very active area of research.
Essentially, what nutrigenetics is, is looking at how different versions of your genes can interact with your environment, like your diet, to impact how your body is functioning.
So I'll give you an example, a classic example, is variance in a certain gene can prevent the body from breaking down the amino acid phenylalanine.
This can lead to really high toxic levels in the body.
So for people who have variance in this gene, they need to really try and reduce the amount of phenylalanine in their body so that they're not having these toxic effects.
This is a condition called phenylketonuria, or PKU, which may be something that you have heard of before.
If you've been out in the world and looking at cans of diet soda, you may have seen warnings about aspartame for people with PKU, and that's because aspartame is actually made with the amino acid phenylalanine.
So if people have PKU, they need to avoid aspartame because it could lead to really high toxic levels in their blood.
Yeah, so that's a really great example of the relationship between one's genetics and how they're gonna eat throughout their life.
And that's a really extreme example because it can be very dangerous for somebody with PKU to ingest a lot of phenylalanine.
In this personalized nutrition space that we're starting to talk about today, where there are gonna be companies offering tests to see the quote unquote right or wrong way you should be eating for your genetics, it's gonna be a little different, right?
Because for PKU, I mean, that's diagnosed in birth, right?
We know almost instantly whether somebody has PKU.
Am I remembering that correctly?
Yes, absolutely.
Testing for PKU is something that is done right after an infant is born.
And the reason that that is done is because it is so critical to make sure that you manage the amount of phenylalanine that an infant consumes to prevent the toxic effects of PKU.
So yes, this is a pretty extreme example that really ends up being a major driver of how an individual would eat over the course of their whole lifetime.
So what is an example of nutrigenetics applied to one's lifestyle in a less extreme way?
Like if we were to give a nutrition recommendation based on one's genetics to somebody who doesn't have a life-threatening condition, at least acutely life-threatening, what would be an example of that?
Certainly.
So there's been a lot of research in nutrigenetics that are looking at more nuanced differences in how a body is functioning.
So I'll give you an example.
There are variants in a certain gene called APOA1.
APOA1 is a gene that plays a really important role in how your good cholesterol, your HDL cholesterol functions in your body.
And people who have different versions of this APOA1 gene can end up having different levels of HDL cholesterol, either higher levels of this good cholesterol or lower levels of this good cholesterol.
And there have been studies showing that for people who have a certain variant in this APOA1 gene, when they eat a lower amount of polyunsaturated fatty acids in their diet, so those are things like your omega-6s and your omega-3 fats, they still have really high levels of the good HDL cholesterol.
So this is an example of how a gene variant can interact with your diet to impact how your body is functioning.
Yeah, that's so cool.
So there's going to be these differences between individuals that can, I guess, inform the way that nutrition information should be interpreted, right?
Like certain people are going to say, oh, well, my genetic variants point to the fact that I maybe need to be a little more concerned about this and less concerned about that.
And we're not giving any specific recommendations here, at least yet, but this points to this idea that there's a lot we're about to learn about the role of genetics and nutrition.
So before we really dig into the state of the current science, I just want to know if we're going to embrace this idea of futurism and science fiction, what would be like the really exciting best case scenarios here when it comes to eating based on our genetics?
Well, I think that there could be a future where we could look at all the different gene variants that can influence your risk of developing chronic diseases and that can impact how your body responds to food to identify what the healthiest dietary pattern is for you.
And that could take into consideration how your metabolism responds to, say, saturated fat or protein to, in turn, have a healthier metabolism that lowers your risk of chronic disease.
So I think that there could be a future where that happens.
That future could also integrate things like genetic variants that influence your taste preferences.
So there are certain genetic variants that influence how strongly you can taste bitter flavors.
And so for some people with those genetic variants, they really dislike bitter foods like Brussels sprouts, for example.
So there could also be, I envision a future where you could have an understanding of perhaps some of the genetic predisposition to your taste preferences.
And in turn, perhaps there could be suggestions on how to prepare bitter tasting foods in ways that are less bitter.
Like maybe you really like your Brussels sprouts roasted because it tamps down the bitterness.
So I think there are potentials in the future where we can integrate together how your body may respond to food and preferences to help tailor a healthy dietary pattern for you.
I think a lot of people start to translate these ideas into, oh, maybe there'll be some machine that just like creates a little pill that's like the perfect formulation of nutrition for my body.
You know, this sort of like Jetsons era version of nutrition, which I think is cool to think about, but what you're mentioning are more, you know, like adjustments to how you're gonna prepare food in your kitchen.
It's pretty pedestrian, which I think is an interesting idea that, you know, all of this information, we can have a spreadsheet with your whole genome and it's gonna boil down to like how you're gonna roast your Brussels sprouts.
I like that, I'm comforted by that idea that this is not going to make food an entirely different experience.
It's just gonna help us take care of ourselves and enjoy our food more.
I like that feature, thank you.
Right, and I think that eating all your food in a pill form would be really sad.
I love having dinner parties and enjoying my food with loved ones.
And I hope that that's something that, you know, really continues to be a part of our culture.
Yeah, so let's try to understand how we get from a big spreadsheet with the data of your genome into nutrition information.
How are we doing that exactly?
Can you explain this translation process of a person's genome into nutrition recommendations or information?
Certainly.
So there's a lot of research going on in this field right now.
And a lot of these studies are something called genome-wide association studies.
These are often abbreviated as GWAS.
So if you want to sound really cool at your next cocktail party, you can talk about GWAS.
But essentially what these are doing is looking at associations between gene variants and various health outcomes.
And so once researchers have identified these particular gene variants that are impacting, say, how your body responds to insulin, we can then take those gene variants and see if there are interactions with particular diets, dietary patterns.
So really they start off as these big population studies where we're, it's kind of like a big fishing expedition.
You're trying to see out of all the genes that exist, are there any variants that are popping up as being important for the particular health outcome we're looking at.
Now I want to point out that these are associations and of course we know that correlation is not causation.
So it's a lot of hypothesis generation.
Yeah, that's really important to point out.
And can you give us the scope of the genome?
Like when we're fishing, how big is the water we're fishing in?
It is a big, huge, giant ocean.
So the human genome has about 3 billion base pairs in it.
Base pairs are the individual letters.
So you may have heard of the genome is made up of A's, T's, C's and G's.
So 3 billion letters in the genome alphabet.
And those are in turn are generally organized into about 30,000 genes, plus a bunch of stuff in between the genes.
Wow.
Okay.
And we're looking at these genes and we're looking at specific variants.
So that kind of adds to the complexity too.
It's not just looking at the gene, it's saying which variant does an individual have compared to another, right?
Exactly.
And when I'm talking about a variant in this case, typically I'm talking about a change in one letter in the gene.
This is called a single nucleotide polymorphism or SNP.
And so what a SNP is, is a one letter difference in a gene.
And that one letter difference, it could maybe impact how that gene is functioning when it turns into a protein, or it could impact perhaps how much of that gene is turned into protein when the gene is turned on.
So the idea here is that a one letter change in the gene can in turn impact how it functions in the body.
Can you give us another example of a single nucleotide polymorphism, a SNP, a variant that leads to a significant change in how we experience the world?
Yes, okay.
So there are variants that exist in a gene called CYP1A2.
So the gene CYP1A2 produces an enzyme that is responsible for breaking down caffeine.
Now, when you drink a cup of coffee, the caffeine travels through your bloodstream, it goes to your liver, and this enzyme in the liver will break down the caffeine.
Now, there can be single nucleotide polymorphisms, changes in one letter in the CYP1A2 gene, that can make that enzyme more sluggish and function more slowly.
What that means is that when you drink a cup of coffee, the caffeine will be broken down more slowly, and you may be feeling the effects of the caffeine for longer, because your body's just slower at breaking it down.
That's a great example.
And that's interesting too, because it is explained by a SNP, a mutation, a variant, we'll use the same word, I'll just say all the words, but ultimately it comes down to a felt sense of how caffeinated you are.
So this is something where you can kind of feel this variant within you.
Hypothetically, yes.
Now the reason I say hypothetically is, this is actually a gene variant that I know that I carry.
And so I am genetically a slow metabolizer of caffeine.
And there have been studies showing that people who are genetically slow metabolizers of caffeine, they tend to not like coffee very much because it makes them feel really jittery because their bodies are processing the caffeine more slowly and they feel really jittery from the caffeine.
That is not my experience.
I love coffee.
I drink lots of it and I'm drinking some right now.
So I find in my experience, I don't feel jittery from coffee.
And in turn, it's something that plays a pretty regular part of my dietary pattern every day.
That's such a good way to clarify.
So even though you have this information about your genetic variant, it doesn't really, the story that we're telling people doesn't really line up with your felt experience.
Right, exactly.
And there are lots of examples of that.
I guess another way to look at it is how clinically meaningful is a genetic variant in your health or in your experience.
And so for me, I don't feel the impact of that genetic variant in how I experience caffeine.
Now, is it possible that perhaps I might have other health outcomes due to high consumption of caffeine given that I'm a slow metabolizer?
There's some evidence to suggest maybe.
There's some evidence showing that for people who are slow metabolizers of caffeine and who also drink a lot of coffee, that they may have a higher risk of developing high blood pressure later on in life.
Maybe.
Maybe, yeah.
Okay, so it sounds like you're taking this with a grain of salt.
And could you speak a little bit to why that is?
Yes, absolutely.
So I'm definitely taking this one with a grain of salt, also thrown in with maybe a little bit of bias because I love caffeine so much.
Sure, it's a good bias to have.
But I also think that when looking at other nutrigenetic associations, it's really important to be able to differentiate between something that is statistically significant versus functionally relevant.
And so when I say functionally relevant or clinically relevant, I'm meaning does it actually make a difference in your health?
Yeah, so that makes a lot of sense.
And so it sounds like you've taken at least one nutrigenetics test.
I wonder if we could just step away from the science for a second.
Just I'd love to hear your experience interacting with these tests.
Absolutely.
So I did a test called GenoPalate.
And so this is a nutrigenetics test where you can send in a sample of DNA to be genotyped, or you could also submit your genotype data from other companies.
So if you've done something like 23andMe or Ancestry, you can submit your DNA results from those tests to GenoPalate.
And then what GenoPalate does is they look at 150 different genetic variants.
And based on those genetic variants, they will make nutrition recommendations for you.
And you also get a free 20-minute consultation with a dietitian to review your genetic results.
Okay, thank you.
So I'd like to dig into your experience with this because I want, first of all, this is not a paid advertisement for GenoPalate.
I want to be very honest about what this experience is like for folks and how much faith we should have in things like their interpretation of your genetic information or the types of nutrition recommendations that follow.
And so could you just tell us a little bit first about what information was given to you by GenoPalate in your results?
Certainly.
So there were three categories that underlie the nutrition recommendations.
The first category were macronutrient recommendations.
So essentially recommendations on what proportion of my diet should come from fat, protein, carbs, and like within that, you know, should I consume higher levels of certain types of fats like monounsaturated fats versus saturated fats.
The second category are specific vitamins and minerals.
So really looking at the micronutrients that we consume in very tiny amounts.
And then the third category are sensitivities.
So things like the caffeine sensitivity that we spoke about earlier.
Okay, so macro, micro, and then sensitivities.
So can we talk macro for a sec?
I'd love to know how are they even coming up with an idea for whether somebody should be leaning towards a more high versus low carbohydrate eating style or high versus low protein?
And how are they encouraging folks to think about distribution of macronutrients, protein, carbs, and fat through the genetic information?
Great question.
So essentially what my experience with looking through the GenoPalate data was that they would identify a particular variant and tie it back to a study showing that people who have my particular genetic variant responded in this way to a higher fat diet or a higher protein diet.
Now I'm gonna get into the weeds just a little bit here for a second because it's really important for how we interpret how meaningful these associations are.
Many of these associations were coming from studies that had been done previously looking at, for example, weight loss.
There was a very large weight loss study that was done called the Pounds Lost Study where participants were randomized into four different diets, high fat, low fat, high protein or low protein.
And they were randomized to these diets for two years.
And at the end of the study, the researchers found didn't matter which diet you were randomized to.
There were no differences in how much weight was lost across those four different dietary patterns.
But then when the researchers looked at how individuals responded to each of those dietary patterns, there was a lot of variability.
So after they finished the study, they looked back to say, okay, are there maybe different gene variants that are influencing how people are responding to a diet?
And so that's where a lot of the associations were coming from in my GenoPalate recommendations.
It was from looking back at this study and saying, oh, for the people who responded more to the high protein diet, they had these certain gene variants versus people who responded more to the low carb diet, they had these other gene variants.
And when I say respond, this could be things like they had better insulin sensitivity or they had lower levels of the bad LDL cholesterol or in some cases, they lost more weight.
Okay, that's fascinating.
And I think that that's important you brought that up, because the results of that post-hoc analysis, I think this was a seed was planted here and a lot of different flowers bloomed in the form of companies that are making promises for weight loss based on genetic information.
So I'd love you to keep talking about what we do when we see that type of association in outcomes like weight loss in the pounds loss trial.
And what is the next step for science when we have that information?
Certainly.
So in this case, I feel like a lot of the associations are great at generating hypotheses.
But as a scientist, what I would want to know is should DNA be used to tell me how to eat in order to change my health outcomes?
And so what I would want to see is an intervention study that says, based on your genetics, we are going to recommend a particular dietary pattern to you and see what happens to your health.
Is a lot of the marketing for these direct-to-consumer tests about the impact of your genetic information on weight loss?
Because we talk about it all the time on the show.
You know, weight loss is really the lever that gets pulled by companies to sell products to people.
You know, we can look at things like insulin sensitivity or HDL or LDL cholesterol, but at the end of the day, the marketing is almost entirely weight-focused because of the culture we're swimming in, right?
And so, is that the case in this genetic world too with the products that you've seen?
I have noticed that there is a fair bit of marketing that is directed at weight loss.
There's also other marketing that's really directed at eating for your DNA to be the healthiest version of yourself.
And I think that there's kind of problems in both of those framings, because in my opinion, the evidence is not there that this really makes a big difference.
Okay, all right, cool.
So let's move on to micronutrients.
So this is kind of fun.
I mean, I love talking vitamins and minerals.
And so what did you learn from your GenoPalate data?
And I guess, what are you willing to share?
I mean, this is your personal genetic information.
So don't let me ask you something you're not comfortable sharing.
Absolutely.
And you know, I'm really glad you brought that up because something that I think is really important to think about before you do a nutrigenetic test or any type of test where you're getting your DNA sequenced is recognizing that while you may be consenting to creating this data set of your genes, that that is also revealing information about your family members, your currently living family members, and your even potential future offspring who don't exist yet because we do share genetics with our family members.
So think about that before you do a genetic test and also to think carefully about whether your family members want you to share the information that you learn with them or not.
So those are some really important things to consider.
I know in our episode today, I've disclosed that I am a slow caffeine metabolizer and I've previously spoken with family members of like, yep, we feel comfortable sharing that.
But otherwise in general, I'm actually being intentionally vague when I talk about which genetic variants I have in order to respect my own privacy and also the privacy of my family members.
Wow, that is so interesting.
So you've really thought through this, huh?
It sounds like you've spent a lot of time considering the moral implications of what these results mean.
Absolutely.
And I think this can be especially important when looking at other genetic variants that can be really strong predictors of disease.
So for example, there's a genetic variant called APOE4.
There's different versions of this gene that can increase your risk, your predisposition to developing Alzheimer's disease.
And Alzheimer's disease is pretty scary.
So I think that it's really important to decide whether you want to know that information about yourself and whether you want to share that information with your family members.
In my opinion, it also often comes down to is there something actionable that you can do about that information?
But at the same time, there are some people who may feel that learning about their genetic predispositions actually makes them more pessimistic and feel like there's nothing they can do.
So I think there's quite a lot of variability in how people respond to receiving genetic information.
And so that's why I think there really needs to be a lot of thought before you do a test and how you decide to disclose your information.
And that's even without getting into questions surrounding security.
That's so fascinating.
Let's put a pin in this idea of how people respond to learning about their genetic information.
I'd like to come back to that.
But let's talk about micronutrients just generally.
What do we know about how one should or shouldn't eat based on their genetics from the perspective of maintaining healthy levels of vitamins and minerals?
Great question.
What I noticed when I was reviewing my GenoPalate results and specifically looking at the references that were used to support the nutrition recommendations for me, I noticed that many of the studies were looking at an association between a gene variant and levels of that vitamin in the blood.
So for example, they tested for a gene variant that is associated with having higher or lower levels of vitamin C in your blood.
Now, based on associations with a gene variant and lower levels of vitamin C, that could then lead to a recommendation to consume more vitamin C.
Where my brain went with this is, oh, but how do I know if consuming more vitamin C would actually increase the vitamin C levels in my blood?
I don't know that.
I also don't know if, does it matter for my health if I have a slightly higher or slightly lower level of vitamin C in my blood?
So those are some of my questions that I felt were unanswered by the evidence that was being referenced for this particular nutrition recommendations.
Even in a world where you could titrate your vitamin C intake up or down based on the actual information, like how much circulating vitamin C you have, you mentioned that you still want to know that that's going to make a meaningful impact on your health.
You're not just doing it for the sake of doing it.
You want to know that this is going to have an impact.
Exactly.
And I think when we're navigating the world of nutrition guidance, I think it's really important to focus on what matters most, because we could get really bogged down with trying to eat perfectly in all the different ways and track everything.
And I think that actually has more of a risk of distorting your relationship with food and in turn leading to negative health outcomes, whereas I feel like I'm not really convinced that this extreme detail is really necessary based on meaningful health outcomes.
Yeah, and if that's hard for you to discern, that's definitely going to be hard for the average person to discern.
And a lot of people are going to see their results from a test like this and they're going to say, oh gosh, I got to focus on my vitamin C intake really specifically.
And this is going to occupy a big part of their thinking when it comes to nutrition, but it might have an almost insignificant impact on their actual health.
So that's really important to point out.
I want to turn our attention to the third category of your GenoPalate results, which was sensitivities.
And just to be clear, we're not talking about food sensitivities here in the classic IgG food sensitivity tests that we talked about in the past episode.
What we're talking about with genetics here is more like the caffeine example from earlier, right?
Do you have a genetic variant for fast or slow caffeine metabolism?
So, can you let us know some of the other sensitivities that are looked at with these tests?
Certainly.
So, there were four different sensitivities that were looked at in the GenoPalate test, and it was alcohol sensitivity, and that is essentially looking at variants in enzymes that are responsible for breaking down alcohol.
So, are you a fast metabolizer of alcohol or a slow metabolizer of alcohol?
And that can be important because if you're a slow metabolizer, what that means is that the toxic breakdown products of alcohol end up floating around for longer in your body.
So, that was one of the sensitivities that was looked at.
So, we've mentioned caffeine already.
There was also a sensitivity for lactose, so lactose intolerance, and that one can definitely make a pretty big difference in how you experience food if you are lactose intolerant.
And then, the final one was gluten sensitivity, which is also actually a genetic variant that I have some questions about whether this is something that should be really disclosed to customers in a direct-to-consumer fashion.
Oh, let's talk about that, because we live in a world where so many people are encouraged to go gluten free for vague reasons, having nothing to do with celiac disease.
And so it sounds like this is a space where people might get an elevated alarm that they need to avoid gluten because of some genetic information that may or may not actually impact their health.
Am I reading into this correctly?
Absolutely.
Oh my goodness, I have so many thoughts on this.
So in order to have celiac disease, you have to have one of these two genetic variants.
They're called HLA-DQ2 or HLA-DQ8.
Scientists need better naming conventions.
But essentially in order to have celiac disease, you have to have one of those two genetic variants.
However, having those genetic variants does not mean you absolutely will get celiac disease.
Only about 3% of people who have those genetic variants end up developing celiac disease.
So knowing just the genetics doesn't tell you that you have celiac disease.
So that's part one.
Part two is that there's another less understood condition called non-celiac gluten sensitivity.
And it turns out that there is not a relationship between having these celiac disease genes and having non-celiac gluten sensitivity.
So my concern with direct to consumer tests that will tell an individual that they have one of these celiac disease genes is that it may make them afraid of gluten, even if they tolerate it just fine.
And so when we look at our current world where there is a lot of fear about gluten, I get worried that hearing that you have a genetic variant related to celiac disease may make you even more fearful of gluten and perhaps end up eliminating very nutrient dense whole grain foods from your diet unnecessarily.
Yeah, that's a really important point to make.
And so we've gone through the type of results that you'd get from a test like GenoPalate that talks about your macronutrients, your micronutrients and your sensitivities.
And it sounds like there's differences in these types of recommendations.
Some are really specific, like how good are you at metabolizing alcohol?
And then some seem really complex, like they're based on your lifetime risk of a certain health outcome, right?
And so isn't that strange that there's sort of both baked into these results?
Yeah, I think there is.
I think one of the feelings I had was when I looked across all my recommendations, I had the question of what is the most important?
Like if I'm going to make a quote-unquote evidence-based change to my diet, what is the most important thing for me to focus on?
And I felt like I couldn't really get a sense of that from my recommendations.
And to dive into this just a little bit more, when I was looking at the various profile of gene variance I carry and how that led to, say, a particular recommendation to consume a lower fat diet, what I noticed is that each gene variant may make a slightly different recommendation.
Maybe I have some gene variants that say, oh, I would respond better in my metabolism to a high fat diet, but in weight loss to a low fat diet, for example.
But then ultimately all those different variants get turned into one overall recommendation.
And I didn't have a good understanding of how those different variants are weighted.
Are some more important than others?
Are some health outcomes more important than others?
I guess I had trouble really believing my recommendations because I didn't understand the nuts and bolts of how they were synthesized together across all the different variants that I have.
I think I would feel the same way.
I think another thought I would have is, over my lifetime or let's say over the next 20 years, are we going to see new associations and a thousand more variants that are going to be factored into these recommendations and change how I should or shouldn't be eating in a significant way?
My concern is also not that they're going to encourage them to eat more or less vitamin C, but that they're going to lead to more worry about food, more restrictive eating, more hyper fixation on good or bad foods.
And so I think that's the ultimate outcome for so many people is it puts a significant strain on our relationship with food, and I don't see how this test is any different.
I definitely agree with you there.
And so I think with all of these tests, it's always important to look at what are the benefits and the benefits would need to be evidence-based.
We've talked today about how, you know, it doesn't really seem like there's a strong evidence base for the benefits.
Then we also need to look at the harms.
So we've identified some harms in your relationship with food.
I think there also could be some other harms that I would love to talk to you about in relation to some genetic variants that were shared that may predispose you to certain eating behaviors.
Ooh, tell me everything.
So one of the other types of data that GenoPalate provides is something called an Eating Insights Report.
And what this does is it reports on certain genetic variants that have been associated with different types of eating patterns.
So for example, overeating or excessive snacking.
Now, how would you respond if I told you, Matt, you carry a gene for excessive snacking?
Yeah, it's almost like going to a fortune teller and they make a declarative statement about your life.
Some people are going to go, wow, how did you know that?
And other people are going to go, this person's full of crap, right?
So it's going to be interpreted differently, but it's going to change my reality from that point forward.
Yes, that's my concern is that it could change your mindset.
And there is some data to suggest that that's a thing that happens when you receive genetic information.
So there was a study that was done where participants were genotyped for variants that impact their cardiorespiratory fitness, so how well they run on a treadmill, for example, and other gene variants that impact their satiety, so how full and satisfied they feel when eating a meal.
So in this study, participants were genotyped for these gene variants, and they put them on a treadmill test to see how well they ran on the treadmill, and they asked them to eat a meal and rate their satiety.
Then several weeks later, they said, oh, hey, guess what, here's what your genetics say about you, but they actually randomized.
They said they told some people that they were predisposed to having poor cardiorespiratory fitness, even though maybe they had great cardiorespiratory fitness based on their genes, and they had to come back once they were told their fake genetic results, and then they had them run on a treadmill.
And for the people who were told that they had genetics for poor cardiorespiratory fitness, they actually performed more poorly on the treadmill test, even if they had good genes for it.
Whoa.
Wow.
I was not ready for that.
That is so interesting.
So this is not a nutrition study.
This is a psychology study.
Yeah.
Yeah.
They also found something similar with the satiety tests.
So they found that when they told people, oh, you have genes that predispose you to very low satiety when you eat a meal.
When they had those participants then eat a meal, they all rated their satiety as much lower and even had lower levels of certain satiety-inducing hormones like GLP-1 in their blood.
So it seems like the mindset may also be changing your physiology.
Oh my gosh.
So this is really, you know, we talk in nutrition research all the time about the placebo, but this is a step further.
This is asking questions about free will versus determinism and fatalism that we never really get into in nutrition research that I'm just finding so fascinating.
So our genetics is a form of determinism, if you will, that takes our free will away for certain people.
But I would imagine it has a counterintuitive effect for others where if you tell them, okay, you are high risk for heart disease, they don't just go, oh, well, screw it then.
They really try to double down on hyper heart healthy eating and exercise.
I would imagine it kind of splits the population based on the type of person you are.
Yeah, I really agree with your opinion there.
I feel like there are some people who would respond in a very proactive, optimistic way, and other people who may respond in a more deterministic, kind of pessimistic way.
And I think what I took away from that treadmill and satiety study was really that your genes may play a predisposing factor in how your body functions, but that for some things, your mindset is even more powerful.
Absolutely.
And you know, when we start to talk about satiety, right?
Like I spend a lot of time in the principles of intuitive eating, right?
Which have a lot to do with connecting closely with what our body is telling us.
And what I'm hearing in a lot of the marketing for genetic tests that talk about these types of traits is this idea that your body already has predicted how closely you can connect with your internal cues.
It gives us this sense that it's not work that we can do.
It's almost saying this is all predetermined.
And so you don't really have any agency here.
And it really undercuts a lot of the work I've seen be so impactful for people.
So it does bring up some frustration in me to think that people are going to point to genetics as the explanation for one's relationship with their internal cues.
Right, absolutely.
And from my assessment of the literature, it seems like those genetic predispositions play a pretty small role, whereas other behavioral factors and some of the mindfulness training plays a much larger role in determining feedback like satiety.
And so, you know, I would be concerned that a harm of learning this information and doing these tests is feeling like you're genetically predetermined and, as you say, lose agency, whereas, in fact, the behavioral steps that you can take can play a much larger, more impactful role.
Love it.
Awesome.
We have some agency, we have some free will still, and, you know, I think that's a great place to end this conversation.
Lara, we could not have done these first two episodes about personalized nutrition without you.
I hope folks will join us next time in our third and final installment in this holy trinity of nerdiness where Jen and I will be discussing personalizing your nutrition based on your metabolic response to foods.
So, Lara, I want to sincerely thank you for joining us for these first two episodes.
My question is, will you join us again down the road when we need the services of a friendly nutritional biochemist?
I would be happy to be a long-term friend of the show because, as you now know, I love getting into the weeds.
Awesome.
And folks should definitely check out your wonderful YouTube channel, Nourishable.
We'll have a link in the show notes, and thanks again for joining us.
See you next time.
That was my pleasure.
Nutrition For Mortals is a production of Oceanside Nutrition, a real life nutrition counseling practice in beautiful Newburyport, Massachusetts, where we provide individual nutrition counseling, both in person and online via telehealth.
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