Worth your salt? Genes, taste perception and salt sensitivity and you

This episode covers the topic of the role of salt sensitivity and salt taste perception.

Nutrigenetics is promises to revolutionize our approach to nutrition and health by tailoring dietary recommendations to our genetic makeup. Dr Leta Pilic delves into this fascinating field, focusing on how our genes affect our reaction to dietary salt and its impact on blood pressure. She embarked on a PhD journey to explore this topic, demonstrating a commitment to uncovering personalized nutrition strategies.

The connection between salt intake, blood pressure, and genetics is critical. Dr Pilic sheds light on the nuanced relationship between our genetic predispositions and how we process salt. This insight is key to developing more individualized nutrition plans, which could significantly improve health outcomes, especially concerning hypertension.

UK dietary guidelines suggest a maximum salt intake of 6 grams per day. However, she highlights the need for more tailored guidelines that take into account individual genetic sensitivities to salt. This raises important questions about the adequacy of current public health recommendations and the potential benefits of personalized nutrition advice.

The call for personalized dietary recommendations is compelling. Existing guidelines overlook genetic variations that could influence optimal salt intake for individuals. She advocates for a shift towards customized nutrition advice, which could lead to better health outcomes by considering each person's unique genetic profile.

Despite the focus on personalization, she offers a general guideline for reducing salt intake to possibly lower than the current UK recommendation, suggesting a target of 4 to 5 grams. This advice emphasizes the importance of moderating salt consumption for better health, alongside the move towards personalized guidelines.

The idea of genes influencing dietary choices and intake is revolutionary. Understanding one's genetic predispositions can inform more effective dietary strategies. She speaker touches on how genetic information can shape our eating habits and health strategies, opening new avenues for dietary planning.

The potential for personalized nutrition to transform public health guidelines and individual health outcomes is immense. By focusing on the interaction between genetics and diet, Dr Pilic brings attention to the limitations of current dietary recommendations. They envision a future where nutrition advice is tailored to individual genetic makeup, offering a more effective approach to preventing and managing health issues like hypertension.

We discuss a few questions:

1. What is the difference between Nutrigenomics and Nutrigenetics?

2. What role do genes play in blood pressure regulation?

3. Who is more affected by genetic salt sensitivity

4. Why do genetically at risk women need to pay extra attention to their salt intake during Menopause?

5. How do you actuallly measure salt sensitivity?

6. What policy changes are needed to account for genetic difference in salt intake recommendations?

Transcript: 19 min read (3751 Words)

00:00:07 So, yeah, it's great to have you, Doctor Leta, Pilic. Yeah. No. It's great. Great to finally sit down with you. And, of course, my, idea is really to have a lot of, discussions with experts like yourself who or have a very particular area of interest or where you, you know, the area that you did your PhD in, which is really at this intersection of nutrition and technology and really getting that kind of angle out there because there's so much misinformation and people want to know, but then they're not sure which find it and, like, and and then when they do find it, it's not really easily understandable.

00:00:20 And so it's kind of nice to just have a very informal conversation around it and there's see what your experience and what your learning has been and act also as a as a nutritionist. You can explain it in a good way. So do you wanna tell us a little bit about yourself before we start?

00:01:04 Yes. Of course. Well, so I am a nutritionist. So, my undergraduate degree is in nutrition Science, which, I then followed with the masters in public health. So not really personalized nutrition. However, while I was doing my, final dissertation for the masters, my my mentor at the time was telling me all about the Nutri genetic and kind of the exciting prospect of using it for public health, I guess. And I decided to to do a PhD, in in the topic, in NutriGenetics, and I found a PhD that was exploring how our genes interact with, salt intake and how that affects our blood pressures. So I spent 3 years exploring, basically, salts sensitivity of blood pressure and how genes, affect it. And then also trying to link it with, our taste, So how are we able to taste, salt, and, how that drives our salt intake, actually, and, kind of, again, looking at the genetic basis of our salt taste perception, and I continued the lecturing and researching in the area of nutrigenetics. So I'm a I'm a lecturer. It's in Mary's University. Where I, teach on our master's program in nutrition and genetics.

00:02:29 I also, do research over see in the areas of an active researcher, exploring, well, different different areas, I would say. It's not solely salt sensitivity and and blood pressure. But, nutrient gene interactions in relation to chronic disease, such as cardiovascular disease, but also types of diabetes, and still looking at the links between genetics, and taste. But I also, work with other nutritionists and professionals, as part of kind of my business role, let say, where I, kind of help them, as a as a consultant, and I also work with with clients offering Nutrogenetic testing.

00:03:28 Right. So you've added entrepreneur to the to the title as well. Yes. Great.

00:03:32 Well, I mean, I well, yeah, if you can call it a lot, but

00:03:37 yeah. We do. So So before we dive, then in, can you can you explain, what the difference is between NutriGenetics and NutriGenomics? Because they are probably, you know, mixed up in the in the everyday language.

00:03:50 Yes. Yeah. Yeah. Yeah. So, well, what we mostly, I would say youth in person personalized is neutral or gene based personalized nutrition is Nutri Genetics. And Nutri Genetics explores how genetic variations. So genetic differences between us, affect the way we respond to different foods nutrients, lifestyle factors and how that in turn affects our health. Whereas Nutrigenomics is kind of the the other side of the of the story. And, it explores how food or nutrition nutrients life cell factors. Again, it doesn't have to be just the diet and how they affect gene expression. So the way our genes are kind of expressed on the on the outside.

00:04:30 So it's just kind of the other way of of looking at it. But we are focusing mostly on how genetic variation genetic differences, affect us and and how we all respond differently to the same foods maybe because of these genetic differences.

00:04:57 Yeah. Yeah. So let's so let's start then on that note. Like, what what is the genetic differences in terms of salt sensitivity. Mhmm. Mhmm.

00:05:07 Well, there there are many. I I think, obviously, we we don't know them all, but we know that our kind of our our blood pressure, and the our our our salt intake are regulated by genes that are expressed in our kidneys, mostly. So so we are looking at these tiny differences or or one letter difference in our genetic code. In genes that that that create these proteins expressed, in our kidneys that regulate blood pressure. And then based on these differences, so, literally, one genetic variation, it can be, we respond differently to the same amount salt in our in our diet, or we may respond differently to the same amount of salt in our diet. So I can have a genetic variation in, ACE gene that's part of a running angiotensinaldosterone system, for example, and I can have a variation that predisposes me to be salt sensitive, which means that if I eat large amounts of salt, my blood pressure may increase significantly. Whereas you may have a different variation in the in the same gene. And actually your blood pressure isn't really going to react to these large amounts of salt.

00:06:20 So you would be considered as salt resistant. Right. So so there are many, many different genes, obviously involved, but that's kind of the the the the idea behind it.

00:06:43 So when you say there are many genes, when we are specifically looking at source sensitivity, How many are we looking at? Are we just looking at 1? Are we looking at a cluster? Are we looking at 5005? Like, what what is that number?

00:06:56 Yeah. That that's a very good question. Well, so, what they always try to explain to to to our students as well. And in in my own practice, is, we tend to avoid or we should avoid kind of think a specific disease by just using genetics. Yeah. If we were to predict someone to have high blood pressure. Let's say we would need to use thousands of of genes and genetic variation. And we well, when it comes to salt sensitivity, we probably don't know as many because, salt sensitivity is very difficult to diagnose. So when we talk about obesity and kind of genetic predisposition to obesity, we are talking about measuring someone's height or weight.

00:07:37 And then doing a large study that explores many genes that would be associated with someone's BMI. With all sensitivity to diagnose it, we, people need to follow a specific dietary protocol that lasts at least 2 weeks. So it's impossible to do very large scale studies to be able to identify thousands of different genes that would be associated with it. So these are smaller studies. So I would say for now, we only have a handful of genes that, there is sufficient evidence that they interact with our salt intake, and in that sense, our blood pressure. So I think, probably the ones that we can use, to provide practical dietary advice. Should be maybe 2 or 3 genetic variations, actually. Yeah. Yeah.

00:08:41 Yeah. And and then if you say, okay, those 2 or 3 Who is really at risk? Who should really be worried, or should be sitting up and listening, when when we're talking about salt sensitivity then? 00:08:56 Well, we have specific groups that would be at particular risk of souls sensitivity. And these groups are older people, postmenopausal women, in the people of African descent. However, I would say that doesn't necessarily mean that everyone else should just be thinking, okay. I mean, it's it's it's kind of useful to know it. Because actually, for everyone, if, they are able to find out their salt sensitivity, status. And if they do have these versions variations that put them at potentially higher risk of being so sensitive, then preventing high blood pressure even from happening, is definitely more likely. So I would say these three groups that I've kind of highlighted, but I think in general, the younger we are, the more useful it would be to know this.

00:09:59 Yeah. Yeah. Very interesting. And of course, you know, menopause is a huge topic. Like, women's health is just, like, you know, going on to the stage, like, big time. What what is the what is the deal there? Can you explain, like, mechanism wise? Why postmenopausal women? Why so specific? Why not fertility? Why not, you know, precon why?

00:10:24 Yeah. Well, Maria, you know, well, As women, when estrogen obviously starts to decline, I think everything goes downhill. Obviously, I'm not trying to put a negative pin. No. No. Things are, but but it's obvious.

00:10:40 No offense taking. I'm in a baller. I'm a no no offense taking.

00:10:45 Yeah. No. No. But, yeah, unfortunately, obviously, estrogen is very protective for us in in a number of of ways So, in this case, it actually then the decline in the levels of estrogen, put put more pressure on our kidneys, this, renin angiotensinaldosterone system, isn't really working properly anymore. It's not being suppressed sufficiently when it should be suppressed if we eat large amounts of salt, and also our blood vessels are potentially unable to dilate as much, as as as they were before, which is then, obviously, if we have high intake of salt here, we need to appreciate that, even if we are salt sensitive, so if we are genetically predisposed, but our salt intake is adequate, then we we probably won't develop high blood pressure. So this is only if we have this kind of an environmental component here. So salt intake, if it is high, then we we are at higher risk.

00:11:55 Yeah. Yeah. Yeah. So so if you you were talking about salt intake, but most people don't know if they are so sensitive or not. They just say, hey. I've got a bit of blood pressure or, you know, my grandmother or my parents had, you know, high blood pressure. Like, how how is the recommendation in terms of salt different between those who are salt sensitive and those who are not even if they don't go in?

00:12:20 Mhmm. That that's a very good question. And I think that no one actually knows this. So so so properly. So in, I would say in NutraGenetics, specifically, if we talk about kind of this area of of personalized nutrition. So gene based personalized nutrition We don't really have specific dietary guidelines that would, that are maybe published by experts that would then make a difference, let's say, between a personalized recommendation for salt based on someone's genetics because they're so sensitive. And then a general recommendation for salt. So that's that's completely up to the, either a genetic testing company or a or a practitioner that is is in this area. So what I would say probably well, here in the UK general recommendation is no more than 6 grams. WHO recommends 5 grams, per day, salt per day.

00:13:07 I would say probably go closer the reference nutrient intake here in the UK, it's 4 grams. So go so go a bit lower than the recommendation. Although we know that currently, we are hitting double the amount even triple. So how realistic is that actually to to achieve this? That's a that's a that's a different story, and we need to consider that as well.

00:13:48 So so so so you have a clinician hats as well, And so if you say to people, like, you know, you need to limit your intake to 5 grams a day or 4 grams a day. Like, what does that mean? Like, people don't know that means. So as a clinician, how do you explain that to people in the whole sense, like your whole diet or your whole dietary pattern will approach? How do you how do you address them?

00:14:13 Yeah. I mean, it's it's very difficult. So we know that we need to, obviously, we can't just even say someone, well, yes, you're so sensitive. So you need to cut down your salt intake to 4 or 5 grams. Exactly. Because what does that mean? To them? How how can they do it? So maybe not pushing the numbers so much, but giving some practical more practical advice that they can adopt.

00:14:29 So either if they're not really aware of feeding the food labels or trying to trying to achieve this pleasure from food because we obviously need to enjoy our food and salt is very important in in the taste. Of food. So then trying to use different seasonings, either, you know, some chilies some lemon, some some herbs to try to still make it kind of tasty without using, too much too much salt. So really kind of focusing on these more practical aspects of it than just focusing on the on the on the number. It it itself.

00:15:17 And you touch there on on on taste and, you know, how food tastes. So so how does taste perception then fall into this this concept of, you know, sensitivity or the genetic predisposition to your taste perception of of salt because it's all been fascinated.

00:15:35 Yes. And and and I would say that we we often confuse, I think, salt sensitivity of blood pressure and then salt taste sensitivity. These are two kind of different concepts, let's say. So when it comes to taste, we know that it's Well, to me, definitely, is and I know I know that research suggests that it's the number one factor that drives us to eat the food or to to choose the food that that we eat. At least one of the of the key drivers So our genes, obviously, we have taste receptors in our in our tongue.

00:16:16 Yep.

00:16:16 That that then enable us to to taste in this example. It's it's salt. So we have, these taste receptors, of course, are created by different genes. And we can have different variations of these genes. So sometimes we have a variation or a version of a gene that's a bit more lazy, let's say. So the the receptor doesn't work as well. Let's let's call it like this. If this is the case, when we talk about salt taste sensitivities, so our ability to taste, salt. If we have this lazy after we may not be able to perceive the the saltiness as intense from food.

00:16:50 So we may want to eat more to achieve kind of this sensory, pleasure from from from food. And of course, that that that would be how then our genes drive our salt intake. So so so that's kind of the the the the key link, I would say, between the 2.

00:17:21 And then how does that tie in with, you know, people say, oh, I crave salt. Is it then is it then they are is is it habitual? Is, you know, they are used to eating salt, or is it the genes that is driving them to pregnant? Like, is there a biochemical reason for the, you know, that is always a very interesting conversation always comes up with dinner parties. So it's kind of like, you know, what is what is driving what?

00:17:50 Well, I think I think there there is a mix. So you mentioned habit. It definitely plays plays plays a huge role. So some research has really shown that, we are able to train our taste buds. So if we if we kind of put effort in, let's say, and and and start eating eating less than our taste buds are going to get adjusted to that. So so we can change by changing our habits, we can also change our perception of of saltiness. Genetics. Yeah, I mean, I would say that definitely there is for for some people, they're just going to kind of I don't know if it's a craving, but they are definitely going to need more because of the reason that I mentioned is that they're just not going to find it as tasty if it's not salty, and that's definitely because of genetics. And then obviously, you know, if we are exercising working in a very hot climate and then really the body needs to replenish the the electrolytes, That's where I would say the actual kind of physiological craving, comes from.

00:19:03 Yeah. Yeah. Fascinating. Fascinating. So can you tell us a little bit more? I mean, you talk now about the kind of the the salt sensitivity. We just bring it back to, again, the actual technology, which is, of course, we also want to explain in terms of how does that actually work? Because it's not like you're gonna go to your GP and then get a quick, quick test or, you know, go to your pharmacist and find out what your, you know, your genetic predisposition is. Can you tell us a little bit about how the technology actually works for the everyday kind of person?

00:19:34 Yeah. Well, when it comes to salt sensitivity, so we're going to our blood pressure, let's say. We we we We don't have the technology yet to to actually be able to diagnose someone. So there there are some efforts where potentially we can just use a simple urine sample from from someone, and then it's able to measure specific proteins that would differ between people that are so sensitive and self resistant. And then based on that, we would be able to to know, but that's kind of not even in some testing. It's it's still in a research stage. Let's let's say. So when it comes to specifically to this topic, I would say, or at least what I'm aware of is, that we are not there yet, that we are able to to easily find out about our assault sensitivity status without having a genetic test.

00:20:35 Yeah. Yeah.

00:20:36 But when we do a genetic test, we are talking about genetic We're talking about probabilities. So we we can't say with, you know, 100% certainty, yes, you are soul sensitive. And then when it comes to, obviously, if we think of salt sensitivity, it's important to know that your salt intake if you are eating too much, not eating too much, and it's very hard to measure this as well. So there are some some efforts from researchers also with some tooth sensors that can then measure, the the the salt intake, which potentially would give you a more accurate or more kind of a real time, information that then you can you can then adjust, your your salt intake based on that.

00:21:24 Yeah. Yeah. So I think, I mean, because even, you know, people can actually use, like, you know, food trackers, you know, food analysis, you know, apps and things like that to actually track their salt intake as well to see. Even I think public health also had upset that that managed for you track your salt and and sugar intake and then see what that can kind of aid you for. So I think I think technology does definitely play a role because I think when it comes to making it visible. It's quite difficult to be able to actually understand what is that? Yeah. I eat bread, I eat cheese, I eat, you know, my back pressed, but all these different things certainly add up that people are generally not, you know, that I'm not aware of.

00:21:54 So I think that is really, an important kind of factor, but what how do you see the future? Because, of course, Nutrogenetics is not kind of an everyday, kind of technology for everybody. You're not everybody's getting test. We how do you see the future considering that we have such a huge problem with cardiovascular disease, you know, risk stroke, dementia, all these. I mean, it seems like it's more important now than ever before, but it's not not that people actually know anymore. So what what is the future?

00:22:39 Well, a personalized nutrition, I would say definitely, and not just trying to, you know, because it's it's the topic, but I I do really think that we maybe not make it, you know, as as fancy. We don't need to potentially measure all sorts of biomark hers and then put it in, like, a fancy algorithm or anything like that, which I'm not saying that it doesn't have its place, of course, but maybe it's not something that everyone can use. And and and and when it comes to salt, it's like, it's more deprived areas as well and and people that really don't have access to it. So my vision kind of would be really to to try to genetic testing is really cheap. So can we at least have this piece of information and make it accessible and make it a bit more, mainstream so people can have this information. And then they at least know about the likelihood of them being so sensitive, and it's it's it's very easy to do. And, well, if we were to convince the the governments and the policy makers that, probably, it would save much more money.

00:23:47 And then spending money on treating cardiovascular disease and hypertension, I would say that, that would definitely be, something that I would really I would really like to like to see. So it becoming a a bit more mainstream and and and really trying to target the groups that would need it the most. So maybe the companies as well, should, you know, create, part of the offering. I know it's not very commercially savvy, but to try to do it for free or for first, you know, we're 1st very cheap for for parts of the population that may really benefit from this information.

00:24:40 Yeah. Yeah. Yeah. Very interesting. Well, let's have a thing, topics to talk about in terms of, Nutra Genetics and your your area of of expertise. But thanks very much for your insight. And and your knowledge and making it so accessible and understandable, and I found that really fascinating. Thank you so much. Thank

00:25:03 you. Thank you, Mariette. Thank you very much.