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Each week, Health Affairs' Rob Lott brings you in-depth conversations with leading researchers and influencers shaping the big ideas in health policy and the health care industry.
A Health Podyssey goes beyond the pages of the health policy journal Health Affairs to tell stories behind the research and share policy implications. Learn how academics and economists frame their research questions and journey to the intersection of health, health care, and policy. Health policy nerds rejoice! This podcast is for you.
Hello, and welcome to A Health Podicy. I'm your host, Rob Lott. We know that diet related disease is a big threat to population health. Diabetes, cardiovascular disease, and many cancers all can be attributed in part to things like people's diet quality and their nutrition security. And yet statements like that, while true, are wholly inadequate.
Rob Lott:There are numerous other interrelated factors contributing to those and other diseases, and there are also numerous other interrelated factors upstream too. Factors as varied as income and environment and countless other drivers of things like diet quality, which as we've said, in turn drives health. And so, yes, although we've known about the food and health connection for generations, less clear are how those connections, and there are so many, relate to each other. And also less clear is where someone like a researcher or a policymaker might start when it comes to developing and evaluating interventions aimed at improving diet and health. That's the subject of today's Health Odyssey.
Rob Lott:I'm here with Doctor. Seth A. Berkowitz, a general internist and associate professor of medicine at the University of North Carolina, Chapel Hill. Together with Drs. Hilary Seligman and Darish Mazafarian, Doctor.
Rob Lott:Berkowitz is the coauthor of an article titled, quote, A New Approach to Guide Research and Policy at the Intersection of Income, food, nutrition, and health. It's one of the key framing articles in the brand new April 2025 issue of Health Affairs, which is dedicated entirely to the subject of food and health. This article very much sets the stage so nicely for many of the other empirical studies in the issue, now available at HealthAffairs.org. Doctor. Seth Berkowitz, we're lucky to have you here to talk about the article.
Rob Lott:Welcome to A Health Odyssey.
Seth Berkowitz:Yeah. Thanks for having me on. I really appreciate the opportunity to talk about it.
Rob Lott:Great. Well, let's dive right in. Your article offers a a quote, new conceptual model for understanding the interrelationships among income, food security, nutrition security, diet quality, and health. Before we talk about the new model, would you paint us a picture of sort of what came before? What was the traditional interpretation of these elements and where perhaps does it fall short that you felt the need to develop a new model?
Seth Berkowitz:Yeah. I think that's a great question. I think in in some cases, there are, you know, sort of older models that people have and a new one is trying to supplant it. In this case, I think it's more that, there was, like, a a general sort of nonspecific sense that these things were kind of related, but there wasn't a lot of specificity to it. And so the newness of this model is is trying to add some specificity to these interrelationships.
Seth Berkowitz:We know, overall, I think that, you know, the income you have might affect the, you know, the food you can buy, and that affects the overall quality of your diet, and that can affect health. But as we've, you know, sort of moved more into this research field, we've realized that, you know, it's actually worth making distinctions between some of these constructs that might, tend to blend together, you know, food insecurity as being separate than nutrition insecurity, both of those being separate from diet quality, income, you know, influencing those, income influencing health through other ways that don't go through that. And so our our goal in in putting the model together wasn't necessarily to say, oh, the old way we thought about these things is wrong. Here's a new way to think about it, but rather to say, you know, people are paying attention to these concepts now. They're interrelated.
Seth Berkowitz:We all know that. But but, specifically, how does that actually work and try to give sort of a scaffolding or or, you know, framework in that sense for people to to use as they're thinking about these different interrelated ideas.
Rob Lott:Got it. Okay, well before we sort of dig into the model, one other background question. I'm wondering if you can say a little bit about why this kind of research is so hard. The sort of obvious example I think about often is, one day you'll read a headline that says, drinking red wine is good for your health and then the next day it's bad, same with chocolate. And I think the same also applies to sort of the more complicated dynamics at play here.
Rob Lott:Is that just the nature of social science and empirical research, or is there something particular about this field that is just really hard?
Seth Berkowitz:Yeah. No. I do I do think there are some some elements that are particularly challenging when it comes to nutrition and things like that. I will take a step back and say that I I think big picture when thought about in, you know you know, what I think at least is the right way or sort of, what what might be a helpful way, I do think we have pretty sound, nutrition science when when we talk about overall dietary patterns. Meaning that I think we know overall, what are more versus less health ful, ways to eat.
Seth Berkowitz:I think we know that, you know, having, you know, a higher proportion of your foods come from plants, a higher proportion of, you know, the fats that you consume be unsaturated, you know, kind of more fat, plant derived fats rather than, animal fats. I think how consuming calories in moderation. I think not consuming too much sugar. I think not consuming too much alcohol. Those kind of big picture things, I think, are relatively well studied.
Seth Berkowitz:And we know that there are a couple different dietary patterns that all kind of do that but are helpful. You know, a Mediterranean diet pattern is helpful. A DASH diet pattern is helpful. A lot of traditional, patterns from different countries around the the world have been studied and found to be, helpful. It gets more complicated, as you say, when you start getting into, like, specific foods or maybe even, like, specific nutrients.
Seth Berkowitz:Like, is this one specific food, you know, the best one for you, or or are foods with this particular phytochemical, good for you and things like that. That's that's a little bit trickier and harder to say, as you say. You know, it's definitely the case that in the popular press because I think we love you know, everyone likes loves to eat, and and so we love articles about eating and things like that. And so it's it's always catchy to say, oh, this this, you know, do this eat this one food and you'll live to be a hundred or, like, drop this one food and you'll live to be a hundred or whatever else. So that that does happen.
Seth Berkowitz:I think the other thing that's just tricky about, like, nutrition and diet in general is you're you're generally talking about exposures that happen over long time frames for their, you know, for their effects to really manifest, you know, years, if not decades, if not, you know, you know, double digit, you know, you know, twenty, thirty, forty years, things like that. And that's just scientifically hard to study. Right? It's much easier to study something, you know, an antibiotic treats your pneumonia in a week or it doesn't, and, like, you know that right away versus, you know, a dietary pattern that you have to adhere to for twenty years or something like that. That's just a harder thing to study.
Seth Berkowitz:I think also just the sheer volume and variety of foods around the world. I mean, you know, we I think of blood pressure medicines as a as a class of drugs where we have a relatively high number of therapeutic agents compared to many things, but that's probably really only, like, 10 or maybe 15 in widespread use. Right? There are thousands, tens of thousands of foods that each have their own, you know, molecular composition, all that stuff. So there's just a lot of variety, and people eat a lot.
Seth Berkowitz:You know? We're doing it multiple times a day and everything. And so measuring precisely what people are consuming is just sort of a difficult scientific task as well. Multiply that over long periods of time. So it is a I think it is a more difficult area to study in some ways, which which adds to some of the complexity around these issues as well.
Rob Lott:Yeah. I get that. I I keep trying to convince my colleagues at health affairs to publish an article about the 10 superfoods that will turn your hair blue or something like that.
Seth Berkowitz:Yeah, get those clicks All
Rob Lott:right, well against that backdrop, tell me a little bit about the model in your paper. Can you walk us through it briefly?
Seth Berkowitz:Sure. Yeah. So I think I think the underlying so a couple of sort of underlying points, that that we make in trying to relate and, again, I guess, it's kind of a mouthful to say all these, but just to say, it's a model that relates income, food security, nutrition security, diet quality, and health. So those are sort of the five key constructs that we're that we're dealing with. One of the key underlying points is that health itself is a very multidimensional construct.
Seth Berkowitz:So there's physical health. There's mental health. Even within physical health, there's, you know, diabetes and cardiovascular disease, there's, you know, kidney disease, there's malignancy, and all those kind of things. So so it's a very multidimensional contract. And one of the key things that we wanted to, get across is that how these different other constructs, the the income, the food insecurity, interest insecurity, diet quality, interact with health has to do a lot with the specific measure or manifestation of health you're talking about.
Seth Berkowitz:And so there might be, you know, even though both physical health and mental health are two key parts of health, diet might have a very different interaction with, you know, some physical health outcomes than other physical health outcomes or physical health versus mental health and these kinds of things. And so we wanna relate that in that sense. The other, kind of key thing that we wanted to to get across is that, you know, income is sort of this enabling factor that, you know, it it provides purchasing power, so it lets people buy various things that they might need to be healthy and can affect their health in different ways. And some of those are food related, and so that's how some of those other things get into. But others have nothing to do with food.
Seth Berkowitz:Right? It lets you buy higher quality housing so you're not exposed to, you know, respiratory, pathogens like mold or, air pollution. It lets you buy, your medicine so you can take those or access higher quality health care. Lets you buy transportation so you can get to where you need to be and all those kind of things. So there there are plenty of pathways that income affects health that don't go through any of the, any of the kind of nutrition related ideas.
Seth Berkowitz:And then finally, there there are these kind of three, distinct but interrelated, ideas, food insecurity, nutrition insecurity, and diet quality. And food insecurity, you know, people usually think about as, access to the food needed for an active health active healthy life, That's sort of a USDA definition of it. It's tightly tied to financial, conditions, and so we expect that there's gonna be a strong relationship between income and food insecurity. If you have too little income, you're you're more likely to be food insecure. We also know that food insecurity is related to diet quality.
Seth Berkowitz:If you look on average, people with food insecurity have lower diet quality than, than people who are food secure, probably because healthier foods are more expensive. However, the magnitude of the difference is, you know, is relatively modest. It's real and measurable and persistent over time, but it's not huge. And in the overall US context, we know that there are a lot of things that affect diet quality that aren't related to food insecurity. The overall level of diet quality in The US across all income groups and and across both, people who experience food insecurity and people who are food secure is relatively low.
Seth Berkowitz:And and so, you know, basically, in The US could there's probably some room for for improvement or at least every income group and and the different food security statuses, there's room room for improvement there. So food insecurity isn't the only thing that determines diet, quality. And then the and then, you know, diet quality, you know, refers to sort of the overall healthfulness of the diets that people are eating and, again, has many influences. So, you know, income and food insecurity are are one of those, but there are others, and there are even some paradoxical findings where, you know, for example, in epidemiologic studies, we know that there's greater junk food consumption amongst, high income children than low income children, which is sort of an opposite pattern of what people might expect. And so we know that there are plenty of other determinants of diet quality that don't go through sort of income and food insecurity and have to do with culture and preferences and the food that's available to us and food marketing and, you know, all those different things there.
Seth Berkowitz:And then finally, kind of the new kid on the block is, nutrition security. And so so that's a construct that I think is still kinda taking shape, and what the, you know, final form, it takes and how we think about it is is a little bit up in the air right now. There's a lot of interest in it. On one hand, we sort of know that that some of our traditional measures of food insecurity, don't really get at the healthfulness of the foods that people have access to. And so, so there's some justification for wanting to, you know, measure not just, do people have access to food overall, but what is the healthfulness of the food that people have access to?
Seth Berkowitz:And so that's sort of one justification for this this idea of nutrition security. Another one is, you know, the diet quality kind of talks about, the overall patterns that of food that people are eating, but it doesn't necessarily get at what someone's nutritional status is in any given point of time. Do you actually consume enough of the macronutrients and micronutrients that you need to stay healthy? And so another way to think about nutrition security is, you know, as a as an indicator of the nutritional status that that people have. And there are kinda different camps within the field who some prefer this sort of access to healthy food interpretation of nutrition security, some prefer this, nutritional status and and overall healthfulness of diets interpretation of it.
Seth Berkowitz:And so we kind of go into a little bit of the these, different ideas within this emerging construct of nutrition security as well.
Rob Lott:So it sounds like a little bit of what you're getting at is that there are these ideas or factors, but then there's also some complexity around how different people interpret those factors, or I guess the term you use is construction. And so how did you attempt to navigate that tension between sort of the facts of the reality, as well as sort of perhaps the nature of the debate around those facts. It seems like you're sort of trying to do both, and I and it's probably the only way to do it, but I'm curious how you thought about that.
Seth Berkowitz:Yeah. No. Totally. And, I mean, I think there's think there's a tendency in academia overall, and this is probably not a good tendency to, you know, hyperfocus on terminology, to make distinctions even if those distinctions maybe don't have a difference and things like that. And and, you know, I'm certainly not gonna say that we're immune to that or or those kind of things, but really the guiding impulse of the this kind of work here was for interventional reasons.
Seth Berkowitz:And in particular saying, you know, because these are different but interrelated constructs, interventions that affect, you know, either only one and not the other of these constructs or or affect the constructs to different extents, you know, maybe more of one than another, are likely to have different impacts on health. And so so the way we really wanted to sort of organize this approach overall is, you know, in in constructing this framework, how might it be used to, you know, one, synthesize sort of existing evidence, make sense of what we know from prior studies, but also provide a way for people to think about, alright. If we wanna change health, we wanna make people's health better in some ways. Which of these different constructs would be the levers that we that we wanna use? And that that might be an intervention that focuses only on one.
Seth Berkowitz:It might be one that that tries to synergistically work on multiple ones at the same time. But having a sense of how they're related, we think will let let us do better at, at addressing each of these issues or at some of these issues to to improve health. And so that's really sort of the underlying name of the game, is how these might be applied to designing interventions or understanding, you know, why interventions that have been done had the results they did have.
Rob Lott:Well, that's a great segue going on to interventions. In the paper, you basically sort of catalog a number of different interventions in this space, as well as the evidence about their effectiveness, things as varied as cash assistance on one hand, steps to improve diet quality on the other. I'm curious as you were looking at those inter interventions, did you encounter any surprises that maybe, caught you off guard?
Seth Berkowitz:I don't know if there were it was so much, surprises, but, I mean, I think just the variety of different health outcomes that, that different interventions, you know, saw effects on was, really spoke to the, sort of the complexity of the situation, but also the potential of using interventions that focus on different, you know, constructs within here to achieve different, different outcomes. Just as you know, kind of an example, you know, for in for interventions that focus particularly on providing income but in a relatively unstructured way, so not, you know, saying, oh, you have to use, you know, this income in this way or whatever, but sort of broad income support. You know, we found impacts on mental health. We found acts impacts on health care utilization, like reduced emergency department visits and things like that. But we didn't find as much on, you know, some of the, like, biomarkers, like hemoglobin a one c, for people with diabetes or things like that.
Seth Berkowitz:On the other hand, you know, some things that were, you know, maybe a little closer on the, you know, on what you might imagine is sort of the causal map, between these things, so interventions that are trying to affect diet quality in particular did that, but but then they were the ones that that, impacted some of these biomarkers a little bit more. So we had a a, you know, food as medicine study, that made health food more affordable for for people with diabetes and that found a a reduction in in hemoglobin a one c for for people with diabetes. And so it just sort of spoke to the different, you know, aspects of health that you may be able to affect by sort of mixing and matching, so to speak, between which of these different constructs your intervention is targeted towards.
Rob Lott:Great. Well, in a moment, I wanna ask you a little bit about putting all that into practice. What does it look like to mix and match, if you will? But first, let's take a quick break. And we're back.
Rob Lott:I'm talking with Doctor. Seth Berkowitz about his paper from the April 2025 issue of Health Affairs offering a new model at the intersection of income, food, nutrition, and health. Okay, let's put this into practice. I'll admit when I hear the term conceptual model, it feels very academic and theoretical to me. I know that that's intentional.
Rob Lott:That's the work we do here. But I'm wondering if you can convince me why something like this might be useful in the real world of policymaking. Let's say you're in the halls of Congress, your congressman is walking down the hall, you're able to grab him for sixty seconds before he ducks into the cloakroom, and and you can put this paper in his hands and tell him why you think it's important for him to know about it. Where do you begin?
Seth Berkowitz:So, I mean, I think the real reason that a that a framework like this is important is because, you know, it it helps you, home in on the the interventional approach that's most likely to achieve the outcome that you want. So, again, you know, health is a very multidimensional construct. We can say, yeah, we wanna improve health. But your immediate next question after that is like, well, what aspect of health, is it? And so, from there, that you know, once you've identified that, I wanna improve hemoglobin a one c for people with diabetes, or I wanna, reduce emergency department visits, or I wanna improve mental health.
Seth Berkowitz:Once you've honed in on that, that's when, you know, sort of the planning starts. You say, okay. That's the goal. How do we do that? And I think a model like this is useful because, you know, there are all these possible intervention targets.
Seth Berkowitz:You know, you could try to provide income support. You could try to reduce food insecurity. You could try to, provide dietary education and counseling and those kind of things. And you wanna have a sense of which one is likely or or what combination of those are likely to achieve the outcome you want. And so that that's really where I think the utility is.
Seth Berkowitz:You have a problem, you wanna have, you know, some rational way to, come up with an intervention that's likely to improve it, and to do that, you know, we've synthesized a lot of information together that can provide some guidance along the way.
Rob Lott:Okay. Certainly for different populations, there are disparities and factors like you mentioned, income distribution, access to services and supports, even health outcomes. But so give us a picture of what it looks like when you, see these factors through an equity lens, and how did you include that in your development of this model?
Seth Berkowitz:So, I mean, health equity is really, an important topic to to all of us, to Hillary and Dari, as well. For for me, you know, I had a book on health equity come out, last year. So, I mean, it's something that I spend a lot of time, thinking thinking about and really sort of informs, what we're doing here. You know, for me, the way I think about health health inequity as injustice that harms health. And what what to me that means is when we have social structures and institutions that sort of aren't providing people with with what they need and what they're due as, you know, sort of an an equal member of society.
Seth Berkowitz:And we see that play out in a lot of things here, the way that income is distributed in The US, the the prevalence of food in insecurity and the distribution of it, who experiences food insecurity, who has low diet quality, all that is really patterned by social structures, institutions, practices that distribute, resources, in The US. So, you know, you think of the the educational system and and whether discrimination and opportunity within that is equally distributed. It's not. And so that that leads to, you know, different labor market outcomes with further aspects of discrimination. And all of that might mean that, you know, based on, you know, sort of factors that should not, play into this, you know, you see lower income distribution, for certain, you know, people in The US.
Seth Berkowitz:You see higher risk of food insecurity for for people in The US. And so thinking about these these structures that sort of put people in, these positions, I think, is really important. And that's why we really, the in the paper, emphasized, you know, not only having specific intervention to sort of mitigate the consequences of this, I. E. Something that, you know, takes someone who, say, is experiencing, you know, diabetes and, you know, low access to healthy foods and provide, say, a food as medicine intervention to to address that, but also at the same time sort of thinking about the the structures and and sort of background social policies that put people in that situation in the first place.
Seth Berkowitz:And so that's why you might use income support interventions, to provide a baseline of, purchasing power for everyone, but then on top of that, add a a food as medicine intervention, specifically for people who are, you know, in worse circumstances at the present moment. And so we wanted people to think both structurally, in a big picture sense, but also be able to think clinically about, you know, say the patient in front of you if you're a physician or, you know, the client in front of you if you're a human service organization or something like that, and provide specific interventions that way as well.
Rob Lott:I wanted to ask about another big factor that we've seen on our radar a fair bit at health affairs, relatively new when it comes to food and health, and that's the rapid uptake and embrace of GLP-1s. And let's say that that continues to expand and grow. Have you thought about how that fits sort of into this model or what someone looking at this model might apply to the the rise of GLP ones in in health care.
Seth Berkowitz:Yeah. No. I think GLP ones are really a very complementary intervention to a lot of the stuff that we're talking about here. So, there are a lot of health benefits to GLP ones, you know, although there there's ever more research into the mechanism of action of GLP ones. You know, a key way that they work is they they tend to reduce appetite, and so people tend to lose, a good amount of weight, while on them.
Seth Berkowitz:But that weight loss is, you know, kind of a blunt instrument in some way. So so some of the weight that people lose is adipose tissue, which is, you know, endocrinologically active and causes some of the harms of excess adiposity. But some of the tissue that people loo or some of the weight people lose is muscle tissue, and so that can cause something called sarcopenia, you know, too low muscle mass, and that can be associated with frailty and other problems, as well. And so having tools that can really cause weight loss like GLP ones is great, but that doesn't obviate the need for people to consume healthful diets, to try to optimize where that weight loss comes from, I e, can it be more adipose tissue and less muscle tissue when when you're losing weight? We also know that that at least right now, because of the current, patent regimes and everything, GLP ones are very expensive.
Seth Berkowitz:And we know that GLP ones have a lot of side effects, and so there there are a number of people who just can't really tolerate, being on them. And so I think there are plenty of ways to use nutrition interventions, to to sort of complement some of that therapy. You know, my my coauthor, Dari Mozaffarian, had a great viewpoint, you know, I think at last year or maybe the year before about using food as medicine interventions initially while people are on GLP ones, and then and then further using it to help people transition off GLP ones. That time of weight loss might be a time to to establish some healthy patterns in terms of how people are eating and things like that. And then, ultimately, you know, once a a good amount of weight loss has been achieved and everything else, maybe people can stop and maintain a more healthier, lifestyle and get sort of the benefits of that treatment, but be assisted by, say, a food as medicine or other kind of nutrition intervention, to, to maintain that weight loss, have healthy diet patterns, and those kind of things.
Seth Berkowitz:So I think there are a lot of ways that that, you GLP ones and, you know, food and nutrition interventions can be, complementary, but but they're also doing different things, and I wouldn't wanna have only one or only the other.
Rob Lott:Great. Well, that might be a good place to stop. Doctor. Seth Berkowitz, thank you so much for taking the time to chat with us today.
Seth Berkowitz:Yeah, thanks so much for having me on.
Rob Lott:To our listeners and our readers, check out Doctor. Berkowitz's article in the April 2025 issue of Health Affairs. And if you enjoyed this podcast, please recommend it to a friend, smash that subscribe button, and tune in next week. Take care all.
Seth Berkowitz:Thanks for listening. If you enjoyed today's episode, I hope you'll tell a friend about a health policy.