Neha Pathak, MD, FACP, DipABLM: Welcome to the WebMD Health Discovered Podcast. I'm Dr Neha Pathak, WebMD's chief Physician Editor for Health and Lifestyle Medicine. Many of us know that heart disease is the number one killer in the United States, but kidney disease is often the silent partner we're not talking about enough.

As a primary care physician, I see it all the time—patients who, in general, feel fine and who are being treated for other conditions like high blood pressure or diabetes, and are really interested in making sure that those numbers are being addressed. But under the surface, their kidneys are also starting to show signs of strain. The truth is, kidney disease often develops quietly with no clear symptoms.

Patients might recognize—there's usually no pain or obvious symptoms until kidney disease is quite advanced—and by then, we've missed valuable time. Today's conversation is important because your kidneys do far more than just filter waste. They play a role in red blood cell production, regulating your blood pressure, balancing electrolytes, and converting vitamin D into a form that the body can actually use.

Kidney function is deeply connected to healthy functioning of your heart, your bones, your metabolism, and your overall vitality. Today we're breaking down what kidney disease really means, in particular what chronic kidney disease really means, who should be screened, what tests actually matter, and what you can do right now to protect your kidney health for the long term.

First, let me introduce my guest, Dr Campbell. Dr Campbell is president of the National Kidney Foundation's Board and a professor of Medicine and chief of the renal division at the University of Pennsylvania's School of Medicine. Welcome to the WebMD Health Discovered Podcast, Dr Campbell.

Kirk Campbell, MD: Thanks so much, Dr Pathak.

Pathak: So Dr Campbell, before we dig into our topic for today, I'd love to ask you—you care for patients with kidney disease, you lead the renal division at a highly respected healthcare system, and you're president of the National Kidney Foundation's Board—so you have a front row seat to both the science and the real-life struggles that people face.

So can you share a little bit about your own health discovery or “aha” moment about what people should know about their kidney health, but that seems to continue to slip through the cracks?

Campbell: Thanks so much. That's such a great question because oftentimes it's surprising to me how little folks know about what kidneys actually do. Folks don't quite understand what they can do to protect themselves from kidney disease, and they don't often know some of the drivers of kidney disease progression and the options that we have to treat this condition.

Pathak: That is a fantastic overview. So thank you for really helping us guide the conversation today. So first, let's dig into what you said—what people probably know around their kidney health or what the kidney does is that it's an organ that filters blood so that waste can be eliminated through urine.

But what are some of the lesser-known functions of the kidneys?

Campbell: That's absolutely right. The kidneys do remove waste and extra fluid from the body through urine, but they really are a 24/7 filtering and balance system and team. Kidneys help really address the right balance of salt, potassium, and other electrolytes in our blood, maintaining the appropriate level of acidity in the body.

The kidneys also release hormones that control our blood pressure, signal our body to make red blood cells, and keep our bones healthy and strong by activating vitamin D. So when the kidneys aren't working well, multiple organ systems can be affected—really beyond the function of removing waste and fluid in the urine.

Pathak: Let's dig into the second piece of what you said—people don't generally recognize, when they hear the term “kidney disease,” that there are all sorts of things that could potentially be going wrong.

So can you help us break down what you mean when you say that someone has kidney disease?

Campbell: Absolutely. So the most common type is chronic kidney disease, and that's really defined as abnormalities of kidney structure or function that have been present for more than three months, with implications for health.

We measure kidney function by a simple blood test that gives us an estimate of kidney function. If that's decreased again for an extended period of time, patients do have chronic kidney disease. But that can be from a number of different causes—it can be from diabetes, can be associated with hypertension, or we can have individuals with genetic abnormalities. About 10% of kidney diseases are a result of genetic causes, so family history is quite important.

There are systemic conditions that are autoimmune, such as lupus erythematosus, which is associated with kidney disease in a large number of patients. Patients who have abnormalities of their kidney structure, such as cysts in their kidneys, or those who've actually had a kidney transplant—but the kidney function's overall normal—by definition, they still do have kidney disease. And you know, there are a number of individuals with kidney stones, which also represent a different underlying etiology.

So we have a multitude of different contributing factors leading to that sort of catchall phrase of “kidney disease,” but it's important when patients see their doctors to define what the actual type of kidney disease is so that the appropriate treatment can be offered.

Pathak: That's really helpful. So let's dig in on what you mentioned as the most common kidney condition that you deal with, which is chronic kidney disease. Can you help us understand some of the biggest drivers of chronic kidney disease? What are they, and are you seeing any shifts in how frequent some of these are over time, just in the length of time that you've practiced?

Campbell: Right. So the most common contributor is certainly diabetes. But we see a lot of individuals with an association with hypertension being a factor in kidney disease prevalence. We're identifying a lot of the protein-spilling disorders, beyond kidney function testing for urine.

Abnormal protein in the urine, called albumin, is really important for this distinction. And we're identifying a lot of the less commonly mentioned kidney disorders that are protein-spilling, for which we have much better treatment options now available. Conditions like IgA nephropathy, for example, is a classic one where we did not have a lot of good treatment options over the last several decades, and really just in the last five years or so, we've had many different options available to patients with diabetic and non-diabetic kidney disease.

There are a lot of agents now available that can slow progression of kidney disease, so it's never been more important to identify kidney disease early on so the right treatment can be offered.

Pathak: So tell us a little bit about when symptoms show up—is that often very late in the course of chronic kidney disease? Is that correct or accurate?

Campbell: That's absolutely accurate. Kidney disease is frequently asymptomatic. Individuals may not see some of the signs and red flags until kidney function has significantly decreased to the point of maybe being irreversible. So early on, it's not uncommon for patients to not have symptoms.

This is why testing matters, right? Blood tests for kidney function, urine tests for urine albumin—but some of the red flags folks could note are swelling in the ankles or feet, swelling around the eyes, foamy urine (which could be a sign of protein in the urine), evidence of blood in the urine, or poorly controlled blood pressure. Changes in urinary frequency—getting up more at night or decreased urine output in some cases—and overall vague symptoms like feeling tired, really having a decreased appetite, having more itching, having more nausea. These are, again, non-specific symptoms but could be a sign of advanced kidney disease.

Pathak: So on your short list of folks that should be screened, even if they're fine, is that everyone at a certain age annually? Who are those people on your list of folks that should be screened regularly?

Campbell: I think folks certainly at higher risk for kidney disease should get more frequent testing and screening. So individuals with diabetes, with hypertension, those with a family history of kidney disease, for example. Folks over 60—they should definitely ask their physicians about their kidney numbers, right? The eGFR, that estimate of kidney function, and the UACR.

It was a great Super Bowl commercial last night, just encouraging folks at high risk to get the UACR test—to test for urine albumin. It's crucially important for those at higher risk to get those tests performed.

Pathak: I was going to ask you about that Super Bowl commercial, so thank you for bringing it up. So what do you think about that in terms of the progression of the types of testing? What should people be expecting as part of their routine screening, and then when does a test like the UACR come into play?

Campbell: Right. So we definitely think, at the very least, those at higher risk—having risk factors for kidney disease—should get blood and urine tests regularly. Anyone in the general population at their annual physical exam can ask about kidney health.

And again, just to emphasize, two tests have to be performed: a blood test (eGFR) for kidney function, and a urine test (UACR) to really assess for any evidence of kidney injury. These measure different aspects of kidney health, so they work well together to define the risk of kidney disease.

Pathak: That's really, really helpful. So can you tell us a little bit about what the different tests tell you?

Campbell: So the eGFR—the blood test—is an estimate of kidney function and tells you how well the kidneys are doing at filtering blood and waste into the urine. But we do know that even if the filtering capacity of the kidneys is intact, there can still be injury to kidney cells, and that can really only be detected by urine testing.

We recommend the urine albumin test, the UACR, because it's a more specific marker of injury to certain types of kidney cells that are quite important for maintaining overall healthy kidney function, and could be a starting point for a more detailed workup to see the type of kidney disease that patients have.

Pathak: So then let's change gears a little bit and talk about what people can do to protect their kidneys. Give us some of your major tips on kidney protection.

Campbell: Sure. Again, for individuals with diabetes, it's very important to have good blood sugar control. There's some evidence that tobacco use and smoking can have an impact on kidney health, so avoiding cigarette use is important.

Heart-healthy approaches are definitely important as well for kidney function—regular physical activity, maintaining a healthy weight, lower sodium intake (really recommending a low-salt diet, which again is not always easy for many patients), and limiting the use of processed foods.

There are some medications that we counsel patients not to use too frequently, like nonsteroidal anti-inflammatory agents such as ibuprofen, which in some individuals can add another stressor for kidney function.

And again, having regular checkups—if a patient does have predisposition or risk factors for kidney disease—if we catch it early, there are a lot of options now available to slow the progression of kidney disease and, hopefully in the future, really reverse the risk associated with kidney dysfunction.

Pathak: You talked a lot, and I think this part is so interesting to me as a primary care doctor around lifestyle changes, because I think so often we think of ourselves as different components and different organs, when we're really an entire whole system. That if you're doing some of these healthy behaviors, you're going to do things that are really going to be protective of your kidneys, your heart, your brain—everything all at once. So can you give us more information around, or do we have more science around, lifestyle changes, whether that's certain types of nutrition patterns that are better for our kidneys or potential eating patterns that might be kidney protective?

Campbell: Certainly, a lot of work is going into better understanding some of the lifestyle-related changes that can have a positive impact on kidney health. And, you know, what we do know is that hydration is important, right? So individuals who have much lower fluid intake, or those who are exposed to a lot of heat through environmental exposure, are at higher risk oftentimes for kidney disease.

So really making sure that there's adequate hydration and avoiding volume depletion is an important starting point. In terms of diet, heart-friendly diets, right? So, you know, less sodium, fewer ultra-processed foods, more fruits and vegetables again have been associated with improved kidney health. Grains, beans, nuts, et cetera, have also been a focus of associations with improved kidney health.

So, again, not necessarily specific for kidney health in many cases, because these are general recommendations for overall heart health, as you alluded to. And that's good, because these organs do work very closely with each other. So again, driving home the message that healthy lifestyles will benefit your heart, your kidneys, your overall metabolism, diminish the risk of type 2 diabetes and obesity. And again, that's overall exceptional.

There are individuals, though, with decreased kidney function who will have to have limits on potassium intake, phosphorus intake, et cetera, based on their labs and based on the stage of the kidney disease. And those are individualized recommendations.

Pathak: So how do you give a general recommendation around hydration if you have optimal kidney health or no clear evidence of kidney disease? And then how do you sort of think about adjusting and personalizing that for someone who might have chronic kidney disease?

Campbell: Right. So I guess on the one hand, there are some individuals for whom we have to recommend an even higher fluid intake target, right? So individuals with kidney stones, or those with polycystic kidney disease depending on what medication they're taking. But for most individuals, it can be a guide with the color of the urine as a rough indicator of how concentrated it is. And again, that's not the same for everyone, but generally, if urine is darker or if the volume of urine is less, patients could have dehydration; they could have volume depletion.

So individuals, again—and this was actually another commercial in the Super Bowl yesterday—again, advising folks to have enough fluid intake so that there's generally pale yellow urine. But the amount of urine per day, again, is a guide to how much folks are taking in, because the fluid that folks are taking in, if they're in balance, has to go somewhere.

So generally, most folks are fine with two and a half liters or so of fluid intake per day. Again, there are individuals who might have certain types of heart disease or decreased kidney function where we need to limit to a liter and a half, or less than a liter, of fluid intake per day. But again, a good guide is how concentrated the urine is and how frequently folks are urinating, because everybody's different. So we do try to individualize some of those recommendations when needed.

Pathak: The other thread I wanted to pull on that you mentioned earlier—so again, thinking about my primary care patients—is I do worry about what's hidden in their medicine cabinets or other things they're taking. So you mentioned NSAIDs, the ibuprofen. Can you talk a little bit about some of the supplements or bodybuilding products? I see a lot of patients that are taking “detox teas” or starting detox teas, quote-unquote. What are some of the major culprits that you want our listeners to know to think about with caution, because they're trying to improve their health but you've seen increased risk for kidney disease?

Campbell: Absolutely. And again, just to be clear on NSAIDs, we're not saying that nobody should take them. They're medications that are effective in many individuals. But the point is to have that conversation with your physician to define whether it's safe to take them, and in what frequency and dosing, because there are some patients who are susceptible to kidney injury on the basis of taking some of these agents.

But again, it's an individualized decision. In terms of some of the over-the-counter supplements, and sort of agents that folks will take for detox or to help with bodybuilding, that again requires a medication review. The best thing is to bring in the bottle to the doctor's office, really go through the ingredients, especially if there's any evidence of kidney disease, making sure that there's no real contraindication to taking some of the supplements.

Part of the challenge is that some manufacturers don't put all the ingredients on the label of the bottle, or the dosing concentration of all these supplements isn't always that well described, so that can be a challenge. But bringing in the medication and discussing it with the physician is the best way to go. Folks need to understand that a lot of these agents are cleared through the kidneys—they're passing through, and every cell in the kidney is being exposed to them as they're going into the urine. And that can cause some injury.

And, of course, another route of metabolizing is through the liver, so some of these can actually have an impact on liver health, and liver disease can be associated secondarily with kidney disease. So it's very important to review any new medication, whether it's prescribed or not, with your provider.

Pathak: And I want to just ask a little bit around something that I am seeing a lot more—folks really interested in upping their protein, their protein intake. Can you talk a little bit about what we need to understand with regard to protein and the kidney?

Campbell: Sure. Absolutely. And that certainly is a very prominent topic these days. The recommended daily allowance, as we know, is about 0.8 to 1 gram per kilogram per day for an individual. So I think folks should use that benchmark generally. And again, if there is evidence of kidney disease, having that conversation with the provider is important because breakdown products from the protein we take in have to be metabolized by the kidney.

So, you know, I think it's important to have some conversations and things in moderation, really advising folks not to overdo it in any one particular food group. A balanced diet is still the general safe way to go.

The other part is we also know that absorbing a lot of these nutrients is more effective in the context of meals rather than supplements. So folks do often ask us about added supplements, and we do say yes, it may or may not be safe, but what we do know is that you may not absorb all of it, and it may not really go to the target cell in your body that you expect it will. But if you have some of these nutrients in a healthy meal, you're much more likely to absorb it effectively than if you took a tablet or added a powder, for example.

So I think that's just real overall sound recommendations. But folks do often have these questions, and whenever folks are motivated to take these supplements or increase their protein intake per day, it's just good to have that conversation to individualize the safety risk.

Pathak: And that was another Super Bowl commercial talking about eliminating processed foods and trying to go for whole foods. So I think that’s definitely in the zeitgeist. Let's kind of focus in now on the person who has been told that they have CKD—or whether that's early CKD—or they're being managed for chronic kidney disease. Help us understand what they should be sort of thinking about as their plan going forward. And I again recognize this is going to be very individualized depending on the stage and the particulars of their case. But in terms of a general sense, what types of testing should they be anticipating? How frequently will this type of testing occur? What can someone anticipate if they are told that they have a diagnosis of chronic kidney disease?

Campbell: Sure. I think that it really depends a lot on what the cause of the kidney disease is. I think a patient with polycystic kidney disease will have different needs from somebody with kidney stones, versus some of the rare protein-spilling conditions, versus diabetic kidney disease.

So the plan will be individualized. And there are some general approaches, though, where we do have overarching recommendations for how frequently kidney function should be tested, based on the risk profile of the individual—what the eGFR level of kidney function is, how much protein or albumin there is in the urine, and how quickly the kidney function is changing. Because if kidney function is deteriorating quickly, patients do need to be followed a lot more closely.

But if kidney function is decreased but stable, individuals with early-stage disease that's quite stable may be followed once a year and often don't even need to see a nephrologist for regular follow-up. They can follow up with their primary care provider, who can communicate with a nephrologist as needed. So it very much depends on the risk of progression and the individualized clinical profile that patients have.

But there are individuals who need to be seen every month when kidney disease is very advanced—when we're preparing patients for dialysis, for kidney transplantation, that stage five kidney disease, if you will. We do need more frequent assessments to monitor symptoms, to treat comorbidities that happen when kidney function is severely decreased. So we need to be monitoring the level of acid in the blood, the level of potassium, phosphorus, those things that could be abnormal and treated, as well as addressing and mitigating the risk of heart disease that's always present in the context of kidney disease as well.

Pathak: So let's zoom out as we come to the end of our time together. What's giving you the most hope right now? You mentioned new medications, transplant advances. Tell me what is giving you real optimism in the care of your patients with chronic kidney disease.

Campbell: Yeah, there was a time when we would be quite passive, right, in the chronic kidney disease approach, especially earlier stages of kidney disease, where we did not have a lot of treatment options for patients. We could identify patients with kidney disease, but we really did not have a way to slow progression. That's changed dramatically in the last few years. You know, we certainly can do a lot more with early detection, both for diabetic and non-diabetic kidney disease. You know, advances in AI, machine learning, they've enabled us to risk stratify. You know, we now can, with more precision, identify which patients are at higher risk for kidney disease progression in a more rapid fashion versus those who might have a more stable trajectory. There have been such innovations in dialysis and in kidney transplantation that the patient experience on those modalities, if patients do progress, is likely to be, again, a lot better—so improved quality of life, earlier detection, better risk stratification, just really more options for treating effectively has me very, very excited.

Pathak: That's great.

Campbell:

Pathak: I'd love to seed the last few moments to you. So for the listener who's listening, who really wants to prevent kidney injury, give us a couple of tips, and then I'll ask you one other question for the person who already has chronic kidney disease. But let's start with the person who's listening and wants to do a couple of things. Your top tips for protecting kidney health.

Campbell: So for kidney health protection, I think the first step is knowing your kidney numbers, right? Asking your provider for your eGFR, your UACR numbers, right? Certainly determining whether you're at risk for kidney disease progression, assessing the risk factor profile. So again—diabetes, hypertension, making sure there's healthy sort of activity levels each day, appropriate weight control, really try to have more home-cooked meals, having a healthy lifestyle, using pain medications more safely, avoiding any that could be harmful, bringing in really labels of bottles of any supplements that you might be taking over the counter to your physician, ensuring that they're safe for you to take. I think those are really, really sound approaches for overarching kidney health, and just understanding, again, that, you know, heart-healthy diet approaches for healthy, you know, hard outcomes are also important to protect the kidneys.

Pathak: For someone who already has chronic kidney disease, what advice would you give to really make the best and the most of future appointments with your doctor if you already have CKD?

Campbell: I think for patients who already have CKD, we are in this age where patients have more access to medical information than ever before, so really doing a deep dive on the condition. So again, knowing that there's kidney disease is really the first step, but what type of kidney disease is it? That's always a question. And targeting a lot of the research and documentation from your standpoint, making sure all your answers are—are all your questions answered around your actual underlying kidney disease is quite important because not only are there great options for, again, risk stratification and treatment, but there may be even more effective treatment options coming down the line in the context of clinical trials. Again, we have had more clinical trials in such a robust pipeline than ever before. So talking to your doctor, adoptable clinical trial opportunities, and oftentimes patients can self-refer for second opinions if there aren't trials or subspecialty opportunities, 'cause again, like every field in medicine, nephrology is becoming super specialized. So you may need to travel away from home to see an expert in the particular condition that you have while still maintaining your connection with your primary nephrologist and primary care physician.

So really empowering yourself, bringing, you know, friends, family members to the visits to make sure that you have another set of ears available to bounce questions off is also important. So I think we're really in the era of patient-centered care, and that's a good thing.

Pathak: That's great. I wanna thank you so much for your time, Dr Campbell. Thank you. Really, really helpful information.

Campbell: Thanks so much for having me.

Pathak: I'd like to share three of my key takeaways from our conversation today. First, kidney disease is often silent, so testing matters. You can't rely on symptoms alone. If you have diabetes, high blood pressure, a family history of kidney disease, or are over the age of 60, you should know two numbers: your eGFR, a blood test that estimates kidney function, and your UACR, a urine test that's measuring albumin. Both are essential. One without the other may give us an incomplete picture.

Second, protecting your kidneys protects your heart, and vice versa. The lifestyle strategies we often talk about—from limiting sodium, staying hydrated, avoiding tobacco, and moving your body—are not just heart healthy, they're kidney protective. These organs work together. What benefits one often benefits the other.

And finally, we're no longer in an era of watch and wait. There are now more treatment options than ever before to slow the progression of kidney disease, but they work best if kidney disease is identified early. So ask about your numbers, bring your supplement bottles to appointments, and don't hesitate to advocate for screening if you are at risk.

If today's conversation feels like a lot, here's your reminder: You don't have to fix everything at once. Start with one small step. Ask about your kidney numbers at your next visit. That single question can open the door to clarity, prevention, and protection for your long-term health. To find out more information about Dr Campbell and the National Kidney Foundation, make sure to check out our show notes.

Thank you so much for listening. Please take a moment to follow, rate, and review this podcast on your favorite listening platform. If you'd like to send me an email about topics you are interested in or questions for future guests, please send me a note at [email protected]. This is Dr Neha Pathak for the WebMD Health Discovered Podcast.