Rethinking the risks of a plant-based diet for kidney patients

[00:00:00] Host Amber Smith: Upstate Medical University in Syracuse, New York invites you to be "The Informed Patient" with the podcast that features experts from Central New York's only academic medical center. I'm your host, Amber Smith. People with kidney disease traditionally have been told to restrict their intake of plant foods. Some researchers are questioning that advice. Here to explain is John Babich, a third-year student in Upstate's Norton College of Medicine. Welcome to "The Informed Patient," Mr. Babich.

[00:00:30] John Babich: Hi Amber. Thanks for having me.

[00:00:33] Host Amber Smith: Why have people with kidney disease been told to avoid plant foods? And I'm assuming we're talking about vegetables.

[00:00:40] John Babich: Yeah. So, this is an interesting area of focus, but traditionally folks with kidney disease have been told to follow a kidney or renal diet. And this restricts plant foods, mainly because there's a concern about potassium content. And plant foods tend to be higher in potassium, and so I've been working with some colleagues looking at the evidence and trying to understand if there is a strong connection between the potassium that's found in the food and whether or not you actually absorb all of that potassium.

[00:01:21] Host Amber Smith: So what makes the body potentially retain potassium?

[00:01:27] John Babich: Kidneys basically act as a filter for your blood, and their job is to get rid of excess electrolytes. And electrolytes mostly include sodium, potassium, bicarbonate, other components of the blood that are important for your body's functions.

But when you have kidney disease, your kidneys are not functioning as effectively as they were prior, and so they're not filtering as effectively. And so this leads to buildup of those electrolytes. And potassium is one of the more concerning ones.

[00:02:02] Host Amber Smith: So when the kidneys aren't functioning, and they're not filtering, that impacts digestion, it sounds like. Is it just potassium, or does it have an impact on other parts of digestion?

[00:02:17] John Babich: So there is a relationship with digestion as well with your gastrointestinal system. And there is some research that shows that when your kidneys are not filtering as effectively, your digestive system will sort of upregulate or increase the amount of excretion of potassium that your body will do to sort of compensate and balance things out.

[00:02:43] Host Amber Smith: Now we need potassium though, right? That's an essential... We need that, but we don't need too much of it?

[00:02:51] John Babich: Right. So just like any component of your blood or any other electrolyte. It's important to have not too much, not too little. But the thing with potassium is that it's mainly found inside of our cells, whereas sodium is mainly found outside of our cells. The relationship between those two is really important for cells to do their normal function.

And so the main issue with having too much potassium, in your blood, which is referred to as hyperkalemia -- hyper meaning too much, and emia meaning of the blood, and the kal being for potassium -- the main concern is that this can lead to abnormal heart rhythms, or cardiac arrhythmia. And that can be very dangerous for patients.

[00:03:40] Host Amber Smith: So that is the fear that... That's why people were told to reduce plant food intake if they had kidney disease, right?

[00:03:50] John Babich: Exactly. So the idea was that you eat these foods and they are high in potassium, and that you absorb probably most, if not all, of that. And since your kidneys are not functioning as well, you may not get rid of it, and it starts to build up. And some dangerous effects and complications can occur.

[00:04:12] Host Amber Smith: So what kinds of foods are we talking about that are high in potassium and potentially dangerous to people with kidney disease?

[00:04:21] John Babich: So the traditional wisdom was really about avoiding many foods like tomatoes, potatoes, greens, et cetera. And there's still a question of how much and how we should be encouraging patients to use those foods.

But the data that we examined showed that many of the instances in some of these research studies of hyperkalemia, or having too much potassium, were from plant foods like fruit juices, purees, sauces, dried fruit, things that are plant foods that have been processed. And so the potassium that is there is a lot easier for your body to absorb.

There are also potassium salt alternatives that are used for people who have high blood pressure. And so instead of it being NACL, which is sodium chloride for common table salt, you have KCL, so potassium chloride. And this potassium is also very accessible for your body. But there are reasons that people would use those salt alternatives, and it's important to understand some of the balances that are necessary to make those decisions.

[00:05:36] Host Amber Smith: Now, don't people with kidney disease also have to watch their protein intake?

[00:05:42] John Babich: Yes. So, that's also something that's typically modified for people with kidney disease. And it's often restricted, moreso in later stages of kidney disease. So as the filtration of the kidneys is diminishing the amount of protein that is recommended in the diet is usually restricted further.

[00:06:05] Host Amber Smith: This is Upstate's "The Informed Patient" podcast. I'm your host, Amber Smith. I'm talking with John Babich, who's in his third year at Upstate's Norton College of Medicine

Your paper, which was published in Advances in Kidney Disease and Health, says that plant foods may have qualities that would blunt potassium retention. Can you explain that a little bit?

[00:06:29] John Babich: Yeah, so there are three factors that we discuss, and those are the alkalinizing effects of plant foods. So they can help to reduce a complication called metabolic acidosis, basically having too much acid in your blood. And this is also linked to having too much potassium, so hyperkalemia.

There's also the fact that, generally speaking, unprocessed plant foods have low potassium bioavailability. And then lastly, plant foods as we know are high in fiber, and fiber has an impact as well.

[00:07:09] Host Amber Smith: I'm just thinking about a vegetarian or a vegan who has kidney disease would really be challenged to eat properly, right?

[00:07:20] John Babich: I think the prevailing wisdom that we are sort of promoting here is that you might actually be able to do this more effectively by eating more plant foods.

[00:07:32] Host Amber Smith: So what are the benefits of plant foods that patients with kidney disease may be missing out on if they've cut back on plant foods?

[00:07:43] John Babich: Just aside from kidney disease, there are a lot of cardiovascular metabolic benefits to eating more plant foods. I think many folks know that eating more fruits and vegetables is generally a good part of a balanced diet. And so, having a restricted diet that is avoiding these things, you're missing out on things like fiber, many of the vitamins and minerals.

[00:08:08] Host Amber Smith: It seems like it can be pretty complicated, following a diet. People with kidney disease may have other health conditions that come with dietary advice as well. So how do they follow more than one eating plan at a time, especially if they conflict?

[00:08:28] John Babich: Yeah, it definitely is a challenge balancing any conditions, as well as maintaining sort of a patient-centered perspective. Because I think any of us who are trying to eat differently or avoiding certain foods in our environments, know that dietary adherence is a challenge. And a prescribed diet can be pretty hard to follow. So you need to strike the right balance between patient wellbeing and, of course, safety.

But as you mentioned, like folks with kidney disease often have other comorbidities like diabetes, hypertension. And so it's really important to understand what's needed in those different dietary patterns, to improve the condition. And my colleagues recommend working with a registered dietician. And there are, also, renal dieticians specifically who work with patients with kidney disease and have an expertise in this area. And there are also online resources like nephrology groups and other patient organizations that can provide good information on this.

[00:09:37] Host Amber Smith: I was going to ask you, because if a person has a nephrologist or a primary care doctor who's following them for kidney disease, but that person doesn't really provide a lot of nutrition advice, should the patient maybe ask for a registered dietician consult?

[00:09:56] John Babich: I think that that is a prudent decision to make, and I would encourage someone to do so,provided that it is something that's part of their insurance and they're able to access that resource. But, the registered dieticians that I know and who are my colleagues are excellent and really try to center the patient's experience as well as balance these priorities. And I think that's something that can be very challenging, for a patient if you don't have as much expertise yourself. So I think it's a great recommendation.

[00:10:30] Host Amber Smith: And you mentioned maybe there's some resources, some trusted websites or books, even, that might explain this to people.

[00:10:39] John Babich: Yeah. From my experience, the the nephrology groups online are starting to incorporate some of these guidelines and move away from the sort of traditional perspective of the renal diet, as we call it. And so I think there are a lot of great resources online now, or are starting to be, that encourage patients to sort of liberate their diet a little bit. Again, with caution, because this is still a moving process, and working with the healthcare team is essential.

[00:11:16] Host Amber Smith: Now you're relatively early in your training, in your third year of medical school. But are you thinking that your practice is going to include some nutrition?

[00:11:26] John Babich: Yeah. I'm really interested in nutrition, and it's been something that I've been focused on prior to enrolling at Upstate and even choosing to pursue medicine.

I learned about this emerging field in medicine called lifestyle medicine. And I actually established a student interest group here at Upstate as well. Basically, lifestyle medicine seeks to treat chronic disease with behavior change through things like nutrition, but also exercise, sleep health, stress management. And we know that so many chronic diseases today are related to these factors. And we need to move toward giving patients information and guidance on how to learn these skills and hopefully to take more control of their health outcomes.

So I really hope to incorporate that into my practice and be an advocate for broadening that perspective in medicine.

[00:12:23] Host Amber Smith: So lifestyle medicine. I had not heard that before, but that seems very, kind of, proactive and like it maybe involves the patient, like they've got to kind of be involved in their health more.

[00:12:35] John Babich: Absolutely. It's a team approach. I've been associated with a lifestyle medicine team in New York City at Health + Hospitals. And seeing this in action -- and it's very much a multidisciplinary approach where you have a dietician, you have a health coach, you have the physician, and many other folks depending on what the patient sort of needs at the moment -- and the idea is working with the patient to learn about positive health changes, and then guiding them to make those changes with support, including from other patients who are going through the same process. And so it really helps to kind of kickstart those behavior changes and to kind of move in the positive direction for their own health.

[00:13:28] Host Amber Smith: Well, that sounds very interesting. Good luck to you. And thank you so much for making time for this interview.

[00:13:33] John Babich: Thank you so much, Amber.

[00:13:35] Host Amber Smith: My guest has been medical student John Babich, who's in his third year at Upstate's Norton College of Medicine. "The Informed Patient" is a podcast covering health, science and medicine, brought to you by Upstate Medical University in Syracuse, New York, and produced by Jim Howe. Find our archive of previous episodes at upstate.edu/informed. If you enjoyed this episode, please tell a friend to listen too. And you can rate and review "The Informed Patient" podcast on Spotify, Apple Podcasts, YouTube, or wherever you tune in. This is your host, Amber Smith, thanking you for listening.