Written by Christopher Kelly
April 9, 2015
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Christopher: Hello and welcome to the Nourish Balance Thrive Podcast. My name is Christopher Kelly. And today, I'm delighted to be joined by Dr. Lynda Frassetto. Hi, Lynda.
Lynda: Hi.
Christopher: Dr. Frassetto is a Medical Doctor and Professor of Medicine and Nephrology at the University of California, San Francisco. She is the Director of Clinical Research Center at UCSF, supervises patient care at three of the university's hospitals and helps teach courses on improved communications and behavior stress modification techniques. Now, that's kind of fancy. I think we should, first of all, since it's the topic of today, explain what nephrology is.
Lynda: Nephrology is really the study of how the kidney works, and what happens when there's problems with the kidneys and how to take care of people whose kidneys don't work anymore, which is dialysis. So there's a bunch of different things that kidney doctors do.
Christopher: Okay. Why don't we start by explaining, giving some background about what the kidneys do? The reason I thought this was an interesting conversation is because I think the kidneys, they're not misunderstood but certainly in mainstream media or science or just lay people like me, the thing that they do -- People think of them just as an organ that filters. Whereas they're far more interesting as an organ that actually regulates homeostasis within the body. So why don't we start by you describing what exactly the kidneys do?
Lynda: All right. Really, the kidneys have probably three different kinds of functions, maybe four. And we're actually learning more about this as time goes on. So one is, yes, filtration. A lot of blood filters through the kidney every minute. So the fluid in the bloodstream is constantly being filtered through the kidneys. That's the first thing. But once the fluid gets through the filters then the body has to decide what to do with all the stuff that's in the fluid.
There are very complicated systems in the kidney tubules which reabsorb the water and the minerals that you need and some of the other things that you don't want to lose. And as the fluid goes through the kidney tubules, there are mechanisms for putting water in and taking water out, putting chemicals in and taking chemicals out from the fluid that's already been filtered. So that's one thing. The second thing is the kidney is able to take things from the bloodstream and put them into the fluid that's in the tubules and vice versa. So exchange of minerals and organic materials goes back and forth across the kidney tubules.
Christopher: So, the kidneys are actually regulating fluid and electrolyte balance right here.
Lynda: Right. And reabsorbing things that you might not want to lose like some small protein compounds and a variety of different things like that. In addition, the kidneys make hormones. So, for example, the hormone that allows you to make red cells is actually made in the kidney tubules. And it's one of the reasons why when your kidneys don't work very well, your blood counts go down and down. And we actually now are able to give you back that hormone so that you can now keep your blood count up.
Christopher: Okay. So, I think, maybe, maybe not, all of the cyclists listening to the show, their ears might have prick up because you're talking about EPO, which is the hormone which stimulates the production of new red blood cells and most endurance athletes know that red blood cells and oxygen deliverability is the main limiting step in the production of energy when you're breathing and using oxygen. So that's a pretty important step right there.
Lynda: Right. It is. And so that's why if you go to low oxygen environments like up on the top of mountains, your body will realize that you're not getting enough oxygen and your red cell count will go up. So that's actually one of the reasons why athletes train at high altitude. And then, finally, the kidneys also regulate blood pressure. So there's a very complicated system by which the body recognizes whether or not there's too little blood pressure or too much blood pressure.
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And the kidneys are part of the system that decides how to make the blood pressures go up and down. So it does a lot of different things. And not all of the things that it does are -- How could I put this? Sometimes, it will do one thing which might be counterproductive for some other kind of thing that it's doing. And so when we talk about people that have kidney problems, oftentimes it's a balance of trying to make the kidneys do what you want them to do.
Christopher: Okay. The other thing I thought that was interesting about the kidneys is they're one of the few organs that are able to produce new glucose from something that wasn't previously glucose. So I'm talking about gluconeogenesis. Am I right in thinking that?
Lynda: Well, actually, it's interesting because it's true. We didn't think so but it's one of the newer discoveries. We usually thought that the liver did that.
Christopher: Right.
Lynda: But it's right. Actually, the kidneys do that too. And there's some evidence that one of the reasons that, as your kidneys fail, your glucose control gets better is that we used to think that it was related to the fact that you just weren't filtering insulin anymore. But it actually may also be regulated by the fact that now your kidneys aren't making glucose anymore. So it's one of the new theories or glucose improvement with advanced kidney failure.
Christopher: Interesting. I mean, I think that was my point. It was I wanted to draw attention to the kidneys as a master regulator within the body. And, of course, they're home to these infamous adrenal glands that sit right on the top of them that we know secrete the most important of all hormones, cortisol. And, yeah, really a lot going on there beyond just filtering the blood and producing urine.
Lynda: You really shouldn't think of the adrenal gland as being part of the kidney.
Christopher: Oh, really?
Lynda: It's actually part of the nervous system.
Christopher: Okay. But that is where it lives though, right? I've got the location right, at least.
Lynda: You got the location right but that's a completely different type of problem. And so really, you don't want to mix up the two.
Christopher: Okay. That makes sense. The reason I started becoming more interested in the kidneys in particular was I saw some crystals on a urine analysis that I did. And I started looking into what causes kidney stones? It seems like they're quite a mysterious condition. Can you tell me what you know about kidney stones? I mean, obviously, not everything you know about kidney stones but just give us some background.
Lynda: Yeah. There's many different kinds. Some of the factors that cause them are genetic and some of them are environmental. There are some very, very specific kinds of kidney stones which are inherited like the one mutation inheritance, which is like cystine stones, which there's now we test newborns for it. We are able to find newborn babies that have this problem and treat them appropriately. There's some very specific things, very specific mutations.
But there are probably also other mutations that are not quite so dramatic. Because we do know that kidney stones run in families and we do know that at least for many years the ratio of males to females who got kidney stones, men were much more likely to get kidney stones than women were. That's not true anymore. And it appears that there's been a big increase in kidney stones both in women and in younger children or adolescents.
So that's actually been something that we've been looking at is why are kidney stone incidents are increasing in these other populations? In addition, there's pretty clearly environmental factors. So diet absolutely positively is one. But possibly global warming. It's been known for many years that there's a latitude incidents with kidney stones that the closer you get to the equator the more likely you are to have kidney stones.
Christopher: No way. It sounds like you're kidding me.
Lynda: Right. And now with global warming, with the temperatures going up at higher latitudes, we're actually seeing that these kidney stone incidents increase going further north. And that may simply be a hydration thing.
Christopher: Oh, really?
Lynda: Kidney stones, like many crystals, form when there's too much, there's a high crystal to water ratio, which allows the crystals to actually -- well, the chemicals -- to actually crystallize and form little tiny crystals.
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And those are the seeds that cause, that help the rest of the stone to grow. So the one thing that we tell everybody with kidney stones is drink lots of fluid because that keeps the concentration of these various chemicals very low all the time. So, hopefully, these little tiny crystals won't form.
Christopher: Okay. So tell me about diet then. How does what I eat make a difference to whether or not these crystals are formed?
Lynda: Right. So they really depend on what kinds of stones you have. I'm going to make this really simplistic. Some kidney stones form in acid urine and some kidney stones form in alkaline urine. And so depending on whether your urine is acid or alkaline you're more likely to get one kind of kidney stone or the other. And what you eat will make your acid, your urine more acid or more alkaline. So depending on the type of kidney stones that you have, you would want to try to do exactly the opposite. So if you have a kidney stone that forms an acid urine, you would want to try to eat a high alkaline diet or take alkali supplements. And if you have the stones that form an alkaline urine, you'd want to try to do the opposite.
Christopher: Okay. I think the two most commonly known are uric acid and calcium oxalate. So which way round does it go?
Lynda: Right. Both of those stones form an acid urine. And oftentimes they are found together. So a stone doesn't have to be just one kind of crystal. It can be multiple kinds. So oftentimes you find stones that are combination of uric acid stones and they have calcium oxalate in them. But calcium oxalate is far and away the most common kind of stone for people to have. In western diet, most people are eating a high acid diet and so their urine is acidic.
Christopher: Okay. Yes, so tell me -- So walk me through the process how you go about diagnosing this. First of all, do you worry when you see the crystals on the urine analysis or do you not worry about that?
Lynda: There's many different kinds of crystals and they can be completely normal. So just seeing crystals on a urinalysis is not something specifically to worry about. I mean, most people, when they come in with kidney stones come in with pain. I mean, kidney stones hurt. This is not some subtle hard to figure out kind of diagnosis. This is somebody coming in going, "Wow, for the past three days I haven't been able to like this. It hurts to much."
Christopher: Right.
Lynda: Really?
Christopher: Yes. So this is what I'm all about really, is kind of digging into the blood work and whatever other bio markers I can get my hands on to see if you can spot this happening before you've got a kidney stone and you're in the doctor's office complaining with stabbing pains. I mean, what do you look for? Say, for example, you just talked about hydration. And this is something that really interests me because I noticed since I switched to a high fat ketogenic diet that my thirst really changed. I'm a lot less thirty than I used to be. I'm not sure whether that's a good thing or not. Are there any markers? Do you look at a specific gravity or is there anything I can quantify that shows whether or not I'm properly hydrated?
Lynda: So specific gravity is probably the most useful simple thing that you could measure because it's measured on these little dipsticks so you get the answer in like 30 seconds.
Christopher: So you can buy these things from Amazon even.
Lynda: Oh, yeah.
Christopher: I'd forgotten the name of the company, the one where I bought. But it's super cheap. They're like $7 for these dipsticks.
Lynda: Right, exactly. So if your kidneys are working, okay, and you drink a lot of extra fluid, then the kidneys are going to dump all the extra water. And when you do that -- I mean, you know this. If you pee after you've been drinking a lot of water, the urine is almost clear. And that's because it's mostly water because the kidneys are working and they're dumping all the extra water. On the other hand, if you're in the desert and you don't have any water at all, the kidneys need to hold on to all the water that they can. And so then you would put out a very, very concentrated urine, as concentrated as the kidneys can make it. So there's no one right specific gravity. It depends on what the situation is.
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Christopher: Okay. Interesting. Interesting. With regards to kidney health, is there anything -- So I thought this BUN on the blood chemistry and then also creatinine, which are typically or traditionally regarded as kidney markers. What do you look for in a blood chemistry when you're trying to assess somebody's kidney health?
Lynda: Right. So those are the two things that we look at. And they are very easy to measure. They've been used for many years. And they look at -- BUN is blood urea nitrogen. And creatinine is something that comes from muscle. And muscles, they build up and break down all the time, more or less creatinine secretion is constant over 24 hours. And so it gives us an -- Looking at creatinine gives us an idea of how much creatinine is being made versus how much creatinine is being excreted in the urine.
And the balance of that gives us the number in the bloodstream. And so that tells, that gives us an idea of what is normal. Blood urea nitrogen comes from protein breakdown. So if you eat a big steak, your blood urea nitrogen levels will go up. If you eat an extremely low protein diet, then your blood urea nitrogen levels will go down. More or less, as your kidneys fail, both of those numbers go up. The rate at which one or the other one goes up helps tell us what kind of kidney problems you might be having.
Christopher: Okay. So the commonality there is that these two compounds have been produced elsewhere in the body and it's the kidney's job to get rid of them. And when you see an elevation that might be an indication that the kidneys are not doing as good a job as they should, correct?
Lynda: It's the change and the balance.
Christopher: Right.
Lynda: Either increased production or decreased excretion so that the balance is higher.
Christopher: Okay. So the problem I see with this is you could have -- It's not enough information to actually pin down whether or not there's dysfunction. So if I was to have poor kidney function and also be eating a low protein diet, then you would see this normal ratio and you wouldn't be able to make a diagnosis. Am I right in thinking that?
Lynda: No. Actually, that's not true. So what you would see then is you would see that the blood urea nitrogen levels are fairly low but the creatinine levels would be fairly high.
Christopher: Okay.
Lynda: And so that would be one of the things that we would look at and we would say, "Aha, maybe you have a kidney problem."
Christopher: Okay. And then so the creatinine, that comes when the breakdown of muscle, but am I right in thinking that if there's -- If you have low muscle mass then you'd also see low creatinine. So I'm thinking in particular of the elderly. So they have got maybe a low protein diet, that poor kidney function, low muscle mass. I'm just wondering whether it would be possible to see normal results and then still have an issue.
Lynda: Yeah. Actually, that's a great point. So that's right. If you are very small with low muscle mass, so small Asian women and old people with low muscle mass, and people who are not eating well, although obese people can have low muscle mass and not eat very well too. But yeah, that would -- The numbers would look okay but that doesn't necessarily mean that you're okay. We have other tests that we do to try to guess whether or not your kidney function is really okay or not.
Christopher: Okay. Interesting. That was something else that I was interested in, is that how beat up would your kidneys have to be before you start seeing problems on your blood chemistry? Because I've heard that you can even have a kidney removed and still have a very normal looking blood chemistry? So how bad does it have to get?
Lynda: Okay. So as kidney function declines -- And I don't want to talk about transplant because there you have somebody with two normal kidneys of which you've taken out one normal kidney.
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And so although you're going to have transient rises in the chemistry levels, the other normal kidney is actually going to grow in order to help get rid of the extra [0:20:19] [Indiscernible]. So now one kidney has to do all of the work for two kidneys and that one kidney actually grows in order to be able to help take the stress of the added load off of itself.
So that is a different kind of problem. What we talk about when we talk about most kinds of kidney dysfunction is, one, age. As you get older, chances are your kidney function is going to decline. And it's taught that that's normal. However, when we've done some studies, we can see that there's always a group of people whose kidney function does not decline with age and that actually makes me think that kidney function getting worse with age is actually pathologic, meaning that there's something wrong with kidney.
And in the western societies, the most common reasons, and this is far and away. This accounts for three-quarters of all kidney disease, high blood pressure, diabetes, obesity and atherosclerosis. All of which are vascular problems. So there is damage to the vascular system which then damages the kidneys as well as damaging the other organs in the body like the heart and the brain and whatnot.
But we see this in the kidneys. And so really as you get older, your blood vessels get all clogged up and that's bad for the kidney and kidney function slowly declines. But you're probably not going to see it until you lost about half of your kidney function. And that would be only with blood test. Like you couldn't feel it. Like you can't look at somebody or listen to what they're complaining of and tell them what their kidney function is. It's a blood test only thing.
Christopher: Okay. And then is it presumably an advanced blood test I probably never heard of. This is not something you're going to see on the standard blood chemistry or basic--
Lynda: No, we would first look at BUN and creatinine. And then the other thing that we'd look for is protein in the urine. Many diseases like obesity and diabetes and poorly controlled high blood pressure damage the kidney filter system so that now you're leaking protein into the urine.
Christopher: Okay. And so what's your best advice then for anybody that's concerned about their kidney function or kidney health? What do you think they should be eating? What type of diet?
Lynda: Well, okay. So what we really tell people is you should control your blood pressure. Make sure you don't have diabetes or control your diabetes. Get yourself checked out so that if you have protein in the urine. There are specific things we do for that to try to lower the urine protein excretion which we think helps keep the kidneys functioning better. And then if you're really overweight -- So I'm not talking about a couple of pounds overweight.
I mean, if you're obese or if you're morbidly obese, then you have a much greater chance of actually causing the kidneys to fail because the stress of filtering all of the poisons from being really, really overweight can be damaging to the kidneys.
Christopher: What do you mean by poisons?
Lynda: The kidney filters a lot of different things. And the sort of catch all phrase for them is uremic toxins. And some of these are small water soluble molecules like urea. Some of them are larger molecules like beta-2 microglobulin or parathyroid hormone. And some of them, the ones that they can't filter are these highly, small highly found protein molecules or nitrogen compounds. And all of these things build up in kidney failure. And some of them we actually believe that build up itself actually causes the kidneys to fail faster. And so they go under this catch all phrase of uremic toxins.
Christopher: Okay. Interesting. So the diet recommendation then, how do you think the paleo diet, or I'll be more specific, a diet that's got a ton of vegetables in it and some high quality protein, unprocessed protein, and then maybe 50% or more saturated fat. How do you think that would jibe with the kidneys? Is that a good thing or is that too alkali or what?
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Lynda: Right. So if you have -- So let's get back to kidney stones. If you have calcium oxalate or uric acid stones, you would want to eat an alkaline diet which means the diet high in fruits and vegetables. Absolutely, positively. No two ways about it. And remember that in the diet, it's not any one thing that's bad. It's the overall balance of the acid foods versus the alkaline foods. So if you're eating a paleo diet but it's all protein and it's no vegetables or fruit, then you're going to eat a very high acid diet. I mean, paleo is not one diet.
Christopher: Of course, yeah. That's why I try to be more specific in a not so elegant fashion. I was trying to pluck something at the top of my head that the actual type of diet that the people are eating where paleo doesn't mean much.
Lynda: And then really, so it's going to be the balance of the alkaline foods versus the acid foods. So if you're eating a mostly alkaline diet and you have a tendency to form calcium oxalate or uric acid stones, then it would be really good. There are other kinds of stones that form an alkaline urine. And if you have those stones and you do not want to be eating an alkaline diet and you would want to be eating a more acid producing diet. So first, you have to know what kind of stone you have to know what kind of treatment you need. And so it's obviously not the same for all stones.
Christopher: Okay. And so, the PH of your urine then, is that a reliable indicator of how acid or alkaline your diet is?
Lynda: When your kidneys are working, yeah.
Christopher: Okay. I want to simplify everything down but, of course, it's always more complicated. Yes, so for me personally, my urine sample was very, very alkali. It was 7.5, which is the top end of the reference range. I wanted to ask you about the ketogenic diet specifically because that's the way that I eat and I know a lot of people listening are interested in this diet. Now, I think of ketones as being acidic and maybe making your body more acidic environment but that's the opposite of what I'm seeing on this urine sample here. What are your thoughts on like high fat ketogenic diet and kidney health?
Lynda: Right. So ketones are neutral but turning ketones into ketoacids make urine acid. And whether or not you have a high ketone diet or not will depend on what else you're eating. So there was a really excellent paper by woman named Virginia Hood, who showed that if you're eating a high acid diet then your body tends to make less organic acids. And if you're eating a high alkaline diet, then your body tends to make more organic acids. And ketoacids are organic acids.
So really it's going to depend on the balance of what else you're eating. And to decide where are you going to come out on the scale. It's not any one thing. I mean, everything that the kidney does is the balance versus, production versus excretion.
Christopher: Okay. So I found a couple of papers that I thought were quite interesting showing an increased risk for children that were being treated with a ketogenic diet for epilepsy and their increased risk for kidney stones. Do you think there's anything going on there that's some kind of random noise or maybe something else related to--
Lynda: No. Actually, the same thing with the Atkins diet.
Christopher: Right. Yeah.
Lynda: Yes, it's a high acid diet in general because most people do not eat an alkaline diet. Most people eat an acid diet. And now you're eating a lot of things that cause acids. And so if you have a tendency to form kidney stones at low acid urines and now you're eating a high acid diet, you are putting yourself at risk for forming kidney stones. The problem is, is that we don't really know who's at risk. Yeah, there are some genetic predispositions but that doesn't mean that I can look at any one person and say, "I know you're going to get kidney stones."
I mean, kidney stones are not uncommon but they're not hugely common either. We say 1% of the population might get them. That's a lot of people. But percentage wise, it's not a huge -- I mean, 99% of people are not going to get it.
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It's really impossible for us to project who will get kidney stones. But once you have a kidney stone, it's very easy for us to predict that you're at risk for a second one.
Christopher: Okay. I should clarify. When I'm eating a ketogenic diet, that it's not really Atkins and I'm just eating far too many vegetables. Like when you look at the volume of the food that I eat it's by a far a plant-based diet and every single plate has multiple servings of vegetables. It's still a ketogenic diet just about because of the calorific content of the fat and mostly metabolizing fat for energy. But yet it's not -- So do you think then that the problem with the Atkins diet or the children that are on this ketogenic diet for epilepsy is they're just not really consuming any fruit or vegetables at all. They're just consuming maybe weird milkshake mixes with high fat in them or something like that.
Lynda: Right. Well, it's really hard to -- When you're on a ketogenic diet, you're trying to do something very, very specific. And even though the body is going to try not to make ketoacids, ketoacids are one of the ways that the body excretes acid. And so it only has a limited number of ways to excrete acid and excreting ketoacids is one of them.
Christopher: All right. I move on. I wanted to just finally get a quick update on the paleo PCOS study. So for those of you that didn't listen to Lynda on my last podcast, Lynda is organizing this study that looks at the efficacy of the paleo diet for treating PCOS. And so can you just give us an update what's happening with the study?
Lynda: Yeah. Thanks for asking. We've actually started recruiting for the study. So anybody listening to this, if you have polycystic ovarian syndrome and can come to the UCSF Clinic for the PCOS, we'd be interested in maybe trying to recruit you for our study. So we started to recruit. We have our first two subjects. And so far, it's actually going pretty well. So we're really pleased. And I have to say that it's not just me.
I have a whole team of people that I'm working with including the PCOS clinic director, a couple of study coordinators, our diet coaches, my colleague from the diabetes clinic and our electronics and diet questionnaire guys from the Osher Center. So actually there's a lot of different people here working on this study.
Christopher: Okay. And then so what's the criteria? How do I know if I'm going to be eligible? Is there a questionnaire online or something?
Lynda: There is not. Women with PCOS, there are a variety of things that they're told to do. Typically, if those don't work, they're referred to UCSF clinic. And so these are mostly women who have not been able -- Like for example, there's a medication called Metformin that we often use. So these are women who, for some reason or other, Metformin didn't work or they couldn't tolerate it or, for some reason, you know, they just couldn't take it. Or they were put on hormone therapy and they couldn't tolerate it. We're mostly working with people for whom medication therapy or PCOS hasn't worked.
Christopher: Okay. Interesting. So if you get in touch then, if I provide the contact details and if you think you might be eligible if you get in touch then you'll be able to assess whether or not you are eligible to take part in the trial.
Lynda: Yes, absolutely. And it's also on the UCSF and clinicaltrials.gov website.
Christopher: Oh, excellent. So that means that if it doesn't work and it turns out that paleo is a terrible intervention for PCOS, it's not just going to disappear into the ether and everybody will know about it.
Lynda: I mean, the reason we started doing this in the first place is because with our last study, it worked particularly well in the people who were the most insulin resistant. And so really that's what we're looking for in this study, is people who are particularly insulin resistant.
Christopher: Okay, interesting. I would definitely link all this information in the show notes for this episode.
Lynda: Thank you.
Christopher: I want to thank you so much for coming on and sharing your knowledge. It's a pretty amazing thing to have someone like yourself just come on and tell all this amazing stuff about the kidneys. I'm really grateful for it. Thank you.
Lynda: I really appreciate it. I hope it wasn't too, either too non-specific or too hard to follow. I mean, actually kidney medicine is a sub-specialty of internal medicine. So after you spend three years learning internal medicine, you spend another couple of years just learning about the kidneys.
Christopher: Right. What we're saying is it's almost an impossible task to reduce it down into a 30-minute conversation.
Lynda: 30 minutes of what does the kidney do, exactly.
Christopher: Excellent. Well, thank you so much. It was a pleasure. And hopefully, we can get you back on again and talk about the PCOS study again, see how that's going.
Lynda: Okay. Thanks.
Christopher: Cheers, Lynda.
Lynda: Great. Bye.
Christopher: Bye.
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