Increase in filtration rate?! : I hear a lot... - Kidney Disease

Kidney Disease

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Increase in filtration rate?!


I hear a lot about the importance of a kidney-friendly diet for kidney patients.

But what I don't quite understand is if this diet actually helps the kidneys function better.

Ok, so we have less protein and potassium and other substances (depending on our body needs), we stay hydrated, and so on.

The eGFR (Glomerular "filtration" rate) raises and it makes us feel happy! But isn't it just because we are having less of those things? We have less protein, we'll have less creatinine in our blood.

The increase in "filtration" rate as a result of having less protein doesn't really sound like the filtration rate is increasing. It seems more like deceiving ourselves because there's less to get filtered anyway!

Or maybe I don't really understand the way it works. I don't know. Maybe, it is because the kidneys don't have to work as hard to remove waste products and excess fluid from the body, and the less hard they work the longer they can stay in shape! and as a result, the progression slows down?

But still, to me it doesn't sound like the filtration rate is improving!

Does anyone know anything about this?

34 Replies

Kidney friendly diet is to lessen the burden on the kidneys. There may be an increase in kidney function as a result of an appropriate diet. For CKD people the goal is to stabilise kidney function or at least slow the decrease in function as much as possible.I don't believe the filtration rate can increase more than a few points, unless you have been thrashing your kidneys through diet or other abuse. I keep remembering a saying ," we are what we eat", certainly appropriate.

Once you are on the slippery slope of CKD there is no turning back. Don't forget that kidney function depletes with age, naturally.

Sharam in reply to Cheyne13

I know what you mean...I hope it's not too late for me now.

Unfortunately, my doctor doesn't say anything to help me know where exactly I am. Or if I should start a diet or not. She just ordered more tests for next months the other day. It's been two months now and I hope the way she's acting do slowly doesn't get me on the slippery slope one of these days! (I don't even know if I'm there now)

Cheyne13 in reply to Sharam

I don't think it is a bad thing to eat wise regardless of what you kidney state may be. For years I ate what I fancied without concern. There is no doubt that some of what I consumed has not helped my health, and that is fine by me. If I had known earlier would I have changed, who knows, but I have changed now and although I still miss some of the crap I used to consume, in general I feel better for it. For the most part the brain has recognised it doesn't need all the crap food off the shelves, doing without is becoming easier. I used to laugh at being vegan, thought they were absolute nutters, but the new reality for me is I'm so close to being vegan it is no longer something to laughing about.You have the chance to protect your health, what you make of it is up to you.

If you are in the early stages of CKD there is no need to panic, life continues with some changes.

I have had little support from Dr's and had to find my own way through. This forum was the turning point for me and life looks miles better than the first perception of CKD.

I’m in exactly the same boat as you ! We’ve taught ourselves to enjoy/accept/almost relish the almost- vegan diet because we know how it helps us!

Sharam in reply to Cheyne13

True. I've started a diet anyway. Regardless of my kidney condition. Of course it isn't as strict as most kidney patients do, but I think it is wise to eat wisely anyway. Almost no red meat for now, and no junk food or processed food. A simple life style change would do me good anyway.

Cheyne13 in reply to Sharam

One other thing I discovered is that dark cola drinks are seriously bad for anyone with impaired kidneys, and not too good for anyone else. The colouring can not be filtered by the kidneys and is barely possible with 100% function. It also eats the calcium from your bones. The sugar free drinks the sugar substitute damages kidneys. Rule of thumb is to limit the intake to one medium glass per day with good kidneys, none for those of us with CKD. With CKD have you vitamin D levels checked as this impacts your immune system, kidneys produce the vitamin D. Don't take vitamin D without Dr's control as too much can have severe consequences.

BassetmommerNKF Ambassador

GFR is a number equated to amount of filtration ability left in the kidney. Protein is a product that leaks out of the impaired kidney and can cause other issues to the body. Not eating certain types of protein help the kidneys to function. But just changing the protein will not improve the kidney. Its the whole diet and lifestyle that makes the improvement. But in some cases, all the good diet and healthy living will not stop the decline. It will only slow it down. Here is a good article to explain it.

Sharam in reply to Bassetmommer

Well, yes. You're right about proteins.

To calculate GFR though they use serum creatinine, age, race and gender. Creatine (not creatinine) is a natural substance in our muscles and creatinine on the other hand is the waste produced when creatine breaks down.

So when the kidneys don't do their job well, that is, they can't filter the waste (creatinine) and excrete it into urine, the amount rises in the blood. The less protein we take the less creatine is in our muscles and as a result less waste (creatinine) is produced.

So it seems like it's not the kidney's ability to filter the waste that is increasing. It's just that the amount of waste is decreasing because of decrease in the substance from which it's produced! Same thing seems to go for potassium, calcium, sodium and so on... Well it's how I understand the process, and I might be wrong.

Creatinine in blood and creatinine in urine seem to be two different things. Cause when it's in the urine it means the kidneys have filtered the waste and the amount in the blood has decreased.

When it comes to proteins though, it should be the other way. Just as what you said. There shouldn't be too much protein in the urine...

Thank you so much for sharing the link, btw. 🙏

God bless

apopnj01 in reply to Sharam

i dont understand why they dont put height and weight into the equation and some measurements do - age race gender means someone age 50 at 6'2" 150lbs has the same metabolic rate as someone 50 5"10 185lbs - doesnt make any sense -

Sharam in reply to apopnj01

I don't know, either!I was reading an article and it said that a creatinine level of 1.9 can be normal for a very muscular persons.

There seem to be a lot more factors than just race, gender and age to consider before conclusion...

But sometimes it becomes complicated cause many doctors don't care about GFR at all!

Even if it isn't an accurate indicator (though many websites say it is), doctors should take it into consideration.

I think as some people just said it is best to order complementary tests like Cystatin C (which seems to be more accurate), if the GFR is higher than normal.

Darlenia in reply to Sharam

Completely agree with you. The tests should be fine tuned to reflect height, weight, etc. Recently, there was an exchange on here regarding the GFR bias against the black race . Apparently race doesn't matter at all - that's a holdover from prior times preventing that population from getting proper treatment but it's still used today in many labs. (Many articles point out this problem.) Much more needs to be done to accurately reflect each person's actual health status.

Sharam in reply to Darlenia

Oh, wow! How upsetting! I had no idea it might have to do with racism! Though I still hope it isn't true!

Bet117NKF Ambassador

Hi Sharam,

The point of healthy eating is to take the pressure off your kidneys and try to stabilize and stop progression of the disorder.

All good questions and food for thought.

Jot your thoughts down and review them with your nephrologist when you see him/ her as they would be the best person to break these concepts down and explain them to you in relation to your individual case. Please note the response and review.

Looking forward to hearing how your appointment went.


Sharam in reply to Bet117

Hello, Bet

I hope you're doing well.

Yes! That's what I was thinking.

Taking the pressure off the kidneys must be what a renal diet does, not increasing the actual ability of the kidneys to filter the waste (maybe in some cases or to some extent it does. I'm not sure!) ...

I will ask my next nephrologist about these things to better understand what I'm gonna do.

Unfortunately my current doctor isn't interested in answering her patients' questions. All she did last time was order more tests for next month, and prescribe a muscle relaxant, and some other medicine for my high blood pressure. I emphasized that my blood pressure was usually low (9 on 6) and I thought it was high then because of anxiety and stress (I was really stressed in her office!) , but she said I could take some and quit if I felt bad!

I think I'd faint immediately if I took the BP pill and muscle relaxant together!

orangecity41NKF Ambassador in reply to Bet117

I agree the diet is important and takes the pressure off the kidneys thereby is less damage.

Bet117NKF Ambassador

Hi Sharam,

Good to hear from you!

We are hanging in there in these crazy times, thanks for asking.

Gosh what an awful time that you are having with your PCP/GP.

Think about this; if any doctor whose job is to listen to, communicate clearly with, and provide the best care for their patients and is being paid well to do so and doesn't do so, are they worth keeping?

You deserve the best care possible and a medical team who communicates openly with both you, the patient and other members of your medical team.

If this person is giving you muscle relaxers with no explanation and is not clear about BP medication, then perhaps it is time to seek the care of a doctor who will give you the answers and care that you deserve.

Unfortunately, as patients we have to be our own advocates; read, ask questions and not simply accept a medication etc. without a purpose and explanation.

Here is an article about when to part company with your doctor. Give it some thought.


Stress and anxiety is neither good for you, your family who supports you and your kidneys.

Please reach out and let us know how you are and what direction you have taken.

It will work itself out; you'll see!

Positive thoughts!


Sharam in reply to Bet117

Good to hear from you, Bet.Glad to hear you're hanging in there. We all must...

Right. Doctors must listen to their patients and try to explain things when the patient has concerns about something. I don't know maybe my doctor feels I'm questioning her knowledge when I ask her questions about the test results! Some doctors are just too arrogant (SOME doctors!)

You are totally right about anxiety. That's weird cause I keep telling people around me about the bad effects of too much stress and anxiety, but when it comes to myself, I can't help it! Maybe it's time I visited a psychologist for that now!

Thank you so much for the positive and hopeful thoughts.

Back at you.


Bet117NKF Ambassador in reply to Sharam

Hi Sharam,

You are no different than anyone else; we are often our own worst enemies and can't see ourselves even if we had 15 mirrors.

Great that you have loved ones to bounce ideas off and share ..and you have us.

If you feel that you would like an impartial person to talk to, it is no shame as you are taking care of yourself. Only you know yourself and what you need.

At this point, consider another PCP asap and clarification and direction from a nephrologist before jumping the gun as to the physical - it is hard. Get that great and communicative medical team together.

Making some diet modifications to healthier eating is laudable. Once set with a definite dx from a nephrologist and working with a dietician will best set your lifestyle and what foods will best meet your needs.

Remember that it is all a process and you are at the beginning. Waiting is far from easy as is the unknown.

Reach out as always here to listen.


Sharam in reply to Bet117

Yes, of course. the next step is to visit a new nephrologist! I'm really glad I met you nice people here. It's helped me a lot since I received my first test results.

God bless you all!


Bet117NKF Ambassador in reply to Sharam

Our pleasure! We are glad to have you as well. Be will all work out!


Sharam, you might find the subject of cystatin-c and its relationship to the diagnosis and prognosis of kidney disease interesting.

Sharam in reply to Marvin8

Yes, Marvin. You're right. I read about that somewhere, but my doctors haven't ordered that test so far. Maybe I'll ask my doctor about it next time (Hope he won't think I'm trying to tell him what to do! Some of them are just too sensitive about it, at least where I live hahaha)

Marvin8 in reply to Sharam

Many doctors are completely unaware of the cystatin-c test. You have to be a little bit assertive to get the test done, but I've never had a problem. The combined creatinine and cystatin-c formula tends to be the most accurate of all the eGFR measurements because each test by itself has different shortcomings.

Once nephrons are dead, they are gone. Your body will not replace them. Kidney function never improves. Creatinine is just one of many things your body removes and is used to ESTIMATE kidney function. Cystatin-c is another. Creatinine in general is a very poor indicator of kidney function because every person produces different amounts of creatinine (and the amount you produce changes all the time) based on many many factors. The eGFR calculation was created by averaging a group of people with confirmed kidney disease. The reason they use it at all is because it is a cheap and easy blood test. There has never been a large scale study to find out what creatinine levels should be in healthy people, so we aren't really even sure what is 'normal'.

Sharam in reply to MattKansas

That makes total sense! None of my doctors have ordered a Cystatin test though. I don't know why. Maybe they thinks it's not necessary now. But I'll ask my doctor about it and whether it's ok to do it now. Thank you for your informative response.

MattKansas in reply to Sharam

What's really bad is the people who created the eGFR calculation never intended for it to be used to diagnose CKD, but here we are.

Hey Sharam! Believe me, I’m with ya on that one! Lol! When I was reading your post, I couldn’t believe how much we think alike! But, I have to say, I’m pretty sure everyone here would say the same. You’re right, our GFR probably does get better because we have made those adjustments to our diets. But then, I suppose that’s because our kidneys are now more positively responding to not being hammered by large amounts of the substances that, in their weakened state, they can’t process very well anymore. The whole reason why our kidneys fail us at some point in our lives might be due to so many things. Age is definitely one factor, but genetics is another, and let’s face it, all the processed foods, the use of anti-inflammatory medications, and other chemicals we ingest from time to time over the years, may also be contributing to it.

It may even just be an evolution thing. We live in an ever-changing atmosphere. Or maybe the impact on our systems, of living inside of a world that some scientists have said is like living inside of a microwave. I know many people might disagree, but I believe that the effects of global warming on our bodies is most likely taking its toll on our health in many ways. And I believe that this is true of most diseases we hear so much of these days that we’re not as prevalent years ago. It’s sad really. But the only way to survive it, is to try to make the lifestyle changes we need to slow any progression of it. Unfortunately, right now, it’s the only option we have if we expect to exist for as long as possible without the need for dialysis.

You are right though. It is as though we are accommodating the illness, but really, what other choices are there? God bless. 😊🙏✌️

Sharam in reply to Sammi_n_Munk

Hello, Sammi!Hope all is well with you!

I know right! Though, I don't really know how knowing about the process can actually help me or anyone struggling with CKD, but these are the kinds of thought that flash across my mind every now and then! It's not like I'm trying figure out a way to cure the disease hahaha

Some might think it's a waste of time to think about stuff like this. "Just do what the doctor says. Why would a patient think about how the process happens!"

I don't know, maybe they're right. You might be better off not knowing things that can cause even more anxiety! lol

And you're totally right... For now, that's all we can do anyway... A life style change. Better late than never... My doctor hasn't told me anything about whether it's time for a diet. But I have started a healthier diet now. Much less red meat for now. and other substances in moderation. I didn't really care much about what I had before. But I guess it's time now. Whatever the results...

Thank you so much for all the positive thoughts.

God bless

Google DadAdviceTV....this man is a Kidney Patient and does an excellent job of explaining the relevance between diet and our kidneys.

It also depends on WHY your kidney function has decreased...Is it from a bad fall ? of your medications or vitamin?...that after you heal or stop taking you kidney may rebound...or if your kidney dysfunction is permanent.

Until you know all those things you might want to follow a kidney wont hurt you either way.....Best Wishes

Oh, thank you so much. I'll look it up asap.

Actually my nephrologist suspected an infection or something (resulting in glomerulonephritis) cause I've been suffering from ITP for 5 years now (my doctor said the ITP must have started following an infection)

But the thing is none of my doctors did anything about the infection.

I remember telling my doctor about pain in my submandibular lymph nodes (below my jaw) , a few years ago and he said "It's nothing serious. It'll go away"

But it never did...

If they had done something about the infection, I wouldn't be struggling with a kidney problem now.

It's all in the past, I know... But I sometimes think to myself, if some doctors were more responsible...

For now, as you said, a healthy diet wouldn't hurt... That is all I can do anyway.

WYOAnneNKF Ambassador

Ask your nephrologist.

Bet117NKF Ambassador in reply to WYOAnne

Agreed! 👌

Sharam in reply to WYOAnne

I would. Unfortunately she doesn't seem to be interested in answering these sorts of questions! But I will definitely ask my next doctor!

Sharam,A kidney friendly diet heals by decreasing the load on the kidneys, lowering the pressure inside their filters and helping the coping mechanisms in the kidneys which are on overdrive in patients with CKD. Thus they decrease scarring and over time, you see actual improvements in filtration.

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