Eating Cooked Meat and Kidney Disease(creatinine_GFR)

[obsidianom]

Eating Cooked Meat Can Distort CKD Stage in Diabetes

Miriam E. Tucker
Oct 02, 2013



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Eating cooked meat can raise serum creatinine significantly enough to drop the estimated glomerular filtration rate (eGFR) calculation and in some cases lead to a misclassification of chronic kidney disease (CKD) stage in patients with diabetes, a new prospective study has found.
 
The cooking process converts creatine to creatinine in meat, which in turn transiently increases the diner's serum creatinine. Fasting is not routinely recommended for renal-function tests, but these results suggest that it should be or, at the very least, that patients should avoid eating cooked meat before undergoing such tests, say Sunil Nair, MRCP, from the University Hospital Aintree, Liverpool, United Kingdom, and colleagues in their paper published online September 23 in Diabetes Care.
 
The message "is that serum creatinine and eGFR should not be considered absolute values, and there are several factors that introduce variability in their measurement," Dr. Nair told Medscape Medical News.
 
The findings have numerous clinical implications, since eGFR thresholds are the basis for starting and stopping certain medications and for performing expensive tests, he and his colleagues note.
 
Cooked Meat's Effect Is Significant but Transient
 
The researchers explain that diabetic nephropathy is a leading cause of end-stage renal disease (ESRD) and that accurate screening and staging of CKD is essential for timely intervention as recommended by national and international guidelines and to guide dose adjustment of other medicines. Glomerular filtration rate (GFR) is recognized as the best measure of kidney function in health and disease, and the easiest way to assess it is to estimate it based on serum creatinine and other variables such as age, gender, race, and body size.
 
Dr. Nair and colleagues studied 64 adult patients with type 1 (14%) or type 2 diabetes (86%) and chronic kidney disease, with 16 in each of 4 CKD stage groups: 1 and 2, 3a, 3b, and 4. A group of 16 healthy volunteers was also studied, for a total of 80 subjects.
 
Subjects were given 1 of 2 meals, each containing about 44 g of protein: One consisted of 2 grilled quarter-pound beef burgers, the other 2 grilled vegetarian burgers. Both meals also included 2 buns, a vegetable salad, and 250 mL of water.
 
Blood samples were taken before the meal (fasting) and at 1, 2, and 4 hours after. Blood samples were also taken the morning after the meal following a 12-hour overnight fast.
 
Significant differences in serum creatinine and eGFR were seen following the meat meal in the healthy volunteers and the patients with CKD. The maximum rise in creatinine occurred at 2 hours after eating for the healthy volunteers and those with CKD stages 1 and 2, whereas for CKD 3a and 3b the maximum rise was seen at 4 hours postprandially and in CKD 4 the 4-hour creatinine was just 0.5 µ mol/L lower than the 2-hour value.
 
With the cooked-meat meal, the changes in both serum creatinine and eGFR from baseline to 2 hours achieved significance of P < .01 for the healthy volunteers and those in CKD stages 1 and 2, 3b, and 4, while for CKD stage 3a the significance was even greater, with P < .001.
 
As a result of the meat consumption, the median eGFR in the CKD 3a group fell from 52 to 45.2 mL/min/1.73 m2 at 2 hours, dropping further to 42.8 mL/min/1.73 m2 at 4 hours, shifting 6 of those 16 patients into the CKD 3b category, the doctors report.
 
In contrast, there were no significant differences in serum creatinine or eGFR at any point within 4 hours after the nonmeat meal in any of the participants. Nor were there any changes the following morning (12 hours) after either the meat or nonmeat meal.
 
Numerous Clinical Implications
 
Dr. Nair told Medscape Medical News there are important clinical implications for the management of diabetes patients. For example, recommendations call for reducing the dose of metformin when eGFR falls below 40 mL/min/1.73 m2 and for stopping the medication if eGFR drops below 30 mL/min/1.73 m2. Similarly, recommendations for limiting use of glucagonlike peptide-1 (GLP-1) agonist drugs are based on eGFR cutoffs varying from 30 to 60 mL/min/1.73 m2.
 
What's more, he said, overestimation of creatinine and underestimation of eGFR could result in unnecessary hospital admission. For instance, patients undergoing coronary angiograms are recommended to receive prehydration and drugs such as N-acetyl cysteine or bicarbonates if eGFR is below 60 mL/min/1.73 m2.


 

[MaryD]

Very interesting!

[renalwife]

Maybe that's the reason that my creatinine and gfr are all over the map.  I have never had them fasting.  But I think for the next few tests, I'll fast and see if the numbers fluctuates.

[Sax-O-Trix]

My creatinine is almost always lower if I don't eat meat for a few days before labs. 

[kristina]

Perhaps my very strict vegetarian diet has kept my Creatinine so stable over the past 7 years
with a pre-dialysis kidney function of 10-12% without hardly any fluctuation ?

Perhaps my regular walks (whenever I am able to do so) have kept my Urea so stable over the past years
without hardly any fluctuation ?

Mind you, I don’t suffer from Diabetes, but perhaps my vegetarian diet has assisted me greatly all the same ?

[Athena]

Hmm, just came across this very old discussion and want to highlight an important conclusion of this study that Obsidianom has posted. In all participants - from healthy to Stage 4 CKD patients - serum creatinine levels eventually reverted back to baseline levels. In CKD patients, it just took longer to do so. This study seems to demonstrate that eating cooked meat only has a transitory temporary effect on serum creatinine levels. It therefore seems to suggest that eating animal protein diet may not in fact be harmful to kidney function ... If I'm understanding this study correctly.

[cassandra]

Is creatinine not just a waste product of used muscle i.e. meat? Eating it or using it will increase creat levels?

[Charlie B53]

I've had talks with my team, asking if there are any foods I should avoid immediately before blood draws for labs, as I am sure some numbers may be skewed by the short-term effect of some foods.

They claim it really doesn't make that much difference.  This study makes me believe I am correct.  I hate to think meds may be ordered because of a unusual dinner.

[noahvale]

*

[Athena]

Is creatinine not just a waste product of used muscle i.e. meat? Eating it or using it will increase creat levels?

Cas, the issue for us in the 'pre-dialysis' phase is that serum creatinine levels & BUN is regularly monitored. As kidney function declines, the serum creatinine levels start creeping up and the look of depression on my Neprologist's face is something you can cut your teeth on!

However, this study seems to indicate that dietary protein can temporarily skew these results so it's just a little reassurance for when I go for my next labs - which will be soon!

[cassandra]

Aha thanx Athena, I would definitely follow the 'low K+ veggie diet' before tests than

     


Keep fighting girl, and lots of luck, and love

NB I seem to remember that using your muscles also increases your creatinine, so maybe also try to do less physical activity before?

[MuddyGurl]

Mind you, I don’t suffer from Diabetes, but perhaps my vegetarian diet has assisted me greatly all the same ?

I have researched extensively on this, and ALL the  serious research points to a LOW protein diet as helpful across the board for kidney function in all…and NO meat protein even better. One of the reasons is the phosphorous, and amino acids that are tied to meat digestion and their wastes building up.  add in a low magnesium, high calcium diet ( Mg & Ca MUST be balanced) and (80% men, 70% women) are way too low in Mg..and Docs never  even address this!!
then they prescribe calcium channel blockers!!   the easy way is to addMg, which CAN be done transdermally for us CKD stage 3-5. 

you can't test for mg normally, as we all have 1% Mg in blood all the time ..so we look good, but the intracellular  story is different.[there are tests]

I am following a low protein diet, and when I renal test next week I am hoping even this short 3 week trail will make a difference in Unloading the poor kidney.

I spoke to the chemist who designed the amino acids for super low protein diets for kidney failure, and he describes meat waste as "building site debris"  it stays there until someone pays a hauler to drag the waste away…we can;'t hire  them  with drugs, but we can 'go green" and build 'easier on the planet' by choosing less red meat, any processed meats, and only eat the cleanest fish, chicken, even pork  grown/fed well is better, not cheaper, but better if you want meat.

I tend to write long…but bear with me.

I am doing my N=1 study..and I am betting my life on a low protein, no meat, plant based diet.  I AM losing weight, I am satisfied and feeling good nutritionally with a Low Carb diet…the proof will be if my kidney slows it's drop and I continue to feel 'well'.

[PaulBC]

What's your view on egg whites? When I was working on a spreadsheet for renal diet planning (now mostly replaced by heuristics and guesswork) I could not find a better way to load up on protein without adding much phosphorus. My daughter is on PD and needs to replace lost protein, so it's a question of maintaining albumin rather than kidney function. (Sadly, she wasn't on board with 8 oz of pasteurized egg whites a day, so it's not as easy as I hoped.)

I know that low protein is recommended when the goal is to preserve existing kidney function, and that switches after ESRD. Do you think it is really just a matter of regulating phosphorus, or does any protein damage the kidneys? I can imagine there is some strain, since healthy kidneys are not supposed to leak protein, but I'm not sure what protein does when passing through kidneys.

[MuddyGurl]

Paul..are you asking me?  I dont know about her needing albumin to consume?? so forgive.

But if you NEED a great protein that is like eggs please look at hemp seeds. hempseed.ca  They are organically grown in Canada and imported, most health food stores have them.  as the whole seed (size of a rice grain) or hulled they look like minced nuts.  they are far better than protein from whey (like power builders use..but god for our needs too)  Milk whey is a waste from dairy, is often over processed so it tastes like a McDOnalds shake, has added sugars and junk not needed. so is not the good nutrition choice daily. I used to buy the best, purest  whey and add it to a kale/berry almond milk shake sometimes.  Now I found hemp seeds I choose them.

I am still learning how to do this, I am using a simple paper notebook and charting protein, carbs, Mg and total fat% I am trying <40 gr protein a day, no added amino acids yet. <20-30  gr you need to use them to not consume heart muscle/other body muscles..

MY ANSWER for  the BEST protein after eggs is Hemp Seeds… amazing food..the hulled seeds taste like walnut meat, mild and sweet, and ready to eat by hand, or sprinkled on salads over veggies, or in a blender for a shake.   Hemp seeds can be baked into  other foods too.  THREE tbl of hemp seeds are 10 gr protein, with all 20 aminos and ALL NINE essential amino acids, so no other pills or supplement needed!!  and it is a plant, so no waste for the kidney.  I am so thrilled to find such a perfect food that tastes good and  is easy to like.

It is not the kidney 'passing' the meat thru, it is that after digestion takes place it is the kidney stuck with the waste leftovers sent to it(oxidative stress)  see the articles attached. Reducing meat protein for plant diet makes a real difference in every area.  .

Meat breaks down to "methionine"  which is VERY HARD to process…

Lowered methionine ingestion as responsible for the decrease in rodent mitochondrial oxidative stress in protein and dietary restriction possible implications for humans.
RESULTS:   In addition, the mean intake of proteins (and thus methionine) of Western human populations is much higher than needed. Therefore, decreasing such levels to the recommended ones has a great potential to lower tissue oxidative stress and to increase healthy life span in humans while avoiding the possible undesirable effects of DR diets.     

[Athena]

Mind you, I don’t suffer from Diabetes, but perhaps my vegetarian diet has assisted me greatly all the same ?

I have researched extensively on this, and ALL the  serious research points to a LOW protein diet as helpful across the board for kidney function in all…and NO meat protein even better. One of the reasons is the phosphorous, and amino acids that are tied to meat digestion and their wastes building up.  add in a low magnesium, high calcium diet ( Mg & Ca MUST be balanced) and (80% men, 70% women) are way too low in Mg..and Docs never  even address this!!
then they prescribe calcium channel blockers!!   the easy way is to addMg, which CAN be done transdermally for us CKD stage 3-5. 

MuddyGurl, I'd like to know what 'serious research' you've found on this subject because I've asked both my Nephrologists about what the go is on Low Protein diets for kidney patients and both have told me not to go low protein. It was once advocated but seems to have fallen out of favour in recent times. The fact is if we don't eat enough protein, our Albumin levels decrease to unhealthy levels which increases our risk for infections as well as general malaise.

ACE inhibitors & ARB drugs have largely eliminated the need for following ulta-low protein diets in recent times it was explained to me by one nephrologist.

[MuddyGurl]

Athena, I wrote a very long post and lost it.  There is significant proof that a lower protein NO meat diet can and does protect the function of the kidney.

I dont have time now, will find and post laster.

also this site does NOT want me to place urls inside the message,but when I added 6 report links it refused to allow them…so I will post one for now

what you do is your choice..whom you believe also. Considering Nephs are mostly not nutritionists I do not expect them to have more than a cursory  knowledge. Anyone wo wants to ignore the research of Dr. M. Walser can, of course.

http://cjasn.asnjournals.org/content/6/2/257.full
Vegetarian Compared with Meat Dietary Protein Source and Phosphorus Homeostasis in Chronic Kidney Disease

http://rawfoodsos.com/2014/03/09/new-animal-protein-study/
Eventually it emerged that calorie restriction, for most species, was only effective if it also restricted protein intake.

[Athena]

Because this was such an interesting and useful thread in the past, I'm just providing a bit of a news update about what I've discovered after refraining from eating meat for quite a few weeks now. The most recent lab results show that my eGFR has gone up markedly from where it's been for most of the time this year (Woohoo!). Weight is the same, meds the same, just my diet has become meat-free. I do still eat a number of eggs each day and also now eat low-salt cheese almost every day to replace the meat protein. But no meat is no meat.

My Neph thinks it may be a false result, which it may indeed be, but all my other lab results are the same as previously. So who knows? It may just be a real sign of a vegetarian diet being beneficial. As always, there is the next lab results to wait for. But until then, I feel quite positive about adopting a plant-based diet (though I will never give up on my eggs!).

[MuddyGurl]

Athena said to me: MuddyGurl, I'd like to know what 'serious research' you've found on this subject because I've asked both my Nephrologists about what the go is on Low Protein diets for kidney patients and both have told me not to go low protein.


Athena said about herself:  what I've discovered after refraining from eating meat for quite a few weeks now.

well, so much for providing information..it seems people must relearn for themselves before believing anyone else.

[Michael Murphy]

My understanding is prior to dialysis a low protein diet can prolong kidney function, after the start of dialysis the best predictor of patients long term health is the albumen level, low levels show patients with less life expectancy and a higher hospital admission rate and a higher infection rate.

[Athena]

Athena said to me: MuddyGurl, I'd like to know what 'serious research' you've found on this subject because I've asked both my Nephrologists about what the go is on Low Protein diets for kidney patients and both have told me not to go low protein.


Athena said about herself:  what I've discovered after refraining from eating meat for quite a few weeks now.

well, so much for providing information..it seems people must relearn for themselves before believing anyone else.

Muddygirl, as I previously said my nephrologists and 2 dieticians have not advised me to follow a low protein diet, in fact one Neph encouraged me to eat much higher amounts of protein than what is generally recommended for CKD patients - no one was recommending a vegetarian diet as a way to better preserve kidney functioning. I have been reading other people's experiences on this subject for quite some time and have only in recent few weeks adopted a meat-free diet, as an experiment. And I have found that my most recent labs show a very welcome improvement in eGFR.  That is all I have reported here.

In light of what Obsidianom posted about how meat protein may affect eGFR levels, the jury is out as to whether this increase in eGFR is a real fundamental change in kidney functioning or whether avoiding meat just helps to raise eGFR in lab results but without altering the true level of kidney functioning. That is the question that has been raised in light of my most recent experiment with my diet.