Optimal Protein Intake?

[Stavia]

George, very interesting.
How would one factor in relationship of creatinine to muscle mass though?

[Tincup]

George, very interesting.
How would one factor in relationship of creatinine to muscle mass though?

Good question.

Here is Rosedale on creatinine:

Creatinine Creatinine is a marker of kidney function. It is a breakdown product of creatine, a constituent of muscle tissue. When the kidneys are functioning properly, creatinine is excreted at a constant rate. If the kidneys are diseased or damaged, however, excretion becomes less efficient, and creatinine builds up in the blood. A primary contributor to kidney damage is diabetes, and as the cells become more sensitive to insulin and blood glucose levels normalize on the Rosedale Diet, creatinine levels often go down. The ideal range for creatinine is 0.7 to 1.0 mg/ dL. (Levels vary among individuals depending on muscle mass; creatinine is generally higher in men than in women.) Although up to 1.4 mg/ dL is considered within normal limits, levels of 1.3 or 1.4 mg/ dL are indicative of borderline kidney function. When levels are over 1.4 mg/ dL, you are looking at partial kidney failure. Creatinine: 0.7 to 1.0 mg/ dL optimal; 1.1 mg/ dL to 1.2 mg/ dL acceptable; 1.3 to 1.4 mg/ dL borderline high; 1.4 mg/ dL and above high.

Rosedale M.D., Ron; Carol Colman (2009-10-13). The Rosedale Diet (p. 180). HarperCollins. Kindle Edition.

In our case:

Theresa creatinine (first 4 tests about 6 months apart): 0.8 0.81 0.74 0.76 last day of 7 day fast: 0.82
Theresa BUN: 13 9 7 7 last day of fast: 9

Me creatinine (first 4 tests about 6 months apart): 0.9 0.9 1.07 0.88 last day of 7 day fast: 1.03
BUN: 23 20 20 18 last day of fast: 15

Note I obviously read the wrong line above then I said both of our BUN scores were 18 eating a normal diet. Theresa's was much lower.

[Julie G]

Good question, Stavia. Help me understand how creatine levels could possibly help a physician interpret optimal protein intake. Too high might equate to high protein? From a lab 8 months ago. Mine was 0.8 eating around 13% protein.

I'd appreciate any insight from Stavia and any of our physicians, PA's, etc. Does it seem reasonable to use complete protein, BUN, and creatine to determine adequate protein intake, along with the clinical picture, of course? TIA.

[Stavia]

Julie I dunno. All I know is that if a young muscular crossfit person eats too much protein their blood creatinine rises and it looks as if their eGFR is impaired but in fact they have perfect kidney function by the Gault-Cockroft.
Conversely a sarcopaenic tiny old person has a low serum creatinine thus their eGRF looks better than it actually is.

I have no idea how this knowledge would inform optimal dietary protein intake.
I'm just wondering if its necessary to manage your protein as tightly as 10 or 20 grams here or there?

[Hepoberman]

Blood Urea Nitrogen: What it is & Why is Yours High (or low) - https://www.metaboliceffect.com/blood-u ... gh-or-low/ by Jade Teta

I don't know Jade (the author), but the information is accurate.

As a loose, rule-of-thumb guideline, I personally consider BUN 10 & Albumin 4.5 ideal when considering optimal protein consumption. Creatinine should be pretty stable and more indicative of kidney function. Mine has been stable throughout the various n=1's, but BUN seems to follow my protein intake nicely. Keep in mind though, BUN can move for reasons other than protein consumption (see article linked above).

[Julie G]

Thanks! Great link, Hep. Stavia, your comments are actually very helpful.

I have no idea how this knowledge would inform optimal dietary protein intake.
I'm just wondering if its necessary to manage your protein as tightly as 10 or 20 grams here or there?

LOL, apologies for my pseudo Orthorexia Nervosa. (See link here.) I'm taking a deep dive into my own macronutrient ratios in preparation for an upcoming talk and simply wanted to pick the collective wisdom of the community. Your advice in the primer is excellent. You present the two schools of thought and you make the point that each person's needs would vary a bit.

A revelation that has occurred to me through an examination of the evidence is that the lower (longevity) recommendations for protein presume optimal health. (Props to Theresa for that understanding.) Malabsorption or sub-acute disease could very well affect protein needs. The various blood biomarkers discussed in this thread offer insight into that clinical picture. I find this novel understanding to be important in that it melds the two schools of thought on protein together beautifully. Lower/longevity levels of protein may be aspirational for those of us working on optimizing our health.

[Stavia]

Thanks Julie.
We don't use urea in my country, I haven't ordered it in decades. The reason is that is so variable and hence an unreliable marker of renal function, which is basically what doctors are looking for in the overwhelming majority of people when the doctors order bloods in this group of tests (the group is creatinine, urea, eGFR, 24hr creatinine clearance, Gault Cockroft GFR).
Creatinine is less variable, however it is proportional to muscle mass and somewhat influenced by intake protein (but in my experience only when excessive).

Urea is variable with more than just protein intake and I would caution that you were aware of all the factors influencing its variability before you were certain it was an accurate measure of protein intake.

[apod]

A revelation that has occurred to me through an examination of the evidence is that the lower (longevity) recommendations for protein presume optimal health. (Props to Theresa for that understanding.) Malabsorption or sub-acute disease could very well affect protein needs. The various blood biomarkers discussed in this thread offer insight into that clinical picture. I find this novel understanding to be important in that it melds the two schools of thought on protein together beautifully. Lower/longevity levels of protein may be aspirational for those of us working on optimizing our health.

You might find this talk interesting, looking at glutathione in vegans vs omnivores. A diet / exercise / lifestyle rich in hormetic stressors might warrant a higher sulfurous amino acid intake (eg. methionine / cysteine) + glycine. These seem highest in meat + organs + dairy + eggs and lowest in plant protein sources.
https://www.youtube.com/watch?v=odu4IXlhYV4

5-oxoproline seems like an intersting biomarker wrt glycine sufficiency. (https://www.ncbi.nlm.nih.gov/pubmed/2751957)

Creatine seems like a particularly useful supplement for overall health, which can mess up blood creatinine tests.

[Julie G]

Thanks for the warning, Stavia. I didn’t realize that urea was so unstable, but I do understand that all of these biomarkers are typically used for other purposes and are imperfect proxies to access adequate protein intake.

Great link, apod. Given that glutathione is the most prevalent antioxidant in the brain, we can hypothesize that E4 carriers need even more given our greater susceptibility to oxidative stress. Masterjohn makes a strong case for a nose-to-tail omnivorous diet, rich in plants for the hormetic effect, to best upregulate the synthesis. Anybody take NAC to support the process? I'm not sure how creatine fits in... but need to take a deep dive there.