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Fundamental Flaws with RDA Recommendations for Protein
Sarauk2sf
Posts: 28,072 Member
The current Recommended Daily Allowance (“RDA”) for protein is currently 0.8g/kg which is 0.36g/lb. They do not set any additional recommendations for those involved in endurance or resistance training.
Putting the research that indicates protein requirements increase for those who exercise or those at a deficit aside for now, both of which have studies showing that protein requirements increase for, the fundamental issue with the basis for the RDA’s recommendations is that it is based on studies using nitrogen balance as a proxy for protein synthesis. We will be creating a follow up post to discuss why protein requirements increase when at a deficit and/or exercising.
Tests using the nitrogen balance methodology look to assess net nitrogen status. Simplistically, are nitrogen losses more or less than nitrogen intake? Protein is the only macronutrient to contain nitrogen and so this was used as a proxy for protein recommendation. There are a number of limitations of this method which understates protein requirements, that include:
a) Nitrogen losses can be understated. Understating can come from, among other things:
i) Just not capturing all the losses – they are estimated by measuring nitrogen in urine, feces, sweating, breathing and other secretions.
ii) Limited time period in which the losses are assessed. Many of the studies are very short term but urea turnover (re nitrogen in urine) is relatively long term (up to a few days).
iii) Not setting the individuals in the tests to a balanced state at the beginning properly.
b) The formulas to convert nitrogen losses into protein requirements have been called into question, both from the intake by way of dietary protein and the output sides
c) The assumption that nitrogen usage relates to purely to protein synthesis for skeletal muscle growth/repair, whereas in reality, it is used by the body for more than just that.
d) It does not tell you what is optimal. Adequate =/= optimal.
A significant amount of research has been done to assess whether the RDA recommendations are optimal or even adequate. We will be posting a more detailed write up at some time, but many of the studies can be found here: http://www.myfitnesspal.com/topics/show/823505-research-on-protien-intake
In summary, the methodologies used in the RDA underestimate protein requirements.
Putting the research that indicates protein requirements increase for those who exercise or those at a deficit aside for now, both of which have studies showing that protein requirements increase for, the fundamental issue with the basis for the RDA’s recommendations is that it is based on studies using nitrogen balance as a proxy for protein synthesis. We will be creating a follow up post to discuss why protein requirements increase when at a deficit and/or exercising.
Tests using the nitrogen balance methodology look to assess net nitrogen status. Simplistically, are nitrogen losses more or less than nitrogen intake? Protein is the only macronutrient to contain nitrogen and so this was used as a proxy for protein recommendation. There are a number of limitations of this method which understates protein requirements, that include:
a) Nitrogen losses can be understated. Understating can come from, among other things:
i) Just not capturing all the losses – they are estimated by measuring nitrogen in urine, feces, sweating, breathing and other secretions.
ii) Limited time period in which the losses are assessed. Many of the studies are very short term but urea turnover (re nitrogen in urine) is relatively long term (up to a few days).
iii) Not setting the individuals in the tests to a balanced state at the beginning properly.
b) The formulas to convert nitrogen losses into protein requirements have been called into question, both from the intake by way of dietary protein and the output sides
c) The assumption that nitrogen usage relates to purely to protein synthesis for skeletal muscle growth/repair, whereas in reality, it is used by the body for more than just that.
d) It does not tell you what is optimal. Adequate =/= optimal.
A significant amount of research has been done to assess whether the RDA recommendations are optimal or even adequate. We will be posting a more detailed write up at some time, but many of the studies can be found here: http://www.myfitnesspal.com/topics/show/823505-research-on-protien-intake
In summary, the methodologies used in the RDA underestimate protein requirements.
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Just as another point of reference for those who have the time and inclination to learn more, Alan Aragon, Eric Helms and Ian McCarthy discuss this topic (and related studies) in The Protein Roundtable video:
https://www.youtube.com/watch?v=SFObr7rc1kA 0 -
Pinging to save and bookmark for later.
Thank you to you both for providing the links and information.0 -
Just as another point of reference for those who have the time and inclination to learn more, Alan Aragon, Eric Helms and Ian McCarthy discuss this topic (and related studies) in The Protein Roundtable video:https://www.youtube.com/watch?v=SFObr7rc1kA
I actually got most of the above from that video as well as some of Aragon and Helms' other articles and videos.0 -
My reading on the RDA for protein is as follows:
1) it is a a dumbed-down recommendation accessible to the general public as it talks about body weight and not LBM. Ideally protein needs shoud be based on several factors which include activity, sex, age, LBM and other medical considerations.
2) Given 1) and the likelihood that for the large majority of the population a significant increase in protein is not harmful - this recommendation can be read as a minimal/average recommendation.
3) Optimal use of protein, especially for any activity but especially weight lifting and muscle development is going to be higher.
4) "Catabolic protection" during either long term/high deficit or high cardio activity suggests that not only protein consumption should be higher (how high might be another detail, of weight) but that some of the disease states that can be emergent (thyroid disease to other metabolic syndromes) can have some risk reduction at higher proteins.
5) However, protein supplementing, along with the variety supplements that body builders use does generate some risk of kidney damage. The number of BB with kidney issues is higher than in many sports and while likely a multi factorial issue, I'm willing to bet that protein over-consumption is a factor to creating a risk tableau.
Btw, high protein in blood is NOT due to diet but a function of kidney/liver/bone marrow function. The albumin transport system is a good and necessary system for nutrient, fat transport and use.
If you get to the point that *clear* urine is frothy and remains so, you have some risk of having proteinuria - see a doctor.0 -
^^agree with the above - we are hoping to expand to include the requirements for people at a deficit and for people who train as noted in the OP.
Would you mind linking anything you have on the bb side of kidney issues re #5 - not doing a 'please cite' on you, just trying to make sure I can sync with other data/commentary I have seen.0 -
I had no idea how they actually performed these tests but knew it was for suggested minimums and according to wikipedia does not include 'energy metabolism'. Nice to see more info on it. Now to post this on all the protein threads I see :P0
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^^agree with the above - we are hoping to expand to include the requirements for people at a deficit and for people who train as noted in the OP.
Would you mind linking anything you have on the bb side of kidney issues re #5 - not doing a 'please cite' on you, just trying to make sure I can sync with other data/commentary I have seen.
Fair question. When I wrote it's higher I do not have a morbidity prevalence study I can cite (have not seen any) but can only base this on the many anecdotal reports one sees in the medical literature. So yes, I would challenge the factuality of my statement
. I'll cite a few below.
Note - I am not suggesting that a high protein diet alone is a risk factor - the infamous Brenner hypothesis (http://www.nejm.org/doi/full/10.1056/NEJM198209093071104) has been challenged by various reviews (http://www.nutritionandmetabolism.com/content/2/1/25)
What I am saying is that it is very difficult to assure that their is not an underlying chronic low grade nephropathology, and possible undiagnosed, due to a variety of diseases, like hepatitis, Epstein-bahr, etc or other viral, medical conditions in which we might think we are healthy and the high protein diet would create additional stress.
10% of the general population has a diagnosed chronic kidney disease - the prevalence of known risk factors is well above 45%. (http://www.kidney.org/professionals/kdoqi/pdf/Med2003CKDguideline.pdf) Somewhere in between the two is the likely true rate of undiagnosed disease...
In terms of supplements - steroid use and renal function damage is so well known that there is a plethora of articles, I won't cite those - renal damage risk is part of the product insert.
Creatine is generally safe but it does stress the kidneys and should be taken with some consideration of that -
http://www.ncbi.nlm.nih.gov/pubmed/19124889
The literature is littered with poorly evaluated single cases of renal/organ damage for creatine or other supplements like:
http://www.ncbi.nlm.nih.gov/pubmed/17046619
http://www.ncbi.nlm.nih.gov/pubmed/18452122
http://www.ncbi.nlm.nih.gov/pubmed/20861797
Despite these anecdotal report, even the most pro-creatine article does put out limits and a cautionary statement for renal risk (http://www.ncbi.nlm.nih.gov/pubmed/21399917) - the following is funny in its unclarity - probably not necessary but you just might:A pre-supplementation investigation of kidney function might be considered for reasons of safety, but in normal healthy subjects appears unnecessary
In other words - think of how we normally use NSAIDs (anti-inflammatory drugs like Asprin, ibuprofen, etc...) which are generally safe for people but have an incidence of renal adverse drug effects - we are seeing the same incidental reports with undiagnosed renal dysfunction - one could argue that the underlying condition was already there and that protein and supplements is just bringing it to light or on the other hand that the reported incidents are being "caused" by the supplements/protein diets.
Obviously, I'm in the first camp - but the fact that renal issues do crop up in some individuals is sufficient to add the warning - you might have a risk that you are not aware of, consider yourself healthy and this lifestyle will highlight that - keep your eyes open and be safe. And in the absence of real long-term studies on all these supplements - don't go overboard and play the Sorcerer's Apprentice.
Supplements are not guaranteed safe or well-regulated and it is a shame we might be taking something for health benefits that might cause injury. http://www.ncbi.nlm.nih.gov/pubmed/22700641
I do take whey, casein and the occasional creatine but am putting this out with the idea that one does need medical follow-up as an athelete and "more is better always" is a risky proposition.0 -
^^thank you for the further explanation. The purpose of this thread was to show the flaws in the RDA recommendations rather than to discuss the more optimal recommendations - however, I think it very important to highlight, as with anything, that caution should be used, especially with very high doses. When we do more follow up threads of where the studies are for higher recommended doses we should obviously raise these points. As far as I am aware, there have been no studies done on very very high amounts of protein and common sense needs to be applied with applying the minimum recommendations.0
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Interesting post. This is another reason, among many, to disregard the FDA. It is run like a political organization. They disregard science more often than they adhere to it.0
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Interesting post. This is another reason, among many, to disregard the FDA. It is run like a political organization. They disregard science more often than they adhere to it.
I don't think this has anything to do with ignoring science - it is just a case of using older studies that used nitrogen balance as a proxy for protein requirements and being behind the times.0 -
Interesting post. This is another reason, among many, to disregard the FDA. It is run like a political organization. They disregard science more often than they adhere to it.
As far as I know the RDA do not come from the FDA.
If you want to discuss the failures of the FDA, and suggest that they ignore science I will take you to task to prove that. I was on the opposite end of the FDA for many years and I can tell you that they are highly critical of study methodology, results, clinical end points, etc. "Ignoring science" is not something one can blame the FDA easily about. But we can take that to another thread, if you like.
Have you ever seen a drug filing? It literally fills an 18 wheeler of documentation and electronic copy.0 -
^^thus is my understanding also. The FDA regulates what goes onto nutrition labels but not the setting of DVs, which are based on RDIs (which in turn are based on RDAs)0
This discussion has been closed.