Long term high protein

[clsupnorth]

Can anyone provide me with links to reputable research or abstracts discussing the long-term effects of high protein diets on the body? I'm looking for both sides, for and against. Thanks!

[strongchick]

I don't believe there have been any long-term studies. Any study I've seen has been short in duration, and usually NOT in healthy people.

[clsupnorth]

Really? Wow.... that surprises me. I would think 'someone' has done a study. Bodybuilding and high protein diets have been around long enough that you'd think renal effects could have been studied.

[liberty]

My understanding of the renal connection to high protein diets is that if you have a pre-exisiting renal condition, high protein diets cause more damage at a faster rate than low protein diets. When we get people in the renal clinic the first thing they do is have the dietician tell them to cut way back on protein to preserve renal function. Now for a normal healthy person, high protein does not bother the kidneys at all even over the long haul. I have not seen studies just asked my nephrologist. ( I work as the renal social worker 2 mornings a week :) )
C

[strongchick]

Originally posted by clsupnorth@May 27 2006, 10:17 PM
Really? Wow.... that surprises me. I would think 'someone' has done a study. Bodybuilding and high protein diets have been around long enough that you'd think renal effects could have been studied.
Who would pay for it?

There could be. but long term studies are very expensive.

[clsupnorth]

Hmm.... I would think a University or such might conduct that sort of study. I hear alot of people say what they've heard or what the believe, but I like to see factual, scientific evidence.

[strongchick]

But who would pay for it? University studies are funded by the government or private companies. And long term stuff is very pricey.

[Erik]

Originally posted by clsupnorth@May 27 2006, 10:17 PM
Really? Wow.... that surprises me. I would think 'someone' has done a study. Bodybuilding and high protein diets have been around long enough that you'd think renal effects could have been studied.
In that sense there are many long term, informal studies done. Bodybuilders aren't dropping like flies due to kidney failure.

This whole protein scare is really stupid.

[Robben]

The Impact of Protein Intake on Renal Function Decline in Women with Normal Renal Function or Mild Renal Insufficiency
Eric L. Knight, MD, MPH; Meir J. Stampfer, MD, DrPH; Susan E. Hankinson, RN, ScD; Donna Spiegelman, ScD; and Gary C. Curhan, MD, ScD

18 March 2003 | Volume 138 Issue 6 | Pages 460-467


Background: In individuals with moderate to severe renal insufficiency, low protein intake may slow renal function decline. However, the long-term impact of protein intake on renal function in persons with normal renal function or mild renal insufficiency is unknown.

Objective: To determine whether protein intake influences the rate of renal function change in women over an 11-year period.

Design: Prospective cohort study.

Setting: Nurses' Health Study.

Participants: 1624 women enrolled in the Nurses' Health Study who were 42 to 68 years of age in 1989 and gave blood samples in 1989 and 2000. Ninety-eight percent of women were white, and 1% were African American.

Measurements: Protein intake was measured in 1990 and 1994 by using a semi-quantitative food-frequency questionnaire. Creatinine concentration was used to estimate glomerular filtration rate (GFR) and creatinine clearance.

Results: In multivariate linear regression analyses, high protein intake was not significantly associated with change in estimated GFR in women with normal renal function (defined as an estimated GFR 80 mL/min per 1.73 m2). Change in estimated GFR in this subgroup over the 11-year period was 0.25 mL/min per 1.73 m2 (95% CI, –0.78 to 1.28 mL/min per 1.73 m2) per 10-g increase in protein intake; the change in estimated GFR was 1.14 mL/min per 1.73 m2 (CI, –3.63 to 5.92 mL/min per 1.73 m2) after measurement-error adjustment for protein intake. In women with mild renal insufficiency (defined as an estimated GFR > 55 mL/min per 1.73 m2 but <80 mL/min per 1.73 m2), protein intake was significantly associated with a change in estimated GFR of –1.69 mL/min per 1.73 m2 (CI, –2.93 to –0.45 mL/min per 1.73 m2) per 10-g increase in protein intake. After measurement-error adjustment, the change in estimated GFR was –7.72 mL/min per 1.73 m2 (CI, –15.52 to 0.08 mL/min per 1.73 m2) per 10-g increase in protein intake, an association of borderline statistical significance. High intake of nondairy animal protein in women with mild renal insufficiency was associated with a significantly greater change in estimated GFR (–1.21 mL/min per 1.73 m2 [CI, –2.34 to –0.33 mL/min per 1.73 m2] per 10-g increase in nondairy animal protein intake).

Conclusions: High protein intake was not associated with renal function decline in women with normal renal function. However, high total protein intake, particularly high intake of nondairy animal protein, may accelerate renal function decline in women with mild renal insufficiency.


Editors&#39; Notes



Context


Although dietary protein restriction appears to slow the decline in renal function among patients with moderate renal insufficiency, its effect on normal and mildly decreased renal function is unknown.

Contribution


Among women from the Nurses&#39; Health Study with normal renal function, protein intake was not associated with decline in glomerular filtration rate (GFR). In women with mild renal insufficiency, high protein intake, particularly of nondairy animal origin, was associated with more rapid than expected decline in GFR.

Implications


High protein intake is associated with declining GFR among women with mild renal insufficiency. A causal connection has not been demonstrated. Additional studies are needed to show that reducing protein intake protects the kidney.

–The Editors





Author and Article Information


From Brigham and Women&#39;s Hospital, Harvard Medical School; and Massachusetts General Hospital, Harvard School of Public Health, Boston, Massachusetts.

Acknowledgments: The authors thank the participants of the Nurses&#39; Health Study. They also thank Elaine Coughlan for carefully reviewing the statistical programming and manuscript content, Sue Malspeis for helping with the programming necessary to perform the measurement-error adjustment, Diane Feskanich for helping to interpret the food composition tables, Melissa Francis for assisting with manuscript preparation, and Walter Willett for reviewing the manuscript and making helpful suggestions.

Grant Support: By the National Institutes of Health (T32DK0740, T32DK07791, DK52866, CA87969, and HL34594).

Potential Financial Conflicts of Interest: None disclosed.

Requests for Single Reprints: Eric L. Knight, MD, MPH, Channing Laboratory, Nurses&#39; Health Study, 3rd Floor, 181 Longwood Avenue, Boston, MA 02115; e-mail, elknight@partners.org.

Current Author Addresses: Drs. Knight, Hankinson, and Curhan: Channing Laboratory, Department of Medicine, Harvard Medical School and Brigham and Women&#39;s Hospital, 181 Longwood Avenue, Boston, MA 02115.

Drs. Stampfer and Spiegelman: Department of Epidemiology, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115.

Author Contributions: Conception and design: E.L. Knight, G.C. Curhan.

Analysis and interpretation of the data: E.L. Knight, M.J. Stampfer, S.E. Hankinson, D. Spiegelman, G.C. Curhan.

Drafting of the article: E.L. Knight, G.C. Curhan.

Critical revision of the article for important intellectual content: E.L. Knight, M.J. Stampfer, S.E. Hankinson, D. Spiegelman, G.C. Curhan.

Final approval of the article: E.L. Knight, M.J. Stampfer, S.E. Hankinson, D. Spiegelman, G.C. Curhan.

Provision of study materials or patients: G.C. Curhan.

Statistical expertise: E.L. Knight, M.J. Stampfer, D. Spiegelman, G.C. Curhan.

Obtaining of funding: G.C. Curhan.

Administrative, technical, or logistic support: E.L. Knight, M.J. Stampfer, S.E. Hankinson.

Collection and assembly of data: E.L. Knight, S.E. Hankinson, G.C. Curhan.




Related articles in Annals:


Summaries for Patients
The Effect of Dietary Protein Intake on Kidney Function in Women with Normal or Mildly Abnormal Kidneys
Annals 2003 138: I-51.

[clsupnorth]

Oh, good, there we go - thanks Robben.


This whole protein scare is really stupid.

But that&#39;s the kind of comment I hear alot - with no evidence behind it. How do we know if it&#39;s really stupid if no one is studying it?
I have some concern because kidney failure runs in my family on the female side - and you don&#39;t exactly find out you&#39;ve got poor kidneys until some of the irreversible damage starts to show up.
So, I am kind of worried that a high protein diet may indeed cause problems for me.... since the studies that have been done show that pre-existing kidney issues can be aggravated by the increased protein intake.

[Erik]

Originally posted by clsupnorth@May 28 2006, 03:40 PM
So, I am kind of worried that a high protein diet may indeed cause problems for me.... since the studies that have been done show that pre-existing kidney issues can be aggravated by the increased protein intake.
And there&#39;s where the evidence lies.

If you have kidney issues, high protein is not good. Otherwise, there is no documented evidence to suggest otherwise.

And again, bodybuilders are freaks for protein intake and protein intake far above what is even reasonable and yet .... no renal epidemic.

[andi]

Originally posted by Thunder@May 28 2006, 03:01 PM
And there&#39;s where the evidence lies.

If you have kidney issues, high protein is not good. Otherwise, there is no documented evidence to suggest otherwise.

And again, bodybuilders are freaks for protein intake and protein intake far above what is even reasonable and yet .... no renal epidemic.
Yah, I&#39;m a freak&#33; :woohoo:

[Tina]

And again, bodybuilders are freaks for protein intake and protein intake far above what is even reasonable and yet .... no renal epidemic.

Good point.

[tanyab]

what is considered too high for women? How much is appropriate?

[CraveMuscle]

as far as I know, protein intake is more about bodyweight vs. male or female. why would intake be different for a man and woman of the same weight?

[tanyab]

I am just wondering for me personally. I am a female 140lbs.

[CraveMuscle]

well, protein intake alone when not discussing the rest of your daily cals is a bit of an extrapolation.

but many here generally recommend 1-1.5 grams of protein per lb of bodyweight.

yes, this is much higher than "normal" recommendations, but "normal" usually refers to little, if any, weight-lifting individuals.

then again, I don&#39;t know if the same protein intake would be recommended for a sedentary individual to just maintain what muscle they have.

and there was a recent thread, I think started by Rachel, regarding the safety of higher protein intakes.

[tanyab]

thank you.

[CraveMuscle]

ok, I&#39;m dumb as a rock. the "recent thread" wasn&#39;t started by Rachel, and it is THIS thread. :lol:

[clsupnorth]

Originally posted by CraveMuscle@May 29 2006, 02:19 PM
ok, I&#39;m dumb as a rock. the "recent thread" wasn&#39;t started by Rachel, and it is THIS thread. :lol:
:blink:

[CraveMuscle]

I know, I know. :oops:

I was just replying to the previous question without even looking at the thread title. I&#39;m sorry. and I was thinking of Rachel b/c I seem to remember her starting a similar thread on O2. maybe I&#39;m hallucinating. it&#39;s quite possible. :baby:

[krispy1138]

Originally posted by CraveMuscle@May 29 2006, 06:28 PM
I know, I know. :oops:

I was just replying to the previous question without even looking at the thread title. I&#39;m sorry. and I was thinking of Rachel b/c I seem to remember her starting a similar thread on O2. maybe I&#39;m hallucinating. it&#39;s quite possible. :baby:
You&#39;re not hallucinating - I recall the thread you&#39;re talking about.

[CraveMuscle]

thanks. :)

[clsupnorth]

Sure.... I think you two are just in cahoots with each other.... trying to make me go crazy.

[CraveMuscle]

:unsure:

it really was an honest mistake. I&#39;m sorry.

[funnyesq]

Originally posted by Thunder@May 28 2006, 03:01 PM
And there&#39;s where the evidence lies.

If you have kidney issues, high protein is not good. Otherwise, there is no documented evidence to suggest otherwise.

And again, bodybuilders are freaks for protein intake and protein intake far above what is even reasonable and yet .... no renal epidemic.
What about the fact that apparently "acid" is built up in the system on a high protein diet? I&#39;ve read that this acid build up can start drawing on calcium in the bones leading to osteoporosis, damaging other systems etc. Granted the muscle building may offset the osteoporosis but with women who may be a bit pre-disposed due to on set of menopause etc...which reduces estrogen levels which then starts to take bone away...isn&#39;t it "reasonable" to have a more balanced amount of protein? Something in the nature of .5-.75 for each lb of weight? Assume a normal healthy individual without renal issues.

[clsupnorth]

Originally posted by funnyesq@May 30 2006, 12:47 PM
What about the fact that apparently "acid" is built up in the system on a high protein diet?
I&#39;ve heard about what you are referring to - pH balance in the body. Diets high in animal products produce an acidic effect, whereas vegetables and other stuff produce a basic effect. Very popular theory in the natural health world. One of the reasons I take liquid chlorophyll everyday - detoxifier and reduces blood pH.