deleterious effects of high protein intake?

[TPT]

so we're all on high protein diets. but, is chronic excess dietary protein safe?

well over the years two controversial issues have arisen within the literature: renal disease and bone loss.

yeah, you guys better be concerned! lol.

anyway, the following paper on bone loss caused considerable uproar when it was published. take a read. its still interesting. ome people believe high protein diets causes increased calcium loss through urine because of acid content.

http://jn.nutrition.org/cgi/reprint/128/6/1051

Excess Dietary Protein Can Adversely Affect Bone


Manuscript received 27 January 1998. Revision accepted 9 March 1998.

Uriel S. Barzel and Linda K. Massey*,

Division of Endocrinology and Metabolism, Department of Medicine, Montefiore Medical Center and The Albert Einstein College of Medicine, Bronx, NY 10467 and * Food Science and Human Nutrition, Washington State University, Spokane, WA 99201 The average American diet, which is high in protein and low in fruits and vegetables, generates a large amount of acid, mainly as sulfates and phosphates. The kidneys respond to this dietary acid challenge with net acid excretion, as well as ammonium and titratable acid excretion. Concurrently, the skeleton supplies buffer by active resorption of bone. Indeed, calciuria is directly related to net acid excretion. Different food proteins differ greatly in their potential acid load, and therefore in their acidogenic effect. A diet high in acid-ash proteins causes excessive calcium loss because of its acidogenic content. The addition of exogenous buffers, as chemical salts or as fruits and vegetables, to a high protein diet results in a less acid urine, a reduction in net acid excretion, reduced ammonium and titratable acid excretion, and decreased calciuria. Bone resorption may be halted, and bone accretion may actually occur. Alkali buffers, whether chemical salts or dietary fruits and vegetables high in potassium, reverse acid-induced obligatory urinary calcium loss. We conclude that excessive dietary protein from foods with high potential renal acid load adversely affects bone, unless buffered by the consumption of alkali-rich foods or supplements.

Key words: humans, protein, bone, acid, potassium.

The Journal of Nutrition Vol. 128 No. 6 June 1998, pp. 1051-1053
Copyright ©1998 by the American Society for Nutritional Sciences


since then many other studies and theories have come up.
what do you guys think?

the following is the position of the international society of sports nutrition. http://www.pubmedcentral.nih.gov/art...id=2117006#B19
Position Statement
The following seven points related to the intake of protein for healthy, exercising individuals constitute the position stand of the Society. They have been approved by the Research Committee of the Society. 1) Vast research supports the contention that individuals engaged in regular exercise training require more dietary protein than sedentary individuals. 2) Protein intakes of 1.4 – 2.0 g/kg/day for physically active individuals is not only safe, but may improve the training adaptations to exercise training. 3) When part of a balanced, nutrient-dense diet, protein intakes at this level are not detrimental to kidney function or bone metabolism in healthy, active persons. 4) While it is possible for physically active individuals to obtain their daily protein requirements through a varied, regular diet, supplemental protein in various forms are a practical way of ensuring adequate and quality protein intake for athletes. 5) Different types and quality of protein can affect amino acid bioavailability following protein supplementation. The superiority of one protein type over another in terms of optimizing recovery and/or training adaptations remains to be convincingly demonstrated. 6) Appropriately timed protein intake is an important component of an overall exercise training program, essential for proper recovery, immune function, and the growth and maintenance of lean body mass. 7) Under certain circumstances, specific amino acid supplements, such as branched-chain amino acids (BCAA's), may improve exercise performance and recovery from exercise.






ill be back to chat more.

[Frosty]

The Rapist, I actually was reading studies that were showing the complete opposite, that in fact people that ate higher protein diets had better bone mass. "higher" meaning kinda low by our standards, though. I really forget in the papers what reason this might be caused by and right now after working over 12 hours I'm not in the mood to browse through research papers lol.

If you ate your vegetables would you even have an "acid problem"? Would the calcium content of taking in protein shakes change this? What about when you get enough vitamin D like we should?


Although for longevity I do believe in higher fat and lower protein. Protein increases IGF-1 which isn't good news in terms of cancer.

[RDFinders]

interesting you posted this as i have been reviewing some articles and other readings on excessive protein intake.

i will say, i had a male client who had the bone density of a 65 yo post-meno female. he chronically dieted and only followed high protein diets for years. had a hard time trying to change his mind otherwise on lessening the protein in his diet.

on the renal disease - there is much debate about it. healthy kidneys do exp more vein/artery dilation as a result of trying to filter the excess urea that is produced. but it hasn't been proven that this increased blood flow in this area actually causes renal damage. but then the studies i have looked were done for any significant length of time period to see if excessive protein intake was kept constant, if the dilation became permenant or if microscopic tears were produced and if that caused a leakage of proteins in the urine.

[Frosty]

Yeah and just because the kidneys work harder doesn't necessarily mean it's harmful (although is it healthy?). If you eat more food your digestive system has to work harder, but that isn't harmful (let's say 2000 cal vs. 3000 cal, nothing ridiculous here).

In terms of longevity, is a lower protein, higher fat diet healthier? Assuming we're talking healthy food I would probably say the answer is yes. Less insulin, less work for the digestive system as well as other body systems, and lower IGF-1 levels. Now take it another step further. If you ate a higher fat lower protein diet but then cut calories keeping the micronutrients the same, that's probably even healthier because there is less strain on the body, even lower insulin, etc.


But you know what? Who wants to live like that!!! I'm a meat eater through and through and I feel best on a high meat diet. Maybe once I'm old I'll start changing the diet so it's geared more towards longevity.

[TPT]

The Rapist, I actually was reading studies that were showing the complete opposite, that in fact people that ate higher protein diets had better bone mass. "higher" meaning kinda low by our standards, though. I really forget in the papers what reason this might be caused by and right now after working over 12 hours I'm not in the mood to browse through research papers lol.

If you ate your vegetables would you even have an "acid problem"? Would the calcium content of taking in protein shakes change this? What about when you get enough vitamin D like we should?


Although for longevity I do believe in higher fat and lower protein. Protein increases IGF-1 which isn't good news in terms of cancer.

you aint right- at all. lmao.

anyway, the response paper to barzel and massey (1998) argued the opposite. http://jn.nutrition.org/cgi/reprint/128/6/1054 i.e., as long as we received the right amounts of calcium, problems due to calcium excretion would be ameliorated.
Excess Dietary Protein May Not Adversely Affect Bone


Manuscript received 27 January 1998. Revision accepted 9 March 1998.
Robert P. Heaney

Creighton University, Omaha, NE 68178 Too little protein is always harmful for the skeleton. Increasing dietary protein increases endogenous calcium excretion. The ability to adapt depends upon the adequacy of an individual's calcium intake. At a population level, the effect of protein is often minimized because calcium intake rises with increasing protein intake. A dietary calcium-to-protein ratio 20:1 (mg:g) probably provides adequate protection for the skeleton. Excess protein will not harm the skeleton if the calcium intake is adequate.
Key words: protein, calcium, bone, humans.

The Journal of Nutrition Vol. 128 No. 6 June 1998, pp. 1054-1057
Copyright ©1998 by the American Society for Nutritional Sciences


vegetables should help as alkali buffers. fruits too. http://ddr.nal.usda.gov/bitstream/10...ND20581001.pdf

as far as longevity, high protein intake at older ages certainly might be big problem.

[Frosty]

s far as longevity, high protein intake at older ages certainly might be big problem.

Especially since as you age digestive strength weakens, and meats require the most work to digest properly. Eating a bunch of meat isn't going to be healthy if the body lacks the capacity to produce enough stomach acid to break it down.

[TPT]

interesting you posted this as i have been reviewing some articles and other readings on excessive protein intake.

i will say, i had a male client who had the bone density of a 65 yo post-meno female. he chronically dieted and only followed high protein diets for years. had a hard time trying to change his mind otherwise on lessening the protein in his diet.

on the renal disease - there is much debate about it. healthy kidneys do exp more vein/artery dilation as a result of trying to filter the excess urea that is produced. but it hasn't been proven that this increased blood flow in this area actually causes renal damage. but then the studies i have looked were done for any significant length of time period to see if excessive protein intake was kept constant, if the dilation became permenant or if microscopic tears were produced and if that caused a leakage of proteins in the urine.

rdfinders, it is hard to discriminate causal relations with older patients since they usually have comorbidities including correlating osteoporosis, calcium deficiencies, etc.

though the literature is sketchy regarding renal failure and high protein, i dont need studies to tell me to be careful with high protein intake in older ages.

do you think as we age we have reduced renal functions? e.g., the suceptibiltiy of lower blood ph.

[TPT]

Yeah and just because the kidneys work harder doesn't necessarily mean it's harmful (although is it healthy?). If you eat more food your digestive system has to work harder, but that isn't harmful (let's say 2000 cal vs. 3000 cal, nothing ridiculous here).

In terms of longevity, is a lower protein, higher fat diet healthier? Assuming we're talking healthy food I would probably say the answer is yes. Less insulin, less work for the digestive system as well as other body systems, and lower IGF-1 levels. Now take it another step further. If you ate a higher fat lower protein diet but then cut calories keeping the micronutrients the same, that's probably even healthier because there is less strain on the body, even lower insulin, etc.


But you know what? Who wants to live like that!!! I'm a meat eater through and through and I feel best on a high meat diet. Maybe once I'm old I'll start changing the diet so it's geared more towards longevity.

do you think increased igf1 is a problem at an older age and longevity. damn, i want that elevated igf1 when im a senior citizen! lol. i dont know of correlations between igf1 and cancer.

[B7emm]

Are there any studies that link a vegan diet to Alzheimer's? colagedele tn. has the highest concentration of vegan people in my area and something like 52% of the people develop Alzheimer's in there 60s.

[RDFinders]

rdfinders, it is hard to discriminate causal relations with older patients since they usually have comorbidities including correlating osteoporosis, calcium deficiencies, etc.

though the literature is sketchy regarding renal failure and high protein, i dont need studies to tell me to be careful with high protein intake in older ages.

do you think as we age we have reduced renal functions? e.g., the suceptibiltiy of lower blood ph.

on dealing with the elderly - all organ system functions decline with advancing age. so pushing high any thing isn't good IMO with this group. but were we limiting it to just the elderly and high protein?

elderly and bone mass - hard to speculate causes of declining bone mass as it is multifactoral - less time outside (decreased vitamin D), decrease po intake (less calcium rich foods eaten), decreased absorption capacity, decreased HCl production to breakdown protein, decrease glut flora, limited mobility (so they lose lean body mass) and the list can go on.

in middle age adults - we don't know. none of us get bone scans when we reach 24 yoa, so we are not able to mark our bone densities and compare them over time.

[TPT]

Are there any studies that link a vegan diet to Alzheimer's? colagedele tn. has the highest concentration of vegan people in my area and something like 52% of the people develop Alzheimer's in there 60s.

b7emm, yeah their is! well- sort of. open up a thread on this topic.

man, 52 percent is crazy!?

[TPT]

on dealing with the elderly - all organ system functions decline with advancing age. so pushing high any thing isn't good IMO with this group. but were we limiting it to just the elderly and high protein?

elderly and bone mass - hard to speculate causes of declining bone mass as it is multifactoral - less time outside (decreased vitamin D), decrease po intake (less calcium rich foods eaten), decreased absorption capacity, decreased HCl production to breakdown protein, decrease glut flora, limited mobility (so they lose lean body mass) and the list can go on.

in middle age adults - we don't know. none of us get bone scans when we reach 24 yoa, so we are not able to mark our bone densities and compare them over time.

yes aging is sad. not to mention reduced test and hgh.

[RDFinders]

yes aging is sad. not to mention reduced test and hgh.

or you can say - it sucks! but i think a big problem the elderly face is they get used to not doing anything. they really don't stay active mentally or physically, so it stands to reason - the use it or lose it principle is in full effect. key - keep working out to the upmost as you will fair better than your same aged counterparts.

[B7emm]

thanks pt

[Frosty]

do you think increased igf1 is a problem at an older age and longevity. damn, i want that elevated igf1 when im a senior citizen! lol. i dont know of correlations between igf1 and cancer.

IGF-1 can help to promote cancerous growths from what I've read. Although insulin is the main hormone to control for longevity AFAIK.