RoR: Forum

Bill,

That's an awful lot of conjecture from a problematic rat study. What's problematic is:

-they gave the rats 3 amino acids (AA) -- the 3 branched-chain amino acids (BCAAs) -- and expected them to make proteins made up of 20 AAs (proteins are typically made up of about 20 AAs)
-lo' and behold, the rats didn't make 20-AA proteins from the 3 AAs provided
-the excess BCAAs -- because rats didn't magically conjure up the other 17 AAs out of thin air to make protein -- overloaded their system

All this study shows is not to overconsume single amino acids, because it might overload your system. It says nothing about consuming whole protein (made of all 20 AAs).

Ed

Post 81

Thursday, May 21, 2009 - 10:06am

Ed,

What about this part of the article? --

"Unexpectedly, obese people had a distinct metabolic "signature" related to a particular subtype of amino acids called BCAA (branched-chain amino acids). About 20% of the protein in the typical American diet is made up of BCAAs.

"Lean people's bodies tend to make new proteins out of BCAAs. In obese people, Newgard and colleagues suggest, this process gets overloaded. Instead of making new protein, the BCAAs are diverted into a deviant pathway that leads to insulin resistance."

- Bill

Post 82

Thursday, May 21, 2009 - 10:46am

That study doesn't sufficiently conclude that eating a high protein diet is bad. All of the rats gained weight, so obviously you're going to get more insulin resistance just from that. I weigh 174 pounds and I'm 6' tall, and I have 12% bodyfat and I have a 32" waist, and yet I eat a lot of protein. When I was heavy, I had a huge 38" waist and ate tons of carbs, my doctor told me I was at a much higher risk of diabetes at a 38" waist and eating tons of sugar and now my risk of getting diabetes has significantly decreased. And the effects were protein on "bad fat", which is why most athletic diets consist of lean proteins and dietary fat from healthy monounsaturated fats, EFAs, etc. Americans who are obese get diabetes because their diet is shit, and they don't exercise, it's not the protein.

Post 83

Thursday, May 21, 2009 - 12:48pm

Bill,

What about this part of the article? --

"Unexpectedly, obese people had a distinct metabolic "signature" related to a particular subtype of amino acids called BCAA (branched-chain amino acids). About 20% of the protein in the typical American diet is made up of BCAAs.

"Lean people's bodies tend to make new proteins out of BCAAs. In obese people, Newgard and colleagues suggest, this process gets overloaded. Instead of making new protein, the BCAAs are diverted into a deviant pathway that leads to insulin resistance."

Here's the deal. When blood sugar drops the body catabolizes stored muscle protein in order to get the BCAAs in order to make new blood sugar. Obese folks have poor blood sugar control, so they break down more stored muscle protein in order to get their blood sugar back up. The process is indicative of poor blood sugar control, not protein overload.

This is basic biology, so it's odd that the researchers missed this.

ED

Post 84

Thursday, May 21, 2009 - 7:55pm

Looks like the mom took off with her son...possibly to Mexico.
http://www.foxnews.com/story/0,2933,520690,00.html

Post 85

Thursday, May 21, 2009 - 9:14pm

Think of it as evolution in action.

Post 86

Thursday, May 21, 2009 - 10:04pm

How apropos a quote... but sad for the child.

jt

Post 87

Thursday, May 21, 2009 - 11:26pm

That study doesn't sufficiently conclude that eating a high protein diet is bad. All of the rats gained weight, so obviously you're going to get more insulin resistance just from that.

John, as the article notes, "The rats on the BCAA/fat diet didn't eat as much food or gain as much weight as the rats on the high-fat diet -- but they became just as insulin resistant."

There are other reasons that a high protein diet is bad for you. For one thing, it's hard on the kidneys. Ralph Nelson of the Mayo Clinic reports an increase in kidney mass in 20-year old football players on high protein diets. (Nelson, R.A. Quoted in "Are we eating too much protein?" Med. World News, November 8, 1974, p. 106) The stress on the kidneys can, in turn, be a potential cause of high blood pressure, and the excess protein can cause kidney stones.

For another thing, unless you're careful to include lots of alkaline vegetables to supplement the extra protein, you can create an acidic condition in the blood, which leaches out calcium from the bones in order to raise the blood pH to an acceptable level. Over time, this can cause thinning of the bones, especially in women, and predispose to osteoporosis. There is a higher rate of wrist fractures in women who consume more than 95 grams of protein a day.

Also, if your high protein diet includes lots of red meat, it can predispose you to colorectal and prostate cancer later in life.

- Bill

Post 88

Friday, May 22, 2009 - 7:27am

Bill,
*****************
"The rats on the BCAA/fat diet didn't eat as much food or gain as much weight as the rats on the high-fat diet -- but they became just as insulin resistant."
*****************
But -- as I demonstrated (with logic) -- that doesn't mean that "a high protein diet is bad for you." You continue:

*****************
There are other reasons that a high protein diet is bad for you. For one thing, it's hard on the kidneys. Ralph Nelson of the Mayo Clinic reports an increase in kidney mass in 20-year old football players on high protein diets. (Nelson, R.A. Quoted in "Are we eating too much protein?" Med. World News, November 8, 1974, p. 106)
*****************
And weight-lifting is "hard" on the muscles, but that doesn't make weight-lifting "bad" for the muscles. In fact, it (that it's hard on them) is what it is that actually makes weight-lifting "good" for the muscles.

Saying that protein is "hard on the kidneys" -- with insinuation that, therefore, something needs to be done about that -- is like Marx saying that the free market is "hard on the working class."

It doesn't hold the perpespective of how hard it would be without a free market or without (ample) protein. It assumes that everything in life ought to be easy (or that if something is easier it is, automatically, better). But some things in life are hard and that's not a bad thing.

*****************
The stress on the kidneys can, in turn, be a potential cause of high blood pressure, and the excess protein can cause kidney stones.
*****************
As to the first point, the opposite is true. Not getting enough protein is more of a potential cause of high blood pressure (1). As to the second point, conflicting (equivalent) evidence exists -- not unequivalent evidence (2). Yet you write as if it's an acceptable fact.

*****************
For another thing, unless you're careful to include lots of alkaline vegetables to supplement the extra protein, you can create an acidic condition in the blood, which leaches out calcium from the bones in order to raise the blood pH to an acceptable level. Over time, this can cause thinning of the bones, especially in women, and predispose to osteoporosis. There is a higher rate of wrist fractures in women who consume more than 95 grams of protein a day.
*****************
I agree that protein without alkaline fruits and veggies is harmful -- and for the very reasons you mentioned.

*****************
Also, if your high protein diet includes lots of red meat, it can predispose you to colorectal and prostate cancer later in life.
*****************
Again, the evidence is equivocal, whether it's colorectal (3) or prostate (4) cancer. The evidence actually points to the processing and cooking (charring) of red meat, not the red meat itself.

Ed

Notes:
(1) [abstract] Clin Nutr. 2008 Oct;27(5):675-84.
Optimal protein intake in the elderly.
Wolfe RR, Miller SL, Miller KB.
University of Arkansas for Medical Sciences, Department of Geriatrics, Center for Translational Research in Aging & Longevity, 4301W Markham Street, Slot 806, Little Rock, AR 72205, USA. rwolfe2@uams.edu

The recommended dietary allowance (RDA) for protein, as promulgated by the Food and Nutrition Board of the United States National Academy of Science, is 0.8 g protein/kg body weight/day for adults, regardless of age. This value represents the minimum amount of protein required to avoid progressive loss of lean body mass in most individuals. There is an evidence that the RDA for elderly may be greater than 0.8 g/kg/day. Evidence indicates that protein intake greater than the RDA can improve muscle mass, strength and function in elderly.

In addition, other factors, including immune status, wound healing, blood pressure and bone health may be improved by increasing protein intake above the RDA. Furthermore, the RDA does not address the recommended intake of protein in the context of a balanced diet. Concerns about potential detrimental effects of increased protein intake on bone health, renal function, neurological function and cardiovascular function are generally unfounded. In fact, many of these factors are improved in elderly ingesting elevated quantities of protein.

It appears that an intake of 1.5 g protein/kg/day, or about 15-20% of total caloric intake, is a reasonable target for elderly individuals wishing to optimize protein intake in terms of health and function.

(2) [abstract] Eur Urol. 2009 Mar 13.
Diet, Fluid, or Supplements for Secondary Prevention of Nephrolithiasis: A Systematic Review and Meta-Analysis of Randomized Trials.
Fink HA, Akornor JW, Garimella PS, Macdonald R, Cutting A, Rutks IR, Monga M, Wilt TJ.
Geriatric Research Education and Clinical Center, VA Medical Center, Minneapolis, MN, USA; Center for Chronic Disease Outcomes Research, VA Medical Center, Minneapolis, MN, USA; Cochrane Review Group in Prostate Diseases and Urologic Malignancies, VA Medical Center, Minneapolis, MN, USA; Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, MN, USA.

CONTEXT: Although numerous trials have evaluated efficacy of diet, fluid, or supplement interventions for secondary prevention of nephrolithiasis, few are included in previous systematic reviews or referenced in recent nephrolithiasis management guidelines.

OBJECTIVE: To determine efficacy and safety of diet, fluid, or supplement interventions for secondary prevention of nephrolithiasis.

EVIDENCE ACQUISITION: Systematic review and meta-analysis of trials published January 1950 to March 2008. Sources included Medline and bibliographies of retrieved articles. Eligible trials included adults with a history of nephrolithiasis; compared diet, fluids, or supplements with control; compared relevant outcomes between randomized groups (eg, stone recurrence); had >/=3 mo follow-up; and were published in the English language. Data were extracted on participant and trial characteristics, including study methodologic quality.

EVIDENCE SYNTHESIS: Eight trials were eligible (n=1855 participants). Study quality was mixed. In two trials, water intake >2 l/d or fluids to achieve urine output >2.5l/d reduced stone recurrence (relative risk: 0.39; 95% confidence interval: 0.19-0.80). In one trial, fewer high soft drink consumers assigned to reduced soft drink intake had renal colic than controls (34% vs 41%, p=0.023). Content and results of multicomponent dietary interventions were heterogeneous; in one trial, fewer participants assigned increased dietary calcium, low animal protein, and low sodium had stone recurrence versus controls (20% vs 38%, p=0.03), while in another trial, more participants assigned diets that included low animal protein, high fruit and fiber, and low purine had recurrent stones than controls (30% vs 4%, p=0.004). No trials examined the independent effect of altering dietary calcium, sodium, animal protein, fruit and fiber, purine, oxalate, or potassium. Two trials showed no benefit of supplements over control treatment. Adverse event reporting was poor.

CONCLUSIONS: High fluid intake decreased risk of recurrent nephrolithiasis. Reduced soft drink intake lowered risk in patients with high baseline soft drink consumption. Data for other dietary interventions were inconclusive, although limited data suggest possible benefit from dietary calcium.

(3) [abstract] Can Fam Physician. 2007 Nov;53(11):1913-20.
Diet and colorectal cancer: Review of the evidence.
Ryan-Harshman M, Aldoori W.
947 Oshawa Blvd N, Oshawa, ON L1G 5V7. ryanharshman@rogers.com

OBJECTIVE: To investigate whether diet has a role in the development and progression of colorectal cancer (CRC).

QUALITY OF EVIDENCE: MEDLINE was searched from January 1966 to December 2006 for articles on the relationship between diet and CRC using the key words colorectal cancer and folic acid, calcium, vitamin D, red meat, or fibre. Evidence that these factors are associated with CRC came from case-control and prospective cohort studies and some clinical trials.

MAIN MESSAGE: Whether red meat is a culprit in causing CRC remains unanswered, although any effect it might have is likely moderate and related to processing or cooking. The effect of dietary fibre on risk of CRC has also been difficult to determine because fibre intake is generally low. Evidence that folic acid, calcium, and vitamin D reduce risk of CRC is stronger. In particular, recent research indicates that calcium and vitamin D might act together, rather than separately, to reduce the risk of colorectal adenomas. There might also be an interaction between low folate levels and high alcohol consumption and CRC.

CONCLUSION: Before dispensing dietary advice, physicians should understand the potential benefits and harm of specific components of various foods. People might be able to reduce their risk of CRC by increasing their vitamin and mineral levels through eating more vegetables and fruit. Multivitamin and mineral supplements can complement a healthy diet.

(4) [abstract] Cancer Causes Control. 2007 Feb;18(1):41-50.
Meat and dairy consumption and subsequent risk of prostate cancer in a US cohort study.
Rohrmann S, Platz EA, Kavanaugh CJ, Thuita L, Hoffman SC, Helzlsouer KJ.
Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St., Rm. E 6138, Baltimore, MD 21205, USA.

OBJECTIVE: To evaluate the association of meat and dairy food consumption with subsequent risk of prostate cancer.

METHODS: In 1989, 3,892 men 35+ years old, who participated in CLUE II study of Washington County, MD, completed an abbreviated Block food frequency questionnaire. Intake of meat and dairy related foods was calculated using consumption frequency and portion size. Incident prostate cancer cases (n = 199) were ascertained through October 2004. Cox proportional hazards regression was used to calculate hazard ratios (HR) of total and advanced (SEER states three and four; n = 54) prostate cancer and 95% confidence intervals (CI) adjusted for age, BMI at age 21, and intake of energy, saturated fat, and tomato products.

RESULTS: Intakes of total mean (HR = 0.90, 95% CI 0.60-1.33, comparing highest to lowest tertile) and red meat (HR = 0.87, 95% CI 0.59-1.32) were not statistically significantly associated with prostate cancer. However, processed meat consumption was associated with a non-statistically significant higher risk of total (5+ vs. < or =1 servings/week: HR = 2.24; 95% CI 0.90-5.59) prostate cancer. There was no association across tertiles of dairy or calcium with total prostate cancer, although compared tp < or =1 servings/week consumption of 5+ servings/week of dairy foods was associated with an increased risk of prostate cancer (HR = 1.65, 98% CI 1.02-2.66).

CONCLUSION: Overall, consumption of processed meat, but not total meat or red meat, was associated with a possible increased risk of total prostate cancer in this prospective study. Higher intake of dairy foods but not calcium was positively associated with prostate cancer. Further investigation into the mechanisms by which processed meat and dairy consumption might increase the risk of prostate cancer is suggested.

(Edited by Ed Thompson on 5/22, 7:29am)

Post 89

Friday, May 22, 2009 - 11:29am

Ed,

Thanks for your citations. I stand corrected on the effect of red meat in particular on prostate cancer. What do you think is the reason for the connection between processed meat and prostate cancer? Is it the preservatives -- the sodium nitrates and nitrites? Ascorbic acid can neutralize these, can't it? And in processed meats, isn't there now an additive that performs a function similar to ascorbic acid -- which eliminates nitrates and nitrites as risk factors?

The Life Extension Foundation has done some interesting research on diet and prostate cancer. They cite the excess production of arachidonic acid as being a principal cause, as well as saturated fat, omega 6 fats and a deficiency of omega 3 fats, all of which figure prominently in the standard American diet. Of the various meats, red meat does not contain the most arachidonic acid; duck and pork appear to be the biggest contributors.

The LEF research documents the role of chronic inflammatory mediators such as 5-lipooxygenase (5-LOX) and tumor necrosis factor-alpha (TNF-α) in the genesis of prostate and other cancers. 5-LOX, it turns out, is stimulated by arachidonic acid.

Two friends of mine have recently been diagnosed with prostate cancer. Their diets have not been the best. As LEF points out, poor dietary choices can break down the body�s innate defenses against prostate cancer, while fueling its spread. Consuming a healthy diet can provide protection against the disease.

LEF notes: "A comprehensive strategy to fight prostate cancer should focus on inhibiting the 5-lipoxygenase (5-LOX) enzyme, which is central to the cancer�s propagation, infiltration, and spread. This can be done by limiting intake of foods that contain or stimulate arachidonic acid and thus increase 5-LOX production, such as red meat, egg yolks, dairy products, saturated and omega-6 fats, and high-glycemic carbohydrates. Healthier dietary choices are cold-water fish, fish oil, and sesame lignans."

Obviously, red meat is just one of the factors that contribute to arachidonic acid and it is by no means the most significant. It would play a role only as one additional source of AA in conjunction with the many other sources in the standard American diet.

LEF advertises an herb from the Bowellian plant that has been used as an anti-inflammatory agent in India for centuries. The herb, given the trade name "5-LOXIN," binds directly to 5-LOX, which is produced to handle the excess production of arachidonic acid, and inhibits its activity. It is that enzyme that is a key factor in the genesis of prostate cancer. (See "Eating Your Way to Prostate Cancer," LE Magazine, February 2007)

As for your point that the stress on the kidneys from a high protein diet isn't harmful, this is simply not true. A high protein diet can reduce kidney function throughout life, and is especially bad for diabetics, who are advised to follow a low protein diet in order to preserve kidney function. This is not even controversial within the medical community.

- Bill

Post 90

Friday, May 22, 2009 - 1:49pm

Bill I don't think high protein diets are bad for the kidneys, I only say that because millions upon millions of weightlifters have eaten high protein diets over prolonged periods of time, and there is no epidemic of kidney failure or disease in this population, at all. The fact is your kidney and liver can handle loads of protein. I'm not sure how the study you cite of increase kidney mass from high protein diets is actually bad, is a large kidney unhealthy? If so why? Also I do eat 4-5 servings of vegetables and two fruit servings a day. And I get plenty of calcium in my diet too. I stay away from red meat, except for the occasional 8 oz sirloin twice a month. Other than that it's tilapia, skinless chicken breast, salmon, tuna, and some delicious protein shake recipes I've come up with. Now that doesn't mean I cut out all my carbs. I get about 40 - 50% of my calories from low glycemic carbs (except for after my heavy workouts, I take a recovery drink with simple carbs) and about 30% protein. The rest is from healthy fats.

Post 91

Friday, May 22, 2009 - 8:23pm

Bill, I'll take our disagreement first:

As for your point that the stress on the kidneys from a high protein diet isn't harmful, this is simply not true. A high protein diet can reduce kidney function throughout life, and is especially bad for diabetics, who are advised to follow a low protein diet in order to preserve kidney function. This is not even controversial within the medical community.

There are two points there:
(A) high protein diets can or do reduce kidney function throughout life
(B) high protein diets are especially bad for diabetics' kidneys

Point A is a common meme or belief of many people (even of doctors). It is, however, unfounded. Here is the proof of that:
***********************
High Protein Intake Associates with Cardiovascular Events but not with Loss of Renal Function.
Halbesma N, Bakker SJ, Jansen DF, Stolk RP, De Zeeuw D, De Jong PE, Gansevoort RT; PREVEND study group.
*Division of Nephrology, Department of Medicine, Department of Epidemiology, and Department of Clinical Pharmacology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands.

The long-term effects of higher dietary protein intake on cardiovascular and renal outcomes in the general population are not clear. We analyzed data from 8461 individuals who did not have renal disease and participated in two or three subsequent screenings (6.4-yr follow-up) in a prospective, community-based cohort study (Prevention of Renal and Vascular ENd-stage Disease [PREVEND]).

We calculated daily protein intake from 24-h urinary urea excretion (Maroni formula) and used Cox proportional hazard models to analyze the associations between protein intake, cardiovascular events, and mortality. We used mixed-effects models to investigate the association between protein intake and change in renal function over time. The mean +/- SD daily protein intake was 1.20 +/- 0.27 g/kg.

Protein intake was significantly associated with cardiovascular events during follow-up. The associations seemed U-shaped; compared with intermediate protein intake, individuals with either higher or lower protein intake had higher event rates. All-cause mortality and noncardiovascular mortality also were significantly associated with protein intake; individuals with low protein intake had the highest event rates. We found no association between baseline protein intake and rate of renal function decline during follow-up.

In summary, in the general population, high protein intake does not promote accelerated decline of renal function but does associate with an increased risk for cardiovascular events.
J Am Soc Nephrol. 2009 May 14.
***********************
Recap:
Notice that the mean protein intake was already 50% above the RDA for protein. "High protein" in this study was, therefore, at levels even higher than that. Three things were found in this medium-to-long-term, wide-scale study -- when folks ate a lot of protein:

(1) they had more cardiovascular events
(2) they had less deaths (compared to those on a low-protein intake)
(3) they had no accelerated decline of kidney function

Point B is contradicted (at least in part) by a small-scale, short-term study where diabetics were given the Zone diet (30% protein, 40% carbs, 30% fat) for 8 weeks and -- on top of lowering their blood pressure -- it didn't hurt their kidney function (1). Even on reduced calories, consuming 30% of your calories as protein is still a high-protein diet. If high protein is especially bad for diabetics, then 30% protein diets should show harm.

Also, another study found that only the kidneys of diabetics with macroalbuminuria were helped by lower protein intake (2). And those diabetics with normo- or microalbuminuria had no improved kidney function from eating lower amounts of protein. I don't know the percentage of diabetics with macroalbuminuria, but whatever it is, it's likely how right you are. If 50% of diabetics have macroalbuminuria, then your point B is likely 50% correct. If only 10% do, then point B is likely mostly wrong (based on the evidence).

An interesting aside is that those same diabetics who had gotten kidney help from lower protein intake also had lower HbA1c (biomarker for diabetes progression) levels on the higher protein intake. In other words, the lower protein intake helped them more with their kidneys, but the higher protein intake helped them more with their diabetes. Again, this muddies the issue so as to detract from your statement that high protein is especially bad for diabetics.

Ed

Notes:
(1) J Am Diet Assoc. 2005 Apr;105(4):573-80.
Effect of high protein vs high carbohydrate intake on insulin sensitivity, body weight, hemoglobin A1c, and blood pressure in patients with type 2 diabetes mellitus.
Sargrad KR, Homko C, Mozzoli M, Boden G.
Nutrition Center, Department of Bioscience and Biotechnology, Drexel University, Philadelphia, PA 19104, USA. ksargrad@drexel.edu

BACKGROUND: Extremely low carbohydrate/high protein diets are popular methods of weight loss. Compliance with these diets is poor and long-term effectiveness and the safety of these diets for patients with type 2 diabetes is not known.

OBJECTIVE: The objective of the current study was to evaluate effects of less extreme changes in carbohydrate or protein diets on weight, insulin sensitivity, glycemic control, cardiovascular risk factors (blood pressure, lipid levels), and renal function in obese inner-city patients with type 2 diabetes.

DESIGN: Study patients were admitted to the General Clinical Research Center for 24 hours for initial tests including a hyperinsulinemic-euglycemic clamp (for measurement of insulin sensitivity), bioelectrical impedance analysis (BIA) and anthropometric measurements (for assessment of body composition), indirect calorimetry (for measurement of REE), electronic blood pressure monitoring, and blood chemistries to measure blood lipids levels along with renal and hepatic functions. Six patients with type 2 diabetes (five women and one man) were randomly assigned to the high-protein diet (40% carbohydrate, 30% protein, 30% fat) and six patients (four women and two men) to the high-carbohydrate diet (55% carbohydrate, 15% protein, 30% fat). All patients returned to the General Clinical Research Center weekly for monitoring of food records; dietary compliance; and measurements of body weight, blood pressure, and blood glucose. After 8 weeks on these diets, all patients were readmitted to the General Clinical Research Center for the same series of tests.

INTERVENTION: Twelve study patients were taught to select either the high-protein or high-carbohydrate diet and were followed for 8 weeks.

MAIN OUTCOME MEASURES: Insulin sensitivity, hemoglobin A1c, weight, and blood pressure were measured.

STATISTICAL ANALYSES: Statistical significance was assessed using two-tailed Student's t tests and two-way repeated measures analysis of variance.

RESULTS: Both the high-carbohydrate and high-protein groups lost weight (-2.2+/-0.9 kg, -2.5+/-1.6 kg, respectively, P <.05) and the difference between the groups was not significant (P =.9). In the high-carbohydrate group, hemoglobin A1c decreased (from 8.2% to 6.9%, P <.03), fasting plasma glucose decreased (from 8.8 to 7.2 mmol/L, P <.02), and insulin sensitivity increased (from 12.8 to 17.2 micromol/kg/min, P <.03). No significant changes in these parameters occurred in the high-protein group, instead systolic and diastolic blood pressures decreased (-10.5+/-2.3 mm Hg, P =.003 and -18+/-9.0 mm Hg, P <.05, respectively).

After 2 months on these hypocaloric diets, each diet had either no or minimal effects on lipid levels (total cholesterol, low-density lipoprotein, high-density lipoprotein), renal (blood urea nitrogen, serum creatinine), or hepatic function (aspartate aminotransferase, alanine aminotransferase, bilirubin).

(2) Nutr Hosp. 2008 Mar-Apr;23(2):141-7.
Effect of protein restriction diet on renal function and metabolic control in patients with type 2 diabetes: a randomized clinical trial.
Vel�zquez L�pez L, Sil Acosta MJ, Goycochea Robles MV, Torres Tamayo M, Casta�eda Limones R.
Medical Research Unit, Regional Hospital in Mexico City, The Mexican Institute of Social Security (IMSS), Mexico City, Mexico. lubia2002@yahoo.com.mx

OBJECTIVE: To assess the effect of a low protein diet (LPD) on renal function and metabolic control in three sub-groups of patients with type 2 diabetes those with or without nephropathy.

RESEARCH DESIGN AND METHODS: A randomized clinical trial was conducted on 60 patients with type 2 diabetes in primary care -19 with normoalbuminuria, 22 with microalbuminuria, and 19 with macroalbuminuria-. All patients experienced a screening phase during the 3 months, and were designated according to percentages of daily caloric intake (e.g., carbohydrates 50%, fat 30%, and 20% of protein). After this period, they were randomly assigned to receive either LPD (0.6-0.8 g/kg per day) or normal protein diet (NPD) (1.0-1.2 g/kg per day) for a period of 4 months. Twenty nine patients received LPD and 31 received NPD. Primary endpoints included measures of renal function (UAER, serum creatinine and GFR) and glycemic control (fasting glucose and glycosylated hemoglobin A1c).

RESULTS: Renal function improved among patients with macroalbuminuria who received LPD: UAER decreased (1,280.7 +/- 1,139.7 to 444.4 +/- 329.8 mg/24 h; p < 0.05) and GFR increased (56.3 +/- 29.0-74.2 +/- 40.4 ml/min; p < 0.05). In normoalbuminuric and microalbuminuric patients, there were no significant changes in UAER or GFR after either diet. HbA1c decreased significantly among microalbuminuric patients on both diets (LPD, 8.2 +/- 1.6-7.2 +/- 1.8%; p < 0.05; NPD, 8.8 +/- 1.9-7.1 +/- 0.8%; p < 0.05) and among macroalbuminuric patients who received NPD (8.1 +/- 1.8-6.9 +/- 1.6%; p < 0.05).

CONCLUSIONS: A moderated protein restriction diet improved the renal function in patients with type diabetes 2 and macroalbuminuria.

(Edited by Ed Thompson on 5/22, 8:56pm)

Post 92

Friday, May 22, 2009 - 8:45pm

John,

Good points about the millions of protein-stuffing bodybuilders without kidney disease or decline. Also, nice job on putting together a good eating program for yourself.

Ed

Post 93

Friday, May 22, 2009 - 9:43pm

Thanks Ed. I read recently in Iron Man magazine an interview with Anthony Almada who is a nutrition scientist and founder of EAS supplement company, and he said this about doctor's knowledge of nutrition:

"Medical doctors are among the worst sources of information relevant to nutrition. The medical-school curriculum offers nutrition as an elective, or voluntary, course, and most med students feel they are already overburdened with the study of traditional medical courses, so few future doctors have seen the minimal training in nutrition science."

I think this ignorance combined with studies that have shown high protein diets are bad for people with pre-existing kidney disease leads them to believe high protein diet is just harmful for everyone. But a perfectly healthy kidney can handle the protein just fine, and we have a whole population of weightlifters to look to for that evidence.

And sometimes these studies can be flawed in their controls. Take for instance the studies on calcium loss from high protein diets. Those studies were done on a calcium restriction diet. Another words the test subjects were not allowed to consume more calcium in their diet then what was set for them. Most weightlifters get plenty of their protein from dairy sources such as cottage cheese and whey/casein protein shakes. So the studies like that are flawed, they rarely take in what the typical athletic diet really is.

Post 94

Saturday, May 23, 2009 - 12:24am

I'm not sure how the study you cite of increase kidney mass from high protein diets is actually bad, is a large kidney unhealthy? If so why?

John, all I know is that enlarged kidneys are associated with renal insufficiency. It may be possible for someone to have an enlarged kidney that is perfectly healthy. I certainly can't rule that out a priori.

The evidence you cite of body builders on high protein diets not showing any signs of kidney failure is interesting. Have these body builders been followed well into their later years? I've read that on the standard American diet, kidney function declines by 30 to 50 percent over the course of a lifetime. The fact that you have two kidneys may be a saving grace. But if you donate one of them, you could put yourself at increased risk later in life.

For what it's worth, the American Kidney Fund made the following statement:

American Kidney Fund Warns About Impact Of High-Protein Diets On Kidney Health

"[R]esearchers studied five fit endurance runners who consumed a low, then a medium, and finally a high-protein diet. During the high-protein phase, the runners consumed about 30% of their total calories from foods such as eggs, steak, and so-called "power bars". Blood tests showed that increasing the protein intake led to a progression toward dehydration, and that a greater strain was placed on the kidneys due to the excessive amount of protein.

"Increased protein intake leads to a build-up of nitrogen in the blood. The nitrogen ends up at the kidney in the form of urea, where it needs to be cleaned from the blood and gotten rid of in the urine," explained Dr. Crawford. "The resulting increase in urination can cause dehydration, further straining the kidneys," he added.

In otherwise healthy individuals, a protein intake of no more than 2 grams of protein per kilogram of body weight was recommended by the researchers in order to avoid negative long-term effects. Dr. Crawford also discussed the risk that bodybuilders take in eating high-protein diets while building muscle. He noted, "Bodybuilders could be predisposing themselves to chronic kidney disease because hyperfilteration (the strain on the kidneys) can produce scarring in the kidneys, reducing kidney function."

"Chronic kidney disease is not to be taken lightly, and there is no cure for kidney failure. The only treatments are kidney dialysis and kidney transplantation. This research shows that even in healthy athletes, kidney function was impacted and that ought to send a message to anyone who is on a high-protein weight loss diet," concluded Dr. Crawford.

I'd be interested in statistics on the blood pressure of body builders. How many have hypertension? Don't the kidney's regulate blood pressure?

- Bill
(Edited by William Dwyer on 5/23, 1:12am)

Post 95

Saturday, May 23, 2009 - 9:25am

Bill,

Blood tests showed that increasing the protein intake led to a progression toward dehydration, and that a greater strain was placed on the kidneys due to the excessive amount of protein.

It's true that protein helps to dehydrate you, but that can get fixed with a few extra glasses of water. During and leading up to an endurance event -- where you can't even get water in your system fast enough to replace losses! -- protein would be bad for you (because of impairing hydration). A strain on the kidneys is just that, neither good nor bad until someone proves so.

Endurance running places a "greater strain" on the heart and leg muscles -- but you don't see these researchers condemning running, do you? There's something to be said for "use it or lose it." Organs respond to environmental demands, usually for the better. The question at hand is whether a given amount of protein is considered an "abuse." Researchers condemning high protein diets lack all perspective regarding the scientific fact that humans evolved on higher protein intakes (it's one of the differences between humans and chimps). Also, in the short-to-medium term, the kidneys of bodybuilders were able to handle the extra protein just fine (1,2).

I'd be interested in statistics on the blood pressure of body builders. How many have hypertension?

I'm willing to bet that many of them using high-dose anabolic steroids have hypertension, but that is due to endothelial dysfunction (inelastic blood vessel walls) from the steroids (3) -- not necessarily to some kind of kidney dysfunction supposedly caused by high protein intake. Resistance training itself does not cause any residual hypertension (4).

Don't the kidney's regulate blood pressure?

As I said above, besides the kidney, there is the vascular system. While the kidney indirectly controls the total fluid volume in the system, the system itself can break down -- leading to dysregulated blood pressure. Also, eicosanoids (extremely short-lived hormones) regulate blood pressure on a second-by-second basis. So that's at least 3 things that regulate blood pressure: kidney, vasculature, hormones.

Ed

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Notes:
(1) [abstract] Z Ernahrungswiss. 1995 Mar;34(1):10-5.

Effects of a high protein intake on renal acid excretion in bodybuilders.

Manz F, Remer T, Decher-Spliethoff E, H�hler M, Kersting M, Kunz C, Lausen B.

Forschungsinstitut f�r Kinderern�hrung, Dortmund.

Bodybuilders often prefer a high protein diet to achieve maximum skeletal muscle hypertrophy. In this study the effect of a high protein diet on renal acid load and renal handling of proton excretion was studied comparing dietary intake and urinary ionograms in 37 male bodybuilders and 20 young male adults. Energy intake (+ 7%), protein intake (128 vs 88 g/d/1.73 m2), and renal net acid excretion (95 vs 64 mmol/d/1.73 m2) were higher in the bodybuilders than in the controls, however, urine-pH was only slightly lower (5.83 vs 6.12). In the bodybuilders renal ammonium excretion was higher at any given value of urine pH than in the controls. In a regression analysis protein intake proved to be an independent factor modulating the ratio between urine-pH and renal ammonium excretion. The concomitant increase of renal net acid excretion and maximum renal acid excretion capacity in periods of high protein intake appears to be a highly effective response of the kidney to a specific food intake leaving a large renal surplus capacity for an additional renal acid load.

(2) [abstract] Int J Sport Nutr Exerc Metab. 2000 Mar;10(1):28-38.

Do regular high protein diets have potential health risks on kidney function in athletes?

Poortmans JR, Dellalieux O.

Department of Physiological Chemistry, Institute of Physical Education and Kinesiotherapy, Free University of Brussels, Belgium.

Excess protein and amino acid intake have been recognized as hazardous potential implications for kidney function, leading to progressive impairment of this organ. It has been suggested in the literature, without clear evidence, that high protein intake by athletes has no harmful consequences on renal function. This study investigated body-builders (BB) and other well-trained athletes (OA) with high and medium protein intake, respectively, in order to shed light on this issue. The athletes underwent a 7-day nutrition record analysis as well as blood sample and urine collection to determine the potential renal consequences of a high protein intake. The data revealed that despite higher plasma concentration of uric acid and calcium, Group BB had renal clearances of creatinine, urea, and albumin that were within the normal range. The nitrogen balance for both groups became positive when daily protein intake exceeded 1.26 g.kg but there were no correlations between protein intake and creatinine clearance, albumin excretion rate, and calcium excretion rate. To conclude, it appears that protein intake under 2. 8 g.kg does not impair renal function in well-trained athletes as indicated by the measures of renal function used in this study[.]

(3) [abstract] Eur J Clin Invest. 2006 Jul;36(7):483-8.

Impaired vasoreactivity in bodybuilders using androgenic anabolic steroids.

Lane HA, Grace F, Smith JC, Morris K, Cockcroft J, Scanlon MF, Davies JS.

Department of Endocrinology, University Hospital of Wales, Heath Park, Cardiff CF14 4XW, Wales, UK. laneha@cf.ac.uk

BACKGROUND: Anabolic androgenic steroids are used by some bodybuilders to enhance performance. While the cardiovascular implications of supraphysiological androgen levels requires further clarification, use is associated with sudden death, left ventricular hypertrophy, thrombo-embolism and cerebro-vascular events.

MATERIALS AND METHODS: To further understand the effect of androgenic anabolic steroid abuse on vascular function, this study assessed vascular stiffness (pulse-wave analysis) and cardiovascular risk factors in 28 male, bodybuilding subjects, of whom ten were actively receiving anabolic agents (group A; 26.4 +/- 7.2 years) and eight had undergone a 3-month "wash-out" period (group B; 32.1 +/- 7.1 years). The remaining ten bodybuilding subjects (group C; 24.4 +/- 4.4 years) denied any past use of anabolic steroids or other performance enhancing drugs. Comparisons were made with ten sedentary male controls (group D, 29.3 +/- 4.7 years).

RESULTS: Endothelial independent dilatation in response to glycerol trinitrate was significantly impaired in the group currently using anabolic steroids (group A) compared with the other three groups [A (5.63 +/- 3.24%) versus; B (11.10 +/- 4.91%), C (17.88 +/- 9.2%) and D (14.46 +/- 3.9%), P < 0.0005, respectively], whereas no significant differences in endothelial-dependent dilatation were detected between the groups [A (5.0 +/- 3.0%), B (7.4 +/- 3.4%), C (9.6 +/- 4.5%) and D (8.2 +/- 3.3%), P < 0.059, respectively].

CONCLUSIONS: Previous studies described a decline in vascular reactivity occurring in bodybuilding subjects which is independent of anabolic steroid use and may result from smooth muscle hypertrophy with increased vascular stiffness. This study revealed impaired vascular reactivity associated with anabolic agents and that improvement in vascular function may occur following their discontinuation.

(4) [abstract] Can J Sport Sci. 1988 Mar;13(1):31-4.

Blood pressure in resistance-trained athletes.

Colliander EB, Tesch PA.

Department of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.

Resting systolic and diastolic blood pressures were measured in age-matched bodybuilders (n = 31) and medical students (n = 37). Also, systolic blood pressure and heart rate were assessed during progressive cycle ergometer exercise at 100-200 W. Systolic and diastolic blood pressures at rest and systolic blood pressure response during exercise were comparable in bodybuilders and students. Bodybuilders, however, displayed lower (p less than 0.01-0.001) heart rate at identical power outputs of exercise. Consequently, when considering intergroup differences in muscle mass, circulatory responses were similar in bodybuilders and students. The results of the present study together with other observations suggest that intense long-term strength training, as performed by bodybuilders, does not constitute a potential cardiovascular risk factor.

(Edited by Ed Thompson on 5/23, 4:15pm)

Post 96

Saturday, May 23, 2009 - 11:43am

Ed,

Thanks for the information from the clinical studies you cited.

Someone told me that resistance training lowered diastolic pressure more than systolic. Do you have any info on that? I would assume that, by itself, resistance training confers positive cardiovascular benefits, provided the person is not at risk for heart disease. Running itself can predispose to heart attacks if the runner has serious cardiovascular risk factors.

Also, I would like to congratulate John for his improved health profile based on his apparent dietary changes and resistance training. Just curious, John. How much can you bench press? When I was 20 years old, I was 5' 11 1/2" and weighed about 165 pounds. I could bench 200. I'm sure that Ed can do substantially more. Right, Ed? Now that I'm approaching 70 and have a rotator cuff problem, I don't push it any more, but I still do some resistance exercise.

Mike, are you out there? Mike Erickson used to be able to do 5 one-arm chins. I've never seen anyone do that, and I think there's very few people in the world that can do it.

- Bill

Post 97

Saturday, May 23, 2009 - 12:08pm

Thanks Bill!

Wow 5 one arm chinups? That is insane! Kudos to Mike Erickson! I didn't even think to try something like that. I can't say I've gotten to that level, but now I want to get home from work and try one!

I'm not sure what my max bench press is actually. I do all of my workouts at home and I started out with this workout DVD program called P90X. The infomercial selling it is constantly playing on TV, so I bought it and it did wonders for me. The resistance training in that program was primarily focused on pullups, pushups, all bodyweight stuff and dumbell exercises done in a circuit training style, and some cardio routines and one yoga workout. I did two rounds of it and where I could only do 8 pushups and two pullups in the beginning, 6 months later I can now do 50 pushups to failure 15 pullups. I just started a new workout routine and bought some equipment for my home to do squats, benchpress, deadlifts, etc, more traditional weightlifting program because the P90x wasn't giving me anymore results and I plateaued, and I wanted a little more muscular size (it's not all just about the health, there's also vanity involved). I bought a power-rack which lets you do squats and benchpresses safely if you are alone because it has safety catches, but I'm still a little nervous about trying to do a max bench without a spotter. I don't want to injure myself.

Post 98

Saturday, May 23, 2009 - 1:27pm

John,

Yes, it's a good idea not to try a max bench without a spotter. When I did mine, I had a spotter. Now, of course, I wouldn't try a one max anything, because it's too dangerous for someone my age.

If you can only do 15 two arm pullups, you won't be able to do a one-arm pullup. I could do 18, and couldn't begin to do a one-arm. The program your talking about looks excellent and very challenging. You got really good results with it. Good luck in extending those results with your new equipment. Just curious: Any reason you don't want to enroll in a gym? You could get access to a lot of additional equipment, plus some potential spotters, if you did.

- Bill

Post 99

Saturday, May 23, 2009 - 2:32pm