Low Protein Diet Information
for People
with Kidney Disease



WARNING      

This information is from my personal research. I'm not a doctor or nephrologist
so please, please check with your doctor first before you try anything you read here!!!

It is possible to become protein deficient if you go to extremes so please be careful. If your body doesn't get enough protein through food or supplements, it will start breaking down the protein in your muscle. It's probably best to pick a high and low for the amount of protein you want to eat and try to stay with in that.

 As far as I know, everything here is accurate but I've listed where I found the information so you can verify it yourself.
Each source that I've quoted from has its own color. The quotes from that source will be in same color.



THE POLYCYSTIC KIDNEY RESEARCH FOUNDATION'S NEWSLETTER ON LOW PROTEIN AND SOY PROTEIN IN THE DIET.

WHAT IS A LOW PROTEIN DIET ?

WHAT ARE KETO ACID SUPPLEMENTS ?

HOW MUCH PROTEIN DOES MY BODY NEED ?

SO HOW EXACTLY DO I FIGURE THIS OUT ?

WHAT FOODS ARE LOW IN PROTEIN?

HOW CAN I FIND A DOCTOR FAMILIAR WITH LOW PROTEIN DIETS FOR KIDNEY PATIENTS?

WHAT TEST(S) SHOULD I HAVE DONE TO MONITOR MY KIDNEY FUNCTION?

WHAT IS GFR?

WHAT IS A NORMAL GFR?





THE POLYCYSTIC KIDNEY RESEARCH FOUNDATION'S NEWSLETTER ON LOW PROTEIN AND SOY PROTEIN IN THE DIET.

The news letter for the Polycystic Kidney Research Foundation (Vol.13, issue 1, Special Issue 1998) states that The Nutrition Research Group for the Retardation of Polycystic Kidney Disease studies have shown the restriction of dietary protein early in the course of PKD (before the manifestation of clinical symptoms) can significantly slow disease progression. The rate of enlargement of kidney cysts, including total kidney size, is significantly reduced. In addition, the amount of time for progression to kidney failure is delayed considerably. Also, We have demonstrated that soy protein isolate (an ingredient manufactured from soybeans and used in various food products), when substituted for animal protein (in the form of milk casein), was found to retard the progression of PKD. The progression of PKD in Japanese patients is significantly slower than that for corresponding North Americans. The slower rate of progression of PKD in Japan has previously been attributed to genetic factors. We are pursuing the likely possibility , based on our animal experiments, that the slower progression of PKD in Japan may partly reflect the differences in the Japanese diet. The Japanese diet has lower levels of protein (including higher intakes of low-protein, carbohydrate-rich, rice-based foods) and much higher levels of soy-based products and associated micronutrients.


WHAT IS A LOW PROTEIN DIET ?

It is a diet that limits protein to the minimum you need to be in good health. There are two versions of low protein diets used for kidney disease. One is a moderately restricted low protein diet where you get all your protein from food and the amount of protein is limited to only the amount necessary for good nutrition. This is the diet the Polycystic Kidney Research Foundation's newsletter mentioned.
There is also the severe protein restiction diet where you are limited to a small amount of protein (under 25 gms. usually) with keto acid or amino acid supplements supplying the rest of the protein intake. In some studies, this diet has shown better results in preserving kidney function than the moderate restricted low protein diet but this also included other types of kidney disease. It is also harder to comply with. This is a rather strict vegetarian diet with meat of any kind, eggs, milk or cheese forbidden or rarely allowed. It requires a nephrologist's monitoring and mineral and vitamin supplementation (especially vitamin B-12 which is found almost exclusively in animal products). Calcium and potassium supplements may also be needed. If you are interested in trying this diet, you should read "The Kidney Patient's Book New Treatment, New Hope" by Timothy P. Ahlstrom which I will be quoting from like crazy in the next few questions.


WHAT ARE KETO ACID SUPPLEMENTS ?


Protein is made up of amino acids. There are about 20 different amino acids in protein of which 9 can not be made by the body and are called the essential amino acids. The other amino acids are called non-essential amino acids because the body can convert other amino acids into the ones it needs.
Keto acid supplements are a chemically different form of amino acids, created in the laboratory. The body transforms them into the essential amino acids it needs. Both supplements -- amino acid and keto acids -- provide the essential amino acids the body needs, but in a pure form that does not overload the diseased kidneys with the needs to process the phosphorus or nitrogen that would come from foods. (The Kidney Patient's Book New Treatment, New Hope by Timothy P. Ahlstrom)
For those of you interested in amino acid supplements, here's information about where you can get them. This is from an e-mail which Dr. Mackenzie (who is involved in research on low protein diets on kidney disease) was kind enough to send me.
"The amino acid preparations sold in food stores are useless. The only preparation consisting exclusively of essential amino acids, sold in US, is Aminess, marketed by Nestle (800 776 5446)."
I do want to add a warning here that I don't think it's a good idea to try the extreme low protein diet with supplements without a nephrologist who's had some experience with this. This isn't the easiest diet in the world and I think it's too easy to get confused doing it by yourself. That said, you're perfectly free to ignore me if you like.


HOW MUCH PROTEIN DOES MY BODY NEED ?

Most Americans eat much more protein than they need to stay healthy, by some estimates 2 or 3 times as much protein than needed. Your kidneys then have to break down all this extra protein and get rid of it. This makes your kidneys have to work harder and wear out faster than if they only broke down the amount of protein your body actually needed. Your body on average requires .6 gms. of protein / per kg. of bodyweight / per day. This can vary from a low of .45 gms. to a high of .8 gms. of protein (Polycystic Research Foundation Newsletter). Factors such as a higher percentage of muscle mass can require a higher intake of protein. I think this means wimps like me are on the lower end.


SO HOW EXACTLY DO I FIGURE THIS OUT ?

Part 1. First convert your weight to kilograms (kgs.) by dividing your weight in pounds (lbs.) by 2.2. If you're not from the U.S, you probably already know your weight in kgs. and can skip this part.

Ex. My weight is usually around 120 lbs.

120 lbs divided by 2.2 is 54.55 kgs.

Part 2. Next you multiply your weight in kgs. by .6 (.45 for wimps or .8 for you weight lifters). Personally, I suggest sticking with the .6 and adjusting your protein up if you feel tired or down a little if you think you'll feel ok.

Ex. 54.55 kgs multiplied by .6 is 32.73 gms. of protein I can eat.

Also make sure to tell your doctor that you're trying a low protein diet and want to be tested after a few months to make sure you aren't cutting it too close and getting a protein defeciency.


WHAT FOODS ARE LOW IN PROTEIN?

Fruits and most vegetables have little or no protein. There are some exceptions to this like peas, beans (both can be rather high) and some starchy vegetables (like potatoes and corn which are in the medium range). Listed below are some examples. The amount of protein can vary depending on serving size, if the food is fresh, dried (usually higher in protein) or frozen, and other factors so check the nutrition label for a more accurate measurement of protein when it's available. These are only averages.



Type of Food Amount of Protein
texturized vegetable protein 1/2 Cup/ 43 gms 23 gms
meat - 1 oz 10 gms
cheese - 1 oz 10 gms
black eye peas - 1/4 Cup dry 9 gms
kidney beans - 1/4 Cup dry 9 gms
pinto beans - 1/4 Cup dry 7 gms
pasta - 2 oz uncooked 7 gms
peas - 2/3 Cup frozen 7 gms
soymilk 1 Cup/140 ml 6 gms
potato - 5.5 oz 4 gms
bread - 1 slice/oz whole wheat 3 gms
rice - 1/4 Cup uncooked 3 gms
corn - 2/3 Cup frozen 3 gms


Click here for the  text version of this chart


HOW CAN I FIND A DOCTOR FAMILIAR WITH LOW PROTEIN DIETS FOR KIDNEY PATIENTS?

Click here for the doctor listing from "The Kidney Patient's Book New Treatment, New Hope" by Timothy P. Ahlstrom.


WHAT TEST(S) SHOULD I HAVE DONE TO MONITOR MY KIDNEY FUNCTION?

There are 4 main tests used to determine kidney function for PKD.

Creatine - test that measures levels of creatine in your urine.

BUN - test that measures levels of urea nitogen in your blood.

24 Hr. Creatine clearance - 24 hour collection of urine sample that is measured for creatine levels.

Radionuclide studies(GFR)- test that uses an isotope solution injected into your vein, with a gamma camera taking pictures to show the blood supply to each kidney.


Radionuclide studies that measure the glomerular filtration rate (GFR) are suppose to be the most accurate test for kidney function but can be more expensive than tests generally done. Creatine and BUN tests are affected by the amount of protein you eat and I don't think they are very reliable indicators for someone on a low protein diet. These tests depend on the break down rate of protein and if you take in less protein than the average person, it will throw the results off. My tests have alway come back on the low side of the normal range. This really surprised the nephrologist I went to when I first had my tests done after going on a low protein diet.
As far as I 've been able to find out, a 24 creatine clearance is unaffected by change in the amount of protein consumed but can be affected by certain conditions and drugs (advanced age, cachexia, liver disease, ketoacidosis Cephalothin, cefoxitin, aspirin, cimetidine, trimethoprim - "1997 Current Medical Diagnosis and Treatment 36th Edition edited by Lawrence M. Tierney, Jr. MD, Stephen J. McPhee MD, and Maxine A. Papadakis MD") The last time I had testing done, It did show my kidney function to be just a little below normal so I think this test does work for someone on a low protein diet.
If you can't have a lab measure the GFR, your doctor can estimate it using tests based on simpler and less expensive test measuring creatine in your blood and in your urine. With those measurements he can use a formula that will give a working estimate of GFR. (The Kidney Patient's Book New Treatment, New Hope by Timothy P. Ahlstrom)

The sources where I found this information are listed below.

"The Kidney Patient's Book New Treatment, New Hope" by Timothy P. Ahlstrom

Kidney specialists at the National Institutes of Health say that people most at risk for kidney disease -- those with high blood pressure, diabetes, or a family history of kidney disease -- would benefit from a more accurate measurement of their kidney function than simply the measurement of creatine in their blood.

From "The Encyclopedia of Medical Tests" by Michael B. Brodin, M.D.

Blood Urea Nitrogen (BUN)

Urea is the main waste product of protein metabolism. Blood levels of it are referred to as blood urea nitrogen (BUN) and are used to evaluate kidney disease.
A high BUN is the hallmark of kidney disease. It is also high in heart failure, increased protein breakdown, diabetic acidosis, dehydration, intestinal bleeding, and muscle degeneration. Certain drugs cause an elevated BUN, as will a recent meal heavy in protein. Low BUN is associated with excess fluid intake, malnutrition, liver disease, and pregnancy.

Creatinine

Creatinine is a waste product of normal metabolism. Blood levels--along with blood urea nitrogen--are the most common kidney function tests.

BEFORE THE TEST You should fast overnight.

High creatinine is associated with any of a number of kidney diseases, but provides only a rough approximation of the extent of disease and does not identify its cause. High levels can also be due to decreased blood supply to the kidney, as occurs in shock. Diseases such as hyperthyroidism and muscle disorders may also increase creatinine, as will several ingested substances, including meats, vitamin C, cimetidine (Tagamet), and some antibiotics. Low creatinine is seen in debilitation and some severe liver diseases. More accurate information about kidney function can be obtained with creatinine clearance.


WHAT IS GFR?

The filtering action of the kidneys processes about 120 milliliters of blood per minute. Doctors measure this rate as an indication of how well the kidneys are working and call it the glomerular filtration rate or GFR for short. (The Kidney Patient's Book New Treatment, New Hope by Timothy P. Ahlstrom)


WHAT IS A NORMAL GFR?

The chart below lists values for GFR.

KIDNEY FUNCTION GLOMERULAR FILTRATION RATE
100% 120 ML/MIN NORMAL KIDNEYS
50% 60 ML/MIN FAILING KIDNEYS
25% 30 ML/MIN CHRONIC RENAL FAILURE
5% 6 ML/MIN END-STAGE RENAL FAILURE


Click here for the  text version of this chart


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