[653] in Vegetarian_Support_Group
protein
daemon@ATHENA.MIT.EDU (elsiedee@MIT.EDU)
Mon Sep 11 11:49:04 1995
From: elsiedee@MIT.EDU
Date: Mon, 11 Sep 1995 11:47:40 -0400
To: vsg@MIT.EDU
The Protein Myth
****************
In the past, some people believed one could never get too much
protein. In the early 1900's, Americans were told to eat well over 100
grams of protein a day. And as recently as the 1950's,
health-conscious people were encouraged to boost their protein intake.
The reality is that the average American takes in twice the amount of
protein he or she needs. Excess protein has been linked with
osteoporosis, kidney disease, calcium stones in the urinary tract, and
some cancers. Despite all this, many people still worry about getting
enough protein.
The Building Blocks of Life
+++++++++++++++++++++++++++
People build the proteins of their bodies from amino acids, which, in
turn, come from the proteins they eat. Protein is abundant in nearly
all of the foods people eat. A varied diet of beans, peas, lentils,
grains, and vegetables contains all of the essential amino acids.
Animal products are high in protein, but are undesirable because of
their high fat and cholesterol content. Fat and cholesterol promote
heart disease, cancer, and many other health problems. One can easily
meet the body's protein requirements with plant foods. It used to be
believed that various plant foods had to be eaten together to get
their full protein value, but many nutrition authorities, including
the American Dietetic Association, have determined that intentional
combining is not necessary.1 As long as one's diet includes a variety
of grains, legumes, and vegetables, protein needs are easily met.
The Trouble With Too Much Protein
+++++++++++++++++++++++++++++++++
The average American diet contains meat and dairy products. As a
result, it is too high in protein. This can lead to a number of
serious health problems:
Kidney Disease
--------------
When people eat too much protein, they take in more nitrogen than they
need. This places a strain on the kidneys which must expel the extra
nitrogen through urine. People with kidney disease are encouraged to
eat low-protein diets.2 Such a diet reduces the excess levels of
nitrogen and thus can help prevent kidney disease too.
Cancer
------
Although fat is the dietary substance most often singled out for
increasing one's risk for cancer, protein also plays a role.
Populations that eat meat regularly are at an increased risk for colon
cancer,3 and researchers believe that the fat, protein, natural
carcinogens, and the absence of fiber in meat all play roles. In 1982,
the National Research Council noted a link between cancer and
protein.4
Osteoporosis and Kidney Stones
------------------------------
Diets that are rich in protein, especially animal protein,5 are known
to cause people to excrete more calcium than normal through their
urine6 and increase the risk of osteoporosis. Countries with
lower-protein diets have lower rates of osteoporosis and hip
fractures.7 This holds true even in countries with low calcium intake.
Increased calcium excretion increases risk for kidney stones.
Researchers in England found that by adding about five ounces of fish
(about 34 grams of protein) to a normal diet the risk of forming
urinary tract stones increased by as much as 250 percent.8
For a long time it was thought that athletes needed much more protein
than other people. The truth is that athletes need only slightly more
protein, which is easily obtained in the larger servings athletes
require for their higher caloric intake. Vegetarian diets are great
for athletes.
To consume a diet that contains enough, but not too much, protein,
simply replace animal products with grains, vegetables, legumes (peas,
beans, and lentils), and fruits. As long as one is eating a variety
of plant foods in sufficient quantity to maintain one's weight, the
body gets plenty of protein.
References:
+++++++++++
1. Position of the American Dietetic Association: Vegetarian diets. J
Am Diet Assoc, 1988;88:351-355.
2. El Nahas AM, Coles GA. Dietary treatment of chronic renal failure:
ten unanswered questions. The Lancet, 15 March 1986:597-600.
3. Pellet PL. Protein requirements in humans. Am J Clin Nutr,
1990;51:723- 37.
4. Committee on Diet, Nutrition, and Cancer of the National Research
Council. Diet, Nutrition, and Cancer. Washington, DC, 1982.
5. Zemel MB. Calcium utilization: effect of varying level and source
of dietary protein. Am J Clin Nutr, 1988;48:880-3.
6. Sherman HC. Calcium requirement in man. J Biol Chem, 1920;44:21.
7. Hegsted DM. Calcium and osteoporosis. J Nutr, 1986;116:2316-2319.
8. Robertson PJ, et al. The effect of high animal protein intake on
the risk of calcium stone-formation in the urinary tract. Clinical
Science, 1979;57:285-288.
For more information, contact:
++++++++++++++++++++++++++++++
Physicians Committee for Responsible Medicine
P.O. Box 6322
Washington, DC 20015
(202) 686-2210
