In Defense of Oxalic Acid
| Moderate OxalateContent: - barley, cooked - corn bread - corn tortilla - cornmeal - cornstarch - flour, white or wheat - oatmeal - rice, brown - unsalted saltine or soda crackers - spaghetti in tomato sauce - sponge cake |
| High Oxalate Content: - Fig Newtons - fruit cake - graham crackers - grits, white corn - kamut - marmalade - soybean crackers - wheat germ |
| Low Oxalate Content: - acorn squash - alfalfa sprouts - cabbage - cauliflower - peas, frozen and fresh - peppers, red - radishes - turnips, roots - zucchini - squash |
| Moderate Oxalate Content: - asparagus - artichokes - brussels sprouts - broccoli - carrots - corn - cucumbers, peeled - kohlrabi - lettuce - lima beans - mushrooms - onions - potatoes, white - peas, canned - snow peas - tomato, fresh - tomato sauce |
| High Oxalate Content: - beans (green, wax, dried) - beets (tops, roots, greens) - celery - chives - collards - dandelion - eggplant - escarole - kale - leeks* - mustard greens - okra* - parsley - parsnips - peppers, green - pokeweed* - rutabagas - sorrel - spinach* - summer squash - sweet potatoes* - Swiss chard* - tomato soup - vegetable soup - watercress - yams |
| Low Oxalate Content: - any not listed |
| Moderate Oxalate Content: - basil, fresh - malt, powder - pepper |
| High Oxalate Content: - cinnamon, ground - parsley, raw - pepper, more than 1 tsp/day - ginger - soy sauce |
The word
"Oxalic" formed from the Latin "oxalis", which referred to plants with leaves
similar to clover. A plant such as wood sorrel - belonging to Genus Oxalis.
In the early 17th Century via Latin to Greek "wood sorrel," from
oxus "sour" or "oxygen", because of the taste of its leaves.
It
was believed in the late 18th century (
In 1776, Oxalic acid was prepared synthetically for
the first time by Scheele.
Oxalic acid (IUPAC name: ethanedioic acid,
formula H2C2O4) is a dicarboxylic acid with structure (HOOC)-(COOH). Because of
the joining of two carboxyl groups, this is one of the strongest organic acids.
It is also a reducing agent. The anions of oxalic acid as well as its salts and
esters are known as oxalates.
Biological
Hazards:
Oxalic acid and oxalates are mild nephrotoxic acids
that are abundantly present in many plants, most notably fat hen (lamb's
quarters), rhubarb and sorrel. Oxalic acid irritates the lining of the gut when
consumed, and can prove fatal in large doses. The LD50 for pure oxalic acid is
predicted to be about 378 mg/kg body weight, or about 22 g for a 60 kg human.
Oxalic acid can also be present in the body due to the consumption of another
toxin, ethylene glycol (generally known as automobile antifreeze), because over
time, the body metabolizes ethylene glycol partially into oxalic acid. Estimated
fatal dose is 5 to 15 grams.
Bodily oxalic acid may also be
synthesized via the metabolism of either glyoxylic acid or unused ascorbic acid (vitamin
C), which is a serious health consideration for long term megadosers of vitamin
C supplements. 80% of kidney stones are formed from calcium oxalate. Some
Aspergillus species produce oxalic acid, which reacts with blood or tissue
calcium to precipitate calcium oxalate. There is some preliminary evidence that
the administration of probiotics can affect oxalic acid excretion rates (and
presumably oxalic acid levels as well.)
Action of
Poisoning:
Oxalic acid also combines with metals such as
calcium, iron, sodium, magnesium, and potassium in the body to form oxalate
crystals which precipitate and irritate the gut and kidneys. The calcium oxalate
preciptate (better known as kidney stones) obstruct the kidney tubules. Because
it binds vital nutrients such as calcium, long-term consumption of foods high in
oxalic acid can lead to nutrient deficiencies.
Healthy individuals can
safely consume such foods in moderation, but those with kidney disorders, gout,
rheumatoid arthritis, or certain forms of chronic vulvar pain (vulvodynia) are
typically advised to avoid foods high in oxalic acid or oxalates. Conversely,
calcium supplements taken along with foods high in oxalic acid can cause oxalic
acid to precipitate in the gut and drastically reduce the levels of oxalate
absorbed by the body (by 97% in some cases.)
Symptoms of
poisoning are weakness, burning in the mouth, death from cardiovascular collapse; on the
respiratory system - difficulty breathing; on the eyes, ears, nose, and throat -
burning in the throat; one the gastrointestinal system - abdominal pain, nausea,
vomiting, diarrhea; and on the nervous system - Convulsions,
coma.
Oxalic Acid Containing
Foods:
The root and leaves of rhubarb contain dangerously high
concentrations of oxalic acid.
Foods that are edible, but still contain
significant concentrations of oxalic acid include - in decreasing order -
buckwheat, star fruit (carambola), black pepper, parsley, poppy seed, rhubarb
stalks, amaranth, spinach, chard, beets, cocoa, chocolate, most nuts, most
berries, and beans. The gritty feel one gets in the mouth when drinking milk
with rhubarb desserts is caused by precipitation of calcium oxalate. Thus even
dilute amounts of oxalic acid can readily "crack" the casein found in various
dairy products.
Leaves of the tea plant (Camellia sinensis) are known to
contain among the greatest measured concentrations of oxalic acid relative to
other plants. However the infusion beverage typically contains only low to
moderate amounts of oxalic acid per serving, due to the small mass of leaves
used for brewing.
Research is being done on methods to safely reduce
oxalate in food.
Plants Containing
OXALIC ACID (Dr. Duke's Phytochemical and Ethnobotanical
Databases)
Uses:
In household
chemical products such as Bar Keeper's Friend, some bleaches, and rustproofing
treatments.
In wood restorers where the acid dissolves away a layer of dry
surface wood to expose fresh material underneath.
As a mordant in dyeing
processes.
Vaporized oxalic acid is used by some beekeepers as an
insecticide against the parasitic Varroa mite.
Tests
for Oxalic Acid:
Titration with potassium permanganate can
reveal the presence of oxalic acid (as the acid is only a weak reductant, and
needs an oxidant as strong as permanganate in order to react). However, this
test will confuse ascorbate and oxalic acid, as will most test based on reducing
power: the solution is to run a second test for strong reductants using, for
example, iodine.
Preparation and
Manufacture:
Oxalic acid can be conveniently prepared in the
laboratory by oxidizing sucrose using nitric acid as the oxidizer and a small
amount of vanadium pentoxide as a catalyst. On a large scale, sodium oxalate is
manufactured by absorbing carbon monoxide under pressure in hot sodium
hydroxide.
What Should We
Consider:
The human body can synthesizes oxalic acid
from ascorbic acid (Vitamin C). It also may combine with calcium, iron, sodium,
magnesium, or potassium to form less soluble salts known as oxalates.
Since oxalic acid binds with important nutrients, making them
inaccessible to the body, regular consumption of large amounts of food high in
oxalic acid over a period of weeks to months may result in nutrient
deficiencies, most notably of calcium.
Oxalic acid is a
strong acid, and is irritating to tissue all by itself. Extremely high
doses are fatal. Oxalates, on the other hand, form tiny little insoluble
crystals with sharp edges, which are also irritating to tissue. So, high levels of
oxalic acid/oxalates in the diet lead to irritation of the digestive system, and
particularly of the stomach and kidneys. They may also contribute to the
formation of kidney stones (the most common form of kidney stone is composed of
calcium oxalate).
Hard water (which contains calcium and magnesium) will
tie up much of the oxalate consumed in the diet within the gastrointestinal
tract, thereby decreasing oxalate absorption.
Calcium
carbonate (precipitated chalk) is used to remove excess acid from juices. It is used
extensively to remove oxalic acid from Rhubarb juice.
What
About Rhubarb?
All parts of the rhubarb plant contains
oxalates, but anthraquinone glycosides is also contained in the plant. It is
possible that the combination of both compounds are the problem.
So-How
much rhubarb do you have to ingest to induce poisoning?
If you weight about 145 pounds, it will take about 25 grams of pure oxalic
acid required to cause death. In essense-you will have to eat about 11 pounds of
it. These numbers are relative, and it would take a lot less to become
ill.
Drink plenty of fluids. Drink more than 8 cups of fluid every day.
Your urine should be as clear as water. If it isn't, drink more
fluids.
To help prevent oxalate
stones from forming, limit oxalates to 40 to 50 mg per day.
Drinks:
Low Oxalate
Content:
Moderate Oxalate
Content:
High Oxalate Content:
Apple
juice
Coffee(limit to 8
oz/day)
Any juice made from high oxalate fruits
Beer-bottled or
canned
Cola(limit to 12
oz/day) Beer,
draft
Cider
Cranberry
juice
Chocolate, plain
Distilled
alcohol
Grape
juice Chocolate
milk
Ginger
Ale
Orange
juice
Cocoa
Grapefruit
juice
Orangeade
Coffee Powder (instant)
Lemon
juice
Ovaltine
Lemonade/limeade Tea,
brewed
(made without peel)
Lime juice
Milk(skim, 2%, whole)
Orange
soda
Pineapple
Root Beer
Tea,
instant
Water
Wine
Dairy:
Milk (skim,
2%,
whole)
None Chocolate
milk
buttermilk
yogurt with allowed
fruit
Cheese
Meat:
Beef, lamb,
pork
Beef
kidney
None
Eggs
Liver
Fish/shellfish
Poultry
Meat Substitutes, Beans, Nuts, and Seeds:
Eggs
Garbanzo beans
canned Almonds,
cashews, peanuts, pecans and
Lentils
Lima
beans
walnuts
Water
Chesnuts
Split peas,
cooked Baked
beans canned in tomato
sauce
Green beans, waxed and
dried
Peanut
butter
Sesame and sunflower
seeds
Tofu (soybean curd)
Fats and Oils:
All
None
None
Fruit:
Apples,
peeled
Apples with
skin Blackberries
Avocado Apricots
Black raspberries*
Bananas
Black
currants
Blueberries
Cantaloupe
Cranberries,dried
Red Currants
Casaba Grapefruit Dewberries
Cherries,
bing
Oranges Figs,
dried
Coconut
Peaches Grapes,
purple
Cranberries,
canned
Pears Gooseberries
Grapes,
green
Pineapple Kiwi
Honeydew Plums Lemon
Peel*
Mangoes
Prunes Lime
Peel*
Nectarines Orange
Peel
Papaya Red
Raspberries
Raisins Rhubarb
Watermelon Strawberries
Tangerines
Bread
and Starches:
Bread
Breakfast cereals
Noodles, egg or
macaroni
Rice, white or wild
Vegetables:
Condiments:
So,
it would seem that the key to preventing problems is a diet that is varied.
Moderation In All Things.
At least 75 percent of kidney
stones are composed of calcium combined with phosphate or oxalic acid. Medical
experts believe that these stones result from an accumulation of unused calcium,
and lack of exercise is generally thought to be a factor.
A study
conducted in 1973 showed that cranberries help prevent stones in some people by
reducing the excessive amounts of calcium commonly found in the urinary tract.
There is some scientific evidence that this may also be true of rose
hips, which have traditionally been used to ease various urinary tract
infections. Since the calcium-phosphate stones are most common in alkaline
urine, cranberries and other herbs that acidify urine also help prevent
stones.
Many years ago, an enzyme (an oxidase) that breaks down oxalic
acid into CO2 and H2O2 was discovered and found to be naturally present in
spinach leaves. However, nitrate, which can also be present because of the use
of common nitrate-based fertilizers, inactivates the enzyme.
In the
controlled-environment agricultural technique, done by Corinne Johnson-Rutzke of
Cornell Research Foundation, Inc., for
Oxalic acid is even needed by our body for many functions
(including peristalsis), and plays an important role in colon health, so much so
that when it is not gotten through the diet, the body synthesizes it from
ascorbic acid.
When you cook the spinach the heat crystalizes,
destroying it, the acid particles making them salt atoms, then the crystalized
particles you obtain called oxalate bind with other salts such as calcium and
potassium and they become stones. The calcium becomes unavailable and stones are
therefore created. Therefore,,it's not the oxalic acid that bind with other
minerals making them bio-unavailable, but oxalates that are only formed when
heat destroy and then crystalize the acid particles.
According to the
book "Fresh Vegetable and Fruit Juices" by Dr. Walker (1936 --BTW, his
reference to organic means raw food):
"Organic oxalic acid is one of the
important elements needed to maintain the tone of, and to stimulate peristalsis.
. .
If the important organs comprising the alimentary and eliminative
departments of our system, or any parts of them, are moribund or dead, the
efficiency of their function is impaired, to say the least. This condition can
result only from a lack or deficiency of live atoms in the food nourishing the
cells and tissues concerned. Live food means that food which contains live
organic atoms and enzymes found only in our raw foods. . . .
It is very
vital to stress this matter in regard to oxalic acid. When the food is raw,
whether whole or in the form of juice, every atom in such food is vital ORGANIC
and is replete with enzymes. Therefore, the oxalic acid in our raw vegetables
and their juices is organic, and as such is not only beneficial but essential
for the physiological functions of the body. ...
The oxalic acid in
cooked and processed foods, however, is definitely dead, or INORGANIC, and as
such is both pernicious and destructive. Oxalic acid readily combines with
calcium. If these are both organic, {meaning raw} the result is a beneficial
constructive combination, as the former helps the digestive assimilation of the
latter, at the same time stimulating the peristaltic functions in the body.
....
When the oxalic acid has become INORGANIC by cooking or processing
the foods that contain it, then this acid forms an interlocking compound with
the calcium even combining with the calcium in other foods eaten during the same
meal, destroying the nourishing value of both."
In 1997, a research
division of a healthcare provider conducted a double-blind study with a group of
64 patients who had a history of renal calculi to determine if
potassium/magnesium citrate would prevent the recurrent formation of calcium
oxalate kidney stones (Ettinger et al. 1997).
The patients were given 42
mEq (milliequivalent) potassium, 21 mEq magnesium, and 63 mEq citrate or a
placebo daily for 3 years. New renal calculi formed in 63.6% of patients
receiving the placebo. However, patients receiving the potassium/magnesium
citrate protocol presented with 12.9% recurrent renal calculi. Ettinger et al.
(1997) concluded that "potassium/magnesium citrate effectively prevents
recurrent calcium oxalate stones, and this treatment given for up to 3 years
reduces risk of recurrence by 85%."
Contrary to what was considered to be
"common sense" thinking in the past, two major studies have shown that calcium
should not be reduced for patients with a history of kidney stones (Takei 1998;
Williams 2001). It was originally thought that patients with a history of renal
calculi should limit their intake of calcium.
In fact, current
recommendations from the National Institutes of Health published on their Web
site continue to call for calcium-restricted diets. Such dietary changes also
affect the alkali and pH of the body by calling for the restriction of foods
such as apples, beets, parsley, broccoli, spinach, and pineapples. However,
newer findings contradict these dietary restrictions and offer scientific
evidence that uncombined intestinal oxalic acid is the real culprit for calcium
oxalate kidney stones (Ohgitani 2000).
Harvard researchers studied nearly
92,000 nurses over a period of 12 years to determine the relationship between
calcium intake and the occurrence of renal calculi . The conclusion of this
massive study was that those nurses who consumed diets that were higher in
calcium were at lower risk for kidney stones.
Another study conducted in
South Africa found that "mineral water containing calcium and magnesium deserves
to be considered as a possible therapeutic or prophylactic agent in calcium
oxalate kidney stone disease" (Rodgers 1997). French mineral water containing
calcium (202 ppm) and magnesium (36 ppm) was selected as the delivery method.
Twenty subjects of each sex who had previously formed calcium oxalate renal
calculi and 20 healthy volunteers of each sex participated in the study. Each
subject provided 24-hour urine collection samples each day during the study. The
mineral water was ingested over a 3-day period. Then the participants switched
to tap water. The cycle was repeated at least twice by each subject. The male
stone formers received the most benefit, showing nine risk factors that were
favorably affected by the mineral water containing calcium and magnesium (Rogers
1997).
In considering the literature below, it would seem that by
themselves to have very little impact. However, if we build on the information
some interesting conclusions can be made or assumed.
In the Book
"Oxalic acid in Biology and Medicine" by A. Hodgkinson, it is stated
that:
"The decomposition of solutions of oxalic acid by y-radiation has
been made the basis of a method for measuring radiation dosage, in the
sterilization of food and medical products (Holm and Sehested). The absorbed
dose is determined from the decrease in oxalic acid concentration which occurs
during irradiation". .....
"A mean value of 288mcg of anhydrous oxalic
acid/100ml was reported for normal human blood" (Pernet and Pernet).
....
And then add the information that oxalic acid is high in foods
reported to be great cancer fighters, like carrots, spinach, beets, nuts, and,
hundreds of other foods and beverages.
Also The National Institute of
Environmental Health and Sciences and The U.S. Department of Energy
published a booklet called "Questions and Answers About E- M- F, Electric and
Magnetic Fields Associated with the Use of Electric Power", which links
epidemiological studies with cancer.
"When oxalic acid is in our blood;
in foods & beverages we eat and drink, and testimonials confirm oxalic acid
kills cancer cells, virus, bacteria, and decalcifies the material in plaque in
arteries; and is in the blood of all warm blooded mammals".
Radiation is
given as a "just in case" and the number, time and power of each treatment will
determine how completely oxalic acid in the blood is decomposed.
The
decomposition of the oxalic acid in the blood by radiation may so weaken the
immune system so that one cannot fight off any viral or bacterial disease.
Therefore it is understandable that many cancer patients die from
cancer related to viral pneumonia.
There are many questions that are
left unanswered that cover the effects and sources of E-M-F as well as a
discussion of the history of Oxalic Acid, and Cancer
diets.
Here is an abstract (patent) where oxalic acid is used
for a health benefit:
US6133318: Oxalic acid or oxalate
compositions and methods for bacterial, viral, and other diseases or
conditions.
What is claimed is:
1. A bactericidal composition for
treating infectious or pathogenic bacterial diseases or conditions in warm
blooded animals sensitive to treatment comprising: a bactericidal composition
including an effective amount of at least one therapeutically effective
bactericidal form of at least one of oxalic acid and oxalate and at least one of
a carrier and diluent for said at least one of oxalic acid and oxalate, wherein
said effective amount is less than a lethal dosage of oxalic acid and wherein
said bactericidal composition is adapted to be administered to warm blooded
animals on a periodic basis in less than a lethal dosage.
And let's
not forget that oxalic acid is a chemical in Chocolate!!
References:
Kidney stone disease by Coe FL, Evan A,
Worcester E, on NIH website
Aspects of oxalosis associated with
aspergillosis in pathology specimens by Pabuccuoglu U. on NIH website
Use of a probiotic to decrease enteric hyperoxaluria by Lieske JC,
Goldfarb DS, De Simone C, Regnier C. on NIH website
Gastrointestinal
oxalic acid absorption in calcium-treated rats by Morozumi M, Hossain RZ,
Yamakawa KI, Hokama S, Nishijima S, Oshiro Y, Uchida A, Sugaya K, Ogawa Y. on
NIH website
Milk and calcium prevent gastrointestinal absorption and
urinary excretion of oxalate in rats by Hossain RZ, Ogawa Y, Morozumi M, Hokama
S, Sugaya K. on NIH website
Biodegradation of oxalic acid from spinach
using cereal radicles by Betsche T, Fretzdorff B. on NIH website
Back to
Eden by Jethro Kloss
Boning Up by Lynn Grieger
Fresh Vegetable and
Fruit Juices by Dr. Walker 1936
Go Light on Oxalic Acid, by Mary Schrick,
N.D.
Growth Conditions To Reduce Oxalic Acid Content of Spinach -John F.
Kennedy Space Center, Florida
King's American Dispensatory, Acidum
Oxalicum-Oxalic Acid by Harvey Wickes Felter, M.D., and John Uri Lloyd, Phr. M.,
Ph. D., 1898.
Low Oxalate Diet (Information for Patients), University of
Pittsburgh Medical Center
Oxalic acid in Biology and Medicine"by A.
Hodgkinson
Practical Organic Chemistry by Julius B. Cohen, 1930 ed.
preparation #42
Questions and Answers About E- M- F, Electric and
Magnetic Fields Associated with the Use of Electric Power, published by The
National Institute of Environmental Health and Sciences and The U.S. Department
of Energy
The Rhubarb Compendium from
http://www.rhubarbinfo.com/
U.S. Patent 1602802
U.S. Patent:
6133318: Oxalic acid or oxalate compositions and methods for bacterial, viral,
and other diseases or conditions.
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