Oxalic acid and oxalates are abundantly present in many plants, most notably rhubarb and sorrel. The root and leaves of rhubarb contain dangerously high concentrations of oxalic acid. Other foods that contain significant concentrations of oxalic acid include – in decreasing order – buckwheat, star fruit, parsley, poppy seed, rhubarb stalks, amaranth, spinach, chard, beets, cocoa, chocolate, most nuts, most berries, and beans.
In our body oxalic acid may also be synthesized via the metabolism of 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. Kidney stones are not caused by oxalic acid by animal protein and inorganic calcium.
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 precipitate (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, are 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.) Calcium citrate is recommended as it is regarded as organic but calcium carbonate and bicarbonate are inorganic and should be avoided.
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.
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: “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 potassium, magnesium citrate or a placebo daily for 3 years. New kidney stones were formed in 64% of patients receiving the placebo. However, patients receiving the potassium / magnesium citrate supplements formed only 13% stones. The conclusion of the study was that potassium / magnesium citrate effectively prevents recurrent calcium oxalate stones, and reduces risk of recurrence by 85%.
It is a well-known fact that oxalic acid is high in anticancer foods, like carrots, spinach, beets, nuts, etc.
The decomposition of the oxalic acid in human body by radio therapy effectively weakens the immune system leading to inability of cancer patients to fight off any viral or bacterial infections and their frequent deaths from viral pneumonia.
To prevent excessive accumulation of oxalic acid in the body try to drink 9 glasses of distilled water every day. Your urine should be as clear as water. If it isn’t, drink more water.
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
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
Biodegradation of oxalic acid from spinach using cereal radicles by Betsche T, Fretzdorff B. on NIH website
Back to Eden by Jethro Kloss
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.
Oxalic acid in Biology and Medicine”by A. Hodgkinson
Practical Organic Chemistry by Julius B. Cohen, 1930 ed. preparation #42
The Rhubarb Compendium from http://www.rhubarbinfo.com/
U.S. Patent: 6133318: Oxalic acid or oxalate compositions and methods for bacterial, viral, and other diseases or conditions.