Let’s think about this logically. Animals have ways to make sure they don’t become some other animal’s dinner (including a human being’s). They can run away, or they can stay and fight with claws, horns, or teeth. If they win, great. If not, fire up the BBQ! Plants aren’t so lucky. Since they can’t defend themselves physically, they’ve evolved multiple insidious ways of warding off predators biochemically. Plants produce a variety of harmful substances collectively known as antinutrients. (Not harmful to the plants, but harmful to the poor saps who eat them.) They’re exactly what they sound like: they work against you absorbing nutrients from those foods.
Foods that contain significant amounts of oxalic acid are ( in order from highest to lowest): buckwheat, star fruit, black pepper, parsley, poppy seed, rhubarb stalks, amaranth, spinach, chard, beets, cocoa, chocolate, most nuts, most berries, and beans. If you had to really avoid oxalic acid that would be difficult.
Phytic acid—also called inositol hexaphosphate, or IP6—is comprised of six phosphorus molecules and one molecule of inositol. It has been mistakenly described for decades as an "anti-nutrient" because it impairs mineral absorption. However, in the 1980s food biochemist Ernst Graf, Ph.D., began to tout phytic acid for its beneficial antioxidant properties achieved through mineral chelation. [32]
Phytic acid in foods or bran should be distinguished from supplemental phytic acid, which is derived from rice bran extract. In foods, phytic acid binds to iron and other minerals in the digestive tract and may interfere with mineral absorption. As a purified extract of rice bran, taken between meals so it will not bind to minerals in the digestive tract, phytic acid is readily absorbed into the bloodstream, where it acts as a potent mineral chelator. [33] Phytic acid binds to any free iron or other minerals (even heavy metals such as mercury, lead and cadmium) in the blood, which are then eliminated through the kidneys. Phytic acid removes only excess or unbound minerals, not mineral ions already attached to proteins.
So maybe nuts and chocolate and berries and beans are still worth eating. I do recall my dad warning me as a kid not to eat raw rhubarb. It was because of the phytic and oxalic acids but he couldn't articulate that reason but that's what it was. Not because it's particularly poisonous--I mean people made rhubarb pie (delicious) for Godssakes--but because he knew of the wisdom of cooking certain vegetables. Here are the facts on rhubarb:
From an MSDS (Material Safety Data Sheet) for Oxalic acid, LD50 (LD50 is the Median Lethal Dose, which is the dose of a drug or chemical predicted to produce a lethal effect in 50 percent of the subjects to whom the dose is given) in rats is 375 mg/kg. So for a person about 145 pounds (65.7 kg) that’s about 25 grams of pure oxalic acid required to cause death. Rhubarb leaves are probably around 0.5% oxalic acid, so that you would need to eat quite a large serving of leaves, like 5 kg (11 lbs), to get that 24 grams of oxalic acid. Note that it will only require a fraction of that to cause sickness. – The Rhubarb Compendium
Oxalic acid poisoning symptoms include weakness, burning in the mouth, death from cardiovascular collapse, on the respiratory system, throat – burning in the throat, abdominal pain, nausea, vomiting, diarrhea, convulsions, and coma.
Oxalic acid binds with some nutrients, making them inaccessible to the body. To eat large amounts of high oxalic foods over a period of weeks to months may result in nutritional deficiencies, most notably of calcium.
The main sources of oxalate in diets were regular tea and coffee (80-85%). Only 15-20% of oxalate was derived from other plant foods. Patients did not adhere to high fluid diet and, what is more, as common beverage they chose rich-oxalate black tea. Patients' daily intake of calcium was low and didn't exceed 520 mg. Vitamin C consumption was higher than Polish Dietary Reference Intake (DRI) and vitamin B6 lower than DRI.
Eating oxalic acid foods together with calcium-containing foods such as yogurt, milk and other dairy products may reduce the risk of kidney stone formation, advises the University of Maryland Medical Center. In addition, a study published in 2005 in the “Journal of Agricultural and Food Chemistry” reported that several cooking methods help lower the oxalic acid content of vegetables. The researchers tested nine raw and cooked vegetables and found that boiling and steaming significantly reduce oxalic acid in vegetables with a high content of the compound, such as spinach.
It has been assumed that black tea due to its high oxalate content increases kidney stone formation but recent research has shown it to have a preventive effect.
Victoria Boutenko of the Raw Food Family cites research on how high oxalic acid foods actually reduce the formation of kidney stones. The true cause of kidney stones is not oxalic acid but actually animal protein.
Oxalic acid linked to the cure or prevention of cancer:When cancer is diagnosed there is always a low level of oxalic acid in the blood. It is important to have the enough oxalic acid in our blood because this eliminates all abnormal cells without harmful side effects.
Every alternative cancer cure that is successful is filled with foods, herbs, grasses, and teas that are full of high amounts of oxalic acid.
American Cancer Society conducted tests over 50 years ago using oxalic acid in the treatment of cancer and the results in papers and evidence were positive.
“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”. From booklet.“ Questions and Answers About E- M- F, Electric and Magnetic Fields Associated with the Use of Electric Power.
Radiation will decompose oxalic acid in the blood. This usually weakens the immune system so the body is unable to fight off viral or bacterial disease. Is this why many cancer patients die from cancer related to viral pneumonia.
Ascorbate (the active ion in vitamin C) does increase the body's production of oxalate. Yet, in practice, vitamin C does not increase oxalate stone formation. Drs. Emanuel Cheraskin, Marshall Ringsdorf, Jr. and Emily Sisley explain in The Vitamin C Connection (1983) that acidic urine or slightly acidic urine reduces the UNION of calcium and oxalate, reducing the possibility of stones. "Vitamin C in the urine tends to bind calcium and decrease its free form. This means less chance of calcium's separating out as calcium oxalate (stones)." (page 213) Also, the diuretic effect of vitamin C reduces the static conditions necessary for stone formation in general. Fast moving rivers deposit little silt.