The Organic Acids Test by The Great Plains Laboratory, Inc. is the only OAT on the market that evaluates levels of oxalates in urine. Oxalate (and its acid form, oxalic acid), is an organic acid that is primarily derived from three sources: the diet, fungus (such as Aspergillus and Penicillium), possibly Candida, and also human metabolism. Oxalic acid is the most acidic organic acid in body fluids and is used commercially to remove rust from car radiators. Antifreeze (ethylene glycol) is toxic primarily because it is converted to oxalate in the body. Two different types of genetic diseases are known in which oxalates are high in the urine, hyperoxalurias type I and type II, which can also be determined from the Organic Acids Test.

Foods especially high in oxalates are often foods thought to be otherwise healthy, including spinach, beets, chocolate, peanuts, wheat bran, tea, cashews, pecans, almonds, berries, and many others. People now frequently consume “green smoothies” in an effort to eat “clean” and get healthy, however, they may actually be sabotaging their health. The most common components of green smoothies are spinach, kale, Swiss chard, and arugula, all of which are loaded with oxalates. These smoothies also often contain berries or almonds, which have high amounts of oxalates as well. Oxalates are not found in meat or fish at significant concentrations. Daily adult oxalate intake is usually 80-120 mg/d. A single green smoothie with two cups of spinach contains about 1,500 mg of oxalate, a potentially lethal dose.

“If oxalic acid is very high in the blood being filtered by the kidney, it may combine with calcium to form crystals that may block urine flow and cause severe pain. However, such crystals may also form in the bones, joints, blood vessels, lungs, eyes, skin, heart, thymus, skeletal muscle, joints, fat, teeth, mouth, nerves, and even the brain.”
-William Shaw, Ph.D.

Studies show that oxalates in the urine are much higher in individuals with autism than in non-autistic children. In the figure below, it shows that 36% of the children on the autism spectrum had values higher than 90 mmol/mol creatinine, the value consistent with a diagnosis of genetic hyperoxalurias, while none of the non-autistic children had values this high. 84% of the children on the autism spectrum had oxalate values outside the normal range (mean ± 2 sd). None of the children on the autistic spectrum had elevations of the other organic acids associated with genetic diseases of oxalate metabolism, indicating that oxalates are high due to external sources.

A low-oxalate diet is being used extensively to treat children with autism and other disorders. Researcher, Susan Owens discovered that the use of a diet low in oxalates markedly reduced symptoms in children with autism and PDD. For example, the mother of an autistic son reported that he became more focused and calm, that he played better, that he walked better, and had a reduction in leg and feet pain after being on a low oxalate diet. Prior to the diet, her child could hardly walk up the stairs. After the diet, he walked up the stairs very easily. Many children with autism throughout the world are now being placed on this diet with good results.

Implement a low-oxalate diet. This may be especially important if the individual has had Candida for long periods of time and there is high tissue oxalate buildup.
Use antifungal drugs to reduce yeast and fungi that may be causing high oxalates. Children with autism frequently require years of antifungal treatment. Arabinose, a marker used for years for yeast/fungal overgrowth in the Organic Acids Test is correlated with high amounts of oxalates.
Supplements of calcium and magnesium citrate can reduce oxalate absorption from the intestine. Citrate is the preferred calcium form to reduce oxalate because citrate also inhibits oxalate absorption from the intestinal tract.

N-Acetyl glucosamine supplements can stimulate the production of the intercellular cement, hyaluronic acid, to reduce pain caused by oxalates.

Chondroitin sulfate can prevent the formation of calcium oxalate crystals.

Vitamin B6 is a cofactor for one of the enzymes that degrades oxalate in the body and has been shown to reduce oxalate production.

Excessive fats in the diet may cause elevated oxalates if the fatty acids are poorly absorbed because of bile salt deficiency. If taurine is low, supplementation with taurine may help stimulate bile salt production (taurocholic acid), leading to better fatty acid absorption and diminished oxalate absorption.

Probiotics may be very helpful in degrading oxalates in the intestine. Individuals with low amounts of oxalate-degrading bacteria are much more susceptible to kidney stones. Both Lactobacillus acidophilus and Bifidobacterium lactis have enzymes that degrade oxalates.

Increase intake of essential omega-3 fatty acids, commonly found in fish oil and cod liver oil, which reduces oxalate problems. High amounts of the omega-6 fatty acid, arachidonic acid, are associated with increased oxalate problems. Meat from grain fed animals is high in arachidonic acid.

Supplements of vitamin E, selenium, and arginine have been shown to reduce oxalate damage.

Increase water intake to help eliminate oxalates.