Oxalates
Oxalates are a natural substance found in certain foods. They are molecules with a negative charge. In the body, oxalates combine with positively charged minerals like calcium, iron, magnesium, and copper. Once bound to these minerals oxalates are removed from the body through stool (in most people). If not removed in stool, they may be excreted in the urine or stored in tissues.
Quick Facts
Oxalates are often considered anti-nutrients because they inhibit the absorption of important minerals.
Oxalates can bind with calcium and form crystals with sharp edges which cause pain and inflammation.
When not bound to calcium, oxalates can damage mitochondria and impair energy production, cause faulty sulfation, oxidative stress and inflammation, deplete glutathione, cause histamine release, interfere with biotin, cause pain, fatigue, anxiety, seizures, and sleep issues.
Symptoms of oxalate overload
The symptoms of oxalate overload are varied and many. They include:
Headaches
Depression and anxiety
Pain (which can be anywhere and may manifest as self-injurious behavior such as eye poking indicating pain behind the eyes or headbanging to indicated headache)
Low energy
Burning feet
Bedwetting and incontinence
Cloudy urine or crystals in the urine
Sandy stools or black specs in stool
Skin rashes
Poor growth
Vulvodynia in young girls or women
Candida or yeast overgrowth
Foods containing Oxalates
Below are the foods containing the highest amount of oxalates. For a full list of foods containing oxalates, click here.
Fruits:
Some berries like raspberries and blackberries
Vegetables:
Spinach, swiss chard, rhubarb, okra, beets, sweet potatoes, baked potato with skin
Grains & Legumes:
Corn grits, cornmeal, buckwheat groats, bulgur, millet, bran flakes, shredded wheat, and rice bran
Most beans
Nuts, Seeds & Their Oils:
Other:
Miso soup
Cocoa powder and chocolate
Stevia
Chemical reactions
The body can respond to foods and/or chemicals in many different ways including allergies and sensitivities. If you suspect a chemical reaction, you can either choose to avoid the chemical or additional testing.
Oxalates & Autism in the Research
Children with ASD demonstrated 3-fold greater plasma oxalate levels and 2.5-fold greater urinary oxalate concentrations compared with controls. [1]
It is thought that people with autism may be susceptible to oxalate issues because they have an altered intestinal microbiome and a lack of probiotic strains that break down oxalates.
Those with autism also often have limited diets and may not be getting enough minerals to bind oxalates. Fat malabsorption can affect this as well, with fat binding to calcium and being excreted. The calcium is then not available to bind to the oxalates.
Autism is associated with altered intestinal permeability which may allow oxalates to be absorbed more readily.
References
[1] Konstantynowicz J, Porowski T, Zoch-Zwierz W, et al. A potential pathogenic role of oxalate in autism. Eur J Paediatr Neurol. 2012;16(5):485-91.
[2] Shaw PHD, W., 2015. OXALATES CONTROL IS A MAJOR NEW FACTOR IN AUTISM THERAPY — The Great Plains Laboratory, Inc.. [online] The Great Plains Laboratory, Inc. Available at: <https://www.greatplainslaboratory.com/articles-1/2015/11/13/oxalates-control-is-a-major-new-factor-in-autism-therapy> [Accessed 11 October 2020].
Author
Elisa Rocks, RDN
Brittyn Coleman, MS, RDN/LD, CLT
