Low Oxalate Diet
What Is the Low Oxalate Diet?
A low oxalate diet is one in which foods that contain high levels of oxalates are restricted. It is thought that individuals with autism may be susceptible to oxalate issues because they may have imbalanced intestinal bacteria and a lack of probiotic strains that break down oxalates. A low oxalate diet can improve mineral absorption and the symptoms associated with oxalate overload.
Oxalates are molecules with a negative charge. They are found in certain foods. In the body, oxalates combine with positively charged minerals like calcium, iron, magnesium, and copper.
Once bound to these minerals oxalates can be removed from the body in three ways:
Excretion in urine
The formation of insoluble calcium oxalate and elimination in the stool
Oxalate degradation by gastrointestinal (GIT) microorganisms.
Oxalates are 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.
It is important to note that other special diets like the Specific Carbohydrate Diet or the GAPS diet, can be high in oxalates. Vegetarian diets high in beans, nuts, grains, and certain vegetables may also be high oxalate.
The symptoms of oxalate overload are many and varied. They include headaches, depression and anxiety, pain (which can be anywhere), low energy, difficulty sleeping, burning feet, bedwetting and incontinence, cloudy urine or crystals in the urine, sandy stools or black specs in stool, skin rashes, and poor growth. Yeast overgrowth issues may also be caused by a high oxalate diet.
It is thought that calcium deficiency may exacerbate oxalate overload in the body.
There is a link between oxalate levels and kidney stone formation.
There are three types of primary hyperoxaluria (excess oxalate in the urine). All are based on different gene-mutations affecting the glyoxylate metabolism in the liver. The condition is marked by increased oxalate production within the body and thus massively elevated urinary excretion of oxalate.
In very rare cases, individuals with the genetic condition, primary hyperoxaluria type I (PH I) is caused by a deficiency of the liver-specific enzyme alanine-glyoxylate:aminotransferase (AGT). PH I is responsive to treatment with vitamin B6.
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. Lastly, autism is associated with altered intestinal permeability which may allow oxalates to be absorbed more readily.
When following a low oxalate diet, there is a detoxification process that typically occurs. When oxalate intake is limited, the body is able to remove the oxalate that has been stored in the body. This is referred to as “dumping”.
Dumping can cause unwanted symptoms so reducing oxalate intake should be slow and gradual.
Dumping often happens in cycles and can even occur over the course of a few years.
Who Would Benefit From This Diet?
This diet may be a good option for people that have:
Tested positive for high oxalate levels on an organic acids test
Experience the following symptoms:
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 head banging to indicated headache)
Low energy
Burning feet
Bedwetting and incontinence
Cloudy urine or crystals in urine
Sandy stools or black specs in stool
Skin rashes
Poor growth
Vulvodynia in young girls or women
Candida or yeast overgrowth
People may benefit from this diet if they have mitochondrial dysfunction, inflammatory bowel disease or if they have issues with the aforementioned symptoms. Others may want to give this diet a try if they have yeast overgrowth issues that don’t seem to be improving with a low carbohydrate diet.
Recommended Foods
Low oxalate foods like:
Proteins:
Eggs, beef, lamb, pork, poultry, fish, and shellfish
Fruits:
Avocados, cherries, green grapes, honeydew, lemons, peaches, watermelon, certain apples like golden delicious, granny smith and red delicious
Vegetables:
Grains & Legumes:
White rice, barley, corn
Nuts, Seeds & Their Oils:
Olive Oil
Dairy:
Cheddar cheese, butter, ghee, yogurt, parmesan cheese
Foods to Avoid
High oxalate foods like:
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:
Nuts (especially almonds including almond flour, cashews and peanuts)
Chia and sesame seeds, tahini
Other:
Miso soup
Cocoa powder and chocolate
Stevia
Lifestyle Changes
Reducing the oxalate content of the diet should be done very gradually to prevent an intense “dumping” reaction. In addition, supplements should be added very slowly.
Once oxalate intake is decreased, the body may begin the release of stored oxalate, provoking a “dumping” reaction, with flu-like symptoms and burning stool or urine. The slow removal of oxalates will mitigate the severity of dumping.
Helpful Resources
Recommended Supplements
Vitamin B6 (those with a B6 deficiency may be more susceptible to issues with oxalates)
Calcium and magnesium supplements can help bind oxalates [2]
The probiotic Oxalobacter Formigenes has been said to assist in the intestinal excretion of oxalates. [1, 4, 9-10]
Certain supplements can help manage dumping symptoms like magnesium, L-arginine and D-ribose (these are amino acids).
Certain foods can actually be converted to oxalate in the body and these should be limited. They include vitamin C supplements, vitamin D supplements, fish oil, glycine (found in meat and bone broth), fructose, other sugars, and sugar alcohols.
DISCLAIMER: Before starting any supplement or medication, always consult with your healthcare provider to ensure it is a good fit for your child. Dosage can vary based on age, weight, gender, and current diet.
Low Oxalate Diet in the Research
How to Reduce Oxalate Levels
Treatment options like a low oxalate diet, probiotic oxalobacter formigenes use, enzyme supplementation or oxalate binding treatments may be helpful for children with ASD with greater plasma and urinary oxalate levels. [1]
Calcium supplementation appears to be a reasonable therapy to decrease urinary oxalate in gastric bypass patients who maintain a low fat and oxalate diet. [2]
Half of participants experienced urinary oxalate excretion under increasing dosages of B6. [3]
Magnesium, citrate and phytate inhibits calcium oxalate crystallization, and may treat and prevent calcium oxalate kidney stones. [5]
Modifying diet to prevent stones could help many people who suffer from stone formation to avoid recurrence. [6]
In healthy volunteers with diet-induced hyperoxaluria, treatment with ALLN-177 significantly reduced urinary oxalate excretion by degrading dietary oxalate in the gastrointestinal tract and thereby reducing its absorption. [7, 8]
Oxalobacter Probiotic and Oxalates
O. formigenes induces colonic oxalate secretion, thereby reducing urinary oxalate excretion and stimulate oxalate transport in intestinal cells. [4]
Human Oxalobacter strain promotes a secretion of oxalate in the distal ileum, caecum and distal colon and these correlate with the beneficial effect of reducing renal excretion of oxalate. [9]
O. formigenes lowers the intestinal concentration of oxalate available for absorption, resulting in decreased urinary oxalate excretion. [10]
Potential Causes of High Oxalate Levels
Decreased dietary zinc intake was independently associated with incident calcium kidney stones. [11]
Excess oxalate in urine was the common observation in rats with vitamin B6, A and B1 deficiencies and there was increased bio-availability of oxalate from the gut in vitamin-A- and vitamin-B6-deficient rats. [12]
The breakdown of ascorbic acid is non-enzymatic and results in oxalate formation. [13]
The Bottom Line
Overall, there is evidence to suggest that a low-oxalate diet in addition to proper supplementation would be helpful for those with oxalate overload. However research on the relationship between oxalates and autism is limited. The low oxalate diet is not excessively difficult to manage, but the risk of dumping is cause for a slow and conservative approach when implementing this diet. Consider this diet a marathon, not a sprint. The diet has been well utilized and many resources are available with clear-cut guidance on what foods to avoid. For those with symptoms of oxalate overload, this diet is definitely worth trying.
Scale: 1 - 5 Stars ★
We rate the quality and quantity of the Research supporting the efficacy of the diet in improving symptoms as well as the Ease of Adherence, taking into account the cost, resources available, time required, social acclimation to the diet including options available in restaurants and grocery stores which assist in convenience and adherence
Ease of Adherence ★★★
The diet is somewhat restrictive but there is a wealth of guidance available.
Research ★★★★
Much research has been done to support the use of diet and supplements for oxalate overload.
Grade: B
Disclaimer: The information provided in the Autism Nutrition Library is intended for educational purposes only and should not be interpreted as medical nutrition therapy, nutrition counseling, diagnosis, prognosis, health care treatment, instruction, advice, or any other individualized medical service. Always let your physician know about any of your health concerns, and check with your doctor or dietitian before making any diet, medication, exercise, or lifestyle changes.
The information provided in the Autism Nutrition Library is intended for educational purposes only and should not be interpreted as medical nutrition therapy, nutrition counseling, diagnosis, prognosis, health care treatment, instruction, advice, or any other individualized medical service. Always let your physician know about any of your health concerns, and check with your doctor or dietitian before making any diet, medication, exercise, or lifestyle changes.
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[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] Espino-Grosso P, Monsour C, Canales BK. The Effect of Calcium and Vitamin B6 Supplementation on Oxalate Excretion in a Rodent Gastric Bypass Model of Enteric Hyperoxaluria. Urology. 2019;124:310.e9-310.e14.
[3] Hoyer-Kuhn H, Kohbrok S, Volland R, et al. Vitamin B6 in primary hyperoxaluria I: first prospective trial after 40 years of practice. Clin J Am Soc Nephrol. 2014;9(3):468-77.
[4] Arvans D, Jung YC, Antonopoulos D, et al. Oxalobacter formigenes-Derived Bioactive Factors Stimulate Oxalate Transport by Intestinal Epithelial Cells. J Am Soc Nephrol. 2017;28(3):876-87.
[5] Grases F, Rodriguez A, Costa-Bauza A. Efficacy of Mixtures of Magnesium, Citrate and Phytate as Calcium Oxalate Crystallization Inhibitors in Urine. J Urol. 2015;194(3):812-9.
[6] Kotsiris D, Adamou K, Kallidonis P. Diet and stone formation: a brief review of the literature. Curr Opin Urol. 2018;28(5):408-13.
[7] Langman CB, Grujic D, Pease RM, et al. A Double-Blind, Placebo Controlled, Randomized Phase 1 Cross-Over Study with ALLN-177, an Orally Administered Oxalate Degrading Enzyme. Am J Nephrol. 2016;44(2):150-8.
[8] Lingeman JE, Pareek G, Easter L, et al. ALLN-177, oral enzyme therapy for hyperoxaluria. Int Urol Nephrol. 2019;51(4):601-8.
[9] Hatch M, Freel RW. A human strain of Oxalobacter (HC-1) promotes enteric oxalate secretion in the small intestine of mice and reduces urinary oxalate excretion. Urolithiasis. 2013;41(5):379-84.
[10] Siener R, Bangen U, Sidhu H, Hönow R, von Unruh G, Hesse A. The role of Oxalobacter formigenes colonization in calcium oxalate stone disease. Kidney Int. 2013;83(6):1144-9.
[11] Tasian GE, Ross ME, Song L, et al. Dietary Zinc and Incident Calcium Kidney Stones in Adolescence. J Urol. 2017;197(5):1342-8.
[12] Sharma S, Sidhu H, Narula R, Thind SK, Nath R. Comparative studies on the effect of vitamin A, B1 and B6 deficiency on oxalate metabolism in male rats. Ann Nutr Metab. 1990;34(2):104-11.[13] Knight J, Madduma-Liyanage K, Mobley JA, Assimos DG, Holmes RP. Ascorbic acid intake and oxalate synthesis. Urolithiasis. 2016;44(4):289-97.
