Foods high in oxalate may cause or increase inflammation, pain, and burning, irritate tissues and mucous membranes, and contribute to the formation of calcium oxalate kidney stones. Oxalate is found in varying degrees primarily in plant foods including vegetables, fruits, grains, legumes, spices, herbs, and almost all nuts and seeds.
When too much oxalate is absorbed into the bloodstream via the gut, it can team up with calcium to form sharp calcium-oxalate crystals. These crystals can then wedge themselves into tissue almost anywhere in the body causing damage and/or exacerbating pain and inflammation. Excess oxalate can also lead to oxidative damage and the depletion of glutathione. The latter is essential for metabolizing many toxic environmental chemicals that enter the body.
How do high oxalate foods cause problems?
Most people are able to safely metabolize and process oxalate out of the gut through the stool. According to researcher Susan Owens, M.A., Director of the Autism Oxalate Project, a problem occurs when excess oxalate is absorbed through the gut due to intestinal permeability, poor fat digestion, inflammation, or prolonged diarrhea or constipation. Overuse of antibiotics may also pose a problem since this can reduce or eliminate the oxalate-degrading bacteria in the intestines. In her overview of the scientific research, Owens says there may be a link between excess oxalate in the body and the following conditions:
- Thyroid disease
- Calcium-oxalate Kidney Stones
- Cystic Fibrosis
Excess oxalate may be one among several factors like genetics and environmental triggers that contribute to these disorders and to other conditions reported by members of the Trying Low Oxalates Yahoo forum, started by Owens.
Oxalate and the Pain Project
Taking a slightly different twist, Clive Solomons, Ph.D., former director of research at the University of Colorado Health Sciences Center, has explored the connection between excess oxalate, pain, and weakened connective tissue in his research, which is aptly called the Pain Project. In addition to a low-oxalate diet, he recommends that a graded program of connective tissue stabilization, using a small number of supplements, also be employed to gain relief from symptoms and provide longer-term healing of connective tissue. People who have participated in the Pain Project have reported recovery or improvement from a variety of painful conditions including:
- Irritable bowel syndrome
- Vulvodynia (vulvar pain)
- Vulvar vestibulitis
- Lichen sclerosus
- Lichen planus
- Dyspareunia (painful sex)
- Nonbacterial prostatitis
- Urethral syndrome
- Interstitial cystitis
- Pelvic floor dysfunction
Solomons has observed that almost every participant in the Pain Project with these diagnosis’ reveal periodic hyperoxaluria upon testing. The term hyperoxaluria refers to excreting greater than normal amounts of oxalate via the urine at certain times of the day, but normal amounts at other times.
The Low Oxalate Cookbook, which explains Solomon’s research underscores:
“It is important to understand that the metabolic abnormality that causes pain is internal. The amount of oxalate that appears in urine is determined not only by dietary intake of oxalate (food), but also by intestinal bacteria that are able to degrade oxalate, intestinal permeability (how easily the intestinal wall lets substances like oxalate pass through it into the body’s tissues), endogenous (internal) synthesis of oxalate within the body, and the handling of oxalate by the kidneys.
Foods and beverages high in oxalate content merely add fuel to the flame. In addition, tissues are affected by exposure to chemicals in the environment such as chlorine and formaldehyde.
Although reducing dietary oxalate may only have a partial effect, any reduction in pain is a good thing. Over 70% of patients in the Pain Project, who utilize connective tissue stabilization supplements in addition to the low-oxalate diet, have reported significant improvements or complete recovery.
If you have any of the above conditions, you may want to explore the potential benefits of trying a low-oxalate diet, after consultation with a medical professional. Be forewarned that there is a great deal of incomplete and incorrect information about the low-oxalate diet on the internet.
Many people have reported relief from pain, inflammation, and a range of disorders on a low oxalate diet.
Oxalate levels in food
Oxalate occurs in low to high amounts in a wide range of plant foods including fruits, vegetables, legumes, grains, spices, herbs, and almost all nuts and seeds. Meat, dairy, and eggs contain negligible amounts of oxalate.
Many people are able to process oxalate in their body without any problem whatsoever, but others absorb too many oxalate which can then link to calcium and form into sharp crystals that lodge in almost any tissue in the body causing or contributing to pain, inflammation, and other conditions.
The amount of oxalate in a particular food can vary depending upon the soil in which it is grown, the climate, how it’s cooked and other factors. Despite this caveat, a good amount of useful information has been garnered in recent years on oxalate levels in foods using more reliable testing methods. This data serves as a guide for trying a low oxalate diet.
Here are a few examples of high oxalate foods:
- Sesame seeds
- Beet greens
- Sweet potato
- Swiss chard
- Soy milk
- Most grains
- Most legumes
Reliable resources for oxalate content
Inaccurate information on the oxalate content of food abounds on the internet. It is often based on outdated analysis techniques and typically has not been revised as new information has emerged. This can include information provided on medical sites for dealing with calcium oxalate kidney stones or even information from a medical provider if they have not updated their materials.
Finer methods of content analysis have evolved in recent years and these provide much more accurate data. In addition, several patient groups who are using the low oxalate diet compile and share their knowledge and experience in online forums. If a low oxalate diet did not work for you in the past, it may be due to not having accurate information or not implementing the diet correctly due to lack of proper instructions.
These are the most reliable resource I have found
Trying Low Oxalates Yahoo Group – This is a discussion group for those trying a low oxalate diet. Susan Owens, M. A., researcher and list owner, regularly updates the forum with information on breaking research about oxalate and its effect in the body. There is a wealth of useful information in the files section of the group and much to be learned from the experience of other members. Susan also provides an overview of oxalate information and the diet at www.lowoxalate.info too. The information there is excellent, however the food tables are not always as current as the information available in the forum. The forum is an incredibly helpful resource for learning how to implement the diet correctly and thus avoiding potential pitfalls.
The group uses data from testing done at the labs of Dr. Liebman, Ph.D., a professor of Human Nutrition at the University of Wyoming. He is a specialist in oxalate research.
Implementing the low oxalate diet
The menu options on a low oxalate diet are numerous and varied. The diet provides a good nutritional base as long as your eat an array of the available foods.
Implementing the diet requires study, counting numbers, and ongoing dedication. A low oxalate diet generally means keeping your intake of oxalate from food and beverages between 40 and 60 mg. per day, depending upon your weight. Some people find they need a very low oxalate intake, while others can tolerate more. Each person needs to experiment and find their own level. To use the diet correctly, you will have to count your daily intake and be cognizant of portion sizes.
It is also helpful to bear in mind that oxalate levels can vary dramatically due to growing conditions as well as cooking methods. The lists provided are guides, not the ultimate truth. While some foods routinely test low for oxalate and people rarely report problems with them, others do not. Zucchini and green beans are examples of foods that test at different levels. There may also be reasons other than oxalate content for why you react to a particular food. Each person needs to experiment in order to find the foods they best tolerate, but having accurate low oxalate lists and support from others on the diet gives an excellent starting ground.
Meat, dairy, and eggs contain negligible amounts of oxalate. However, eating large amounts of meat is not advisable as this can also contribute biochemically to increasing oxalate levels in the body.
Cooking and preparation methods influence oxalate content of foods. For example, some vegetables have a lower oxalate when boiled, although it appears there are different explanations for this. One explanation is that the oxalate leaches into the water. Therefore, you never want to drink or use the water in which your vegetables are cooked. While boiling vegetables goes contrary to modern nutritional advice in terms of retaining the most nutrients, there are plenty of good nutritional choices on the diet. Obviously, avid juicing is not part of the diet, although small amounts of specific juices can be used.
It’s also recommended not to make a dramatic shift to a low oxalate diet. Most people begin by cutting out high oxalate foods and then over a period of time gradually reducing their intake of medium oxalate foods. This gives your body time to adjust to the change. Some people find they can tolerate up to 2 servings of medium oxalate foods per day, as long as the remainder of their foods are low oxalate. Others find they can only tolerate foods in the low and very low oxalate category and some can only handle very low oxalate foods.
There can be a short term increase in symptoms when the diet is started and symptoms can flare periodically while on the diet. One theory is that during the low oxalate diet a chemical shift occurs at a cellular level from time-to-time causing larger amounts of oxalate to be released from tissue and therefore symptoms as well. The term “dumping” has been coined to describe this feature. Ascertaining whether symptoms are due to eating too much oxalate or simply a biochemical shift is not necessarily easy. This is where support from others on the diet is really useful.
Both approaches to the diet provide a recommended list of supplements either for connective tissue stabilization or to help optimize the processing of oxalate in the body and reduce symptoms.
At times, people report very quick results on the diet, but others find it can take 6 months to see results. According to Susan Owens, it can take 1-4 years on the diet for the stores of excess oxalate to leave tissues.
There’s much more to learn about the diet than can be provided in a brief article. The best approach is to obtain the Low-Oxalate Cookbook from the Vulvar Pain Foundation and to utilize the information available from the Trying Low Oxalates Yahoo forum hosted by Susan Owens, which includes participation from people with a variety of conditions with autism being one of the main ones.
Remember, this is cutting edge research so it’s almost like participating in an experiment in process, rather than being an exact science.