A low-oxalate diet may benefit sufferers of kidney stones as well as those suffering from many other chronic conditions. Oxalates are organic acids that occur naturally in plants, animals and humans. Only when there is an excess or sensitivity to them are there problems such as kidney stones, inflammation, pain, and irritation of tissue and mucous membranes. They are eliminated in the urine, but because they are crystallized in structure when combined with calcium, they may irritate vulvar tissue and cause vulvar pain.
Too much oxalate in the bloodstream can result in depleting levels of glutathione, which metabolizes many of the toxic environmental chemicals that enter the body. There may be a link between too much oxalate in the body and conditions such as thyroid disease, vulvodynia, calcium-oxalate kidney stones, cystic fibrosis, asthma and autism. The amount of this organic acid is not only determined by food intake but also by the ability of intestinal bacteria to degrade oxalate, by the permeability of the intestinal wall, by kidney function and by internal synthesis ability in the body. The benefits of a low-oxalate diet may only be a partial solution to the problem if the other causes are not also addressed.
An acceptable amount for those following a low-oxalate diet is between 40 to 60 milligrams a day. Levels present in foods can vary according to factors such as the type of soil the food has been cultivated in, the climate, and the cooking methods. A very general guideline for a low-oxalate diet is to eat meat, dairy and eggs, which are very low sources of oxalate. Plant foods and virtually all nuts and seeds are low to high sources. Some examples of high level foods are almonds, spinach, soy milk, potato and tomato.
The issue of oxalates in the body is very closely linked to gut problems and gut function. People who have these problems find that one of the benefits of a low-oxalate diet is improved gut function. Others who follow this diet but did not have any initial kidney trouble have experienced improvements in other chronic conditions. There are a few conditions such as absorptive hypercalciuria type II, enteric hyperoxaluria and primary hyperoxaluria, which require a very low-oxalate diet. These are very rare conditions in which the recommended level of oxalate equals about a 1/4 cup of raw spinach.