Vulvodynia, Oxalates, and Diet
March, 2006
By J. Byron for med-owl.com

Vulvodynia (also called vulvar vestibulitis or vulvular pain syndrome) is a condition that involves irritation and pain in the vulva and surrounding tissues. There is little controversy in the scientific community as to whether this disease exists, although its prevalence is unkown, and many doctors still may not recognize and diagnose it. And modern medicine is still uncertain as to the cause of vulvodynia. One theory is that vulvodynia can be caused by oxalates.

Oxalate is an organic compound that is found in many foods, and is also a by-product of some metabolic processes in the body.  Oxalates (in the blood in the form of free oxalic acid) are ordinarily filtered by the kidneys into the urine, and eliminated from the body.  If the kidneys do not filter fast enough, oxalates can form crystals that develop into painful kidney stones.  If the concentration of oxalates in the urine is too high, microscopic crystals can form in the bladder. Some cases of vulvodynia has been linked to microscopic oxalate crystals irritate the nerves in a the urethra.

How strong is the Evidence?

In early 2006, there were two articles on the PubMed database that involved research into oxalates and vulvodynia.  The first article from 1991 (PMID:1816400:) was a case report of a woman that had suffered from vulvodynia for 4 years, and the condition had become debilitating.  A series of tests showed that the alkalinity and oxalate level of her urine often rose to abnormal levels, and her discomfort was linked to these surges in oxalates.  The woman was put on a program to control oxalates that included a calcium citrate supplement. The woman improved significantly by a 3 month follow up, and was symptom free after a year on calcium citrate. When the woman stopped taking calcium citrate, her symptoms would return; when she restarted the supplement, her vulvodynia went into remission.  So in one case, a strong relationship between oxalates and vulvular pain was demonstrated.

A second study was conducted in 1997 that included 130 women with vulvular pain syndrome (PMID:9322615).  Lab tests showed that just under half of the women (59 patients) had elevated oxalate levels.  These 59 were put on a program that included a low oxalate diet and calcium citrate. The results of this study were less dramatic than in the first case study: 24% (14 patients) demonstrated an 'objective improvement' and 10% (6 patients) improved to the point of being able to have normal sexual intercourse.  The researchers concluded that oxalates might aggravate vulvodynia, but was not the cause for most women in the study.

From the limited research (and from anecdotal information on the web), it can be said that a program to reduce oxalates in the diet along with a supplement of calcium citrate might provide a measure of relief to some women with vulvodynia. It does not appear to be a 'cure' in any sense, but it may reduce symptoms, and if combined with other appropriate treatments, could make life more bearable. And that is a good thing.

Other Notes

Calcium citrate works by increasing the solubility of oxalates in the urine - the citrate portion of the supplement prevents the crystals from forming, and lets the oxalate be flushed out of the body. Another supplement that does the same thing is magnesium citrate; some research has suggested that magnesium citrate may be even more effective than calcium citrate.  Other forms of calcium or magnesium bound to 'Krebs-Cycle intermediates' also appear to be effective. These include calcium or magnesium bound to succinate, malate, or fumarate.  

The most common forms of calcium found in supplements (calcium carbonate and magnesium oxide) do NOT appear to reduce oxalates as it is not just the calcium or magnesium that helps - the citrate (or malate) is also needed.  Cal-trate (TM) is one widely marketed brand of calcium citrate, and others are mentioned below.

Calcium citrate is generally well tolerated, although those with a pre-existing medical condition (particularly kidney or heart disease) should consult their doctor before adding a calcium or magnesium supplement.  These supplements are beneficial for many people, but not all.  

Calcium tends to slow the bowels (perhaps even causing constipation) while magnesium can work in the opposite direction. A mix of calcium and magnesium is less likely to have these side effects. The body needs both magnesium and calcium, and taking too large a supplement of either can throw off electrolyte balance over time.  

These supplements are widely available and inexpensive.  By way of comparison, Vitacost's NSI Calcium Citrate Malate -- 1,000 mg - 200 Caps costs $9.99 for a 40 day supply.  Their NSI Calcium & Magnesium -- 240 Caps (a calcium citrate/calcium malate/magnesium citrate combo) costs $14.99.

 

Other Nutritional Notes

Several studies have shown that for most people, oxalate levels can be reduced simply by drinking more water.  While drinking water like a maniac can also deplete the body of electrolytes and cause problems, increasing your intake by a few glasses a day is a free and safe option for any one.

The mineral Boron has been shown to increase the excretion of oxalates. A 'normal' diet may contain 3 milligrams of Boron per day, a diet rich in fresh fruits and vegetables may contain 10-15 mg. per day, while a diet high in processed junk foods may contain only 1 mg.  Nature's Way Boron supplements (Nature's Way Boron -- 3 mg 100 Caps) costs less than 3 cents per capsule while a premium brand (like Twinlab Tri-Boron -- 3 mg - 100 Capsules ) costs 3.5 cents per capsule.  

Several studies have shown that a deficiency of Vitamin B₆  (pyridoxine) increases the risk of oxalate deposits. In one study that compared diet and oxalate kidney stones, those consuming the most B₆ had had a risk reduction of 34% (PMID:10203369).  The value and safety of a high dose of B₆ has not been proven, although a modest supplement of B vitamins (perhaps as a daily multivitamin) may have some benefit.  Curiously, many people with oxalate problems also have problems in their serotonin metabolism.  A 1988 study from Germany found that 10 of 90 people with oxalate kidney stones had difficulty metabolizing tryptophan into serotonin, but improvement was seen over time with a daily supplement of pyridoxine.  (PMID3407338)

Foods High In Oxalates

There are diet books for all reasons and all seasons. My favorite (for selfish reasons) is the "Think-Thin, Eat Chocolate Diet."   Unfortunately, chocolate is a high-oxalate food, and should be avoided or minimized if you want to go down the low oxalate diet road.  It's not clear to what degree oxalates need to be reduced to see benefits - is it enough to eliminate the worst offenders, or should a stricter diet be followed?  In the long term, I believe that eliminating the worst offenders and using a calcium/magnesium supplement is better than trying to live off of the 3 foods that are considered low oxalate (lard, white sugar, and basil leaves). But I'm being a little flippant, you have to make your own decision on that.  

Conclusions

Oxalates don't seem to be "The Cause" of vulvodynia, but they probably do contribute to the problem.  Diet and nutritional supplements seem to help some, but more as an adjunct or supporting therapy.  I can't say if they are right for you, but there is evidence they help some.