Oxalates. Beyond Kidney Stones
Ask about oxalates to most doctors and they will respond that oxalates are an organic acid (oxalic acid) that is found in certain foods, is synthesized in our bodies and it binds to minerals that can cause stones - mostly in our kidneys. Is that all there is to know?
According to experts we should be paying closer attention to the number of oxalates we are consuming in our foods even if we have not had in the past or are now experiencing kidney stones. It may be that oxalate exposure could influence health problems such as mast cell activation syndrome, skin disorders, painful and stiff joints such as rheumatoid arthritis, peripheral neuropathies, myofascial and muscular pain syndromes, fatigue, dizziness, cramps, painful urination conditions such as vulvodynia, and interstitial cystitis and abnormal bowel movements such as IBS, digestive problems such gall bladder problems, lipomas, headaches, mood changes and osteoporosis. Also oxalates can form in the heart and cause problems there.
The leading expert in this area, Sally K. Norton, has a nutrition degree and a master’s degree in public health and author of a new book Toxic Superfoods. She has been outspoken about how reducing oxalates in her diet and her patient’s diets has been instrumental in improved outcomes with various health issues beyond kidney stones.
Oxalates are an acid, but they bind easily to minerals to form an oxalic salt. They bind most easily to calcium because oxalates have a negative charge of -2, and calcium has a positive charge of +2. This salt or crystal then needs to be excreted through the kidneys. Problems occur from two issues. Either because of a genetic weakness in elimination called primary hyperoxalaturia or an acquired weakness from overconsumption of oxalates called secondary hyperoxalaturia. In both circumstances the result is a buildup of oxalic salts or crystals in the kidneys.
Crystals in the kidneys, or in other areas of the body will have sharpened edges that can interfere with our quality of life. The easiest example to grasp this idea is when you rub your eyes, and a small crystal is removed from a tear duct. Not all crystals are bound up with calcium. If oxalates bind to another mineral such as sodium or potassium, it might be a little softer but even that softer crystal if it is inundated within the connective tissue of your lower back or in a joint, or in the urethra of the bladder or along a nerve sheath, imagine how it might impact your health.
This over burden of oxalates usually comes from exposure from the excess consumption of foods that might surprise you. These foods are considered “healthy and high in calcium” without the disclaimer that it really is high in calcium oxalate. Research is still going on evaluating which foods are high in oxalates and this is one site where you can look up a more detailed list. The top five foods would be:
Beet Greens, Rhubarb, Spinach, Swiss Chard, and Sorrel. These have over 50 mg of oxalate per 100 grams.
However, these foods are high in oxalates too: Endive, Cacao/Dark Chocolate, Sweet and White Potatoes, Peanuts, Almonds, Pine nuts, Hazelnuts, Cashews, Peanuts, Corn Grits, Soybeans, Buckwheat, Quinoa, Teff, Okra, all Beans, Turnip greens, Star Fruit, Chia seeds, Raspberries, Kiwis, Figs, Dates, all Brans and, and Lentils. Surprisingly the spice turmeric, often associated as an anti-inflammatory is high in oxalates.
According to Norton, the average person eats between 600-1000 mg of oxalates a day. However, staying in the 150-200 mg range is best since the kidneys can only handle about 25 mg/day and they filter about 1/10 of the oxalates consumed. Additionally, the only way to reduce (not eliminate) oxalates is boiling the food and then throw away the water. Some supplements such as ascorbic acid can cause extra oxalates to be synthesized in the body. Truthfully, this may be one of the best ways of diagnosing if someone has excess oxalates. If someone is not able to take much vitamin C in the form of ascorbic acid, then this could indicate that they have excess oxalates in their body. There is a urine test to measure oxalic acid, but it may not be a great test because if it is low, it could mean that your body is just not excreting it and instead holding onto the oxalates which would cause inflammation.
Diabetics and obesity could also play a part in the increased production of oxalates. The good news is that there are ways to mitigate excess oxalates. Taking calcium supplements or other mineral supplements especially in the citrate form can bind to the oxalic acid. Citric Acid is high in lemon juice so fresh squeezed lemon on a spinach salad, or another high oxalate food will help bind up the oxalates that naturally occur with the foods listed. Two B vitamins are helpful for lowering oxalates. Vitamin B1 (thiamine) can shunt oxalic acid to a non-toxic ketoacid molecule and B6 (pyridoxine) can help with about 1/3 of the cases of primary hyperoxalaturia. There is also a specific bacteria called Oxalobacter formagenes that can bind to oxalates to reduce the dangerous effects of oxalates. Is it possible that those who have a greater sensitivity are lacking this bacterium?
The only known benefit of oxalates is in our mouth. Our saliva has 10-40x the concentration of oxalates than the rest of our body. It is believed that the oxalates form a tartar on the teeth that might prevent acidic foods from damaging them.
If you suspect that oxalates are a problem with you the best solution is to reduce exposure slowly because a quick change might bring on detox symptoms called oxalate dumping. If you are pregnant or breast feeding you may want to think about this information because oxalates can cross the placenta and show up in breast milk. In recent years it has become an accepted healthy strategy to make spinach smoothies, use almond flour in baking, make cashew cheeses or eat a plate full of Swiss Chard and sweet potatoes. Perhaps some of these strategies need to be re-evaluated – certainly not daily given that this information is now known. Another issue is that you may have more susceptibility to oxalates if you have a leaky gut which would allow a greater absorption of oxalates into your body.
Another source of oxalate exposure is aspergillus mold (black mold). This results in aerosolized oxalic acid that can result in oxalic acid crystals in the lungs in addition to the potential exposure from mold that might be in a water damaged wall, or if grains and nuts were exposed to moisture.