Oxalate, kidney stones
Wednesday, January 16, 2019
Q I form oxalate stones. The only advice I had been given was to drink lots of water and I do drink about a gallon a day. A friend told me I should pay attention to the oxalate content of food. I really like grain products but have been told they might be giving me troubles. What do I need to know? RL, Greenville.
A My best advice to you is to talk with your health care provider asking for more information on how to lower your risk for kidney stones. There are many factors that may play a role. Having said that, Jackson Dellana, a senior dietetic student, wants to explain what you might read about oxalates and stones. Here is what Jackson wants you to know.
Most kidney stones are caused by oxalates, a condition called “hyperoxaluria,” meaning too much oxalate in the urine. When this excess oxalate combines with calcium, it hardens and forms painful kidney stones. Many health care providers suggest that for people have this happen regularly should limit the amount of high oxalate foods they eat.
People are often surprised by the foods that are high in oxalates. They include grains, cocoa, spinach, swiss chard, legumes (such as soy, peanuts and kidney beans), raw nuts, seeds and rhubarb. There is a great information on the web site of University of Chicago ( https://kidneystones.uchicago.edu/how-to-eat-a-low-oxalate-diet ) that should help you.
Some grain products can be enjoyed after they have been sprouted, soaked or fermented. A seed or grain is sprouted when it has formed little white buds after sitting in a warm moist and airy environment for a few days. With more time, these white buds will grow into green spirals, which are intended to dig into the soil so that the seed may grow into a full plant months later.
If you are wondering what an oxalate or oxalic acid is, think of it as a natural plant chemical that allows the plant to protect its minerals and nutrients until sprouted. You can think of this as a natural pesticide which discourages insects and animals from eating the plant. These chemicals are broadly categorized as anti-nutrients which are typically found in the leaves. Anti-nutrients are found in seeds as well and may sprout after an animal, lured by a sweet fruit, carries the seed to a new location where it sprouts. The sprouting process changes the chemical composition of the seeds —reducing oxalates and increasing availability of protein and antioxidants.
The oxalate content of food varies greatly but foods made with sprouted grains are likely to be low. Some tasty products are Ezekiel brand bread, Kashi brand cereals, and One Degree brand sprouted oatmeals. You can make your own homemade bread and rolls using sprouted grain flours marketed by King Arthur and Arrowhead Mills. If you like beans, soaking them overnight before cooking will dissolve some of the oxalates content. You can find tutorials on line (https://www.theblendergirl.com/hint-tip/soaking-nuts-seeds-grains; https://www.weedemandreap.com/guide-soaking-sprouting-grains).
If you haven’t been eating fermented foods, you might like to try kimchi (Korean fermented vegetables) or sauerkraut. They are high in sodium so, be mindful of the effect they might have on your blood pressure. At least one study suggests that the high content of potassium offsets the high sodium content and therefore eating kimchi doesn’t raise blood pressure. Both Kimchi and sauerkraut have lactic acid -- think vinegar -- and shredded cabbage in them. Kimchi usually has Korean radishes and a variety of spices and seasonings. A fun tutorial on fermenting vegetables is at https://www.culturesforhealth.com/learn/natural-fermentation/how-to-ferment-vegetables.
At least one researcher has found that people with too little of the oxalate eating bacterium, Oxalobacter formigenes, in their digestive system were at greater risk for kidney stones. It’s thought that could result from use of oral antibiotics or consumption of meats from animals treated with antibiotics. It’s thought that O formingenes might be in cultured foods, but it’s not clear if eating these products will help.
That reminds me to say, that many people with kidney stones avoid calcium-rich food thinking that calcium causes stones. Yet, it’s well known that getting too little calcium can also lead to stones. Make sure you are getting 1,000 milligrams of calcium a day, preferably from food or beverages and not pills. As you noted, staying hydrated is important, too.
Professor emeritus Kathy Kolasa, a registered dietitian nutritionist and Ph.D., is an affiliate professor in the Brody School of Medicine at ECU. Contact her at firstname.lastname@example.org.