Did you know that one in 10 Americans will get kidney stones over the course of a lifetime? Recent studies have shown that in the United States, kidney stone rates are on the rise across the country. March is National Kidney Month and the National Kidney Foundation (NKF) encourages people to learn about the kidneys and kidney-related conditions, including kidney stones.
Most people are born with two kidneys, but only need one. They are about the size of your fist and located in the lower back, just below the rib cage. The kidneys filter toxins and wastes from the blood in order to maintain a bodily balance of water, salt, potassium and other minerals. In the process, the kidneys create urine, which is how wastes exit the body. And this is where kidney stones come in. When the wastes dissolved in the urine are very concentrated relative to the ratio of liquid in the urine, crystals can begin to form. These crystals can then attract other elements and minerals, joining together to form a solid, or "stone," which can get larger unless passed out of the body with the urine.
After a kidney stone forms, it can stay in the kidney or travel down the urinary tract into the ureter -- the tube connected to the bladder. As kidney stones journey out of the kidney, they can cause severe pain, blockage and bleeding. Maybe you're already squirming imagining what this might feel like. Or perhaps you're the one in ten who has had the misfortune of experiencing a kidney stone first-hand. Either way, the good news is that preventing kidney stones largely rests in your hands and your diet (before wastes ever reach the kidneys).
When it comes to dietary choices, the Dietary Approaches to Stop Hypertension (DASH) diet reigns supreme, according to a new study published in the March issue of the National Kidney Foundation's American Journal of Kidney Diseases. The DASH diet is high in fruits, vegetables, legumes and nuts, moderate in low-fat dairy products, and low in animal proteins, refined grains and sweets. In addition to being a well-balanced low salt diet, it may reduce your risk for developing kidney stones.
I've long touted the DASH diet as a kidney-friendly diet that has many health benefits, including reducing high blood pressure and helping to prevent kidney stones, so I'm very excited to share this new research with you. The study authors found that compared with following a low-oxalate diet -- the frequently prescribed diet for kidney stone prevention and treatment -- a DASH-style diet was more effective at reducing urinary risk markers for calcium oxalate kidney stone formation, the most common type of kidney stone (more than 80 percent).
Oxalate is naturally found in high levels in many foods including: beets, navy beans, bulgur, kale, almonds, sweet potatoes, rice bran, rhubarb and spinach. Many of these foods have other good nutritional value and cutting them out of the diet can feel very restrictive. Because most kidney stones are formed when oxalate binds to calcium while urine is produced by the kidneys, as opposed to during the digestive process, eating and drinking calcium and oxalate-rich foods together during a meal may be a better approach than limiting oxalate entirely. This way oxalate and calcium are more likely to bind to one another in the stomach and intestines before reaching the kidneys, making it less likely that kidney stones will form.
In addition to following the low salt DASH diet and consuming oxalate-rich foods at the same time as calcium, here are four more tips from the National Kidney Foundation to help you reduce your risk of forming kidney stones:
- Drink fluids! Ideally, 2 to 3 liters daily.
- Water is best. Water is the best fluid to drink. Another option is sugar-free fresh lemon or lime juice mixed with water. Tea and coffee also seem to be okay.
- Eat fruits and veggies. In general, eating a diet high in fruits and vegetables, moderate in low fat dairy and low in salt and animal protein might prevent kidney stone formation. Most Americans eat more than the recommended amounts of animal protein and salt.
- Stick to a treatment plan. After a kidney stone, work with a doctor to create an individual treatment plan that considers fluid intake, diet and sometimes medication.
Have you experienced a kidney stone before? When it comes to forming kidney stones, history tends to repeat itself, so what have you done to prevent them from occurring again? Have you made dietary changes to reduce your risk of forming stones? Share your story in the comments below.