By Linda Gale, PA
Studies show that approximately 1 in 11 people in the US will have a kidney stone at some point in their life, and residents in western North Carolina have a higher rate of needing kidney stone treatment than the rest of the country. These rates continue to increase and may be attributed to lifestyle choices, genetics or rare inherited metabolic disorders.
How a Kidney Stone Forms
Kidney stones are formed in the kidneys when the urine contains too many crystals that collect together forming a stone. There are several types of stones, the most common being calcium oxalate stones. Calcium phosphate and uric acid are other more common stones. It is rare to have a cysteine stone.
How Crystal Production Increases in Urine
Dehydration. Dehydration is the most preventable cause of kidney stones. In our bodies, staying hydrated dilutes the urine, which helps keep stones from forming. Imagine dissolving sugar into water. If there is too much sugar relative to water, it does not dissolve and remains as a crystal. Adding enough water will allow the sugar to dissolve.
Oxalate. A substance called oxalate is found in foods grown in the soil and can bind with calcium in the kidney to form stones. Lowering oxalate can help keep stones from forming. Examples of high oxalate foods are spinach, beets, rhubarb, almonds and tea. Yes, tea – the water of the south!
High-fat diets. Ingesting a high level of fat may increase the amount of oxalate in blood and kidneys. Eating low-fat dairy with meals helps prevent excess oxalates from absorbing in the intestines.
Excess salt. Salt should not exceed 2,300 mg per day. Eating foods with a large amount of salt can cause the kidneys to excrete more calcium into the urine. Excess calcium in the urine can cause calcium-based stones like calcium oxalate and calcium phosphate.
Protein. Diets high in protein, especially animal protein, increase urine acidity, making it easier for calcium oxalate stones to form. They also increase urine calcium. Certain proteins also create a substance called purines, which contribute to uric acid stones. Animal protein should be limited to 8 ounces per day.
Some medications. Several medications and vitamin supplements can impact stone formation – such as diuretics and vitamin C, which converts to oxalate in the body. Topamax, Diamox and Zonegran (by lowering citrate) are examples of medications that may cause stones.
Top 10 Things to Prevent Kidney Stones
- See your urology provider. A special test can be performed to check for metabolic abnormalities and to help understand what your particular risk factor may be. Treatment can be directed from there. They will also be checking to be sure you do not have a disorder such as parathyroid nodules, diabetes or bowel diseases.
- Drink plenty of fluids, especially water. Increase water intake if you are sweating. Your goal would be to have clear urine! This means drinking between 2 and 3 liters a day for most people. The larger you are, the more you have to drink. (If you have a history of kidney disease or congestive heart failure – check with your provider first.)
- Avoid foods high in oxalates. The highest food by far is spinach. Tea can be high, especially when a lot of it is consumed.
- Avoid salty foods. Examples include cured meats (bacon) and packaged foods like chips. Read labels on foods and limit salt to 2,300 mg a day.
- Lose weight if you are overweight. Choose a plan that is balanced like the Mediterranean diet.
- Stop high-protein diets that rely on meat or protein shakes. Use the palm of your hand as a guide for how large a serving of meat you should eat.
- Eat plenty of fruits and vegetables (not spinach though). Citrus fruits like oranges, grapefruit and lemons give your body citric acid, which helps prevent kidney stones.
- Eat low-fat dairy products. Be sure you are getting enough calcium – 800 – 1,200 mg per day. Ironically, too little calcium increases your risk of kidney stones (really). Very few people make kidney stones from too much calcium.
- Consume foods high in magnesium. Cashews, sunflower seeds, avocados, broccoli, peas, oatmeal, whole grains, tofu and yogurt are all healthy options.
- Drink plenty of fluids! But not iced tea! Yes, I said it again.
Kidney Stone Treatment
For most kidney stones, you may be able to take care of them yourself at home. Pain medicine may be needed, and you’ll need to drink enough water and other fluids to stay hydrated. Your provider may also give you medicine to help the stone pass.
If a stone is too large to pass on its own or if it gets stuck in the urinary tract, you may need an additional kidney stone removal procedure. Extracorporeal shock wave lithotripsy (ESWL) uses shock waves to break a kidney stone into small pieces. The bits can pass out of your body in your urine.
Other times, a doctor may need to remove the stone or place a small flexible plastic tube (called a stent) in the ureter to keep it open while stones pass.
Linda Gale is a physician assistant with Mission Urology – McDowell and Blue Ridge Urology – Spruce Pine. Mission Health’s urologists provide comprehensive care for kidney stones, focusing on prevention, while also providing the latest techniques and technology for the treatment of painful, problematic stones.
