Kidney stones develop in more than 5 percent of Americans. A kidney stone is made of minerals that separate from urine to form a hard structure. Some stones are small and pass out of the urinary tract easily, whereas others are larger and lodge in the kidney or the ureter, the tube that leads from the kidney to the bladder. When a stone changes position, you may feel extreme back pain, see blood in your urine and experience nausea or vomiting. Certain foods raise the risk of kidney stones in susceptible people. Consult your doctor to develop a diet that can help reduce your risk of kidney stones.
Causes
Kidney stones have compositions that relate to their underlying cause. Some stones form as a result of an inherited metabolic disorder. Others develop in patients with gout in which the purines in food produce stones. Still others appear after a urinary tract infection, which can alter the acidity of urine, allowing stones to form. In some cases, consuming certain types of food or taking excessive amounts of calcium-containing antacids may cause stones. The most common stones contain calcium combined with either phosphate or oxalate.
Fluids
Drinking lots of fluids is helpful in preventing kidney stones, according to the National Kidney and Urologic Diseases Information Clearinghouse. Water is best, but other fluids are also helpful. Consume tea, grapefruit juice and dark colas sparingly, however, if you have had kidney stones containing oxalate. NKUDIC indicates that anyone at risk for kidney stones should drink enough fluid to produce at least 2 quarts of urine daily.
Salt
Maintaining a low-salt diet is another good strategy to reduce the likelihood of kidney stones. Salt contains sodium, which accompanies calcium when your body excretes it in urine. High salt intake leads to a higher urinary calcium concentration, which may result in calcium phosphate or calcium oxalate kidney stones. Avoid foods high in salt such as hot dogs, canned foods and lunch meat, and check labels to determine the salt content of processed foods. NKUDIC states that most Americans consume too much salt and suggests that salt intake not exceed 2,400 mg daily, the daily allowance recommended by the U.S. Food and Drug Administration.
Protein
Proteins derived from animals contain purines, compounds that form uric acid in urine and may contribute to the formation of some types of kidney stones. Organ meats such as liver, brains, sweetbreads and kidney are very rich in purines, and meats such as lamb and game meats also contain high purine levels. Choose fish and poultry instead or substitute tofu for meats in recipes. Avoid anchovies and sardines, as these fish are very high in purines.
Oxalate-Rich Foods
Vegetables rich in oxalates may contribute to the formation of oxalate-containing kidney stones. These foods include beets, rhubarb and green leafy vegetables such as spinach and Swiss chard. Add vegetables low in oxalates to your diet instead. Good examples include peppers, corn, tomatoes and cruciferous vegetables such as broccoli, cauliflower and cabbage. Other foods high in oxalates include wheat germ, peanuts and chocolate. Substitute carob for chocolate where possible, and replace peanuts with other healthy nuts such as walnuts and almonds.
References
- National Kidney and Urologic Diseases Information Clearinghouse: Kidney Stones in Adults
- National Kidney Foundation: Diet and Kidney Stones
- National Kidney and Urologic Diseases Information Clearinghouse: Diet for Kidney Stone Prevention
- Medline Plus: Kidney Stones
- Dietary Fiber Food: Gout Causes: List of Diet/Food Sources High or Low in Purine Content
