Renal Stones & Diet

Renal stones, also called kidney stones, are composed of minerals that build up inside the kidneys when the urine is not sufficiently diluted. They usually don't cause permanent damage, but the pain of passing them can be excruciating. Sometimes there's no clear cause of renal stones and nothing you can do to prevent them. However, you may be able to lower your risk by making changes in your diet.

Fluids

Renal stones are more likely to develop when urine is too concentrated. Therefore, drinking enough water is one of the most important dietary steps you can take to avoid renal stones. The National Kidney and Urologic Diseases Information Clearinghouse recommends drinking at least 12 glasses of water a day--more if you exercise strenuously or live in a hot climate. Ginger ale and fruit juices, especially lemonade, are also good choices, according to the information clearinghouse and the Mayo Clinic, but drink no more than a cup or two per day of coffee, tea or caffeinated soda.

Oxalates

About 80 percent of renal stones formed by U.S. adults are calcium oxalate stones, according to World's Healthiest Foods. Research is inconclusive as to whether limiting oxalate-rich foods affects your risk of developing renal stones. Still, many doctors recommend erring on the side of caution and restricting high-oxalate foods--including beets, collards, okra, spinach, sweet potatoes, almonds and soy products--from your diet in an effort to avoid renal stones.

Calcium

A diet high in calcium is associated with a decreased risk of renal stones, according to the Mayo Clinic, because calcium and oxalates bind together in the gastrointestinal tract to prevent oxalates from being absorbed by the intestine and excreted by the kidney, eventually forming stones. If calcium supplements are taken with meals, they appear to have this same preventive effect as high-calcium foods, such as cheese, yogurt and milk.

Animal Protein

Some studies have suggested a connection between renal stones and diets high in animal protein; others have found no link. Consider reducing the amount of meat in your diet to possibly lower your risk of renal stones. For example, substitute protein from pork, beef, chicken or turkey with that from plant sources such as tofu, beans, soy milk and nuts.

Sodium

Too much sodium can increase your likelihood of developing a renal stone by raising the amount of calcium in your urine. Consuming no more than 2,000 to 3,000 mg of sodium per day is recommended. Processed and prepared foods--such as canned foods, frozen foods and cold cuts--are the primary source of dietary sodium, but low-sodium versions of many such items are available.

References

• Mayo Clinic
• National Kidney and Urologic Diseases Information Clearinghouse
• George Mateljan Foundation for World's Healthiest Foods