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Dietary Changes to Minimize Risk of Kidney Stones

Four major types of kidney stones can form:

Calcium stones are the most common type of kidney stone and can be either calcium oxalate or calcium phosphate.

Uric acid stones form when the urine is acidic. A diet rich in purines (found in animal protein such as meats, fish, and shellfish) may increase uric acid in urine.

Struvite stones result from kidney infections. Eliminating infected stones from the urinary tract and staying infection-free can prevent more struvite stones.

Cystine stones result from a genetic disorder that causes cystine to leak through the kidneys and into the urine, forming crystals that tend to accumulate into stones

Dietary Changes to Minimize Risk of Kidney Stones

Depending on the type of kidney stone a person has, changes in diet can help prevent kidney stones.

In general obesity, higher salt intake and higher sugar and high fructose corn syrup intake and maybe higher animal protein intake is associated with greater risk of forming stones. In contrast, a diet that is rich in calcium, potassium, fruits and vegetables is protective. And the more water you drink the less concentrated your urine is.

Recommendations based on the specific type of kidney stone include the following:

Calcium Oxalate Stones: reduce sodium, reduce animal protein, get plenty of calcium from food and avoiding foods high in oxalate, such as spinach, potatoes, rhubarb, some nuts like almonds in large quantitites, and wheat bran. Calcium supplement pills are associated with a higher risk of stones.

Calcium Phosphate Stones: reduce sodium and get plenty of calcium from food

Uric Acid Stones: limit animal protein. People who are overwieght or obese have a higher risk of forming uric acid stones.

In Addition:

Vitamin C Supplements: it may be prudent for individuals predisposed to oxalate kidney stone formation to avoid high-dose vitamin C supplementation.

Drink adequate water. People who do not drink enough fluids may also be at higher risk, as their urine is more concentrated. Drinking enough fluids each day is the best way to help prevent most types of kidney stones. Health care providers recommend that a person drink 2 to 3 liters of fluid a day. People with cystine stones may need to drink even more. Though water is best, other fluids may also help prevent kidney stones, such as citrus drinks.

Don’t drink sweetened beverages. Researchers recently found that people who reported drinking at least one sugar-sweetened soda each day had a 23 percent increased kidney stone risk more than those who only consumed less than one of a week. And people who drank the most punch in the study had an 18 percent higher kidney stone risk compared with those who drank the least punch. http://cjasn.asnjournals.org/content/early/2013/05/14/CJN.11661112

Certain beverages actually seemed to lower kidney stone risk — particularly orange juice (12 percent lower), coffee (26 percent lower for caffeinated, and 16 percent lower for decaffeinated), tea (11 percent lower), wine (31 to 33 percent lower) and beer (41 percent lower).

Walk Regularly. A study presented earlier this year at the American Urological Association meeting of the government-funded Women’s Health Initiative study showed that exercise — even just a twice-weekly walk — can also help to lower women’s kidney stone. Exercise changes the way the body handles nutrients and fluids that affect stone formation. Exercisers sweat out salt and tend to retain calcium in their bones, rather than having these go into the kidneys and urine where stones form.

Maintain a healthy weight. Overweight and obese people are more likely to get a kidney stone than people of normal weight.

Have medical tests to rule out certain conditions that can cause kidney stones such as hypercalciuria, a condition that runs in families in which urine contains unusually large amounts of calcium; this is the most common condition found in those who form calcium stones; cystic kidney diseases, which are disorders that cause fluid-filled sacs to form on the kidneys;hyperparathyroidism, a condition in which the parathyroid glands, which are four pea-sized glands located in the neck, release too much hormone, causing extra calcium in the blood; renal tubular acidosis, a disease that occurs when the kidneys fail to excrete acids into the urine, which causes a person’s blood to remain too acidic; cystinuria, a condition in which urine contains high levels of the amino acid cysteine; hyperoxaluria, a condition in which urine contains unusually large amounts of oxalate; hyperuricosuria, a disorder of uric acid metabolism; gout, a disorder that causes painful swelling of the joints; blockage of the urinary tract; chronic inflammation of the bowel.

Some medications may cause you to have a kidney stone: Diuretics, calcium-based antacids, indinavir (Crixivan), and topiramate (Topamax).

Sources: National Institute of Diabetes and Digestive and Kidney Diseases;   http://lpi.oregonstate.edu/infocenter/vitamins/vitaminC/

updated 3-13-14

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Diet Modifications for Prevention of Calcium Oxalate Kidney Stones

Studies have shown that being overweight increases the risk of uric acid and calcium kidney stones.

Drinking water and other fluids is the most important thing a person can do to prevent kidney stones.

People who have had a kidney stone should drink enough water and other fluids to make at least 2 quarts of urine each day.

Diets high in salt, or sodium, can increase the excretion of calcium into the urine and thus increase the risk of calcium containing kidney stones. Reducing salt intake is preferred to reducing calcium intake.

Calcium from food can help prevent kidney stone formation and help maintain bone density.

Calcium supplements should be taken with meals so the calcium can bind with the oxalate in food.

Higher potassium intake can also lower the risk for calcium stones.

Eating foods containing calcium reduces oxalate in the urine. Calcium binds oxalate in the digestive tract so it is not excreted into the urine.

Most people with calcium oxalate stones should not avoid oxalate-rich foods unless the doctor specifically recommends a restrictive diet. Some studies, in fact, indicate that eating foods containing oxalates and calcium together may reduce the risk of stones.

Limit these foods that are high in oxalic acid:  beets, soy, black tea, chocolate, cocoa, dried figs, ground pepper, lamb, nuts, parsley, poppy seeds, rhubarb, sorrel, spinach, and Swiss chard.

Foods rich in animal proteins-such as meat, eggs, and fish-contain purines and can increase the risk of uric acid stones and calcium stones. Choose nonanimal protein sources, such as legumes.

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