Know Your Stones...Protect Your Kidneys (cont.)

The oxalate & calcium connection: It was once believed that dietary calcium and oxalate needed to be reduced in order to prevent the formation of calcium oxalate stones. Research has now shown that calcium is actually needed when ingesting oxalate-rich foods in order to assist with decreasing the absorption of the oxalates. The other necessary intervention is to limit your overall intake of oxalate-rich foods. These foods include beets, chocolate, coffee, cola, nuts, rhubarb, spinach, black tea, and wheat bran.

Weight it out: One of the numerous health benefits of weight loss could be lowering your risk of kidney stones. In a recent study of over 200,000 people, being obese and gaining the most weight over the 46 year follow-up period put people at the greatest risk for kidney stones. The risk was solely based on weight and not the diet or fluid intake. If you are overweight, cutting your calories and following a well balanced diet may be the key to kidney-stone prevention.

How can your diet decrease the risk for calcium stones?

Calcium connection: It was once believed that dietary calcium was responsible for calcium stones, and the recommendation was to avoid calcium rich dairy products. Numerous studies have now refuted this advice. In fact, foods high in calcium, including dairy products, are believed to help prevent stone formation. One study of over 45,000 men found that those who consumed fewer than 850 mg of calcium per day were at an increased risk for kidney stones. The goal is to meet the guidelines for an adequate intake of calcium through your diet. The Recommended Adequate Intakes set for calcium are:

    0 to 6 months-210 mg
    7 to 12 months-270 mg
    1 to 3 years-500 mg
    4 to 8 years-800 mg
    9 to 13 years-1300 mg
    14 to 18 years-1300 mg
    19 to 50 years-1000 mg
    51+ years-1200 mg

Fluid fix: Drinking enough fluid will reduce the concentration of stone-forming minerals in the urine by diluting it. The goal is to drink at least 10 full glasses of fluid each day (at least half should be water) in order to produce over 2 quarts of urine on a daily basis. The average daily output of urine is about 1½ quarts, so this is somewhat higher. Some ways to reach your fluid goals are:

  • Have one cup before and after each meal
  • Drink with your meals
  • Drink with your snacks
  • Drink during activities: computer, TV watching, and commuting
  • Eat a lot of water-rich foods (for example, soup, fruit, vegetables)
  • Drink as little caffeine and alcohol as possible

Phytate phenomenon: There is some evidence that some fiber-rich foods that contain a compound called phytates can help prevent both kinds of calcium stones. Phytates are found in natural dietary bran, legumes, beans, and whole cereals.