| Sometimes writers who are kind enough to | | | | high-fat diets are at risk of stones unless they |
| address us in English even though it is not their | | | | consume adequate amounts of fluid. |
| first language don't quite hit their mark. An ad | | | | Vitamin B6 may reduce the risk of kidney |
| promoting a part of Tuscany as "The Delicious | | | | calcifications in women. A study of 85,557 women |
| Italy," for instance, read, "Fine restaurants of | | | | by the Harvard School of Public Health found that |
| Gubbio use all the fruits of the forest to make | | | | women consuming the greatest amount of the |
| the very best of the pasta around. Mushrooms as | | | | vitamin had risk reduced by approximately |
| well as rabbit and other wild game make sure fine | | | | one-third. A study of 45,251 men by the Harvard |
| red wines and kidney stones are guaranteed." | | | | School of Public Health found that consuming |
| And this "guarantee" of kidney stones, known in | | | | vitamin B6 reduced risk of kidney stones by |
| the medical literature as renal calculi, must have | | | | approximately 10 percent. Since vitamin B12 is |
| made the research of four Italian scientists | | | | possibly linked to increased risk of stones, it is |
| named Cirillo, Laurenzi, Panarreli, and Stamler | | | | best to use a B6 supplement rather than a |
| easier. These scientists at the University of Naples | | | | complete B-vitamin. |
| studied the diet of residents of Gubbio in | | | | Or better yet, eat foods that are rich in vitamin |
| relationship to risk of renal stones. They obtained | | | | B6. These include avocados, bananas, barley, bok |
| urine samples from more than 3,000 residents of | | | | choy, brown rice, chicken, chickpeas, fresh pork, |
| Gubbio, of whom 127 had a history of the | | | | mangoes, rice, salmon, and turkey. |
| condition. Urine samples were used to determine | | | | The simplest yet most essential task in |
| their sodium and potassium intakes. | | | | preventing stones in the kidneys is drinking |
| Their findings? The Gubbioni who had the lowest | | | | enough water. Adequate hydration helps ensure |
| levels of potassium and the highest levels of | | | | that the volume of urine will be enough to dissolve |
| sodium in their urine had the highest rates | | | | the minerals that can cause stones. Some other |
| ofstones. Residents in the highest quartile of | | | | beverages are helpful. Survey data collected by |
| sodium consumption were 3 to 9 times more | | | | the Harvard School of Public Health shows that |
| likely to develop stones. | | | | consuming 1 cup (240 ml) of coffee daily (regular |
| The relationship of dietary salt to kidney stones | | | | or decaffeinated) reduces the risk of calcificatons |
| has also been studied in Texas. Scientists at | | | | by 10 percent, the same amount of tea, 14 |
| Southwestern Medical School in Dallas found that a | | | | percent, beer, 21 percent, and wine, 39 percent. |
| high salt diet increased the amount of sodium and | | | | (The data do not show that drinking large |
| calcium excreted into the urine, as well as making | | | | quantities of any of these beverages eliminates |
| the urine much more alkaline. A high salt diet also | | | | the risk of stones). Juices tend to be harmful. |
| decreased the excretion of citrate, leaving more | | | | The same survey also found that drinking a cup |
| citrate in the kidneys to form calcium citrate | | | | of apple juice daily increased the risk developing |
| stones. Clearly, lowering salt is a good idea if you | | | | kidney stones possibly by 75 percent and drinking |
| are prone to having this kidney problem. | | | | a cup of grapefruit juice daily increased the risk of |
| What you can do about stones? The scientists at | | | | stones by as much as 85 percent. While using |
| Southwestern Medical School studied diets that | | | | cranberry juice tablets increases the risk of |
| were unquestionably high in sodium-at least 5 | | | | stones in women, no study has found that |
| grams a day over the amount of salt already in | | | | cranberry juice itself increases the risk of kidney |
| foods, equivalent to 1-2 tablespoons of added salt | | | | stones. |
| at every meal. Demonstrating reduced calcium | | | | Since most stones are made of calcium, it would |
| excretion-less of the raw materials for making | | | | seem logical that reducing dietary calcium would |
| stones-required lowering the daily amount of | | | | reduce the risk of stones. Reducing consumption |
| sodium in the diet to 1,000 mg. I recommend that | | | | of calcium-rich foods does reduce the amount of |
| you consume no more than 1,500 mg a day, and | | | | calcium in the urine, but it increases the amount |
| that you consume nine servings of fruits and | | | | of the other component of most kidney stones, |
| vegetables every day to obtain approximately | | | | oxalate. Rather than reducing the risk of stones, a |
| 3,500 mg of potassium. | | | | low-calcium diet nearly doubles the risk of |
| What you can expect. I can't guarantee that | | | | recurrent kidney stones, at least in men. Even |
| sodium restriction will protect you from future | | | | taking calcium supplements, in the form of calcium |
| attacks. The evidence only suggests that attacks | | | | citrate, does not increase the risk of renal calculi. |
| will be less frequent if you follow a low-sodium, | | | | Similarly, since most renal calculi contain oxalate, it |
| high-potassium diet. | | | | would seem logical to limit consumption of foods |
| What foods may help prevent the formation of | | | | that are high in oxalic acid, such as almonds, beet |
| kidney stones? In the United States, women are | | | | greens, bran, chocolate, rhubarb, spinach, |
| more likely to develop stones if they have a | | | | strawberries, and tea. No study, however, has |
| history of high blood pressure, if they have not | | | | found that restricting consumption of these foods |
| used calcium supplements, and if their diets are | | | | increases the risk of kidney involvement and |
| low in magnesium-rich foods such as beans, | | | | some studies have found that consumption of |
| broccoli, nuts and seeds (especially peanuts), leafy | | | | leafy greens, peanuts, and tea actually reduce the |
| greens, and soy. | | | | risk of stones. The vitamin K in green leafy |
| Women whose sisters develop stones are more | | | | vegetables may be one reason vegetarians have |
| likely to develop kidney stones themselves if their | | | | a lower incidence of kidney stones. |
| urine is high in calcium and unusually alkaline. | | | | Consumption of animal protein is likewise an |
| (Making urine more alkaline by using cranberry | | | | accepted risk factor for kidney stone disease, but |
| extract tablets is a risk factor for kidney stones | | | | clinical testing has found that only about one-third |
| in women.) Men are more likely to develop stones | | | | of people who get kidney stone complications are |
| if they have uncontrolled high blood pressure. Men | | | | adversely affected by a high-protein diet. It |
| whose brothers have stones are more likely to | | | | seems sensible to avoid excessive consumption |
| develop stones as they grow older and if their | | | | of meat, but severe protein restriction probably |
| urine potassium levels are low or their urine | | | | will not help. |
| calcium levels are high. Children on extremely | | | | |