What is a kidney stone?

A kidney stone is a hard mass that forms from crystals in the urine. In most people, natural chemicals in the urine stop stones from forming.

Are all kidney stones the same?

No. The most common types of kidney stones are made from calcium and oxalate. Others being calcium phosphate, triple phosphate, uric acid, cystine. Individual treatment for kidney stones depends on the type of kidney stones that are formed.

Is there a diet I can follow to prevent me from having more kidney stones?

Sometimes following a special diet may be enough to prevent you from forming more kidney stones. Other times, medications, in addition to a special diet, may be needed. Please note that not all dietary recommendations benefit all types of stone formers.

What kind of diet will I have to follow?

You may be asked to make changes to the amount of salt (sodium), calcium, oxalate, protein, citrate, potassium and fluid in your diet. An Urologist / dietician can help you with making these changes.

My doctor told me to drink a lot of fluids. How much is "a lot"? Does it matter what kind of fluid I drink?

Staying well hydrated by drinking enough water is one of the best measures you can take to avoid kidney stones. To lessen your risk of forming a new stone, it is very important that you drink at least 10 -12 glasses of fluid throughout the day. In hotter weather, you may need to drink more to make up for fluid loss from sweating. This will help keep your urine less concentrated. Less concentrated urine reduces the risk of stone formation. Most of the fluid you drink should be water.

I had a calcium stone. What type of diet should I follow? Will I have to avoid high calcium foods?

Calcium is not the enemy. But it tends to get a bad rap! Most likely due to its name and composition, many are under the impression that calcium is the main culprit in calcium-oxalate stones. "I still see patients who wonder why they are getting recurring stones despite cutting down on their calcium intake," said Dr. Amit Goel. "I've even had patients say that their doctors told them to reduce their calcium intake." A diet low in calcium actually increases one's risk of developing kidney stones.

Instead:

Don't reduce the calcium. Work to cut back on the sodium in your diet and to pair calcium-rich foods with oxalate-rich foods. Extra sodium causes you to lose more calcium in your urine, putting you at risk for developing another stone. An urologist / dietician will probably advise you to limit sodium to 2,000 milligrams each day. There are many sources of "hidden" sodium such as canned or commercially processed foods as well as restaurant-prepared and fast foods.

I had an oxalate stone. What type of diet should I follow? Do I need to avoid foods high in oxalate?

Calcium oxalate kidney stones are the leading type of kidney stones. Oxalate is naturally found in many foods, including fruits and vegetables, nuts and seeds, grains, legumes, and even chocolate and tea. 

Some examples of foods that contain high levels of oxalate include: peanuts, rhubarb, spinach, beets, chocolate and sweet potatoes.

 The oxalate content of food can vary due to differences in such things as soil quality and state of ripeness. There may be variation in published data, too, as different methods may be used to determine the oxalate content of food.

Moderating intake of these foods may be beneficial for people who form calcium oxalate stones, the leading type of kidney stones. A common misconception is that cutting the oxalate-rich foods in your diet alone will reduce the likelihood of forming calcium oxalate kidney stones. While in theory this might be true, this approach isn't smart as many high oxalate foods are healthful so it is wise to not overly restrict your diet if not necessary. Most kidney stones are formed when oxalate binds to calcium while urine is produced by the kidneys.

Instead:

Eat and drink calcium and oxalate-rich foods together during a meal. In doing so, oxalate and calcium are more likely to bind to one another in the stomach and intestines before the kidneys begin processing, making it less likely that kidney stones will form.

I had a uric acid stone. What does that mean? What type of diet should I follow?

Another common type of kidney stone is a uric acid stone. Red meat and shellfish have high concentrations of a natural chemical compound known as a purine. High purine intake leads to a higher production of uric acid which then accumulates as crystals in the joints, or as stones in the kidneys.

Instead:

To prevent uric acid stones, cut down on high-purine foods such as red meat, organ meats, and shellfish, and follow a healthy diet that contains mostly vegetables and fruits, whole grains, and low fat dairy products. Limit sugar-sweetened foods and drinks, especially those that contain high fructose corn syrup. Limit alcohol because it can increase uric acid levels in the blood and avoid crash diets for the same reason. Eating less animal-based protein and eating more fruits and vegetables will help decrease urine acidity and this will help reduce the chance for stone formation.

You should also be sure to drink at least 10 -12 glass of water a day to help reduce the risk for stone formation. Making these healthy lifestyle changes can also help reduce your risk for developing gout because high uric acid is a leading risk factor for gout.

Is there anything else I can do with my diet to help prevent kidney stones?

Reducing the amount of animal protein may help. Sources of animal protein include beef, chicken, pork, fish and eggs. Most people need only four to six ounces of high protein foods and three servings of milk or cheese a day.

Chronic kidney stones are often treated with potassium citrate. Studies have shown that lemonade and other fruits and juices high in natural citrate may offer similar stone-preventing benefits. It is believed that citrate in the urine may prevent the calcium from binding with other constituents that lead to stones. Also, some evidence suggests that citrate may prevent crystals that are already present from binding with each other, thus preventing them from getting bigger. Please note that juices made from actual limes and lemons contain higher levels of citrate and beware of the sugar content in juices, because this can increase kidney stone risk. Instead, buy sugar-free lemonade, or make your own by mixing lime or lemon juice with water and using a sugar substitute if needed.

Will it help/hurt me to take a vitamin or mineral supplement?

The B vitamins (which include thiamine, riboflavin, niacin, B6 and B12) have not been shown to be harmful to people with kidney stones. In fact, some studies have shown that B6 may actually help people with high urine oxalate. However, check with urologist or dietician for advice on the use of vitamin C, vitamin D, fish liver oils or mineral supplements containing calcium since some supplements can increase the chances of stone formation in some people.

I do a heavy exercise and work outdoors. Will it increase the chances of stone formation?

Saunas, hot yoga and heavy exercise may be good for your health, but they also may lead to kidney stones. Why? Loss of water through sweating - whether due to these activities or just the heat of summer—leads to less urine production. The more you sweat, the less you urinate, which allows for stone-causing minerals to settle and bond in the kidneys and urinary tract.

Instead:

Hydrate with H2O. One of the best measures you can take to avoid kidney stones is to drink plenty of water, leading you to urinate a lot. So, be sure to keep well hydrated, especially when engaging in exercise or activities that cause a lot of sweating.

I had a stone and got it removed in the past. Is there a chance of recurrence of stone formation?

Passing a kidney stone is often described as one of the most painful experiences a person can have, but unfortunately, it's not always a one-time event. Studies have shown that having even one stone greatly increases your chances of having another. "Most people will want to do anything they can to ensure it doesn't happen again," said Dr.Amit Goel. "Unfortunately, it doesn't seem to be the case that people make the changes they need to after their first stone event." Research conducted shows that about 15% of kidney stone patients didn't take prescribed medications and 41% did not follow the nutritional advice that would keep stones from recurring.

Instead:

Take action! Without the right medications and diet adjustments, stones can come back, and recurring kidney stones also could be an indicator of other problems, including kidney disease.