Dietary guidelines for kidney stone formers

The chances of a person developing a kidney stone during the course of their lifetime are 1 out of 10. So if you have developed kidney stones, do not be alarmed. The condition is manageable and stones can be passed out of your body with medication and the right diet. Further, your doctor will run blood and urine tests to determine any risk factors and then prescribe you medical treatment and a specific diet plan to prevent the recurrence of stone formation.

What is a kidney stone?

A kidney stone is formed by the concentration of crystals in your urine. Usually, the natural chemicals in the urine prevent stone formation, but chemical imbalance and other factors can lead to substances getting concentrated into kidney stones.

What kinds of kidney stones are there?

The most common kind of kidney stones is calcium oxalate stones. Calcium in the urine can combine with chemicals like oxalate or phosphorus and solidify into crystals. With increasing concentration of these crystal substances over time, calcium oxalate kidney stones can be formed.

Another common kind of stones is uric acid stones, formed by the buildup of uric acid. This buildup is caused by the metabolism of proteins. Organ meats, red meat, and fish have large amounts of a natural compound called purines. A high intake of purine leads to high uric acid production, which in turn creates a higher acid load to be excreted by the kidneys. This high acid concentration in the urine makes the kidneys susceptible to uric acid stone formation.

What is the most important aspect of managing kidney stones?

The most thoroughly proven intervention to prevent stone formation from recurring is good hydration. Drinking enough water to keep calcium crystals in solution or keep uric acid concentrations low in the urine is one of the most reliable methods to prevent kidney stones.

How much is enough water for low urine concentration? A water intake that produces a volume of 2.5 litres per day of urine is recommended. Fluid intake from non-sugary and non-alcoholic beverages such as lemonade, freshly-pressed juices, and water with the exception of grapefruit juice is proven to have a beneficial effect.

It is also important to be mindful of the other ways in which your body loses water. If you sweat a lot due to exercise or because of your environment, you must increase your water intake. Loss of water due to excessive sweating can reduce urine production and cause stone-causing crystals to deposit in your kidneys, increasing the chances of stone formation.

Dietary recommendations to manage kidney stones

For calcium-oxalate stones:

1.Increase citrus intake: Citrate reduces the formation of calcium stones by binding with urinary calcium to reduce saturation and by binding with calcium oxalate crystals to reduce crystal growth. Citrus fruits such as oranges, grapes, lemons, and their juices are a rich source of naturally occurring citrates.

2.Limit foods with high oxalate and phosphate content: Oxalate is found naturally in many kinds of food including vegetables, fruits, legumes, nuts and seeds, and grains. A few examples of these oxalate-rich foods are peanuts, spinach, sweet potatoes, beets, chocolate, Swiss chard, and rhubarb. Limiting the intake of these foods can prevent exacerbating current stone formation and also prevent new stones from forming. Avoid colas. Colas contain a high amount of phosphates and increase the risk of stone formation.

3.Include adequate calcium in your diet: Though the name “calcium-oxalate stone” may suggest that calcium leads to stone formation, on the contrary, a lack of dietary calcium actually increases the chances of developing kidney stones. It is advised that calcium and oxalate-rich foods are eaten together in a meal so that they bind in the stomach and intestines before entering the kidneys. The daily recommended intake of dietary calcium to reduce the occurrence of calcium stones is 1000-1200mg per day.

4.Reduce sodium intake/ avoid a high salt diet: High sodium levels in your diet and body can increase calcium buildup. Sodium and calcium share the same transport in the kidneys, so a high sodium intake increases the leakage of calcium into the urine. A high sodium diet thus increases your chances of developing a new kidney stone. Hidden sources of sodium are canned and processed foods, restaurant and fast foods, and even some vegetable juices.

5. Avoid fasting: Fasting, in general, dehydrates the body and concentrates urine. Such conditions are ripe for crystal deposits to concentrate in the urine. Once triggered, this usually leads to stone formation. It has been noted that individuals who keep religious fasts are prone to recurrent stone formation.

For uric acid stones:

1. Reduce animal-based protein in your diet: Animal proteins like red meat, chicken, poultry, fish, organ meats, and gravies containing these foods have high purine content. Reducing purine-rich food in your diet reduces the risk of recurrence of uric acid stones.

2. Eat a plant-based diet: A diet comprising vegetables, fruits, whole grains, and low-fat dairy items is recommended to manage and reduce the recurrence of uric acid stones.

3. Avoid added sugars, sugary and alcoholic drinks: Avoid drinking beverages that dehydrate you, such as alcohol. Alcohol also increases uric acid levels in the blood and urine and the risk of uric acid stones. Sweetened drinks, especially those that contain fructose corn syrup should be avoided. Added sugars increase the risk of kidney stones. Processed foods such as cakes, corn syrup, white sugar, commercially produced desserts are high in added sugars.

Kidney stones can be a painful ailment to live with. However, it is a condition that can be managed effectively with diet and medication. Staying hydrated is a key factor in managing and preventing new kidney stones. Increasing your citrate intake, pairing calcium with oxalates and phosphates, and maintaining regular eating habits can be beneficial as well. Avoiding certain foods such as those containing high sugar and salt, alcohol, and sticking to a plant-based diet are important aspects of an effective diet for stone formers. For more information regarding kidney stones and how to manage them, book an appointment with our urology experts at the Department of Urology and Nephrology at Sagar Hospitals.