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What can I do to prevent kidney stones?

Kidney stones are one of the most common disorders worldwide, approximately 10% of the population has suffered at least one occasion of kidney stones at some time in their lives. Men suffer from kidney stones more often than women. Children can also develop kidney stones; this may be due to genetic factors, low birth weight, intravenous feeding, and deformities or abnormal anatomy of the urinary tract. However, children are also at risk of developing kidney stones if they do not drink enough fluids or eat foods with high salt content.

Kidney stones are crystallized masses that form in the kidney. The development of the stones depends on the chemicals found in the urine. Certain substances can accelerate the formation of stones, while others prevent the formation of these.

Most stones are composed of calcium oxalate, but others can be made up of uric acid, phosphate, and other chemicals. These start being small and get bigger over time. The stones can remain in the kidney or can move through the ureter (the tube that carries urine from the kidneys to the bladder). Stones can also form in the bladder or urethra (the tube that carries urine to the outside of the body).

Risk factors for developing kidney stones

•        Family history of kidney stones

•        Having previously undergone a kidney stone

•        Obesity (a BMI greater than 30)

•        Inflammatory bowel disease (Crohn's disease, ulcerative rectocolitis)

•        Patients undergoing bariatric surgery, since the body absorbs less calcium after gastric bypass procedures

Below are some recommendations to prevent the formation of kidney stones:

Drink enough fluids throughout the day: Insufficient fluid intake contributes to the formation of stones. If you do not drink enough water, the urine will have less fluid and a higher concentration of chemicals that form the stones. That's why drinking more water may help prevent the combination of those chemicals that make up the stones. This recommendation is especially important during the summer when kidney stones are more likely to develop due to dehydration.

It is recommended that adults consume one ounce of liquid daily for every two pounds of body weight. For example, a 200-pound man should drink 100 ounces of fluid per day. We must bear in mind that not all liquids are beneficial, coffee, iced tea, and many soft drinks contain caffeine, which can cause dehydration if consumed in excess. The soda contributes to the accumulation of calcium oxalate, so it is better to avoid consuming it. The reduction of intake of sugary soft drinks significantly decreases the risk of suffering a lithiasis recurrence. Particularly in the reduction of those drinks acidified with phosphoric acid. The consumption of alcoholic beverages also increases the risk of kidney stones.

Decrease your salt intake: High salt intake negatively affects the composition of urine as it increases the excretion of calcium and decreases urinary citrate, favoring the formation of sodium urate crystals. Adults with hypertension or a history of kidney stones should limit sodium intake to 1,500 mg per day.

Avoid foods rich in oxalate: The union of oxalate with calcium in the urine is one of the most important stages in the formation of kidney stones, therefore by decreasing the intake of oxalate-rich foods reduces the formation of kidney stones.  Among the foods with the highest oxalate content are spinach, rhubarb, sweet potato, beet, chocolate, kale, and peanuts.

In addition, excessive consumption of animal proteins such as beef, cheese, eggs, pork contributes to the crystallization of uric acid. Establishing a vegetarian diet at least twice a week allows replacing part of the animal protein with beans, dried peas, and lentils, which are high protein and low oxalate foods.

Monitor added sugars: Added sugars, especially in the form of corn syrup with high fructose content, contribute to the crystallization of uric acid. The natural sugars in fruits are perfectly fine for daily consumption.

Avoid vitamin C supplements: The consumption of more than 500 mg per day of vitamin C predisposes to the formation of greater amounts of oxalate.

Do not be afraid of calcium: contrary to what many people believe, the restriction in calcium intake may increase the risk of stone formation. Calcium binds to oxalate in the intestine; its deficiency causes it to increase oxalate absorption and with it an increase in urinary excretion, thus favoring the formation of kidney stones. Therefore, it is recommended to ingest approximately 1000 to 1200mg of calcium per day.

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