Urinary stones (or lithiasis) are small stones formed from organic or mineral deposits that pass into the kidneys and are eliminated in the urine.

Painful, they rarely go unnoticed, especially because of the bleeding they generate.

"The main culprit in the formation of these crystals is our diet too rich and unbalanced," says Professor Olivier Traxer, urologist at Tenon Hospital (Paris) and member of the lithiasis committee of the French Association of Urology (AFU) .

At the beginning of the last century, urinary stones were less numerous. Their composition was also different. They consisted mostly of urate and phosphate, while 3/4 of the current urinary calculi contain calcium oxalate, a reflection of our excessive intake of protein, industrial sugars and high-salt prepared meals.

Some dietary rules therefore prevent their recurrence.

Drink (at least) 2 liters of water a day

First tip: drink plenty of water since you have to excrete 2 liters a day.

In fact, the more concentrated the urine, the more the risk of making crystals increases. If our urine is almost transparent, it is a sign that we drink enough. Otherwise, we must hydrate ourselves more.

Spring water, tap water and some mineral waters (Evian, Valvert, Volvic) are indicated because they contain few minerals. Attention in contrast to mineral water calcium (Vittel, Perrier, Badoit ...): they can promote the appearance of stones in predisposed people.

"You can only drink it if you consume few dairy products.Patients suffering from lithiasis must ingest between 800 and 1000 mg / day of calcium, neither more nor less," said Professor Olivier Traxer.

It also avoids the abuse of tea, rich in oxalate, as well as beer that contains uric acid. "The ideal is an orange pressed in the morning because the orange juice not only brings water but also citrate that prevents the formation of crystals.In addition, it reduces the acidity of urine," says the specialist.

Limit animal protein

Meat, eggs and fish boost the urinary calcium excretion. Their abuse encourages the body to tap into bone reserves (which increases the risk of osteoporosis) and increases the concentration of urine in calcium. As a result, the risk of calculation escalates. In the case of a history of calcium calculations (opaque on the radio), caution is required.

According to Prof. Traxer, 150 grams of animal protein per day is enough.

Chocolate, spinach, Swiss chard, broccoli, peanuts, almonds, walnuts, rhubarb, beets and sweet potatoes all rich in oxalate are also limited.

Similarly, the salt is drastically reduced, since it promotes the formation of calcium oxalate crystals. Not more than 6 to 7 g per day.

Better also put the spot on the fast sugars (sodas, confectionery, pastries ...). These induce insulin resistance. But insulin decreases renal reabsorption of calcium.

Banana, avocado, cucumber, tomato, apricot, pepper and parsley can however be eaten without counting. Well provided with potassium, they reduce the risk of stones.