Urologist Discusses Foods That Contribute to Kidney Stone Formation

What foods and dishes can contribute to the formation of kidney stones? Dmitry Zhuravsky, a urologist-andrologist, explains.

Kidney stones are a disease

“Urolithiasis is one of the most common urological pathologies. According to statistics, it accounts for more than a third of all diseases of the urinary system. The kidneys are particularly susceptible to the formation of sand and stones, but they may not manifest for a long time, and a person may only learn about their diagnosis when experiencing renal colic,” the doctor explains.

Stones form as a result of changes in the chemical composition of urine and an increase in the level of salts in it.

“The causes of this process can vary — from genetic predisposition to lack of physical activity or taking certain medications. Nutrition also has a significant impact on stone formation, particularly the excess of certain products in the diet,” adds the urologist.

Foods that contribute to stone formation

In fact, there is no single universal list of foods that contribute to urolithiasis. Moreover, stones can be of different types.

“In medicine, several types of kidney stones are distinguished. The main ones are uric, phosphate, and oxalate stones. Uric stones are a mixture of uric acid with potassium and sodium salts, while phosphate stones contain calcium phosphates. In practice, oxalate stones, formed from the combination of oxalic acid and calcium, are most commonly encountered,” explains the urologist.

Doctors recommend reducing the consumption of certain products and, in some cases, completely excluding them from the diet.

Greens: parsley, spinach, sorrel

Patients with oxalate stones should be cautious when consuming foods high in oxalic acid and its derivatives — oxalates. These include sorrel, spinach, parsley, dill, rhubarb, beets, and citrus fruits. An excess of oxalic acid in the diet hinders the elimination of salts from the body, increasing the likelihood of forming new stones or exacerbating existing ones.

Cocoa with milk

Oxalic acid is found not only in greens but also in cocoa powder, and in significant amounts. Therefore, patients with urolithiasis are advised not to overindulge in cocoa, especially in combination with milk, as dairy fats can enhance the absorption of oxalates from cocoa. Dairy products should also be limited in cases of phosphate stones.

Meat

Meat contains a lot of protein, which in large amounts can raise the levels of uric acid and calcium in urine. Additionally, protein includes purine compounds that, during metabolism, convert into uric acid, contributing to the formation of uric stones.

Red meat, offal, lard, fatty broths, and jellied meat are particularly dangerous in this regard.

Salty food

Excessive salt consumption leads to fluid retention in the body, accelerates calcium excretion, and contributes to salt deposition. Reducing salt intake is one of the main steps in preventing urolithiasis. According to the Ministry of Health's recommendations, an adult should limit salt intake to 5 grams per day (about a teaspoon). It is important to remember that this applies not only to salt in its pure form but also to added salt found in various pickles, smoked foods, and sauces.

Alcohol

There are sometimes opinions on the internet about the benefits of beer for preventing urolithiasis. Allegedly, the diuretic effect of this drink helps to expel sand and small stones. There is some truth to this, but the potential harm from regular beer consumption far outweighs its possible benefits.

Excessive consumption of beer and other alcoholic beverages can lead to frequent dehydration of the body, which, in turn, increases urine concentration, salt retention, and stone formation.

Carbonated drinks

Carbonated lemonades (like beer) contain phosphoric acid, an excess of which increases the risk of kidney stone formation and negatively affects the functioning of the urinary system. Popular sodas often also contain sugar substitutes that can reduce kidney function.