What are they?
Kidney stones, with the term renal lithiasis or nephrolithiasis, are characterized by the formation of mineral concretions in the urinary tract.
The appearance of these stones is certainly linked to an unbalanced diet, even if sometimes they are attributable to genetic factors.
Very often kidney stones are asymptomatic, but sometimes the patient experiences a sharp and violent pain in the lower abdomen.
Kidney stones are crystals aggregations formed from the precipitation of mineral salts and particular substances present in the urine, such as calcium, oxalates, phosphates and uric acid.
These aggregations turn into stones, either as a result of their growth or as a result of a decrease in the urine. When this happens, the stones can block the flow of urine out of the kidneys, which over time can lead to serious infections and potential kidney failure.
Based on their composition, we have different types of kidney stones:
- Calcium oxalate or calcium phosphate stones.
- Uric acid stones;
- Calcium urate stones;
- Cystine Stones;
- Ammonium urate stones.
Kidney stones represent the most common pathological condition of the urinary tract. Among the predisposing factors we have:
- Ethnicity (greater diffusion in the Caucasian than Asian race);
- Season. Hot weather tends to trigger dehydration, which can snowball into stone formation. ;
- Abuse of mineral salt supplements;
- Diet rich in saturated fat and cooking salt;
- Hyperthyroidism, due to the catabolic effect on bone mineral homeostasis;
- Hyperparathyroidism which causes calcium levels in blood to rise.;
- Age (greater predisposition after 40 years).
A kidney stone can be diagnosed by:
- Chemical examination of urine;
- Abdominal ultrasound
- Spiral CT scan;
Pharmacological treatment involves the use of antispathic drugs, to reduce the muscle contractions, and analgesics to relieve pain. Very often NSAIDs are used, which act both on the reduction of pain and on the increase of urinary peristalsis, essential for the expulsion of stones.
Usually, as an emergency intervention in the treatment of kidney stones, doctors the patient is invited to drink 1-1.5 liters of low mineralized water in order to facilitate the stone removal.
Diet certainly plays an important role in preventing or treating kidney stones, taking into account that the composition of the urine is also determined by what you eat.
Surely the primary goal is hydration, which should be constant throughout the day, increased especially in summer and during physical activity.
Furthermore, it is necessary to reduce the intake of salt, proteins of animal origin, lower the intake of saturated fats, increase that of monounsaturated or polyunsaturated fats, reduce the consumption of simple sugars, cook without adding fats and oil, therefore prefer steam cooking, microwave, grill or griddle.
Furthermore, if calcium oxalate stones are present, it is important to reduce the intake of foods rich in oxalates such as spinach, rhubarb, chard, wheat bran, tea, dried fruit, soy and derivatives.
For uric acid stones, it is essential to remove alcohols, spirits, salted, pickled, canned, smoked, dried foods, meat broth extracts, snacks such as pretzels, peanuts, chips, popcorn, blue fish rich in purines such as sardines, anchovies, anchovies, molluscs, crustaceans, mussels, game, offal, sausage, mortadella, salami.
For cystine stones it is necessary to reduce the consumption of animal proteins such as meat, fish, eggs and drink approximately 4 liters of water per day.
To reach adequate quantity of water, the advice is to introduce 250-300 ml of liquids every hour both during the day and at night, if possible.
In general the main rules to follow for kidney stones regardless their composition, are the following:
- Give preference to the consumption of whole grains, rich in fiber, alternating them during the week with refined grains;
- Drink skimmed or partially skimmed milk or yogurt once a day;
- Eat well cooked vegetables, to eliminate oxalates;
- Eat two eggs once a week;
- Eat legumes twice a week;
- Eat red meat once a week;
- Eat white meat 2-3 times a week;
- Eat blue fish at least 3 times a week;
- Eat lean and defatted cured meats, such as raw ham, cooked ham, turkey breast and bresaola, once a week.