Preventing kidney stones starts with knowing the conditions (risk factors), increasing the likelihood of having this painful experience (renal colic). If you recognize yourself in one of these risk factors, you might be at risk for kidney stones, and you should follow the prevention recommendations.
Who is at risk for kidney stones?
Not all people have the same risk of getting kidney stones. However, someone may have higher chances like:
- Who live in warm, dry climates and those who sweat a lot;
- Who has someone suffering or has suffered from kidney stones in the same family;
- Who suffer some chronic diseases like diabetes, chronic kidney disease, renal tubular acidosis, cystinuria, hyperparathyroidism and repeated urinary tract infections;
- Who underwent gastric bypass surgery (bariatric surgery), inflammatory bowel disease (Chron, Ulcerous Rectocolitis or chronic diarrhoea);
- Who takes chronic medications to treat other conditions (certain medications indicated to treat chronic gastritis and reflux, migraines, or depression);
If you recognize yourself in a high-risk category, you must consider these lifestyle modifications for preventing kidney stones:
- Stay hydrated;
- Eat healthily. A high-protein diet, high sodium (salt), and sugar intake can increase the stone risk;
- Lose weight.
Urine volume depends on fluid intake, and high fluid intake is a critical component of stone prevention. Urine is a saturated solution of salt in which salts (calcium, oxalates, urates) can aggregate in crystals, starting the formation of calculus. Since the urine volume is a primary determinant of the concentration of these salts, I recommend drinking 2-3 litres of water a day. This water intake will help produce a good urine volume of at least 2.5 L/day and ensure less concentrated urine. However, it is essential to drink regularly during the day. For example, if you drink most of the daily recommended intake only in the morning, you will be not hydrated enough in the afternoon. Your daily activities may prevent you from regularly drinking during the day. Water reminder apps for smartphones are helpful in this regard. You just set the duration of your day, the intake target, and the capacity of your glass. The app regularly sends you “push notifications” to reach your target. Another critical factor it may affect hydration is physical activity. I recommend integrating one additional litre of fluid (sports drink) each hour of outdoor sport. For an indoor activity, half a litre may be enough.
Other drinks we consider friendly in the daily water intake besides simple water. Coffee
is one of them. Moreover, one fresh squeezed lime diluted in a glass of water, with its high concentration of potassium citrate, has a beneficial effect in preventing kidney stones if consumed with every meal. On the contrary, I recommend avoiding grapefruit juice, soda, and any soft drink.
Too much dietary salt increases calcium excretion and the risk of kidney stones. Contrary to what is a common belief, dietary calcium restriction does not protect stone formers. Low calcium intake is associated with an increased risk of stone formation. The lower calcium intake results in insufficient calcium to bind dietary oxalate in the gut, thereby increasing oxalate absorption and urinary oxalate excretion. Excessive oxalate excretion in the urine is the leading cause of calcium-oxalate stones (the most common type of stones). However, excessive supplemental calcium is associated with an increased risk of stone formation.
Let’s resume the dietary recommendations for preventing kidney stones:
- Avoid salt in your diet: we can find high salt content in canned and processed food (fast foods, junk food); a low salt diet is essential to control the blood pressure as well;
- Do not restrict dietary calcium: the proper daily amount of calcium is in one pot of yoghurt plus a glass of low-fat milk;
- Moderate proteins in your diet: prefer fish, white meat, and legumes as a source of proteins; limit the red meat to once a week only;
- Avoid extra calcium supplements;
- Avoid high vitamin C supplements (60 mg/day is enough).
High body mass index (BMI), large waist size and weight gain increase the chance of developing kidney stones. If you are obese or overweight, you should consider seeing a dietician for a hypocaloric, well-balanced, stone prevention-friendly diet program.
Other preventive measures for preventing kidney stones
The diagnostic workup in first-time and recurring patients should investigate the possible causes of kidney stones. The chemical analysis of the stone and other metabolic studies (blood and urine analysis) may guide us in recommending the proper prevention for a single patient.