Kidney stones (renal calculi, nephrolithiasis or urolithiasis) are hard deposits made of minerals and salts that form inside your kidneys.
Diet, excess body weight, some medical conditions, and certain supplements and medications are among the many causes of kidney stones. Kidney stones can affect any part of your urinary tract — from your kidneys to your bladder. Stones form when the urine becomes concentrated, allowing minerals to crystallize and stick together.
Passing kidney stones can be incredibly painful, but the stones usually cause no permanent damage if caught early on. Depending on your situation, you may need nothing more than to take pain medication and drink lots of water to pass a kidney stone. In more severe cases, if stones become lodged in the urinary tract, are associated with a urinary infection or cause complications — surgery may be the only option.
Knowing the type of kidney stone you have helps determine its cause and gives you insights on how to avoid future kidney stone attacks possibly.
Types of kidney stones include:
Most kidney stones are calcium stones, usually in the form of calcium oxalate. Oxalate is a substance made daily by your liver or absorbed from your diet.
Dietary factors, high doses of vitamin D, intestinal bypass surgery and several metabolic disorders can increase the concentration of calcium or oxalate in urine.
Struvite stones form in response to a urinary tract infection. These stones can proliferate and become quite large, sometimes with few symptoms or little warning.
Uric acid stones.
Uric acid stones can form in people who lose too much fluid because of chronic diarrhea or malabsorption, those who eat a high-protein diet, and those with diabetes or metabolic syndrome. Certain genetic factors also may increase your risk of uric acid stones.
These stones form in people with a hereditary disorder called cystinuria that causes the kidneys to excrete too much specific amino acid.
Obscure, painful, and potentially life-threatening, kidney stones affect 1 in 10 people during their lifetime at some point or the other. The awful thing about kidney stones, besides the blatant pain, is that they threaten to come back – the incidence of recurrence being a whopping 70%.
The basic strategy to discourage stone formation is to lower the urinary levels of sodium, oxalate, uric acid, and calcium and increase urinary citrate. Citrate stops crystals from growing into stones. What can you do?
1. Drink plenty of water throughout the day.
For people with a history of kidney stones, The most effective advice anyone could give to avoid kidney stones is to fill up on fluids. Drinking 2.5–3 litres of fluids daily to increase urine volume will help. However, the kind of fluid matters, too. For instance, coffee and beer decrease the risk of non-oxalate stones but increase the risk of calcium oxalate stones. Lemon juice with a high citrate concentration can reduce the chances of stones other than calcium phosphate stones, while they are detrimental to those with calcium phosphate stones. Similarly, grapefruit juice seems to increase the risk of stones for unknown reasons.
Ideally, drink water. If you live in a hot, dry climate or exercise frequently, you may need to drink even more water to produce enough urine. You're likely drinking enough water if your urine is light and clear (like light lemonade).
2. Eat fewer oxalate-rich foods.
If you tend to form calcium oxalate stones, you should restrict foods rich in oxalates such as rhubarb, beets, okra, spinach, Swiss chard, sweet potatoes, nuts, tea, chocolate, black pepper and soy products.
3. Limit or Avoid Sodium-Rich Foods.
Sodium provokes the kidneys to excrete more calcium in the urine. High calcium concentrations can form salts with oxalate or phosphorus, leading to kidney stones. Sodium also lowers stone-fighting citrate levels in urine. We know that urinary calcium levels mirror dietary sodium levels, which can be used to your advantage. Limit your daily sodium intake to less than 2 gm per day.
That hidden salt used to preserve food or just make it taste better drives your daily intake up. As much as 75% of our daily sodium intake comes from processed foods. Before consuming packaged foods, check the Percent Daily Value (%DV) for sodium on the Nutrition Facts label. Sodium equal to or less than 5% is acceptable. If it's higher than 20%, then it’s best to limit intake or avoid it altogether. Look for the labels of processed foods – sodium bicarbonate (baking soda), baking powder, disodium phosphate, monosodium glutamate (MSG), sodium alginate, sodium nitrate, and sodium nitrite.
4. Limit Animal Proteins And Other Purine Sources.
Purines are natural compounds found in the body, our DNA, and in many foods. They can be broken down into uric acid by our body. If we ingest too much purine, urine concentrations of uric acid will spike, and uric acid in the urine can settle and form kidney stones.
If you have a history of recurring kidney stones, you should limit your daily animal protein intake to 80 gm. Be mindful of beef, chicken, pork, lamb, duck, and so on (particularly organ meat and sweetbreads). Some seafood can also be culprits anchovies, crab, fish roes, herring, mackerel, sardines and shrimp.
Do continue eating calcium-rich foods, but use caution with calcium supplements. Calcium in food doesn't affect your risk of kidney stones. Continue eating calcium-rich foods unless your doctor advises otherwise.
If you have questions about managing kidney stones or any questions about your medications, we are here to help.