Kidney stones or renal calculus are crystalline deposits of minerals and salts that harden together and form in concentrated urine, and are found within the kidney or the urethra. It is also known at nephrolithiasis. It is a common medical disorder and usually affects one in every 20 individuals. Kidney stones predominantly present itself as severe pain and discomfort in lower abdominal area, flanks and lower back. It is associated with discomfort with urination, decreased urinary output, blood in urine and nausea. The most common cause of kidney stones is lack of fluid or dehydration. Other causes of kidney stones include food habit, increased intake of certain medications, genetic and hereditary factors. The risk of developing kidney stones increases with aging.
Food Habits and Kidney Stones
Kidney stones are primarily composed of calcium and other minerals such as oxalate. It has been noticed that diet modifications helps in avoiding kidney stones and also their recurrence. Changes in consumption of sodium, animal protein, calcium and oxalate, depending on the type of kidney stone can help is preventing kidney stones. Certain food increases the risk of kidney stone formation in certain individuals. Besides diet modifications, it is advised to drink 2 to 3 litres of water every day for reducing the risk of kidney stone formation. Individuals with cysteine stone should consume more water.
The following foods are recommended based on the types of kidney stones:
- Calcium Oxalate Kidney Stones:
- Limit intake of sodium rich food
- Reduce intake of animal protein such as fish, meat and eggs.
- Avoid intake of oxalate rich food such as rhubarb, nuts, spinach and wheat bran.
- Increase calcium intake.
- Calcium Phosphate Kidney Stones:
- Limit intake of sodium
- Limit intake of animal protein
- Increase calcium intake.
- Kidney Stones made of Uric Acid:
- Reduce intake of animal protein.
Foods to Avoid for Kidney Stones
- Oxalate Rich Foods to Avoid for Kidney Stones: Increased intake of oxalate rich food increases the level of oxalate in body. Oxalate combines with calcium and forms calcium oxalate stones. Food products that contain high levels of oxalate are spinach, nuts, wheat bran, rhubarb, black tea, soybeans, buckwheat, dark chocolate etc.
- Avoiding Sodium for Kidney Stones: Sodium can cause increased excretion of calcium into the urine by the kidneys. High calcium in urine in turn combines with oxalate and phosphates to form renal calculi. Thus it is advised to reduce sodium intake to avoid formation of kidney stones. Sodium rich food includes:
- Canned food
- Processed food
- Luncheon meats
- Hot dogs
- Other junk food.
- Avoid Excess Animal Proteins for Kidney Stones: Animal protein such as meat products, eggs and fish products are rich in purine that breakdown to uric acid. Individuals with increased risk of developing uric acid stone should limit consumption of meat products to 6 ounces a day.
Foods to Take for Kidney Stones
- Increased Fluid Intake for Kidney Stones: Individuals with increased risk of kidney stones are advised to stay adequately hydrated to avoid formation of stones. It is advised to drink at least 2 litres of water a day to prevent the formation of kidney stones. Increased water intake also helps is dissolving existing stones and help in easy passage of the stones. Besides water, other fluids also help in maintaining hydration.
- Increased Calcium Intake to Avoid Kidney Stones: Dietary calcium does not cause kidney stones; however, calcium through additional supplements may cause kidney stones. Calcium binds with oxalate from diet and prevents it from entering the blood supply and urinary tract, thus preventing the formation of kidney stones. It is advised by individuals with risk of calcium oxalate stones to have 800 mg of dietary calcium every day.
Kidney stone is a condition characterised by severe pain in the lower abdomen in view of formation of crystalline deposits in the kidney or urinary tract. This is usually caused by deposition of calcium, oxalates, phosphates or uric acid in urine. Certain food increases the deposition of the causative minerals in the urinary tract. Calcium on its own does not cause stones. Rather, when calcium combines with oxalate or phosphate, it forms kidney stones. Sodium increases the calcium deposition which in turn increases the possibilities of kidney stones. It is advised to drink as much water and fluid as possible to reduce the risk of kidney stones. One should drink at least 2 litres of water every day for maintaining adequate hydration. It has been seen that high intake of vitamin C may also cause formation of stones. It is also advised to limit alcohol intake to reduce the risk of stone formation. Based on the type of stone, a diet plan is prepared for those individuals by an experienced physician or an urologist. One can also consider follow up with a dietician or a nutritionist who can guide in preparing a diet chart based on the individuals age, need and nutritional requirements.