Diet for Kidney Stone Prevention
Diet for Kidney Stone Prevention
Isn’t it amazing how two small bean shaped organs (about 4 to 5 inch in length) are capable of filtering about 180 liters of plasma each day? Or in other words, an average set of kidneys filter your entire plasma volume about 60 times every single day to dispose-off toxins and chemicals in addition to unneeded water.
Healthy kidneys are vital to survival mainly because toxins and nitrogenous waste products produced as a result of biological processes can increase the risk of diseases, disorders and chronic health issues.
In What Way Diet Affect the Kidney Stone Formation?
Renal calculi (also known as kidney stones) is a fairly common condition that affects more than 7% females and 13% males (1). But before going in the details of preventive measures, here are a few key features that you should understand.
- The accumulation or delayed excretion of waste products in the urinary system can lead to the stone formation (mainly due to crystallization of salts). These waste material or salts include oxalate, calcium, and phosphorus.
- Daily diet is an important element that plays a vital role in the pathogenesis of stone formation.
- Besides nutritional forces, there are a number of other factors that can influence the formation of renal stones such as low fluid intake, environmental factors, body weight, basal metabolic status, ongoing infections and genetic factors.
How Many Types of Kidney Stones are There?
- Cysteine Stones: These stones are formed due to accumulation of excessive cysteine in the body. Individuals who are born with ‘genetic disorders of cysteine metabolism are at much higher risk to develop these stones.
- Uric Acid Stones: Uric acid is one of the main excretory substances that is responsible for the acidic pH of the urine. If its quantity is increased due to high intake of purines in the diet, the risk of uric acid stone formation increases in the body. Purines are mainly found in proteins obtained from animals.
- Calcium Stones: Calcium stones are formed in two ways. First, if the calcium salt content of the urine is high (due to dietary, hormonal or pharmacological factors), excessive calcium tends to accumulate with phosphate (to form calcium phosphate crystals). The risk increases if the urinary pH is more acidic. Secondly often times, the oxalate excretion rate of the body is high due to certain dietary preferences. In that case, calcium tends to crystalize with oxalate to form calcium oxalate stones.
- Struvite Stones: these stones are caused due to chronic infection in the kidneys. These stones are often large, irregular and painful.
Dietary Changes that can be Helpful in Preventing Kidney Stones
Research and clinical studies suggests that metabolic disparities in the dietary and excretory functions can directly increase the risk of kidney stone formation. For example, certain foods are acidic in character that may interfere with the pH of urine and may promote crystallization of certain salts (leading to stone formation).
Here are a few dietary changes that may prevent renal calculi formation:
- Fluid intake: Drinking at least 2-3 liters of water each day (religiously) is perhaps the most useful strategy to prevent kidney stones. Water neutralizes all the concentrated substances in the urine and prevent drastic changes in the pH.
- Calcium Phosphate stones:
- Restriction of sodium in the daily diet helps
- Minimizing the calcium intake (especially in the form of supplement) is extremely useful
- Reduction in the intake of animal proteins also plays a vital role in maintaining normal calcium metabolism in the body
- Limit dairy intake
- Uric acid stones:
- Strictly limit the intake of animal proteins
- Calcium Oxalate stones:
- foods with high oxalate like tomatoes, spinach should be avoided if you are at risk of developing calcium oxalate crystals
- Restrict dietary sodium intake
- Maintain caution in the consumption of animal proteins, processed dairy items and heavy calcium supplements
How Do Certain Substances Affect the Kidney Stones?
Sodium: Sodium competes with the calcium for reabsorption within the kidneys. High sodium levels promote flushing of large quantities of calcium in the renal tubules; thereby favoring crystallization. The RDA is 2300 mg.
- Animal protein: Animal proteins contains large amount of purines (nitrogenous substances) in it. These purines are broken down into uric acid and this uric acid is excreted out through urine. If there is high concentration of uric acid it can lead to uric acid stone formation.
- Calcium: Dietary calcium does not promotes renal stone formation, however, high excretion in the tubules favors its crystallization with phosphates or oxalates to culminate in stone formation.
- Oxalates: Oxalates are formed in the body as a result of metabolic processes but apart from that if oxalates are taken in diet in high quantity it can combine with calcium and form stones.
Helpful Tips to Prevent Stone Formation in Kidneys
- A dietitian should be consulted regarding advice and recommendations on a proper diet plan. A dietitian can also help overweight people to lose weight to minimize the risk of renal stone formation.
- Likewise, any infection or disease involving the urinary system should be adequately addressed to prevent backflow or stagnation of urinary flow.
- Increase your intake of antioxidants to prevent oxidative stress (such as vitamin C and E).
- Scales Jr, C. D., Smith, A. C., Hanley, J. M., & Saigal, C. S. (2012). Prevalence of kidney stones in the United States. European urology, 62(1), 160-165.
- Taylor, E. N., & Curhan, G. C. (2013). Dietary calcium from dairy and nondairy sources, and risk of symptomatic kidney stones. The Journal of urology, 190(4), 1255-1259.
- Thomas, L. D., Elinder, C. G., Tiselius, H. G., Wolk, A., & Åkesson, A. (2013). Ascorbic acid supplements and kidney stone incidence among men: a prospective study. JAMA internal medicine, 173(5), 386-388.