Urolithiasis

Over the past few decades, an increasing percentage of Americans have had the misfortune of experiencing the disabling pain that accompanies kidney stones. A National Health and Nutrition Examination Survey (NHANES) in 2007 reported that about 1 in 11 Americans will have experienced at least one symptomatic stone in their lifetime.1 Notable epidemiological risks include being white, male, obese, insulin resistant, and living in hot, arid regions.2

Because most patients with idiopathic kidney stones have some underlying urine metabolic abnormality, there is a recurrence risk of 40% at 5 years and 75% at 20 years.3

Kidney stones are a product of normally soluble material (i.e., calcium, oxalate, etc.) that supersaturate in urine to a level that facilitates crystallization.4 More than 80% of kidney stones primarily consist of calcium, with most being calcium oxalate.

Obese people who develop qualities of metabolic syndrome are at increased risk for stone formation. There is no research that directly studies the potential protective impact of weight loss on the development of kidney stones. However, it has been well established that the risk for stones increases with BMI5; therefore one can reasonably infer that weight loss in individuals with unhealthy BMIs should decrease their risk for nephrolithiasis. This underlines the overall importance of promoting healthy nutrition and physical activity in the prevention of kidney stones.6

Increasing fluid intake is a dietary recommendation that possesses strong scientific support for its role in preventing recurrent renal stones. Several observational studies dating to 1966 have postulated that increased fluid intake is beneficial; results from one randomized controlled trial in 1996 showed that fluid intake achieving a urinary volume of 2 liters reduced stone recurrence rate from 27% to 12%.7 A safe recommendation would be to drink 2–3 liters of water per day.

There is a smattering of studies that have examined the efficacy of encouraging or discouraging intake of different types of beverages for the prevention of stones. Fruit-based juices have especially been studied because of their citrate (protective) content. However, vitamin C has been shown to increase urine oxalate (lithogenic); not surprisingly, evidence for fruit-based juices is still ambiguous.6 Several studies have shown that grapefruit juice increases the risk for stones; on the other hand, lemon juice, orange juice, and cranberry juice have mostly been viewed as protective against renal stones.6 Not much is discussed about the role of soft drinks in stone formation, but the general recommendation would be to limit consumption, possibly because of their high fructose content.8

There have been some studies that have examined combination diets, and those that consisted of a low-protein component had a lower stone recurrence rate.9 Some postulate that a possible relationship between higher intake of carbohydrates/refined sugar and increased urinary calcium is partially responsible for why wealthier countries have higher rates of kidney stones.10 However, the association is too weak to recommend carbohydrate cessation as a form of protection against stone recurrence.

People with uric acid stones are generally advised to avoid a high-purine diet. Purine-containing foods include organ meats, legumes, mushrooms, spinach, alcoholic, sardines, and poultry. Contrary to conventional wisdom, it is not recommended to limit dietary intake of calcium. This conclusion has been proven several times with strong evidence. Two prospective observational studies from the 1990s concluded that kidney stone formation was inversely associated with dietary calcium intake.11

If you suffer from kidney stones, we’d love to discuss all that regenerative medicine has to offer to improve your health.

  1. C.D. Scales Jr., A.C. Smith, J.M. Hanley, C.S. Saigal: Prevalence of kidney stones in the United States. Eur Urol. 62:160 2012
  2. L. Frassetto, I. Kohlstadt: Treatment and prevention of kidney stones: an update. Am Fam Physician. 84 (11):1234-1241 2011
  3. E.M. Worcester, F.L. Coe: Calcium kidney stones. N Engl J Med. 363:954-963 2010
  4. I.P. Heilberg, N. Schor: Renal stone disease: causes, evaluation and medical treatment.Arq Bras Endocrinol Metab. 50:823-831 2006
  5. M.D. Sorensen, T. Chi, N.M. Shara, et al.: Activity, energy intake, obesity, and risk of incident kidney stones in postmenopausal women: a report from the Women’s Health Initiative. J Am Soc Nephrol. 25:362-369 2014 24335976
  6. L.R. Flagg: Dietary and holistic treatment of recurrent calcium oxalate kidney stones: review of literature to guide patient education. Urol Nurs. 27:113-122 2007
  7. L. Borghi, T. Meschi, F. Amato, et al.: Urinary volume, water, and the recurrence in idiopathic calcium nephrolithiasis: a 5-year randomized prospective study. J Urol.155:839-843 1996
  8. J.I. Friedlander, J.A. Antonelli, M.S. Pearle: Diet: from food to stone. World J Urol.33:179-185 2015
  9. H.A. Fink, J.W. Akornor, P.S. Garimella, et al.: Diet, fluid, or supplements for secondary prevention of nephrolithiasis: a systematic review and meta-analysis of randomized trials. Eur Urol. 56:72-80 2009
  10. S. Lewandowski, A.L. Rodgers: Idiopathic calcium oxalate urolithiasis: risk factors and conservative treatment. Clin Chim Acta. 345:17-34 2004
  11. E.N. Taylor, G.C. Curhan: Role of nutrition in the formation of calcium-containing kidney stones. Nephron Physio. 98:55-63 2004