Diet is an important part of the treatment plan for kidney stones, according to research by Grases, Costa-Bauza and Prieto. The majority of kidney stones are composed of calcium oxalate; in fact, a study by Reynolds found that 75 percent of kidney stones were composed of calcium oxalate. Due to the significant percentage of calcium-based kidney stones, understanding the role that dietary calcium intake has in development of these stones could help with prevention and treatment.
Effects
The effects of calcium intake both from diet and supplements still needs more research due to conflicting research results. After studying the effects of calcium intake on kidney-stone risk, Williams et al. found that high intake of dietary calcium decreases the risk, while high intake of calcium in supplement form increases the risk.
Considerations
If you are examining your calcium intake and its relation to kidney stone formation, stay on top of your intake of sodium as well. In fact, "calcium and sodium compete for reabsorption in the renal tubules, excess sodium intake and consequent excretion result in loss of calcium in the urine," states Escott-Stump. A diet low in salt that includes adequate calcium has been shown to be protective of kidney stone reoccurence.
Misconceptions
A common misconception about calcium intake and kidney stones is that it is the calcium itself that is forming the kidney stones. If you have calcium oxalate kidney stones it is generally recommended to reduce foods high in oxalates, purines and protein. Eating foods high animal protein, purine and oxalate can change the pH of the urine, putting you at increased risk for kidney stones. Therefore it is recommended to speak with your doctor or dietitian about how much of these foods you should be eating to help avoid having an increased risk for further kidney stone development.
Getting Enough Calcium
One of the causes of calcium oxalate stones is low calcium intake to help treat these stones adequate calcium intake from food is recommended. It is recommended to eat foods that contain a minimum of 1,000 mg of calcium per day. Foods that are good sources of calcium include dairy products, fortified orange juice, fortified soy milk, broccoli, green leafy vegetables and almonds.
Types/Warning
There are four different types of kidney stones. The majority are calcium oxalate stones; other types of stones uric acid, citrate, cystine or struvite. It is important that your doctor identify the type of stone you have before any recommendation about calcium intake are given. Always consult with your doctor or dietitian before making any dietary changes.
References
- "Journal of Clinical Pathology"; Chemical Pathology Clinical Investigation and Management of Nephrolithiasis; Reynolds, TM; February 2005
- "Nutrition Journal"; Renal Lithiasis and Nutrition; Grases , Felix., Costa-Bauza , Antonia., & Prieto , Rafel; September 2006
- "Nutrition and Diagnosis-Related Care"; Escott-Stump, Sylvia; 2008
- "Journal of Clinical Pathology"; Why oral calcium supplements may reduce renal stone disease: report of a clinical pilot study ; Williams, C., Child, D., Hudson, P., Davies, G., John, R., Anandaram, P., De Bolla, A; January 2001
- "Nutrition in Kidney Disease"; Byham-Gray, Laura,. Burrowes, Jerrilynn, & Chertow, Glenn;
