Anyone who has suffered the pain of passing a kidney stone will want to do all they can to ensure new stones don’t form. Kidney stones are extremely common, with some 500,000 people requiring emergency treatment each year. Though the actual cause of kidney stones is unknown, there are certain diet-related risk factors that might make someone more likely to suffer from them. By reducing some of these foods from the diet it may be able to reduce or prevent the chances of new stones from forming.


What are kidney stones?

Kidney stones are really just a mass of crystals, much like sugar crystals and they contain calcium with either phosphate or oxalate. Some stones may contain uric acid but these tend to occur in those who suffer from gout. Sometimes kidney stones remain as tiny as a grain of sand and pass out of the urinary tract unnoticed. Other times they clump together, causing a much larger stone which may become lodged in the urinary tract, causing intense pain when it passes through.

Why do kidney stones form?

When everything is working as it should, chemicals within the urine prevent kidney stones from forming. But in some cases, this doesn’t always happen. Kidney stones may also form when the urine becomes saturated with waste products, which then crystallize into stones. Some people are more at risk of suffering from kidney stones. For example, healthy men between the ages of 30-50 are four times more likely to be affected by kidney stones than women and family history is another risk factor.

Preventing kidney stones with diet

Because kidney stones often form in highly concentrated urine, a regular intake of fluids, especially water, is essential for diluting the urine, thus reducing the concentration levels. The Mayo Clinic recommend at least 2.6 quarts (2.5 liters) each day. It’s usually quite easy to tell whether you are drinking enough. Simply check the color of your urine which should appear virtually clear rather than dark yellow.

Someone who has been diagnosed with calcium oxalate kidney stones should reduce high-oxalate foods in their diet by limiting their intake to 40 to 50 mg each day. Foods which are high in oxalate include tea, chocolate, nut butters, grits, rhubarb, spinach, sweet potato, carrots, beetroot and potatoes. For a more comprehensive list of high-oxalate foods, the University of Pittsburgh Medical Center provides a guide to high-oxalate foods which should be avoided as well as those which should be limited and others which can be freely eaten.

According to the Mayo Clinic, although most kidney stones contain calcium, this isn’t down to the amount of calcium obtained through diet. Therefore there is no need to reduce dietary intake of this important mineral. However, try to eat a diet which is low in salt since this can increase calcium excretion, possibly leading to an increase in calcium-containing crystals in the urine.

Furthermore, according to a study by the Department of Internal Medicine, Dallas, Texas, a diet featuring a high intake of animal proteins may increase the risk of suffering from uric acid stones. Therefore, those who have a propensity to uric acid stones may find it helps to reduce their intake of animal protein foods which are commonly found in meat, fish, eggs and poultry.

Although the exact cause of kidney stones is unknown, there are certain dietary risk factors which make kidney stones more likely to occur in some people. Therefore, anyone who has a history of kidney stones may find that changing their diet can effectively reduce or prevent the diet-related risk factors associated with the forming of new kidney stones.