I recently recorded a short video about kidney stones and was asked to provide more information about how they occur in children.
Kidney stones are increasing in incidence. This is well proven in adults and it appears to be true among children, as well. A study conducted by Mayo Clinic in Olmsted County, Minn., showed the incidence of kidney stones in children has gone up 4 percent per year for the last 25 years. The reasons for this are uncertain. Are there environmental factors not yet understood, or are we changing our behaviors and that of our children?
Regardless, there are time honored — and well documented — strategies for stone prevention. First is good hydration. In our metabolic studies at Children’s Hospital of Wisconsin, when we look at otherwise healthy patients without a family history of stones, dehydration is easily the most common finding and also the most easily treated. While the adage to drink 8 glasses of water a day is a good start, a far more useful approach is to keep the urine nearly clear. You need far more fluids on a hot summer day while playing sports than on a quiet day in January. Drinks such as lemonade and clear sodas are high in citrate, which helps prevent urinary stones. But watch out for all of the calories. Crystal Light brand drink mix is a good alternative if this is an issue.
A diet high in salt will increase the calcium that is put out in the urine. More than 90 percent of stones contain calcium. Lowering the salt will lower the calcium in the urine. The place to start is avoiding fast foods. Canned goods you buy in the grocery store often have shockingly high amounts of salt as well, and bread may be the biggest source of all in many diets. Salt makes foods taste better, so it is liberally added to many processed foods. Learn to read food labels and you may be surprised at what you see.
So what about calcium? Here, moderation is the key. We all need calcium in our diets, especially growing children and teens. In large population studies, people who have a low-calcium diet actually have a higher risk of developing stones than people who have normal or even high amounts of calcium in their diets. The biochemistry is complex but the risk is real. So, drink 2 to 3 glasses of milk per day, have some cheese and ice cream, but use common sense and don’t consume to excess. Also, be wary of all of the foods that are calcium fortified. Excess calcium in your diet has to come out, and it comes out in the urine.
Aristotle said moderation is the key and he was right regarding stone prevention. Eat a healthy diet, stay well hydrated and you will significantly reduce your chances of developing a stone.
Dr. Durkee is a member of a team of internationally known pediatric urologists at Children’s Hospital of Wisconsin. Our Urology Clinic is capable of caring for the sickest children, including newborn babies who require surgery right after birth. We are the only pediatric hospital in Wisconsin using robot-assisted laparoscopic surgery, a type of minimally invasive surgery.