Ask someone who suffers from kidney stones and they will tell you nothing could possibly hurt more. Diet is most often associated with kidney stones, but there’s a genetic component as well. New research identifying how a certain gene triggers kidney stones has opened new doors to diagnosis and treatment of this excruciating condition.
About kidney stones
Every year about a million Americans discover they have the misfortune of developing kidney stones. Major risk factors for kidney stones include not drinking enough water or eating too much salt, which attaches to calcium and increases the risk of stone formation. The types of kidney stones most often linked to diet are calcium oxylate stones and uric acid stones, which form when there is too much calcium, oxalate and uric acid in the urine.
The genetic risk factor
Another risk factor for kidney stones is genetic. New genetic research by scientists at Washington University School of Medicine in St. Louis helps explain why some people are more prone to develop kidney stones than others.
Previous research has shown that people with a common variation in a gene called claudin-14 lose the ability to regulate the gene’s activity, resulting in a 65 percent increased risk of kidney stones. Senior study author Jianghui Hou, PhD, and his team have defined the role claudin-14 plays in the formation of kidney stones.
Normally claudin-14 isn’t active in the kidney. When claudin-14 is idle, kidneys work normally. Essentials minerals like calcium and magnesium are filtered and reabsorbed into the blood where they belong.
Hou’s team found that clauden-14 is kept in check by two molecules of RNA, the counterpart to DNA. When people eat too much calcium, salt or foods high in purines and oxalates, the RNA molecules lose control of claudin-14. Once set free, the gene blocks calcium from entering cells that line the kidney and separate blood from urine. Without a way back to the bloodstream, excess calcium goes into the urine. Too much calcium in the urine develops into kidney stones.
Kidney stone foods
The body converts purines into uric acid, a catalyst for kidney stones. High-purine foods include organ meats, meat extracts and broths, meat gravies, anchovies, sardines, herring, mackerel and scallops. High-oxalate foods that aggravate kidney stones include rhubarb, spinach, strawberries, chocolate, wheat bran, nuts, beets and tea. High-oxalate beverages include coffee, chocolate drinks, dark beers, soy drinks and juices from high-oxalate fruits.
Better diagnosis and treatment
The new findings could lead to drugs that mimic the RNA molecules that keep claudin-14 in check. They could also be used to develop a test for claudin-14 levels in the urine that indicate an increased risk for kidney stones. That knowledge can prompt people to modify their diet to prevent kidney stones before they ever develop.
Prevent kidney stones
The most important way to prevent kidney stones is to drink more water. You are drinking enough water when your urine is clear or light yellow. If it is dark yellow, you’re not drinking enough. Eat a balanced diet that is not too high in animal protein and increase your fiber intake. The best way to cut down on salt is to avoid processed foods and limit eating at restaurants. Avoid added sugars. Get your calcium from real food like milk, cheese and yogurt instead of supplements.