6 Strange Risk Factors for Kidney Stones

Anyone who has ever passed a kidney stone has probably wondered how such a small object can cause so much discomfort. A kidney stone affects around 1 in every 11 individuals at some point in their lives, and once you've had one, you're about 50% more likely to get another. More bad news: Stones used to be largely a male problem, but new research suggests that this gap is closing, potentially as a result of the growth in obesity.

Most types of kidney stones are solid masses of minerals that have congealed and trapped in your urinary canal. Calcium—typically a mix of calcium and oxalate, but in uncommon circumstances, calcium and phosphate—and, to a lesser extent, uric acid—make up the majority of them.

Now for the good news: By making a few dietary and lifestyle changes, you may be able to reduce your chances of developing a kidney stone in the future—or, better yet, avoid one altogether. But before making some dietary changes, it’s best to consult a nephrologist and primary care physician. Here are some weird risk factors for kidney stones you might not know:

1. A salty diet
Kidney stones are actually the least serious of all the issues that too much salt can bring. However, increasing your salt consumption can lead to an increase in the quantity of calcium your kidneys excrete. This causes calcium to build up in the urine, increasing the risk of kidney stone formation.

2. Living in the South
The Bible Belt is one name for the region in the southeast United States, but urologists call it the kidney stone belt. People who lived in this location had roughly double the risk of stones as people who lived in colder parts of the United States, according to a study published in the American Journal of Epidemiology in 1996.

People in the South tend to lose more fluid by sweating more and becoming dehydrated as the temperatures rise. When you don't consume enough water, you'll have a higher level of minerals in a less amount of urine, which increases the chances of those minerals binding together to form a stone.

3. Salad obsession
You eat healthy foods yet still end up in the urologist's office. Why? Again, oxalates. Leafy greens including spinach, rhubarb, and beets contain these compounds in abundance. Those oxalates should ideally bind with calcium in your colon and be excreted through your urine tract.

However, if the amount of oxalates in the urine is too high, these compounds might concentrate in the urine and form stones.

4. Eating too much meat
Stones can also be caused by eating too much poultry and red meat: According to a 2014 study published in the journal Nutritional Epidemiology, vegans and fish eaters were 30 to 50 percent less likely than people who ate roughly 100 grams of meat per day to develop kidney stones.

5. Drinking too much-iced tea
The Internet was stunned after reading a 2015 study in the New England Journal of Medicine about a 56-year-old man who was sent to the hospital for kidney failure after drinking too much-iced tea. And as it turned out, black tea is also a huge source of oxalate, which can cluster in the urine to form kidney stones.

6. Getting too little calcium
Since in most cases kidney stones form from calcium, it seems logical to exclude the nutrient from your diet. Nope. According to a Harvard Medical School study published in 2013, those who consume more calcium are less likely to develop kidney stones than those who consume less calcium.

If you don't get enough calcium in your diet, molecules called oxalates, which normally bind to calcium in the digestive tract, will instead attach to calcium in the urine, causing stones to form.