If you’ve ever had a kidney stone, you know the specific pain and misery they can cause. It’s long been known in medical literature that individuals in hot climates are more likely to get stones, and people are more likely to get them in the summer or early autumn. That is because sweating more can lead to dehydration that goes undetected by the individual, but makes urine much more concentrated. When that happens, tiny crystals are more likely to clump together in the kidney and cause a stone to form. The longer and more severe the dehydration, the more likely it is for a stone to form and to grow. Sometimes these stones don’t decide to move for months or even years, but when they do, they usually cause excruciating pain.
Jorge Gutierrez-Aceves, M.D., professor of urology at Wake Forest Baptist Medical Center, said this week that kidney stone season is underway in the south, and it’s due to dehydration and consumption of large amounts of iced tea. Your risk is increased if the tea you drink is highly sweetened, Gutierrez-Aceves said.
“More people suffer from kidney stones when the weather is hot and dry because they become dehydrated. Without proper hydration, the urinary levels of mineral and salts such as calcium get more concentrated. This increases the risk for stones.”
Oxalate is a mineral found in certain food and drink, with tea, spinach, and blueberries all carrying high levels of it. It binds to calcium and can quickly form stones in concentrated urine. These stones can be small or very large. Generally, any stone over 5 mm cannot be passed on its own and may need procedures at a hospital to remove it. Kidney stones are more than painful or a nuisance – they can cause kidney infection or even loss of function to a kidney if the stone blocks urine flow for an extended period of time.
What is surprising to some, according to CBS, is that the consumption of calcium – milk, yogurt, cheese, ice cream – does not need to be avoided, as eating calcium-rich food does not increase calcium stone formation. New research also shows that high levels of zinc in the body may contribute to stone formation, according to Science Daily.
The zinc study was conducted by the University of California, San Francisco, and published in the scientific journal PLOS ONE. Dr. David Killilea says that while the research regarding oxalate remains true, scientists believed there were further risk factors.
“Years ago, researchers noticed that fruit flies produced little crystal ‘granules’ in their primitive kidney-like structures, but that finding had been mostly ignored. Only recently have we found that these granules are similar in some ways to kidney stones in people. Fruit flies are easily managed in the laboratory, and we can manipulate their genetics and diet. We started screening the genes that might play a role in calcification, and we came across a gene that plays a role in metabolizing zinc. At the same time, I was analyzing the fly granules to see what was in them, and I found relatively high levels of zinc. The way these results came together was a nice surprise!”
Dr. Killilea noted that the previous studies on calcium stones remain true, and that zinc should not be eliminated from the diet, but it is proving to be necessary to discover what the optimal level of zinc is and not surpass that level. Studies will continue on the zinc correlation.
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