Kidney stone research OKs calcium

New research has recently trumped the long-held notion that kidney-stone sufferers should steer clear of foods with calcium.
The research, done by the University of Wisconsin School of Medicine and Public Health, shows that calcium may actually prevent kidney stones.
It used to be that kidney-stone sufferers were told to avoid high-oxalate foods, which are also healthy food items like beets, nuts, spinach, strawberries, soybeans, and black and green tea.
Kristina Penniston, a dietician with the University of Wisconsin urology department, said the cause of kidney stones can’t be solely blamed on foods.
“We used to think they were caused by high-oxalate foods,” she said. “But, unfortunately, the rise in kidney stones isn’t because Americans are eating too much fresh spinach.”
“That turned everything on its head,” Penniston said about the Harvard University study which showed that several kidney-stone sufferers actually had low levels of calcium in their body.
Along with School of Medicine and Public Health chair of urology Dr. Stephen Nakada and other colleagues, Penniston tested a recent theory where oxalate goes to the kidneys due to the lack of calcium in the gastrointestinal tract, where it would normally be broken down.
In the study, one group of people who tend to form kidney stones were given calcium-citrate supplements while the other group was given foods rich in calcium.
The study showed that both groups had a significant drop in the level of oxalate in their urine, a sign that they may be less likely to form stones.
Penniston’s and Nakada’s research has primarily focused on dietary changes that can prevent kidney stone formation. A few years ago, they published a story showing that because of its acidity, lemonade could prevent kidney stones.
Just this March, they also published another study where they compared the citric-acid content of 21 types of citrus juices and juice concentrates. They found that fresh or concentrated lemon and lime juices were the best sources of citric acid, with concentrations about 10 times higher than those found in lemonade.
Through her research, Penniston has seen different reactions from both men and women. Though men may describe the pain from kidney stores as the worst ever, women say it isn’t all that it’s cracked up to be.