Nov 11, 2013 10:23 AM EST By Jaleesa Baulkman, UniversityHerald Reporter

A daily diet that includes drinking sugary sodas could increase your risk for kidney disease, according to new research HealthDay reported.

Two new studies revealed a link between drinking soda and an increased risk of kidney damage, adding to the body of evidence of side effects associated with the surgery drinks.

In one study, researchers led by Ryhei Yamamoto from Osako University Graduate School of Medicine in Japan found people who consumed more than two sodas a day were more likely to have proteininuria - or increased excretion of protein in the urine, which is a hallmark of kidney dysfunction - than those who had fewer or no sodas daily.

More than 12,000 university employees participated in the three-year study. They underwent their annual check-ups at their health center where their urine was tested for evidence of protein. Then they passed the data on to the researchers.

Almost 11 percent of employees who said they drank two or more sodas a day had protein in their urine during three years of follow-up. Eight percent of those who did not drink and soda and nine percent of those who drank about one can a day tested positive for proteininuria.

Protein in the urine is considered an early, but reversible, marker of kidney damage, according to HealthDay.

A related study in rats, conducted by Case Western Reserve University in Cleveland, Ohio, found that moderate consumption of fructose sugar increases the kidney's sensitivity to angiotension II, a protein that regulates salt balance.

According to the researchers, this lead to increased salt reabsorption by cells in the kidneys, a finding that might explain why soda consumption has been linked to diabetes, obesity, high blood pressure and kidney failure.

Experts said the new findings add to a body of evidence on the unhealthy side effects of soda.

Dr, Anil Agarwal, a kidney specialist at Ohio State University, told HealthDay the new study suggests that even individuals with normal kidney functions are at risk for damage is they drink a too much soda.

He noted that soft drinks sweetened with high-fructose corn syrup may be the most dangerous.

"Fructose is sweeter than glucose, and doesn't cause feelings of satiety," he said. "There is no safe amount of soda," Agarwal said. "If you look at the recommended amounts of sugar we can safely consume every day, one can of soda exceed the maximum level."

The American Heart Association guidelines recommend daily sugar intake is 9 teaspoons for adult men, 5 teaspoons for adult women and 3 teaspoons for children. A 12-ounce can of non-diet soda have about 7 teaspoons of sugar, Agarwal told HealthDay.

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