Cut Down on Cola for Kidney Health

By Maureen Williams, ND

Healthnotes Newswire (August 23, 2007)—People concerned about kidney health are told not to drink soda, and new research showing a link between cola drinking and chronic kidney disease backs this recommendation.

Chronic kidney disease includes conditions that damage and decrease the kidneys’ ability to remove toxins and maintain normal fluid balance. In severe kidney disease, wastes can build to dangerously high levels in the blood. Complications of chronic kidney disease include high blood pressure, anemia (low blood count), weak bones, malnutrition, nerve damage, and cardiovascular disease. Eventually, kidney disease can progress to kidney failure, requiring dialysis or a kidney transplant.

Kidney disease affects about 20 million people in the United States, and this number has been increasing steadily for the past 20 years. Some types of kidney disease are inherited and some are present at birth (congenital), but most often it occurs in people with other conditions that affect the kidneys, such as diabetes and high blood pressure.

Soda drinkers have a higher incidence of diabetes, high blood pressure, and kidney stones. Some studies show an association between kidney stones and chronic kidney disease. Colas in particular contain high amounts of phosphoric acid, a substance known to change the urine in a way that favors kidney stone formation.

The new study, published in Epidemiology, compared the beverage-drinking habits of 465 people with chronic kidney disease to that of 467 people with normal kidney health. As expected, the people with kidney disease were more likely to have a medical history of high blood pressure, diabetes, and kidney stones. They also drank more soda than the people with healthy kidneys, including colas. Drinking two or more cola drinks per day doubled the risk of chronic kidney disease. There was no difference between artificially sweetened and regular colas, and drinking noncola sodas and caffeinated beverages did not affect risk.

“One difference between cola and noncola carbonated beverages is that, while noncola beverages have been predominantly acidified using citric acid, cola beverages are generally acidified using phosphoric acid,” the study’s authors offered as a possible explanation. “Phosphorus may have an effect on the risk of kidney disease.”

“Cola consumption is common and chronic kidney disease is a substantial public health burden,” the researchers concluded. “Our preliminary result of an association between cola consumption and risk of chronic kidney disease deserves to be explored in more detailed studies.”

(Epidemiology 2007;18:501–6)

Maureen Williams, ND, received her bachelor’s degree from the University of Pennsylvania and her Doctorate of Naturopathic Medicine from Bastyr University in Seattle, WA. She has a private practice in Quechee, VT, and does extensive work with traditional herbal medicine in Guatemala and Honduras. Dr. Williams is a regular contributor to Healthnotes Newswire.

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