Some sobering news about diet soda has come to light which should give people pause before consuming such beverages.
Julie Lin MD, MPH, FASN and Gary Curhan, MD, ScD, FASN of Brigham and Women’s Hospital studied more than 3,000 women participating in the Nurses’ Health Study to identify the impact of sodium and sweetened drinks on kidney function.
The information from the participating women, whose median age is 67, was from 1984, 1986, and 1990 and included data about kidney function. Over the course of the years from 1989 – 2000, the shocking data revealed that over 11% of the women suffered a decline of over 30% in their kidney function.
“Thirty percent is considered significant,” says researcher Julie Lin, MD, MPH, assistant professor of medicine at Harvard Medical School and a staff physician at Brigham and Women’s Hospital in Boston. That’s especially true, she says, because most study participants had well-preserved kidney function at the start of the study.
What those women had in common was a thirst for artificially sweetened sodas which exceeded two per day. Other factors were ruled out in reaching that conclusion, including age, caloric intake, obesity, high blood pressure, diabetes, cigarette smoking, physical activity, and cardiovascular disease.
Put another way: the women who drank two or more diet sodas a day had a decline in their glomerular filtration rate, a measure of kidney function, of 3 milliliters per minute per year. ”With natural aging, kidney function declines about 1 mL per minute per year after age 40,” Lin says. No link was found with the other beverages. And less than two sodas a day didn’t seem to hurt. “We didn’t see any association up to two artificially sweetened beverages a day,” Lin says.
”A serving was reported as either a glass, a can, or a bottle of a beverage,” Lin tells WebMD. ”It was not more specific than that.”
”The mechanisms aren’t clear,” Lin says of the association she found. In another study she presented at the meeting, she found higher salt intake is also associated with faster kidney function decline.
Understanding the mechanisms are important because it can help evaluate with certainty whether these results are applicable to men as well.
Unsurprisingly, an industry group remains skeptical of these findings:
Asked to review the study findings, Maureen Storey, senior vice president of science policy for the American Beverage Association, says in a prepared statement: “It’s important to remember that this is an abstract presented at an annual meeting.” She notes that the research needs further scrutiny by researchers.
She acknowledges that kidney disease is serious but that diabetes and high blood pressure account for the majority of kidney disease cases, ”not consumption of diet soda.”
When it comes to dieting and exercise there are no short cuts. Diet soda may help satisfy a craving for a sugary beverage without the caloric penalty, but there may be unintended consequences. For example, what if the body recognizes a discrepancy between the information sent by the tongue, “sugar incoming”, and the message processed by the other parts of the metabolism, “no sugar received”? Logically, if the discrepancy is processed, the body will increase the hunger drive as a way of compensating for the missing sugar, which may cause the person to consume more calories than they would have otherwise.
Even for those people who take the excellent first step towards getting healthy by exercising need to be keenly aware of the law of unintended consequences, because exercise can make you fatter.