Diet Soda: How It May Cause Kidney Damage

Diet soda – it’s a refreshing treat for many who are trying to watch their weight. Most of us suspect that it’s not the healthiest drink around, particularly when we take a quick look through the unpronounceable list of ingredients. But now a new study suggests a specific reason to avoid drinking too much diet pop: it may cause kidney damage.

Nurses’ Health Study Findings

The findings come from the Nurses’ Health Study, one of the largest and longest-running studies of various factors affecting women’s health. The study began in 1976 and expanded in 1989 and has studied 238,000 participating nurses.

Findings from the study relating to diet soda and possible kidney damage were released in October 2009. 3,256 participants were part of this segment of the study, which lasted 6 years. Those who reported drinking 2 or more diet sodas per day (with a soda being defined as a glass, bottle, or a can) had a 30% drop in their level of kidney functioning, which is the rate at which the kidneys can filter the blood.

The study was adjusted to consider other factors that might have caused the drop, such as diabetes, high blood pressure, and the participants’ levels of physical activity. The participants who showed kidney damage had begun the study with kidneys that functioned properly.

Additionally, participants who drank sugar-sweetened drinks such as regular pop, juices and iced tea had no incidence of reduced kidney function.

Why Would Diet Pop Harm Kidneys?

Researchers are wondering how the ingredients in diet soft drinks might cause kidney damage, but the specifics are unknown at this point. Some researches suggest that the sweeteners used in the sodas might cause kidney scarring over a period of time.

How Significant is the Loss of Kidney Function?

You may be wondering how significant the loss of 30% of kidneys’ filtering capability could be. Scientists estimate that normal ages causes kidney function to decline at a rate of 1 mL per minute for each year after age 40. Those who drank 2 or more diet sodas daily lost function at a rate of 3 mL per minute per year, so their rate of kidney function decline was 3 times that of those drinking less than 2 diet pops daily.

Kidney Disease

Kidney dysfunction is on the rise in America, with 20 million of us having some degree of chronic kidney disease. Additionally, the last two decades have each seen a doubling in the incidence of kidney disease diagnoses. Diet sodas could be one contributor to this growing problem.

Study participants who reported drinking one serving of diet soda daily did not show any increased evidence of kidney damage. As we wait for further findings on this issue, one thing seems sure: it’s wise to cut down on your intake of diet soda, or to remove it from your diet totally if possible.

Try alternatives such as water (plain or flavored), teas or low-calorie (and natural) fruit juices.


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  • Linda

    I have just become interested in this topic – diet beverages and declining kidney function – as my MD noticed on a recent blood test that my GFR is below normal. Last year it was only slightly below, 58 compared to >60 which is considered normal range. I’m 66 and have used diet soda and artificial sweeteners to help with weight control for MANY years. This year my GFR had dropped to 54. This might not sound too alarming unless you consider that GFR, as I understand it, is an indicator of kidney filtering ability and declines slightly with age, but never increases. Once you’ve lost filtering ability, you do not regain it! I think this study should be getting MUCH more attention because the two or three year lab tests for artificial sweeteners would not show the significant decline in GFR (if they even consider it) that this data over the long term shows. Anyone else out there who is healthy in every way but with a significant decline in GFR?