February 10th, 2011
01:19 PM ET
Is it really called "diet" soda because it's better for you? A new study is calling that into question, but beware that the results are preliminary and don't entirely support the conclusion.
Researchers at the American Stroke Association's International Stroke Conference 2011 conducted an experiment on this topic, and found that people who drink diet soda may have a much higher risk of vascular events compared to those who don't drink soda. They followed participants for an average of 9.3 years and kept track of vascular events such as stroke that occurred.
They also said their results showed a connection between salt and stroke. After a follow-up period of about 9.7 years years, those taking in more than 4,000 milligrams of sodium per day doubled their stroke risk compared to people who consume less than 1,500 milligrams per day.
"This study suggests that diet soda is not an optimal substitute for sugar-sweetened beverages, and may be associated with a greater risk of stroke, myocardial infarction, or vascular death than regular soda," the researchers said in the study abstract.
But all of the information about how much soda and sodium consumed came from the participants' own reports, not from a controlled setting. It's possible that they remembered or stated their habits incorrectly, or did not maintain those habits consistently over time. Researchers also do not know about the specific brands and flavors of diet and regular sodas consumed.
"There is no scientific evidence to support the idea that diet soda uniquely causes increased risk of vascular events or stroke," Dr. Maureen Storey, senior vice president of science policy for the American Beverage Association, said in a statement.
Storey pointed out that this information comes from a research paper abstract presented at a conference, and was not in a study reviewed for publication by experts in the field. Also, the study authors did not control for weight gain or for family history of stroke.
This is the first time diet soda has been linked to vascular events, but previous research has implicated it in other health issues.
A 2007 study in the American Heart Association journal Circulation found that people who drink one or more soft drinks a day are more likely to develop metabolic syndrome, a heart disease precursor, than people who drink less than one soda a day.
Still, that study also only showed an association, and did not prove that sodas cause metabolic syndrome. There could be something else about people who drink soda regularly that directly leads to risk factors for heart disease.
About $74 billion worth of carbonated soft drinks are sold in the United States every year, with "diet" varieties constituting 30% of that, according to Beverage Digest.
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