Diet Soda Plus High Sodium Diet Greatly Increase Risk of Stroke
One area that many dieters first focus on is “liquid calories” from sodas and other beverages. In an effort to reduce calories, many will trade out their regular soda for a diet, no-calorie version. While this can be very beneficial in dropping pounds, it may not be doing you any cardiovascular benefits, finds a new study from the University of Miami’s Miller School of Medicine. Those who drink diet soda were found to have more than a 60% increase in stroke than those who abstain.
Diet Soda and Stroke Association Not Well Understood Yet
Previous research has found that those who drink more than one soft drink per day, regardless of whether it was regular or diet, were more likely than non-soda drinkers to have metabolic syndrome, a cluster of factors that increase the risk for heart disease risk.
However, in this study “we saw a significant increased risk among those who drank diet soda daily and not regular soda,” says epidemiologist Hannah Gardener who is presented the research at the International Stroke Conference 2011.
Gardener and colleagues evaluated the soda habits of more than 2,500 people that were enrolled in the Northern Manhattan Study (NOMAS). The participants were 69 years of age, on average, and two-thirds were women. The volunteers completed food questionnaires about the type of soda they drank and how often. During the nine-year follow-up, 559 vascular events occurred, including both ischemic and hemorrhagic strokes.
Even after controlling for risk factors such as age, physical activity, caloric intake and smoking, those who drank diet soda daily were 61% more likely to have a vascular event over those who reported drinking no soda at all. Even after accounting for metabolic syndrome, vascular disease and heart disease history, those drinking diet sodas were still at a 48% increased risk.
The association between diet soda and stroke risk is unknown at this point, says Gardener. "You try to control for everything, but you can't," Steven Greenberg, MD, PhD, vice chair of the ISC meeting committee and professor of neurology at Harvard Medical School, told WebMD.
A possibility could be the artificial sweetener aspartame. According to a “Letter to the Editor” printed in the Journal of the Texas Heart Institute in Houston, Dr. HJ Roberts MD FACP FCCP says that phenylalanine, one of the components of aspartame, is “clearly relevant” to hypertension and cardiac arrhythmias in certain patients. This factor could not be evaluated in the study because participants were not asked about the types of soft drinks they consumed, nor the various ingredients involved.
The most likely answer is that not every dietary factor was taken into consideration when calculating the results.
In a separate study, Gardener and her team used the same NOMAS data and evaluated the salt intake of 2,657 participants. Those who consumed more than 4,000 milligrams of sodium per day had more than double the risk of ischemic stroke than those who consumed less than the 1,500 milligrams daily as recommended by the American Heart Association.
Stroke is the third leading cause of death, behind heart disease and cancer, in the United States. More than 137,000 people a year die from stroke, according to the American Stroke Association.
Gardener H, et al "Soda consumption and risk of vascular events in the Northern Manhattan Study" ASA 2011; Abstract P55.
Gardener H, et al "Dietary sodium intake is a risk factor for incident ischemic stroke: the Northern Manhattan Study (NOMAS)" ASA 2011; Abstract 25.