File this one under news that should surprise no one but, soda is bad for you! This study looked specifically at how drinking soda influences the risk of having a stroke. The study also looked at how substituting other beverages such as coffee, caffeinated and uncaffinated, tea, skim milk, or orange juice affect stroke risk. The data to do this study came from two extremely large studies, the Nurses’ Health Study begun in 1976 with over 121,000 female nurses and the Health Professionals Follow-Up Study begun in 1986 with over 50,000 doctors, and pharmacists. That’s a total of nearly 200,000 people followed for decades, the start of a very thorough study. And very necessary since soda drinking has only gone up over the last 3 decades rising to the current per person average of 45 GALLONS per year.

Plenty of studies have been done showing links between drinking soda and increased chance of developing diabetes, hypertension, high cholesterol, gout, and heart disease. Other studies have shown drinking diet soda increases risks of metabolic syndrome and kidney disease. However this study was one of the first to look specifically at stroke risk from both regular and diet sodas.

Unsurprisingly this study found the likelihood of having a stroke was increased by drinking regular or diet soda. Remember this was a very large study done over a long period of time. This allowed the researchers putting together this particular study to control for other factors. What does that mean? Well we know there are many risk factors for having a stroke. The two studies referenced in the beginning, where the data for this study came from, asked all sorts of questions about lifestyle to control for those other factors. This means that no matter what other types of food eaten, how much someone exercises, or how overweight they are drinking soda increases the risk of stroke.

There are many reasons why soda would increase the risk of having a stroke. The huge amount of sugar in soda is in liquid form so it enters your blood stream very quickly. The spike in blood sugar causes your body to release insulin to bring it down. The repeated up and down of blood sugar increases inflammation which causes atherosclerosis and plaque formation in blood vessels, weakening them and increasing stroke risk. The type of sugar in soda, predominately corn syrup, is quickly converted to fat that is stored near our internal organs. It also increases uric acid which increases blood pressure another risk factor for stroke. The caramel coloring used in many sodas has also been linked to increased inflammation. This particular study found an increase in stroke risk also applied to drinkers of diet sodas but the researchers didn’t explore the reasons for this. However other studies have shown that your body tends to treat the fake sugars used in diet sodas much like real sugar and causes the same spikes in blood sugar so stroke risk could be increased for the same reasons as in regular soda.

This study also found that substituting coffee, decaf or regular, for soda decreased stroke risk by over 10%. There was also a decrease stroke risk from substituting with tea, skim milk or orange juice to a lesser degree. So what’s the moral of the story? There is no reason to regularly drink soda! It is one of the worst things you can put in your body on par with smoking. Just say no!

Am J Clin Nutr 2012 May; 95(5): 1190-1199

By Dr Scott Szela