According to a recent study, drinking one less can of soft drink a day translates into nearly a two point reduction in blood pressure.
A handful of studies have suggested that high sugar intake increases blood pressure, but overall, very little research has been done in this area.
People who drink a lot of these beverages could see a significant drop in blood pressure just by switching to diet soft drinks, or preferably, water.
In the study, researchers looked at consumption of sugar-sweetened beverages—regular soda, lemonade, fruit drinks and fruit punch. A typical 12-ounce can of soda contains about 130 calories of sugar, eight teaspoonfuls. Since the researchers found no effect on blood pressure from consumption of diet soda, it's reasonable to assume that the sugar was responsible for the blood pressure increase seen in the study.
The researchers also looked for an effect on blood pressure from caffeine consumption, but none was found.
The study followed 810 adults, average age 50, for 18 months. Blood pressure and dietary intake were recorded at the start of the trial and 6 and 18 months into the trial. Dietary intake was recorded from participant recall (memory). The results at 18 months showed that a one serving per day decrease in soft drink consumption was associated with a 1.8 point drop in systolic blood pressure (the first number in a 120/80 reading) and a 1.1 point drop in diastolic blood pressure.
The association between soft drink consumption and blood pressure remained, even after the researchers adjusted for any weight loss that occurred in the participants (weight loss lowers blood pressure, too).
The study participants, on average, drank about one can of sugary drink per day at the start of the study. This is well below the U.S. average of 2.3 cans. It would be interesting to see just how large a drop in blood pressure is possible when people who drink more sugary beverages than this test group did start cutting down.