Previous Studies Link Sugary Drinks to Several Health Conditions
Previous studies have linked sugary beverages to obesity, type 2 diabetes, and metabolic syndrome, a cluster of risk factors that increase the risk for heart disease and diabetes, but the new study is one of the first to show that drinking too many sweetened beverages can increase blood pressure levels. High blood pressure is considered a major risk factor for heart disease and stroke.
Americans drink about 2.3 servings or 28 ounces of sugar-sweetened beverages each day, and one in three adults in the U.S. has high blood pressure, according to the American Heart Association.
"Cutting back soda consumption will benefit your blood pressure," says researcher Liwei Chen, MD, PhD, an assistant professor of epidemiology at Louisiana State University Health Science Center School of Public Health in New Orleans.
Sugary Drinks and Blood Pressure
The new study involved 810 adults aged 25 to 79 with prehy-pertension or early stage 1 hypertension who were taking part in an 18-month study designed to prevent or reduce high blood pressure with weight loss, exercise, and diet.
Pre-hypertension is defined as a systolic blood pressure reading between 120 and 139 or a diastolic blood pressure of 80 to 89. Stage 1 hypertension is defined as a systolic blood pressure between 140 and 159 or a diastolic blood pressure between 90 and 99. Systolic blood pressure is the upper number in a blood pressure measurement and refers to the pressure when the heart beats. Diastolic blood pressure, the lower number, is the pressure between beats. A blood pressure reading of less than 120/80 is considered ideal.
Most people in the study drank an average of 10.5 fluid ounces of sugar or high fructose corn syrup-sweetened beverages a day including non-diet soft drinks, fruit drinks, lemonade, and fruit punch when the study began.
Halving their soda intake resulted in a 1.8 point reduction in systolic blood pressure and a 1.1 point drop in diastolic pressure.
The public health benefit is "substantial," she says. A 3-point reduction in systolic blood pressure should reduce risk of death after stroke by 8% and heart disease mortality by 5%, according to information cited in the new report.
"Soda consumption is so poplar and high blood pressure is a very significant health problem, and if you reduce sugary drinks, you will reduce your blood pressure in the short term and reduce your risk of heart attack and stroke over the long term," she tells WebMD.
Although weight loss accounted for some of these blood pressure-lowering effects, cutting back on sweetened drinks also had an independent effect on blood pressure levels.
Exactly what accounts for this independent effect is not known, but several theories exist. For example, these beverages are often loaded with sodium, which can increase blood pressure, and the sugar in the drinks may increase levels of hormones known as catecholamines, which can cause blood pressure to rise.
George Bakris, MD, a professor of medicine and director of the Hypertension Center at the University of Chicago Pritzker School of Medicine, says that uric acid also plays a role.
"High fructose corn syrup increases uric acid levels, which has been shown to increase high blood pressure," says Bakris, who is also the president of the American Society of Hypertension.
"Read labels because high fructose corn syrup has to be listed on the label," he says. "If you even reduce what you are taking in by 50% over time, you will see a benefit," he says.
It's not just soft drinks either. "It's in ketchup and a lot of condiments and sauces that people eat and don't appreciate," he says.
Beverage Group Blames Diet
"This study does not show that there is anything unique about drinking sugar-sweetened beverages that leads to increased blood pressure, or that there is something unique about reducing their consumption that leads to reduced blood pressure," says Maureen Storey, PhD, senior vice president of the American Beverage Association in Washington, D.C.
"We know that losing weight by decreasing total calories consumed from all foods and beverages and increasing total calories burned through physical activity has the greatest effect on blood pressure, not the specific foods or beverages that are decreased," Storey says in a written response.
"It's important to recognize that this particular study is a secondary analysis of another study designed to look at the impact of weight loss, not reducing or eliminating specific foods or beverages on blood pressure," she says. "This study only further supports that weight loss is a critical factor to lowering blood pressure. And the key to losing weight involves either decreasing total calories consumed or increasing total calories burned or a combination of the two."
Should there be a ‘Soda Tax'?
"There is a mile-long list of studies that show the negative impact of consumption of sugar-sweetened beverages, and this study is more proof that something needs to be done to change the disease burden caused by these drinks," says Kelly Brownell, PhD, director of the Rudd Center for Food Policy and Obesity at Yale University in New Haven, Conn. He advocates a tax on these beverages.
As it stands, up to 20 cities and states are considering imposing such a tax on soda. "None of the taxes have passed yet, but it is just a matter of time," he says.
- Chen, L. Circulation 2010; vol 121.
- Liwei Chen, MD, PhD, assistant professor, Louisiana State University Health Science Center School, New Orleans.
- George Bakris, MD, professor, director, Hypertension Center, University of Chicago Pritzker School of Medicine.
- News release, American Beverage Association.
- Kelly Brownell, PhD, director, Rudd Center for Food Policy and Obesity, Yale University, New Haven, Conn.