Women who drink sugary beverages every day may raising their risk for heart disease, even if their habit is not packing on the pounds.
Whatever the form -- sweet tea, soda, or coffee drinks that look like desserts — women who drank two or more sweet beverages a day were at an increased risk for heart disease, even if they did not gain weight over the five-year study, according to the findings presented today (Nov. 13) at the American Heart Association's meeting in Orlando, Fla.
Large studies in the past — including the ongoing Framingham Heart Study, now in its 63rd year — have linked drinking sugar-sweetened beverages to heart disease.
"So we looked at its association with individual risk factors" for heart disease, said Christina Shay, lead author of the paper and an assistant professor of epidemiology at the University of Oklahoma Health Sciences Center. "Is it blood pressure, cholesterol, obesity? What is it specifically?"
Shay and her colleagues followed 4,166 people between the ages of 45 and 84 who were part of the larger Multi-Ethnic Study of Atherosclerosis study.
Shay said it was "striking" that women with a sugary drinking habit developed high levels of triglycerides, which area type of fat, but men did not.
Women who drank two or more sugary beverages per day were four times more likely to develop high triglyceride levels than women who drank fewer sugar-sweetened beverages. Women with the liquid sugar habit were also were more likely to develop abnormal levels of fasting glucose, a sign they could be developing diabetes.
"These drinks may be influencing heart disease risk factors even if people don't gain weight," Shay said.
According to the Centers for Disease Control and Prevention, an estimated 26.8 million Americans have heart disease, which ranks as the nation's number one killer. Yet Americans love their soda. The California Department of Public Health reports that the average American drinks 50 gallons of sweetened beverages a year.
Sugar's connection to heart disease
"There are some calories that come like a nuclear attack," said Dr. Stephanie Coulter, director for center for women's heart and vascular health Texas Heart Institute. Eating complex carbohydrates such as oatmeal cause glucose (sugar) to be released slowly into the blood.
"But have a sugar drink, and all the sugar comes rushing into your system," Coulter said. And if the body has lost the ability to use the hormone insulin to regulate blood sugar (a condition called insulin resistance), the extra sugar remains circulating in the blood.
Daily blasts of too-high blood sugar can disrupt metabolism in several ways, said Dr. Stephen Devries, a cardiologist at Northwestern Memorial Hospital in Chicago. High sugar levels increase triglycerides, lower good cholesterol and prompt the body to make an especially damaging, smaller molecule of bad cholesterol. Too much sugar also raises levels of inflammation, another risk factor heart disease, Devries said.
"The body is a delicate ecosystem, so if you change one area it will have an unintended consequence somewhere else," Devries said.
In the new study, many women saw expanding waistlines, even if they did not gain weight. Cardiologists point out that such "belly fat" may have an especially negative effect on heart health.
Why waistlines, why women?
"It's even shown that women who are thin, with big waist lines are at greater risk for heart disease," said Dr. Holly Andersen, of the Perelman Heart Institute at New York Presbyterian Hospital/Weill Cornell Medical Center in New York City.
Unlike the fat right beneath the skin that can be sucked out by liposuction, the fat around the organs in the center of the body produces hormones "that make us more likely to get diabetes, higher blood pressure, higher triglycerides," Andersen said.
The women in the study were middle aged and older, so post-menopausal hormonal shifts might have made it more difficult to keep weight off their middles, she said.
All the more reason why women might want to be careful with a soda habit, Coulter said. "The message is that women have smaller frames then men, and therefore need more calorie restriction," she said.