“Sugar-sweetened beverages are clearly associated with weight gain, as well as with heart disease and type 2 diabetes,” says Vasanti Malik, research scientist at the Harvard School of Public Health. “It’s amazing that the results are so consistent across cohorts, not just here in the United States but in Europe and elsewhere,” adds Malik.
She’s talking about evidence from studies that ask a “cohort”—like the 120,000+ women in the Nurses’ Health Study—what they typically eat or drink and then wait for years to see who gets which disease.
And it’s not just that sugar drinks raise the risk of heart disease and diabetes because they make people heavier.
People who consume more foods with added sugar have a higher risk of dying of heart attacks, strokes, and other cardiovascular events, regardless of their weight. Other studies have found similar links with drinking sugary beverages.
“If you put that evidence together with studies showing that sugars raise the risk factors for cardiovascular disease, it’s very strong evidence,” says Kimber Stanhope, associate researcher at the University of California, Davis.
In her 2015 study, Stanhope gave young healthy adults 0%, 10%, 17.5%, or 25% of their daily calorie requirements in a drink sweetened with high-fructose corn syrup. (On average, adults aged 20 to 60 get 13 percent of their calories from HFCS, table sugar, and other added sugars, but some get far more.)
“We saw an increase in LDL cholesterol and triglycerides after just two weeks,” says Stanhope. “And we saw a dose-response effect.” In other words, the more sugar the participants drank, the higher their LDL (“bad”) cholesterol and triglycerides (a fat found in blood).
“That’s bad news because higher LDL cholesterol is one of the strongest, most valid measures of cardiovascular risk,” adds Stanhope.
How does sugar raise LDL cholesterol and triglycerides? It’s the fructose—which makes up roughly half of both high-fructose corn syrup and ordinary table sugar—that’s to blame. “The liver turns fructose into triglycerides and sends some of it, along with cholesterol, into the blood,” says Stanhope. And that can lead to hardening of the arteries and heart disease.
Sources: Circulation 121: 1356, 2010; 2 BMJ 2015. doi:10.1136/bmj.h3576; 3 Int. J. Obes. 37: 1378, 2013; 6 JAMA Intern. Med. 174: 516, 2014; 7 Circulation 125: 1735, 2012; Am. J. Clin. Nutr. 101: 1144, 2015.
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