Consuming foods and beverages with added sugar is associated with an increased risk of death from heart disease, according to a new study led by researchers at the Centers for Disease Control and Prevention (CDC).
The risk remained significant even after the results were adjusted for other heart-disease-related risk factors such as blood pressure and cholesterol — a finding that suggests, say the researchers, that sugar harms the heart through “additional biological pathways” not yet identified.
The study also found that the risk remained after adjusting for body weight and obesity. People of normal weight in the study who consumed a lot of added sugar were also at increased risk of dying from heart disease.
“Too much sugar does not just make us fat; it can also make us sick,” writes Laura Schmidt, a health policy specialist at the University of California, San Francisco, in a commentary that accompanied the publication of the study Monday.
More than two decades of data
For the study, the researchers analyzed dietary data collected from more than 31,000 adults between 1988 and 2010 as part of the CDC’s ongoing National Health and Nutrition Examination Survey (NHANES).
Added sugar was defined in the study as “all sugars used in processed or prepared foods, such as sugar-sweetened beverages, grain-based desserts, fruit drinks, dairy desserts, candy, ready-to-eat cereals, and yeast breads, but not naturally occurring sugar, such as in fruits and fruit juices.”
The data revealed that American adults consumed, on average, 15.7 percent of their daily calories from added sugar during the years 1988 to 1994. That figure rose to 16.8 percent during the years 1999 to 2004 before retreating to 14.9 percent in 2005 to 2010.
Although we are consuming less of it than we did during the “peak” years of 1999-2004, added sugar remains a significant component of the American diet. The study found that 71.4 percent of adults consumed 10 percent or more of their calories from added sugar during the years 2005 to 2010.
And here’s a truly stunning finding: About 10 percent of American adults consumed 25 percent or more of their calories from added sugar during that period.
Link to heart disease
The researchers then looked more closely at 11,733 people whose diets had been tracked by NHANES for a median of about 15 years between 1988 and 2006. From death records, they found that 833 of those study participants had died of cardiovascular disease, such as a heart attack or stroke.
The study participants were then divided into five groups based on their sugar consumption. Those in the lowest group reported receiving less than 9.6 percent of their daily calories from added sugar, while those in the highest group reported receiving more than 21.3 percent of their daily calories from added sugar.
The researchers compared the cardiovascular death rate for all the groups. They found that people in the highest sugar-consumption group were twice as likely to die from cardiovascular disease during the 15-year period of the study than people in the lowest group.
They also found that the risk increased exponentially: The more added sugar consumed, the greater the association with dying from a heart attack or stroke.
Furthermore, the risk remained significant even after adjusting for such factors as age, gender, education, level of physical activity, smoking and drinking history, body mass index and overall quality of diet.
A need to limit sugar consumption
This study was an observational study, which means it can only draw inferences about the causal link between diets high in added sugar and an increased risk of death from cardiovascular disease. It cannot prove that the sugar caused the deaths.
Still, the authors believe that their findings add to the growing body of research that points to added sugar as a major public health concern.
“Our results support current recommendations to limit the intake of calories from added sugars in U.S. diets,” the authors conclude.
But, as they point out, the U.S. government currently offers no dietary limits for consuming added sugar.
Several nongovernmental groups have attempted to fill the gap by making their own recommendations for added sugar consumption, but those recommendations are far from consistent. According to the Institute of Medicine, for example, we should consume no more than 25 percent of our total calories from added sugar, while the World Health Organization recommends less than 10 percent. The American Heart Association, on the other hand, words its recommendation in terms of calories, not percentages: Added sugars should be limited to less than 100 calories per day for women and to less than 150 calories per day for men. That’s about 5 percent (for women) and 7.5 percent (for men) of a 2,000-calorie daily diet.
To put those numbers in perspective: A single can of soda contains, on average, 140 calories.
Start with sodas
“Public health advocates have long called for a national dietary limit and for the removal of sugar from the US Food and Drug Administration’s ‘generally regarded as safe’ list, which allows manufacturers to add unlimited amounts to any food,” writes Schmidt.
Those unlimited amounts are now found in all sorts of food products, from yogurt to ketchup to pasta sauces. Most consumers are unaware of sugar’s ubiquitous presence on grocery shelves. And because of that, many health officials think the problem cannot be addressed simply by telling people to consume less sugar.
But a good place to start, say many health officials, would be with raising taxes on sugar-sweetened beverages.
The current study “supports the logic for singling out [sugar-sweetened beverages] for taxation,” says Schmidt. “Sugar-sweetened beverages are by far the single largest source of added sugar in the American diet, accounting for 37.1% of all that is consumed nationally. Their prospective analysis further documents that even relatively modest consumption of [sugar-sweetened beverages] — drinking one 12-ounce soda a day — increases the risk of [cardiovascular] mortality by almost one-third, independent of total calories and other cofactors. Their study thus underscores the appropriateness of evidence based sugar regulations, specifically, [sugar-sweetened beverages] taxation.”