Sugary Drinks, but Not Foods, Linked to Increased Mortality

Nancy A Melville

April 11, 2018

Consumption of drinks with a high sugar content, including soft drinks and fruit juices, is associated with an increased risk for all-cause mortality and mortality from coronary heart disease in middle-aged adults, particularly those who are overweight or low-income. 

"Given the strong and consistent evidence of negative health risks associated with sugary beverage intake, it's important for clinicians to ask their patients of all ages about their intake, and to counsel on reducing this intake as appropriate," senior author, Jean Welsh, PhD, MPH, an assistant professor at Emory University and research director with Children's Healthcare of Atlanta, Georgia, told | Medscape Cardiology.

The study of nearly 18,000 people aged 45 years and older in the national, longitudinal Reasons for Geographic and Racial Differences in Stroke (REGARDS) study showed that those who consumed the highest amounts of sugar-sweetened beverages and fruit juices had as much as two times the risk of dying of coronary heart disease as those consuming the lowest levels of the sugary beverages. The mortality risk was higher among those who were overweight or had low income.

Meanwhile, no association was seen between consuming the highest amounts of food with high sugar content and mortality, Welsh reported at the American Heart Association's Epidemiology and Prevention | Lifestyle and Cardiometabolic Health Scientific Sessions 2018.

Whereas the wide variety of negative health effects from sugar-sweetened beverages are well documented, including increases in obesity and the risk for cardiovascular disease (CVD), fewer studies have looked at the relationship between sugary beverages and mortality.

The new study excluded patients with a history of stroke, CVD, and type 2 diabetes at baseline; participants' added sugar consumption, in grams, was calculated from beverages and foods separately by using self-administered Block 98 food-frequency questionnaires.

Over the mean follow-up period of 6.9 years, there were a total of 1465 all-cause deaths and 279 coronary heart disease deaths among the 17,930 participants.

In dividing the participants into quartiles of the lowest and highest consumers of sugary beverages, including soft drinks, fruit and fruit-flavored drinks, and fruit juices, the authors found that the risk for coronary heart disease was significantly higher in the top quartile, representing a mean of 20 ounces (standard deviation [SD], 7.8; hazard ratio [HR], 2.0; 95% CI, 1.12 - 3.54) than in the lowest category of consumption, a mean of 0.8 ounces (SD, 0.6). The risk for all-cause death was also higher in the top quartile (HR, 1.2; 95% CI, 0.99 - 1.52).

The increased risk for CVD and all-cause mortality with the highest consumption was seen after controlling for factors such as age, body mass index, sex, income, region, smoking, alcohol consumption, and physical activity.

The highest quartile for consumption of sweet foods only (20.4 ounces; SD, 11.3), consisting of desserts, candy, and sweetened breakfast foods and foods with caloric sweeteners added, did not show statistically higher mortality rates compared with the lowest quartile (12.3 ounces; SD, 8.9).

No significant differences were seen in terms of sex or race; however, the increased mortality associated with each additional 12 ounces of sugary beverages consumed was significantly higher for low-income vs high-income participants for all-cause but not coronary heart disease deaths (under vs over $74,000 annual salary: HR, 0.69; 95% CI, 0.50 - 0.96; P = .005).

Those who were overweight (body mass index, 25.0 - 29.9) also had higher all-cause mortality associated with the higher sugary drink consumption (HR, 1.12; 95% CI, 1.02 - 1.22; P = .04), but the coronary heart disease mortality rates were not significantly different (HR, 1.20; 95% CI, 0.98 - 1.46; P = .3).

Various hypotheses could explain the higher mortality rates associated with sugary drinks compared with foods, Welsh said.

"There is less compensation for calories consumed in beverages (compared to food), meaning that when calories are consumed in beverages, people tend not to consume less foods and they end up overconsuming as a result," she explained.

In addition, metabolism of sugary foods occurs more slowly than that of beverages because of other ingredients, such as fiber, fat, and protein, and in general, the nutrient content in foods had much more variation than with sugary drinks in the study.

"Much more research is needed to understand the role of the many different types of sugar-sweetened foods and how they impact morbidity and mortality risk," Welsh said.

Metabolism may come into play in explaining the higher risk in overweight or obese people, Welsh said.

"It may have to do with how we store the energy and whether it is being burned right away," she explained.

"It kind of makes sense that if we're burning what we eat more quickly, it may not have as much of an effect."

Previous research on the issue includes a population-based study of data from the National Health and Nutrition Examination Survey (NHANES), which showed as much as a 38% higher risk for CVD mortality in people who consumed 17% to 21% of calories from added sugar compared with those who consumed approximately 8% of calories from added sugar.

Another study published in 2015 linked the consumption of sugar-sweetened beverages with an estimated 184,000 adult deaths per year, including more than 25,000 Americans.

The new research adds to the evidence of the potentially ill effects of excessive sugar consumption, said Alice H. Lichtenstein, DSc, the Gershoff Professor of Nutrition Science and Policy and director and senior scientist of the Cardiovascular Nutrition Laboratory at Tufts University, Boston, Massachusetts.

"These data further strengthen the base on which we recommend people minimize their intake of these beverages," she told | Medscape Cardiology.

It is "notable that high-sugar beverages included fruit juice (in the study), which is an important point that is sometimes overlooked," Lichtenstein added.

Rachel K Johnson, PhD, RD, a professor of nutrition at the University of Vermont, Burlington, underscored the impact of sugary beverages in the diet.

"Sugary drinks are liquid sugar…and are the number one source of added sugars in the American diet, accounting for 47% of all the added sugars consumed," she told | Medscape Cardiology.  

"We have solid consensus on the negative effects of sugary drinks," Johnson said. "Some studies have shown that intakes of all added sugars are harmful. However, these studies did not separate the impact of sugary drinks vs foods containing added sugars."

Limitations of the study include are that the findings don't prove cause and effect and self-reported dietary intakes are often underreported.

"However, underreporting of these foods and drinks would actually attenuate the effects shown in this study," Johnson noted.

The authors, Lichtenstein, and Johnson had no disclosures to report.

American Heart Association's Epidemiology and Prevention | Lifestyle and Cardiometabolic Health Scientific Sessions 2018. Abstract 051 (P222). Presented March 21, 2018.

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