The American Heart Association (AHA) recommends that people consume no more than five percent of their daily calories from added sugars, far lower than current consumption levels. However, according to the latest Dietary Guidelines for Americans advice, published by the US Department of Agriculture in January this year, 35 percent of the average American’s calorie consumption takes the form of added sugars.
With this in mind, the Dietary Guidelines recommend that a maximum of 25 percent of caloric intake should come from added sugars.
This latest research, published in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism, attempted to address the discrepancy between the AHA recommendation and the USDA recommendation by examining whether the 25 percent level could have a harmful effect on heart health.
"While there is evidence that people who consume sugar are more likely to have heart disease or diabetes, it is controversial as to whether high sugar diets may actually promote these diseases, and dietary guidelines are conflicting," said the study's senior author, Kimber Stanhope, of the University of California, Davis.
The researchers found that consumption of three beverages sweetened with high fructose corn syrup per day over a two-week period, as part of an energy-balanced diet, increased risk factors for heart disease, including blood levels of cholesterol and triglycerides.
"Our findings demonstrate that several factors associated with an elevated risk for cardiovascular disease were increased in individuals consuming 25 percent of their calories as fructose or high fructose corn syrup, but consumption of glucose did not have this effect," Stanhope said.
The researchers gave 48 adult participants 3.5 days of baseline inpatient testing while consuming energy balanced diets containing 55 percent complex carbohydrate. They then left the research center and ate their usual diets, as well as three servings a day of either glucose, fructose or high fructose corn syrup-sweetened beverages providing 25 percent of their caloric requirements, with 16 participants assigned to each group.
Subjects then consumed energy-balanced diets with 25 percent of calories coming from sugar-sweetened beverages and 30 percent from complex carbohydrate during another 3.5 days of inpatient intervention testing.
Stanhope added: "Our findings provide evidence that the upper limit of 25 percent of daily calories consumed as added sugar as suggested by The Dietary Guidelines for American 2010 may need to be re-evaluated."
Source: Journal of Clinical Endocrinology & Metabolism
“Consumption of fructose and high fructose corn syrup increase postprandial 1 triglycerides, LDL2 cholesterol, and apolipoprotein-B in young men and women”
Authors: Kimber L. Stanhope; Andrew A. Bremer; Valentina Medici; Katsuyuki Nakajima; Yasuki Ito; Takamitsu Nakano; Guoxia Chen; Tak Hou Fong; Vivien Lee; Roseanne I. Menorca; Nancy L. Keim; Peter J. Havel