Fructose Consumption Increases Risk Factors for Heart Disease

Study suggests U.S. Dietary Guideline for Upper Limit of Sugar Consumption is too High:

A recent study accepted for publication in The Endocrine Society’s Journal of Clinical Endocrinology & Metabolism (JCEM) found that adults who consumed high fructose corn syrup for two weeks as 25 percent of their daily calorie requirement had increased blood levels of cholesterol and triglycerides, which have been shown to be indicators of increased risk for heart disease.

The American Heart Association recommends that people consume only five percent of calories as added sugar. The Dietary Guidelines for Americans 2010 suggest an upper limit of 25 percent or less of daily calories consumed as added sugar. To address this discrepancy in recommended consumption levels, researchers examined what happened when young overweight and normal weight adults consumed fructose, high fructose corn syrup or glucose at the 25 percent upper limit.

“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, PhD, of the University of California, Davis. “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.”

In this study, researchers examined 48 adults between the ages of 18 and 40 years and compared the effects of consuming 25 percent of one’s daily calorie requirement as glucose, fructose or high fructose corn syrup on risk factors for cardiovascular disease. They found that within two weeks, study participants consuming fructose or high fructose corn syrup, but not glucose, exhibited increased concentrations of LDL cholesterol, triglycerides and apolipoprotein-B (a protein which can lead to plaques that cause vascular disease).

“These results suggest that consumption of sugar may promote heart disease,” said Stanhope. “Additionally 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.”

Also working on the study were: Andrew Bremer, Guoxia Chen, Tak Hou Fong, Vivien Lee, Roseanne Menorca, Valentia Medici, Peter Havel and Nancy Keim of the University of California, Davis; Katsuyuki Nakajima and Takamitsu Nakano of Otsuka Pharmaceutical Co. in Tokyo, Japan; and Yasuki Ito of Denka Seiken Co. in Tokyo, Japan.

The article, “Consumption of fructose and high fructose corn syrup increase postprandial triglycerides, LDL-cholesterol, and apolipoprotein-B in young men and women,” appears in the October 2011 issue of JCEM.

 

Too Much Sugar Is Bad, But Which Sugar Is Worse: Fructose Or Glucose?

In 2005, the average American consumed 64 kg of added sugar, a sizeable proportion of which came through drinking soft drinks. Now, in a 10-week study, Peter Havel and colleagues, at the University of California at Davis, Davis, have provided evidence that human consumption of fructose-sweetened but not glucose-sweetened beverages can adversely affect both sensitivity to the hormone insulin and how the body handles fats, creating medical conditions that increase susceptibility to heart attack and stroke.

In the study, overweight and obese individuals consumed glucose- or fructose-sweetened beverages that provided 25% of their energy requirements for 10 weeks. During this period, individuals in both groups put on about the same amount of weight, but only those consuming fructose-sweetened beverages exhibited an increase in intraabdominal fat. Further, only these individuals became less sensitive to the hormone insulin (which controls glucose levels in the blood) and showed signs of dyslipidemia (increased levels of fat-soluble molecules known as lipids in the blood). As discussed in an accompanying commentary by Susanna Hofmann and Matthias Tschöp, although these are signs of the metabolic syndrome, which increases an individual’s risk of heart attack, the long-term affects of fructose over-consumption on susceptibility to heart attack remain unknown.

 

Stanhope KL, Schwarz JM, Keim NL, Griffen SC, Bremer AA, Graham JL, et al. Consuming fructose-sweetened, not glucose-sweetened, beverages increases visceral adiposity and lipids and decreases insulin sensitivity in overweight/obese humans. J Clin Invest. 2009;119 (5): 1322-34.

Comment:
Hofmann SM, Tschöp MH. Dietary sugars: a fat difference. J Clin Invest. 2009;119 (5): 1089-92.