Added Sugar May Be Linked to Hypertension Risk
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Reviewed By Louise Chang, MD
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July 1, 2010 -- Foods and beverages with high amounts of fructose from added sugar may increase your risk of developing high blood pressure, according to a new study in the Journal of the American Society of Nephrology. High blood pressure is a major risk factor for heart attack and stroke.
A type of sugar, fructose is a key ingredient in table sugar and high-fructose corn syrup. Added sugars are found in processed foods such as candy, cookies, and cakes, as well as soda.
For the study, data on 4,528 U.S. adults were collected from the National Health and Nutrition Examination Survey in 2003-2006. Fructose intake was calculated based on self-reported diet information. Those participants who reported eating or drinking 74 grams of fructose or more per day (which the study equates to 2.5 sugary soft drinks per day) had a higher risk of high blood pressure than their counterparts who got less fructose. The findings took into account factors such as age, smoking history, physical activity level, and salt and alcohol intake.
However, the study doesn't prove that fructose was the cause for the rise in risk.
A link between added sugars and blood pressure is controversial. There are several theories about how fructose affects blood pressure levels, but none is firmly established. For example, high-fructose corn syrup may raise uric acid levels, which have been linked to high blood pressure.
"Limiting fructose intake is readily feasible, and in light of our results, prospective studies are needed to assess whether decreased intake of fructose from added sugars will reduce the incidence of hypertension and the burden of cardiovascular disease in the U.S. adult population," conclude researchers who were led by Diana I. Jalal, MD, of the University of Colorado Denver Health Sciences Center in Denver.
Study Flawed, Critics Say
Not so fast, according to The Corn Refiners Association, a national trade group based in Washington, D.C., and others.
The Corn Refiners Association takes issues with the findings and the methodology used in the new study. "The authors failed to learn the true composition of sweeteners used in caloric soft drinks," according to a statement released by the group. "Caloric soft drinks are not sweetened with 100% fructose. The sweeteners they contain are comprised of almost equal portions of the two simple sugars fructose and glucose, because they are sweetened with either sucrose (table sugar) or high fructose corn syrup (corn sugar)."
As a result, "the authors miscalculated the number of beverages represented by 74+ grams of fructose/day," the trade group states. "This actually represents four 12-oz sodas (not 2.5), an amount consumed by only the top 5% of consumers [in the study]. "Thus, the risk of hypertension from fructose is not a matter of concern for the overwhelming majority of Americans."
Another weakness of the study is that it relied on asking participants to recall what they ate and drank in the past.
Maureen Storey, PhD, senior vice president of science policy for the American Beverage Association, a trade group in Washington, D.C., also has concerns about the findings. The new study "furthers the confusion and misunderstandings about high fructose corn syrup and sugar-sweetened beverages," she says in a written statement. "This study fails to show a link between soft drinks and other sugar-sweetened beverages and high blood pressure."
George Bakris, MD, president of the American Society of Hypertension and a professor of medicine and the director of the Hypertension Center at the University of Chicago, says fructose should not be singled out in terms of its role in raising blood pressure.
"It is not the fructose itself, it is all sugars that are deleterious," he tells WebMD. "Sugar is the bad guy and lack of exercise is the bad guy when it comes to causing obesity and hypertension. It is not any one thing. Don't gain weight and your blood pressure won't go up."
SOURCES: Jalal, D. Journal of the American Society of Nephrology, published online July 1, 2010.
News release, American Beverage Association.
News release, Corn Refiners Association.
George Bakris, MD, president, American Society of Hypertension; professor of medicine and director, Hypertension Center, University of Chicago.
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