By Todd Neale, Staff Writer, MedPage Today
Published: July 01, 2010
Reviewed by Dori F. Zaleznik, MD; Associate Clinical Professor of Medicine, Harvard Medical School, Boston and Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planner
People who consume the amount of fructose found in two-and-a-half regular soft drinks a day appear to have a higher risk of hypertension, a cross-sectional study showed.
Consumption of at least 74 grams per day was associated with 26% to 77% greater odds of crossing various thresholds of elevated blood pressure (P<0.05 for all), compared with lower levels of consumption, according to Diana Jalal, MD, of the University of Colorado Denver, and colleagues.
"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," they wrote online in the Journal of the American Society of Nephrology.
There has been a recent increase in the consumption of fructose in developed nations due primarily to the addition of table sugar or high fructose corn syrup to soft drinks, bakery products, fruit drinks, dairy desserts, and candies.
At the same time, the prevalence of hypertension has been rising. However, epidemiological studies have yielded conflicting results as to an association between the two trends.
To explore the issue, Jalal and her colleagues used data from 4,528 adults without a history of hypertension included in the National Health and Nutrition Examination Survey (NHANES) from 2003 to 2006.
The majority (61%) had a systolic blood pressure of less than 120 mm Hg. Another 30% were prehypertensive (systolic pressure of 120 to 139 mm Hg).
The rest of the participants had either stage 1 or stage 2 hypertension (6% and 2%, respectively).
Fructose intake was determined through a self-administered dietary questionnaire. Consumption of natural fruits was excluded to isolate intake of added sugar.
Median intake was 74 grams a day. Increasing systolic blood pressure was associated with increasing fructose intake, a trend that reached borderline statistical significance (P=0.05).
After adjustment for demographics, comorbidities, physical activity, smoking, total kilocalorie intake, and dietary confounders including total carbohydrate, alcohol, salt, potassium, and vitamin C intake, as well as other factors, fructose intake of 74 grams per day or higher was associated with higher odds of elevated blood pressure at the following thresholds (P<0.05 for all):
Additional analyses showed that fructose intake was associated with systolic -- but not diastolic -- blood pressure.
- 135/85 mm Hg: OR 1.26
- 140/90 mm Hg: OR 1.30
- 160/100 mm Hg: OR 1.77
The reason this study, and not some previous studies, found an association between fructose consumption and hypertension could be because of the high level of consumption in the current study, according to Jalal and her colleagues.
In addition, some previous studies looked only at soft drink consumption or included naturally occurring fructose from fruit in their analyses.
There are several possible mechanisms that might explain the positive association between fructose and blood pressure, the authors wrote, "including stimulation of uric acid, inhibition of [the] endothelial nitric oxide synthase system, and stimulation of the sympathetic nervous system, or by directly increasing sodium absorption in the gut."
The study was limited, they wrote, by the inability to establish a causal relationship between fructose and blood pressure using cross-sectional data, the reliance on self-reports, and the possibility of confounding by glucose in the foods assessed on the dietary questionnaire.
The study was supported by grants from the National Institutes of Health.
Jalal reported no conflicts of interest. One of her co-authors is listed as an inventor on several patent applications for lowering uric acid as it relates to blood pressure and metabolic syndrome. He is also author of The Sugar Fix.
Primary source: Journal of the American Society of Nephrology
Source reference: Jalal D, et al "Increased fructose associates with elevated blood pressure" J Am Soc Nephrol 2010; DOI: 10.1681/ASN.2009111111.
Friday, July 02, 2010
Fructose Linked to High Blood Pressure
Watch not only products with HFCS, but any with sugar, as it can be GMO beet sugar, or any with aspartame, sucralose, rebiana, zevia, truvia, or purvia -