Researchers have found that a high-fructose diet raises blood pressure in men, and although the study shows that a drug used to treat gout seems to protect against the blood pressure increase, there are alternative methods for treating gout with no side effects. The researchers note that the drug used in the study can have rare but serious side effects.

Patients with high blood pressure, diabetes and kidney disease often have high uric acid levels and gout. The raise in blood pressure was most likely halted by the lowering of uric acid levels, which affects blood pressure.

"This is the first evidence of a role of fructose in raising blood pressure and a role for lowering uric acid to protect against that blood pressure increase in people," said Richard Johnson, co-author of the study.

Fructose, one of several dietary sugars, makes up about half of all the sugar molecules in table sugar and in high-fructose corn syrup, a sweetener often used in packaged products because it's relatively cheap and has a long shelf life. Glucose makes up the other half. Fructose is the only common sugar known to increase uric acid levels.

Fruit, which has just 4 g to 10 g of fructose per serving, also contains many beneficial substances including antioxidants, vitamin C, potassium and fiber that are believed to counter the effects of fructose alone. The main risk for excessive fructose consumption in the Western diet comes from sweetened drinks and foods rich in sugar or high fructose corn syrup.

The researchers evaluated 74 adult men, average age 51, who consumed a diet that included 200 grams (g) of fructose per day in addition to their regular diet. The amount is much higher than the estimated U.S. daily intake of 50 g to 70 g of fructose consumed by most U.S. adults. Half of the men were randomly assigned to get the gout drug allopurinol and the other half acted as controls.

After only two weeks on the diet, the high-fructose plus placebo group experienced significant average blood pressure increases of about 6 millimeters of mercury (mm Hg) in systolic blood pressure (the pressure when the heart beats) and about a 3 mm Hg rise in diastolic blood pressure (the pressure between heartbeats). They were measured with strap-on monitors that record blood pressure periodically around the clock.

In contrast, men on the high-fructose diet plus allopurinol had significantly lower uric acid levels and virtually no increase in systolic blood pressure (only 1 mm Hg). The blood pressure levels of most of the men returned to normal within two months of the study's conclusion when the participants returned to their normal dietary intake.

The study should be viewed as a pilot and more investigations are needed before doctors consider lowering uric acid in the clinical setting, said Johnson.
References:
1. Richard Johnson, et al. American Heart Association.