To add to this, the study also demonstrates that blood-vessel function is also enhanced, at least in boys, by the change in diet.

The findings are apparently based on a study of 1062 healthy 11-year-old children who were either put on a low saturated fat diet or an unrestricted diet starting in infancy.

Almost 200 children in each diet group had the elasticity of the interior walls (or endothelium) of their veins and arteries measured by using ultrasound to look at dilation of the blood vessels under various circumstances.

Dr. Olli T. Raitakari, from the University of Turku in Finland, and colleagues say that the low-fat diet was associated with better endothelial function in boys and girls, but this was more significant from a statistical standpoint in the boys.

Raitakari says this could mean that early nutrition may play an important role in the later vascular health of males, and may also be associated with less atherosclerosis and a lower future risk of cardiovascular diseases.

Raitakari also says that it is possible that such a significant association was not seen in girls because of differences in sex hormone levels.

The findings are published in the American Heart Association's journal Circulation.

UF researchers are now studying the uric acid pathway in cell cultures in the laboratory, in animals and in people, and are also eyeing it as a possible factor in the development of cardiovascular and kidney diseases because of its effects on blood vessel responses. They are conducting a National Institutes of Health-funded trial to determine if lowering uric acid in blacks with hypertension improves blood pressure control and are collaborating with scientists at Baylor to determine if lowering uric acid will reduce blood pressure in adolescents with hypertension.

"We cannot definitively state that fructose is driving the obesity epidemic," said Johnson. "But we can say that there is evidence supporting the possibility that it could have a contributory role - if not a major role. I think in the next few years we'll have a better feel for whether or not these pathways that can be shown in animals may be relevant to the human condition."

Findings to date suggest certain sugar carbohydrates are actually better than others, he added, because some do not activate the uric acid pathway.

"It may well be we don't need to cut out carbohydrates but just certain types of carbohydrates," Johnson said. "So this may be an alternative to the Atkins type of approach, which cuts out carbohydrates indiscriminately."

As scientists learn more about the pathway, Johnson said, and as studies are completed in people, the findings may influence how to make wise choices about the foods we eat.

"With the caveat that people are different from rodents in many ways, the link between urate levels, blood pressure elevation and insulin resistance demonstrated in rats fed fructose is extremely provocative," said Brian F. Mandell, M.D., Ph.D., vice chairman of medicine for education and a professor of medicine at the Cleveland Clinic Lerner College of Medicine of Case Western Reserve University. "Whether the fructose supplementation to the diet in the United States is partially responsible for the 'epidemic' of obesity remains to be proven - but this is an association which can be tested, and the work of Dr. Johnson and his collaborators makes the evaluation of the fructose-metabolic link in people an academic and public health imperative."

ufl/