Free radicals and other types of reactive oxygen species (ROS) will accelerate aging if present in higher than optimal concentrations. Flavonoids in orange juice quench reactive oxygen species (ROS)

BUFFALO, N.Y. -- Orange juice, despite its high caloric load of sugars, appears to be a healthy food for diabetics due to its mother lode of flavonoids, a study by endocrinologists at the University at Buffalo has shown.

But some reactive oxygen species (ROS) are needed to carry out basic metabolic functions. So would consumption of too much flavonoids make one lethargic?

Consumption of glucose sugar boosts blood ROS. That spike in ROS is probably harmful and best avoided. So one should probably prefer foods that one can eat without getting the ROS spike.

"Many major diseases are associated with oxidative stress and inflammation in the arterial wall, so the search for foods that are least likely to cause these conditions must be pursued," said Paresh Dandona, M.D., Ph.D., head of the Diabetes-Endocrinology Center of Western New York and senior author on the study.

"Our previous work has shown that 300 calories of glucose induces ROS and other proinflammatory responses," said Dandona, who is Distinguished Professor of Medicine in the UB School of Medicine and Biomedical Sciences.

Orange juice did not boost blood ROS. But plain fructose without any flavonoids didn't boost blood ROS either.

The resulting study involved 32 healthy participants between the ages of 20 and 40, who were of normal weight, with a body mass index of 20-25 kg/m2. Participants were assigned randomly and evenly into four groups, who would drink the equivalent of 300 calories-worth of glucose, fructose, orange juice or saccharin-sweetened water.

Fasting blood samples were taken before the test and at 1, 2 and 3 hours after a 10-minute period to consume the drinks.

Results showed a significant increase in ROS within 2 hours in samples from the glucose group but not in those from the fructose, orange juice or water group.

However, two flavonoids found in orange juice inhibit ROS generation.

An additional round of test on the samples showed that neither fructose nor vitamin C suppressed the oxygen free radicals. However the two types of flavonoids in orange juice -- hesperetin and naringenin -- inhibited ROS generation by 52 percent and 77 percent, respectively.

We need orange juice that contains less fructose and more flavonoids.

More generally: We need better availability of fruits that haven't been bred to be very sweet. I always look for apple varieties that taste less sweet but which have tangier taste. Red Delicious is too sweet for my taste. I try to avoid calories while getting more beneficial compounds which have no calorie content.