Diabetics can go ahead and sip that glass of orange juice, for despite its high caloric load of sugars, a study has found that the equally high presence of flavonoids in it make it a healthy food.
The study was conducted by a group of researchers from the University at Buffalo led by Paresh Dandona, MD, Ph.D., head of the Diabetes-Endocrinology Centre of Western New York.
Flavonoids suppress destructive oxygen free radicals, also known as reactive oxygen species, or ROS.
An overabundance of free radicals can damage all components of the cell, including proteins, fats and DNA, contributing to the development of many chronic diseases, including heart disease and stroke as well as diabetes.
As a part of the study the researchers analysed 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.
"Our previous work has shown that 300 calories of glucose induces ROS and other proinflammatory responses," said Dr Dandona, who is Distinguished Professor of Medicine in the UB School of Medicine and Biomedical Sciences.
"We hypothesised that 300 calories-worth of orange juice or of fructose would induce less oxidative stress and inflammation than caused by the same amount of calories from glucose."
"We were intrigued by the fact that there was no increase in ROS or inflammation following orange juice consumption, even though its glucose concentration was the same as in participants in the glucose group.
"This raised the question of what in the juice was responsible for suppressing ROS generation: flavonoids and vitamin C or fructose?" he added.
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 per cent and 77 per cent, respectively.
"Our data are relevant to patients with diabetes because stress from ROS and inflammation are increased significantly in this population and may contribute to development of atherosclerosis. Clearly the choice of foods that either don't increase or actually decrease oxidative and inflammatory stress is important," said Dandona.
The study appeared in the June 2007 issue of Diabetes Care.