Powdered broccoli sprouts may boost antioxidant defenses in people with diabetes, suggest findings from a randomized clinical trial in Iran.
According to findings published in the peer-reviewed European Journal of Clinical Nutrition, a daily dose of five or 10 grams of the broccoli sprout powder was associated with an increase in the total antioxidant capacity of the blood, and reductions in malondialdehyde (MDA), a reactive carbonyl compound and a well-established marker of oxidative stress.
The study adds to the growing body of science supporting the potential health benefits of broccoli and broccoli sprouts.
The tissue of cruciferous vegetables, like broccoli, cauliflower, cabbage and Brussels sprouts, contains high levels of the active plant chemicals glucosinolates. These are metabolized by the body into isothiocyanates, which are known to be antioxidants and powerful anti-carcinogens. The main isothiocyanate from broccoli is sulforaphane.
The new study employed a broccoli sprout powder that provided a dose of sulforaphane isothiocyanates of 22.5 micromoles per gram, and looked at the potential antioxidant activity of broccoli sprout powder to counter oxidative stress in diabetics.
Oxygen-breathing organisms naturally produce reactive oxygen species (ROS), which play an important role in a range of functions, including cell signaling. However, over-production of these ROS from smoking, pollution, sunlight, high intensity exercise, or simply aging, may overwhelm the body’s antioxidant defenses and lead to oxidative stress.
Oxidative stress has been linked to an increased risk of various diseases including Alzheimer’s and cardiovascular disease. Researchers also note that oxidative stress is a key driver in the onset of insulin resistance, which ultimately leads to diabetes. Diabetes itself is associated with increased levels of oxidative stress, and this can promote the development of diabetes-related complications (Journal of Biochemical and Molecular Toxicology 17:24-38, 2011).
Researchers from the National Nutrition and Food Technology Research Institute at the Shahid Beheshti University of Medical Sciences in Tehran, Iran, recruited 81 diabetics to participate in their double-blind, placebo-controlled, randomized clinical trial. Participants were randomly assigned to receive either 5 or 10 grams per day of the broccoli sprout powder, or placebo, for four weeks.
Results showed that both broccoli groups experienced significant decreases in MDA, that well-established marker of oxidative stress, as well as reductions in levels of oxidized LDL cholesterol, another oxidative stress marker.
"The ideal dose of broccoli sprouts has not yet been determined," wrote the scientists. "The doses used in the study provided 225 micromoles and 112 micromoles sulforaphane isothiocyanates daily per 10 g and 5 g broccoli sprout powder doses, respectively.
"Effects on lipid peroxidation parameters were seen only with the higher dose, although positive effects on TAC [total antioxidant capacity] were seen with both doses," they added.
"Further studies with longer duration and different doses are needed to confirm the effects of broccoli sprouts and related mechanisms," the concluded.
European Journal of Clinical Nutrition; Published online ahead of print.