According to findings published in the peer-reviewed European Journal of Clinical Nutrition, a daily dose of five or 10 grams or 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, most often touted for their potential anti-cancer activity.
Benefits of broccoli
The tissue of cruciferous vegetables, like broccoli, cauliflower, cabbage and Brussels sprouts, contain 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 sulphoraphane.
The new study employed a broccoli sprout powder that provided a dose of sulphoraphane 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 ageing, 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 cancer, 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, 2003, Vol. 17, pp. 24-38).
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 five 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 this 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 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," they concluded.
Diabetes affects an estimated 24 million Americans, equal to 8 percent of the population. The total costs are thought to be as much as $174 billion, with $116 billion being direct costs from medication, according to 2005-2007 American Diabetes Association figures.
Source: European Journal of Clinical Nutrition
Published online ahead of print, doi: 10.1038/ejcn.2011.59
“Broccoli sprouts reduce oxidative stress in type 2 diabetes: a randomized double-blind clinical trial”
Authors: Z Bahadoran, P Mirmira, et al