Broccoli and Its Ilk Confer Protection From Ionizing Radiation

Author:  David Lehmann
Institution:  Brandeis University
Date:  December, 2013

Those who dislike broccoli may want to reevaluate their vegetables of choice, thanks to an article published last month in the Proceedings of the National Academy of Sciences. Already known for its cancer prevention properties, DIM (3,3'-diindolylmethane), a compound found in cruciferous vegetables like broccoli, was found to protect rodents against the deadly effects associated with heavy doses of radiation.  

Though DIM’s cancer-preventing properties are well documented, it still does not explain why the researchers hypothesized it might protect animals against the effects of ionizing radiation, a kind of high-energy radiation known to cause extensive biological damage by altering chemical bonds. Eliot Rosen, one of the paper’s lead authors, notes that DIM’s oncologically preemptive role results from its mitigation of oxidative stress. This led him and his colleagues to test “whether [DIM] protects cultured cells against ionizing radiation (because the damage from radiation is due mostly to oxidative radicals). When [they] found DIM to be a strong radioprotector of cultured cells, [they] decided to test if it can protect animals. [sic ]”  

Based on this hypothesis, a group of rats were exposed to lethal, ionizing radiation. Those that were intraperitoneally injected with DIM every day for two weeks afterward had a better chance of surviving than those that were not. That is, rat survival correlated positively with increasing doses of DIM:  while all untreated rats died, 60% of those receiving a maximum dose of 75 mg/kg of DIM survived for at least 30 days. To put that in perspective, half a cup of broccoli contains roughly 27 mg of DIM.  

Rosen emphasizes that these results could ultimately translate into a therapeutic option for those patients undergoing radiation therapy and suffering from its side effects. This speculation is, in part, inductive thinking – if DIM protects cells against lethal radiation, it may protect them against nonlethal radiation. More importantly, Rosen also makes this prediction based on another set of experimental results that showed that DIM was ineffective in protecting cancerous breast cells from radiation treatment. As a first step toward these future uses of DIM, Rosen, along with co-authors Saijun Fan, PhD, and Milton Brown, MD, PhD, has filed a patent through Georgetown University.  

Getting the anti-broccoli camp to consume the vegetable may be a difficult task to achieve. However, conferring its benefits to those who need them may be within reach, regardless of one's eating habits.

This science feature article was written under the guidance of JYI Science Writing Mentor Robert Aboukhalil.