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Just in time for Easter, bunny research reported as evidence of broccoli’s benefits


2 Star

Broccoli May Slow or Reverse Some Atherosclerosis

Our Review Summary

rabbit with broccoliThis story takes a look at a small study investigating the positive effects of a natural compound called sulforaphane–found in cruciferous vegetables including broccoli–on cholesterol levels, inflammation and blood vessel health in rabbits.

Unfortunately, the story implies that the compound–and more specifically broccoli consumption–may be beneficial for humans for the same reasons. That’s a big, unproven leap: Basic research in 15 rabbits is a long way from the kinds of data needed to nail down the value of this compound for people.


Why This Matters

Heart disease is the leading cause of death in America, and anything that has been proven to lower the risk of atherosclerosis in people deserves coverage in national news outlets. But this level of research doesn’t meet that bar, and stories about this study could mislead people into thinking they merely need to eat more broccoli to reverse or prevent heart disease.


Does the story adequately discuss the costs of the intervention?

Not Satisfactory

The rabbits were given a supplement. Is this supplement available and if so, what does it cost? We’re not told.  

Does the story adequately quantify the benefits of the treatment/test/product/procedure?


The story provided comparative quantified specifics on the benefits of sulforaphane in the three groups of rabbits, in the form of percentage decrease in lipid levels. We’ll call that good enough for a Satisfactory rating, although ideally we’d like to see some discussion of what the results might mean for cardiovascular risk in a human. We’ll address that deficiency below under the Evidence criterion.

Does the story adequately explain/quantify the harms of the intervention?

Not Satisfactory

At first glance, it’s hard to imagine there are any dangers: Chemicals in broccoli are harmless, right? But as revealed by this very study–that sulforaphane has the capacity to significantly change blood lab levels–these chemicals can work like medication. That means they also may carry harms, too. In this case, specifically, it’s for people taking the blood thinner Coumadin (warfarin), who must be very careful when eating broccoli and other vegetables rich in Vitamin K.

Does the story seem to grasp the quality of the evidence?

Not Satisfactory

The story does a good job of describing the experiment, which was conducted on 15 rabbits, and it also offers a helpful link to the research article itself. But it makes little effort to help the reader leap the chasm between rabbits and human beings–a problem exacerbated by the headline, which invites application of the results of this small, basic study to people. The only cautionary note in the story occurs at the very end, when the author inserts a “caveat” warning readers that clinical studies in people have not yet been undertaken. It would have been more useful to warn that these findings might not have any application to humans at all. 

And although this appears to be a randomized clinical trial, the story doesn’t explain if there was blinding of the researchers who were examining the rabbits’ blood vessels. This is important because a lack of blinding could affect the results of observations. See a more detailed explanation for why this and other study details matter.

Does the story commit disease-mongering?


Given the ubiquity of heart disease in the American populace, anything that reduces atherosclerosis should be of keen interest. The danger with this piece is the hyping of early animal research, implying the findings are for readers to act upon now.

Does the story use independent sources and identify conflicts of interest?

Not Satisfactory

This story included no quotes from the researchers or outside sources–both could have provided important context and caveats about this kind of early-stage animal research, and the emerging results of this chemical, which also made recent headlines in cancer research, making us curious about why this study, now.

As for conflicts of interest, the article didn’t mention any, and because the study coauthors declare none, we will assume that to be the case.

Does the story compare the new approach with existing alternatives?

Not Satisfactory

There is no discussion of alternate strategies for minimizing either the accumulation of arterial plaques specifically or heart disease generally.

Does the story establish the availability of the treatment/test/product/procedure?

Not Satisfactory

The article offers no information on availability of the supplement, nor does it reflect on the type of intervention that might make sense to people (i.e., eat lots of cruciferous veggies, take sulforaphane supplements). The basic nature of the research likely makes all of that premature, but that then raises the question of why a media outlet would publicize research at such an early stage.

And this is an important question to ask, because it’s not hard to envision that based on this story alone, companies that make supplements (which are held to a much lower standard of efficacy compared to medication classified as drugs) could start marketing this supplement, and use this single study and news story to back up its usefulness.

Does the story establish the true novelty of the approach?


The text asserts that this study of sulforaphane’s effects on atherosclerosis is the first to examine that link.

Does the story appear to rely solely or largely on a news release?

Not Applicable

We could not locate a news release related to this research article, although it seems implausible that WSJ reporters are scouring obscure research journals such as this one for story ideas. But while we have no evidence that the story relied excessively on any news release, we’re hesitant to give credit because there’s no evidence of original reporting. We’ll rate this Not Applicable.


Total Score: 3 of 9 Satisfactory


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