Eating Broccoli May Give Harmful Chemicals The Boot

Jun 23, 2014

By Eliza Barclay

We get a little suspicious when we hear the claims that it’s possible to get rid of the gunk that accumulates in our cells by doing a cleanse with “clean” foods.

But what if some foods actually do help detox the body?

The results of a recent clinical trial suggest that compounds in cruciferous vegetables like broccoli (and kale) prod cells to get rid of certain air pollutants. The intriguing randomized control trial of about 300 Chinese adults found that consuming a beverage made with broccoli sprouts every day for three months led to high rates of excretion (in urine) of two harmful chemicals: benzene and acrolein.

Now, benzene and acrolein are pretty common. If you’re pumping gas at a gas station, you’ll breathe in a little benzene, and if you’re smoking or around smokers, you’ll take in acrolein (and some benzene, too). If you live in a place with heavy pollution, you may get a big enough dose of benzene to make you sick — though that can be tough to prove.

Lately, scientists have been zeroing in on a compound called glucoraphanin that seems to have a protective effect against these and other toxins.

Animal model studies have shown that when vegetables containing glucoraphanin are chewed or swallowed, another compound called sulforaphane appears on the scene and kicks enzymes into action to take up pollutants and clear them from the body in urine. In other words, sulforaphane seems to act like fuel for the body’s own trash collection and disposal services.

 published online in early June in the journal Cancer Prevention Research, set out to figure out whether drinking a half-cup of a beverage containing broccoli sprouts would increase the rate of excretion of benzene and acrolein. (The researchers say they chose these chemicals because they were among the most stable molecules among pollutants to track.)

About half of the 291 Chinese adults in a rural farming community in Jiangsu province — a community with very high levels of air pollution — who participated in the study were given the broccoli sprout drink every day for 12 weeks, while the other half got pineapple and lime juice.

The researchers, who hail from Johns Hopkins University and several other institutions in the U.S. and China, found that among the people consuming the broccoli sprout beverage, the rate of excretion of benzene increased 61 percent throughout the 12-week period. As for the acrolein, the excretion rate went up 23 percent during the trial.

“We thought the pathway might respond initially, and then the [compounds] would wear out their welcome and the body would tune out,” Thomas Kensler, a researcher at both Johns Hopkins and the University of Pittsburgh School of Medicine and an author of the study, tells The Salt. “But the effect was just as vigorous at the beginning as at the end, which suggests that over one’s lifetime, you could enhance this preventative activity in the body [with food].”

4 comments on “Eating Broccoli May Give Harmful Chemicals The Boot

  • I have known for years that broccoli was a good vegetable to include in a healthy diet, but it is the first time I have come across it in the form of sprouted seedlings. It is much more commonly eaten in the various forms of its flower-heads.
    I wonder if there is any difference in the nutrition of the sprouted seedlings compared to the more conventionally consumed flower spikes.



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  • As an idiot smoker, I guess I’d better get started but why’d it have to be broccoli? All a part of my personal curse I suppose. I should have known the only subject on which Dubbie Bush and I ever agreed just had to be wrong.



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  • I came late to broccoli (hated it as a child, love it as an adult). In addition to glucoraphanin, broccoli is also a good source of indole-3-carbinol, which can also be found in other cruciferous vegetables. Indole-3-carbinol can alter estrogen metabolism and therefore theoretically favorably affect certain cancers as well as auto immune disorders such as lupus. Research is currently being done on this attribute of I-3-C.

    Nutrition has long been ignored by conventional western medicine for any benefits outside of those derived from a “balanced diet”. Hopefully there will be a gradual shift back towards optimally utilizing the wide array of nutritive constituents found in the foods we eat.



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