Another Reason to Eat Your Greens: They Might Help Purge Pollutants
From “colon cleanses” to juice rejuvenation diets, we’re bombarded by ads that claim we can remove toxins from our body with a new “detox” product or the latest fad “detox diet.” Mostly, it’s just a sales pitch without much scientific credibility.
Of course there are health benefits to boosting our intake of fruit and vegetables and cutting down on fast food and alcohol, but the nebulous toxins we are supposedly purging from our bodies are, if they are there at all, unlikely to be affected by simple things like a quick swig of a yogurt drink. Then there’s the fact that these kinds of detoxes often mean we’re severely limiting our food intake. That can have serious health implications, from low energy to even dangerous drops in blood sugar.
However, scientists writing in the science journal Cancer Prevention Research this month believe their research adds to a growing body of evidence that certain kinds of vegetables may have one important pollutant-purging ability. Previous research has shown that vegetables like broccoli-sprouts (and, to a lesser extent, broccoli), as well as Brussels sprouts, cabbages, and the newly popular kale, provide us with high concentrations of sulforaphanes. These nifty compounds are linked with a number of health benefits, and research has suggested they may have anticancer and antimicrobial properties, as well as possibly helping to manage aspects of conditions like Type 2 diabetes.
What the researchers were particularly interested in here, however, was whether regular high intake of sulforaphanes could help to remove three carcinogens from the body that people are exposed to as a result of high levels of air pollution. The pollutants included benzene, which is a chemical found in plastics and is used as a gasoline additive; acrolein, which most people are exposed to as part of smoking tobacco or being around someone who is smoking; and crotonaldehyde, which in even moderate concentrations is a dangerous substance but is most commonly used in very small doses as a preservative.
Small amounts of these substances probably don’t affect us but, in higher concentrations and over extended periods of time, say as the result of chronic air pollution, there is evidence that they can be harmful. Benzene, for instance, is linked with causing certain cancers, though proving this as a direct cause is very difficult. Regardless, there’s enough research to say we probably want to either stop these substances getting into our bodies, or we want to find ways to purge them so that they can’t cause lasting damage — and that’s where the broccoli-sprouts come in.
The researchers embarked on a randomized study of nearly 300 participants from a town in rural China that suffers from high pollution levels containing those three pollutants. The townsfolk suffer a much higher level of cardiovascular and pulmonary diseases as a result of this exposure, and so finding a cheap and effective way of offering some kind of defense is important.
About half of the sample in this study were asked to drink a half-cup of a beverage made from broccoli-sprouts, to see if this sulforaphanes-rich drink would increase the rate of excretion of the pollutants. The rest of the participants were given pineapple and lime juice. The study lasted for 12 weeks and involved the scientists periodically checking participants’ urine samples for traces of the pollutants.
What they found was that the test subjects who drank the broccoli-sprout drink excreted on average 61% more benzene and 23% more acrolein, but no increased level of crotonaldehyde. Still, two out of three isn’t bad and the researchers believe this study contains some vital findings — perhaps most importantly the fact that the participants’ bodies didn’t adapt to the increased sulfrophane intake and so the purging effect remained consistent.
“We thought the pathway might respond initially, and then the [compounds] would wear out their welcome and the body would tune out,” Thomas Kensler from Johns Hopkins is quoted as saying. ”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].”
It’s important to put this research in context. While it does build on a growing body of evidence that says that sulfrophanes can be beneficial to us, we don’t yet know whether this effect would translate across various divides. For instance the sample size, though significant, was small. We’d need to see this experiment repeated with bigger numbers of people from many different backgrounds to draw any solid conclusions as to whether sulforaphane-forming foods should be labeled a pollutant fighter.
There’s also that, while the tests subjects didn’t appear to have diminishing returns from their sulfrophane intake, we’d have to see whether sulfrophanes continue to be effective over many months and years before saying that the broccoli sprout drink definitely carries significant benefits.
If those tests do prove promising, it could be that broccoli and many of our leafy green vegetables offer us a cheap and nutritious way of fighting harmful and unwanted pollutants. In the meantime, there are plenty of reasons to be eating your greens, so why not get to it?
Photo credit: Thinkstock.