October 28, 2005
Cruciferous Vegetables Lower Cancer Risk Only For Some With Inactive Genes

Eating cruciferous vegetables only helps lower the risk of cancer if you have inactive forms of glutathione-S-transferase enzymes.

Paul Brennan of the International Agency for Cancer Research and other scientists have just completed a lung-cancer study that appears to back up this theory. In particular, the team studied the diets and genes of more than 4,000 people in Eastern and Central Europe.

According to the results published today in the journal The Lancet, the researchers found that people with an inactive form of the GSTM1 gene were 33-per-cent less likely to get lung cancer if they ate cruciferous vegetables on a weekly basis.

Furthermore, "in people who had an inactive GSTT1, there was a 37-per-cent protective effect, while those with both genes inactivated had a 72-per-cent protective effect."

They found no protective effect in people with active forms of the genes.

Think about that last sentence. If you could get tested and discovered that you have active forms of both genes then you'd have no health reason to eat Brussels sprouts and broccoli. That strikes me as something I'd really like to know.

On the other hand, this result might also provide support for the idea of developing drugs to deactivate the glutathione-S-transferase enzymes so that isothiocyanates will hang around the body for longer periods of time. Or maybe high dose isothiocyanate pills could overwhelm the enzymes that break them down so that the isothiocyanates can still provide protection.

Over 4000 people were used in the study.

For this study, the researchers looked at 2,141 people with lung cancer, comparing them with 2,168 healthy individuals in the Czech Republic, Hungary, Poland, Slovakia, Romania and Russia, where consumption of these vegetables has traditionally been high.

Participants filled out a food questionnaire, and also gave a blood sample so researchers could detect GSTM1 and GSTT1.

The questionnaire listed 23 foods, including three cruciferous vegetables: cabbage and a combination of Brussels sprouts with broccoli.

In non-smokers with active genes there might still be a low protective effect.

When the results were stratified by smoking status, a protective effect was seen in smokers with both genes inactive (OR 0.31; 95% CI 0.12-0.82) but not in people with both genes active. In non-smokers, there seemed to be a protective effect regardless of genotype, however the results did not reach statistical significance.

Share |      Randall Parker, 2005 October 28 02:00 PM  Aging Diet Cancer Studies

toot said at October 28, 2005 10:30 PM:

The study sounds like an awful lot of effort to just avoid eating your broccoli. I'll bet George H. W. Bush was behind it.

Nancy Lebovitz said at October 29, 2005 5:39 AM:

The next question might be whether there's a corelation between liking/not liking cruciferous veggies and whether they're good for you.

Engineer-Poet said at October 29, 2005 7:18 AM:

You can probably dig this up yourself; look for "supertasters" (the characteristic which makes the bitter compound in brocolli etc. taste so much worse to some people than others) and see if it's the same gene or on the same chromosome.

RonG said at October 29, 2005 2:42 PM:

So, what are the odds that any one person has both inactive?

Marvin said at October 30, 2005 6:25 AM:

This Lancet study is what is considered a "throwaway" study. The protocol is so sloppy that nothing is really shown.
Such studies are only meant to suggest better designed (more expensive) studies to test the hypothesis.
This is the problem with media reporting of junk studies. The average person takes what is junk to a researcher as the true gospel. No wonder so many people are so flaky when it comes to medical findings. If you have any memory at all you know that research results are all over the map. That's the way science progresses, by trial and error and then refining the process a bit.

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