July 17, 2008
Gene Determines Benefit Of Eating Broccoli

Why does broccoli reduce the risk of prostate cancer and other disease? Does it deliver that risk reduction for everyone? Sulforaphane found in broccoli and other cruciferous vegetables causes a greater change in gene expression for those with a particular version of the gene GSTM1.

Epidemiological studies suggest that people who consume more than one portion of cruciferous vegetables per week are at lower risk of both the incidence of prostate cancer and of developing aggressive prostate cancer but there is little understanding of the underlying mechanisms. In this study, we quantify and interpret changes in global gene expression patterns in the human prostate gland before, during and after a 12 month broccoli-rich diet.

Methods and Findings

Volunteers were randomly assigned to either a broccoli-rich or a pea-rich diet. After six months there were no differences in gene expression between glutathione S-transferase mu 1 (GSTM1) positive and null individuals on the pea-rich diet but significant differences between GSTM1 genotypes on the broccoli-rich diet, associated with transforming growth factor beta 1 (TGFβ1) and epidermal growth factor (EGF) signalling pathways. Comparison of biopsies obtained pre and post intervention revealed more changes in gene expression occurred in individuals on a broccoli-rich diet than in those on a pea-rich diet. While there were changes in androgen signalling, regardless of diet, men on the broccoli diet had additional changes to mRNA processing, and TGFβ1, EGF and insulin signalling. We also provide evidence that sulforaphane (the isothiocyanate derived from 4-methylsuphinylbutyl glucosinolate that accumulates in broccoli) chemically interacts with TGFβ1, EGF and insulin peptides to form thioureas, and enhances TGFβ1/Smad-mediated transcription.

Conclusions

These findings suggest that consuming broccoli interacts with GSTM1 genotype to result in complex changes to signalling pathways associated with inflammation and carcinogenesis in the prostate. We propose that these changes may be mediated through the chemical interaction of isothiocyanates with signalling peptides in the plasma. This study provides, for the first time, experimental evidence obtained in humans to support observational studies that diets rich in cruciferous vegetables may reduce the risk of prostate cancer and other chronic disease.

If you have the right version of GSTM1 there is good news and there is bad news. The good news is that you can reduce your risk of prostate cancer and other diseases by eating broccoli. The bad news is that you really ought to be eating broccoli.

What would be a useful next step: determine how much consumption of cabbage (or other cruciferous vegetable less undesirable than broccoli) will cause as big a gene expression change as consuming broccoli.

This result illustrates the potential for nutritional genomics to guide personal dietary choices. People swear by different diets as delivering great benefits for them. Well, we are going to discover in the next several years to what extent there is no one ideal diet. Different people will end up having different ideal diets. Cheap DNA testing is going to allow us to find out individually what our best diet would be. There'll be upsides and downsides to knowing this. On one hand, you'll be able to avoid eating some types of food that you do not like that provide benefits for others but not for you. On the other hand, you'll discover that some foods you really do not like are great for you and some foods you do like are bad for you.

Share |      Randall Parker, 2008 July 17 10:52 PM  Nutrition Genomics


Comments
Tj Green said at July 18, 2008 4:36 AM:

Broccoli raw, with a little mayonnaise(with omega3)tastes really good. I agree, with cheap DNA sequencing now available, evolution is no longer in the driving seat, we are.

Greg Hamer said at July 18, 2008 11:42 AM:

Someone should do a study to see if there is a correlation between liking broccoli and having the right version of GSTM1. For people that get a survival benefit out of eating broccoli, the
ones that enjoy it should tend to predominate over the ones that do not enjoy it.

Tom said at July 18, 2008 3:41 PM:

The amount of sulforaphane in broccoli sprouts is much higher than in normal broccoli, so sprinkling some of those on your salad is going to be much more cost effective (and to me, more palatable)

TTT said at July 18, 2008 5:17 PM:

Broccoli with a tiny bit of butter and black pepper tastes good!

I once had a broccoli and crab meat steamed stew in China that was fantastic as well.

Furthermore, any recipe for cauliflower can identically be applied to broccoli.

Randall - given your interest in cruciferous vegetables, you really must explore the vast array of tasty recipes for them that exist in Indian, Thai, and Manchurian cuisine. You will broaden your possibilities greatly, and make it 10 times easier to consume Cauli, Broc, and Cabbage on a daily basis. You will simultaneously manage to consume a lot of cancer-fighting Ginger, Garlic, and Turmeric as well.

I suspect you have no idea how many recipes exist.

KG2V said at July 18, 2008 6:27 PM:

Man, Broccoli with a good vinegar, a little oil, and salt and pepper - YUM. Joke? My 7 YO son LOVES Broccoli (like will eat 1/2 to a full head for dinner), but don't try to get him to eat fruit - except for strawberries

Robert Dennis said at July 18, 2008 9:19 PM:

I happen to love broccoli any old way, even raw, although I prefer it moderately steamed. I also happen to like other cruciferous vegetables as well, including cabbage, cauliflower, and brussel sprouts. On the other hand, I have no idea what my GSTM1 status is. Where do you go to get tested for this? It might be especially useful information given that I am over 50 and have not yet had a PSA test.

Anyway, excellent post, and I appreciate Instapundit for linking here.

Joey Tranchina said at July 18, 2008 10:45 PM:

"This result illustrates the potential for nutritional genomics to guide personal dietary choices. People swear by different diets as delivering great benefits for them. Well, we are going to discover in the next several years to what extent there is no one ideal diet. Different people will end up having different ideal diets. Cheap DNA testing is going to allow us to find out individually what our best diet would be. There'll be upsides and downsides to knowing this. On one hand, you'll be able to avoid eating some types of food that you do not like that provide benefits for others but not for you. On the other hand, you'll discover that some foods you really do not like are great for you and some foods you do like are bad for you."

This is just a GREAT paragraph. This is an ideal first paragraph for any generalists' introduction to nutritional genomics. Congratulations, Randall Parker, you nailed it.

Tom Jones said at July 18, 2008 11:11 PM:

I like my broccoli steamed, then I pour on the extra-virgin olive oil and a bit of salt. The olive oil I
use has a distinctly grassy, vegetal flavor and is only available at my secret store and only for a few
months a year. I have 8 bottles!!!1 They are all mine!!!1

Randall Parker said at July 18, 2008 11:40 PM:

Tom,

There's a group of researchers from Johns Hopkins that founded a company that sells teas laced with broccoli sprouts for the sulforaphane. I forget the company. But you could find it Googling.

TTT,

I just ate half a head of cabbage raw.

Extremely well prepared broccoli: Sure, if you either like to cook or have a girlfriend or wife who is a talented cook. Having had 1 great cook girlfriend I can say that it is great to sit at home and eat food far better that sold at the vast bulk of restaurants. But I'm not into careful food prep.

jeanie said at July 19, 2008 5:25 AM:

Cabbage is less undesirable than broccoli? My genes disagree.

Hucbald said at July 19, 2008 10:52 AM:

I love broccoli any old way but overcooked. The only intrinsically superior vegetable is asparagus, which is totally ruined when canned. Seriously, I'm betting everyone in America who says they don't like asparagus had their moms feed them canned asparagus, as I did. First time I tried it raw, I freaked.

But seriously, people who don't like broccoli are a few fries short of a Happy Meal, IMO.

CharlesWT said at July 19, 2008 6:36 PM:

I put frozen broccoli in fruit smoothies. It doesn't change the taste much and it's a quick and painless way to get your broccoli fix. The same can be done with other vegetables.

KISS Principal said at July 20, 2008 4:25 AM:

I put a bunch of broc (usually 3-4 stalks) in a pressure cooker for about 6-7 minutes at pressure. I put a cup of water at the bottom and use the cooker's veggie tray. Its almost as easy as microwaving something and gives me a course of veggies for three nights. I like it with just real butter, salt and pepper.

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