Monday, July 19, 2004

Eat Your Broccoli, Now!

A recent study suggests that the reason I'm so brainy and engaging has to do with my vegetarian habits. Eating vegetables can even keep humans bright and brainy much longer:

Here's another reason to eat your veggies: A new study suggests certain vegetables like broccoli and spinach may help older women keep their brains sharper.
Researchers found that women in their 60s who ate more cruciferous and green leafy vegetables than other women went on to show less overall decline over time on a bundle of tests measuring memory, verbal ability and attention.
Such foods include broccoli, cauliflower, romaine lettuce and spinach.
The federally funded study didn't include men, but the effect would probably appear in them too, said Jae Hee Kang, an instructor at Harvard's Brigham and Women's Hospital in Boston.

I haven't looked at the actual study to see if it makes sense or not, though. A surprising number of medical studies are very poorly decided and executed, so it's always good to be suspicious. For example, to prove that the difference is truly due to green vegetable consumption, everything else about the subjects life and health should be exactly the same. As we can't do this with real people living their everyday lives, we try to control for these other effects by trying to pick people who are on average the same in all other respects and by using statistical methods to control for any other possible effect that might be operating. But how successful can we really be in doing this? Obviously the answer depends on how good the statisticians' work is and how well all the other possible causes can be anticipated and measured. Another tricky thing is that something like eating green vegetables might not be the cause in the correlation we observe. Instead, it could be something correlated with the real cause, say something to do with the lifestyle or affluence of people who eat a lot of vegetables.

As an aside, note the last sentence in the quote above: "The federally funded study didn't include men". I don't remember that little reminder in any of the many studies that didn't include women, like the one which is the only basis for advocating that people take aspirin for their heart. But it's good that journalists wake up to spotting possible sex discrimination late rather than never, I guess.

This study is based on a large number of nurses, almost all of whom are women. I suspect that it was started because of all those studies which were based on a large number of physicians, almost all of whom were men, and because there were so many complaints about studies omitting women as their subjects. If this is true, the neat little insertion reminds us that it's not really possible to win if you are a feminist. Though of course I'd prefer studies that are valid for both women and men, as would any normal person who has both types among the circle of loved ones.