Why You Are Better Than a Fruit Fly

by DavalosMcCormack on May 14, 2008

When we began this website we started out with a few basic promises; one of them was not to write about animal studies because they rarely had any immediate implications for people. Now a new study has come out that reinforces our position on why studies done only in animals aren’t necessarily important to humans.

The study, published in the May issue of the Proceedings of the National Academy of Sciences, shows that humans have around ten times more protein interactions than fruit flies do, and 20 times more than single-cell yeast organisms.

So why should you care? Because many studies that you see reported in the news or online are done in fruit flies or other creatures like mice. The argument is that in the case of fruit flies, they have some similarities to people, in other words, if a treatment works in a fruit fly, it may also work in people.

It’s a lovely idea. It just doesn’t work out that way very often.

Take this on the most superficial level. People have approximately 24,000 genes. Fruit flies are not far behind, they have around 14,000. So you might think that there would be some similarities, some overlap. You might think that, but you’d be wrong, and that’s where this new study comes in.

This new study shows that the interaction behind different proteins is what drives pretty nearly all the physiological systems in the body. So, from your brain to your bowels, it’s the proteins that are controlling what works, how it works, and when it works.

By identifying just how many more protein interactions humans have than fruit flies, the scientists are able to show just how wonderfully complex we are. It also shows why using fruit flies as a model for drugs or treatments is singularly inadequate.

While this study is new, the idea that animal studies are not particularly useful is not terribly new. In 2006 a paper in the British Medical Journal reported that animal studies are of limited use to human health, because they are frequently poorly done and their results conflict with results from human trials.

For instance, a study looking at corticosteroids to treat head injury showed some promise in animal models, but failed miserably in people. Similarly a trial of a medication called tirilazad, which is used to treat stroke looked good in animal models but in people it proved not only to offer no benefit, there was even evidence it might cause further harm. Definitely not what you are looking for in a drug for strokes!

Clearly there have been some cases where a treatment that looked promising in animals also produced promising results in people. But they tend to be few and far between. Think how often you have seen stories on the TV news about a treatment that cures cancer, only to find it was done in mice. And then you never hear about it ever again.

The bottom line is the same today as it has always been. Never change your lifestyle or habits based on one study. Never pay any attention to animal studies unless they have also been duplicated in people. We won’t either.

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