Of Mice and Men

Bruce Ames Interview

Virginia Postrel from the November 1994 issue

(Page 3 of 7)

Ames: Many kinds of cancer. And eating more meat and saturated fats seems to raise the rate of some cancers. There's evidence for this, and I'm more and more convinced. But then the question is, What are the dietary factors? And more and more, it looks like folic acid is very important, which is one of the vitamins you get from fruits and vegetables, as well as antioxidants.

We're doing experiments with mice. You make them slightly folic-acid deficient, and it breaks their chromosomes. There's a little evidence that the same thing might be true in people, and there's some epidemiological evidence that women who don't eat their fruits and veggies have more kids with birth defects.

Reason:Why does folic acid appear to be the crucial thing?

Ames: Because folic acid is involved in making the purines and pyrimidines that go into DNA. And if you're deficient, what happens is deoxyuridine gets into the DNA. The body's balanced between damage and defense. If you leave out one of the vitamins or micronutrients, then you 're in trouble. Maybe more micronutrients will turn out to be very important, but right now it seems the antioxidants such as vitamin C are important and folic acid's important.

Reason: What do you mean by antioxidants?

Ames: Among the vitamins you need are a set of antioxidants--vitamin C and vitamin E and beta carotene. We've shown that there is a horrendous amount of oxidative damage to DNA just from living--from normal metabolism.

Just living is like getting irradiated. Radiation is an oxidizing agent. You're adding four electrons to oxygen to make water, you add them one at a time, you make superoxide and hydrogen peroxide and hydroxyl radicals, which are the substances you get from radiation. If the DNA gets damage, then repair enzymes, which are always cruising along the DNA looking for trouble, take out the damaged product--this oxidized base--and they repair it. Well, the oxidized base goes into the urine, and we've learned how to fish all these things out of urine and ask how much damage a human gets per day or how much damage a rat gets per day. The higher your metabolic rate, the more damage, so a mouse is battering up its DNA at a higher rate than the rat, the rat higher than the monkey, the monkey higher than a human--which fits with lifespan and the cancer rate. So we're all excited about oxidative damage and aging and all these degenerative diseases associated with aging.

The epidemiologists are finding that antioxidants are some of the ingredients in fruits and vegetables. If people don't eat their veggies then they are in trouble. My main interest now is to find what's the optimum level of all these things. Maybe the optimum level is much more than the RDA. We don't know that but right now people aren't even getting the RDA, the Recommended Daily Allowance.

Reason: Can people take vitamin pills?

Ames: Well, the nutrition people don't like that. They say you should be told to eat balanced diets. Two fruits and three vegetables per day at least. On the other hand, only 10 percent of the population are eating two fruits and three vegetables a day. So I'm coming to the conclusion that people should be taking one-a-day pills. Certainly pregnant women and poorly nourished people and anybody of childbearing age and older people.

Reason: Activists are very suspicious of you.

Ames: All I can say is I've done good science. In part, I think my talent in this area is I've always been a bit of a generalist and being a generalist is hard, because there's so much specialized knowledge. To be a successful generalist one has to know the best people in each field so that you can call them up on the phone and ask them questions and get feedback on ideas.

I've gotten very suspicious of a lot of the activists because I just feel that they are not good problem solvers. If you push in the wrong direction, then you're counterproductive. If we are spending $125 billion a year on EPA regulation, and it's not effective, that kills people, because it diverts resources from important things and it takes money that could be used for starting new companies and generating wealth and generating money for science.

I'm not saying you shouldn't have rules. You don't want every chemical company dumping its garbage out the back door. But what we're telling companies is, Well, air is free and water is free, but be good guys, don't pollute. That isn't how capitalism works. You want to have an incentive in there, so what we should be doing is charging people to pollute. Any time anybody wants to pollute--whether you drive your car or put a log in your fireplace--you should have to pay for pollution cost. Then there are incentives to figure out how to make cars that put out less pollution.

Reason: Within the academic research community, how do people look at people who have gotten involved in public policy debates?