We Can Prevent Cancer: 'If We Behave Ourselves'
Two years ago, on December 12, 1998, Bruce N. Ames received the National Medal of Science— the nation's highest scientific honor—for his major contributions to the understanding of cancer and aging. He and eight other scientists were called "superstars" in their fields.
While you might expect being named one of the nation's top scientific researchers would be a high point in a career, the award doesn't do much for this 70-year-old biochemist: "I'm passionate about my science and if awards come along, that's fine."
As director of the National Institute for Environmental Health Sciences Center at University of California-Berkeley, Ames is driven to prevent cancer and other degenerative diseases of aging by improving the diets of Americans, particularly poor Americans.
Ames spoke recently with John Banker, editor of Arch Publishing.
Banker: You like to clear up misconceptions about cancer. Let me start by asking you this: Are cancer rates soaring?
Ames: They are going up, but not if you take into account two factors. You should correct for age, because cancer goes up with age. That accounts for a lot of the increase, because every year life expectancy gets longer. We're the longest-lived people in human history and life expectancy is getting longer even faster.
The second factor is smoking. Smoking causes one-third of cancer, and that accounts for the major increase in cancer. If you correct for age and correct for smoking, cancer rates are coming down.
Banker: Are synthetic chemicals an important cause of cancer?
Ames: There's no evidence that's really convincing. My own guess is that—with the exception of a small amount of occupational cancer—there is almost nothing there. It's almost all hype.
Synthetic chemicals are just a drop in the bucket compared to natural chemicals. You make a thousand different chemicals when you roast your coffee. Every plant is full of natural pesticides it uses to kill insects. When you add it all up, 99.99 percent of pesticides that go into you are natural, and .01 percent are synthetic residues. The amounts of synthetic chemicals we ingest are just trivial compared to the amounts of natural chemicals we ingest.
It isn't that natural chemicals are harmless and synthetics are bad. You get the exact same hit rate in finding mutagens, carcinogens, or whatever toxicological endpoint you look at when you compare natural or synthetic chemicals. And 99.9 or 99.99 percent of the chemicals that get into you are natural.
The toxicology on synthetic chemicals as a major risk is just not credible. When you look at the huge dose you need to cause cancer in a rat, it doesn’t make much sense that the levels humans are ingesting could be a significant cause of cancer.
Banker: Do you think the word "synthetic” alarms people more than the word "natural”?
Ames: Why do we worship natural things and demonize synthetic chemicals? Well, partially it was Rachel Carson's diatribe against DDT.
DDT saved 100 million lives or more. It was the most valuable chemical ever invented by man. The fellow who invented it got a Nobel Prize. It was amazingly non-toxic to mammals and it killed insects. And it was dirt cheap.
Banker: What do you think about the popular but pricey organic farmers’ markets in which they don't use any pesticides?
Ames: The organic farmers can sell their food for 50 percent more than regular food and make bigger profits, but it is irrelevant to health.
Banker: Let's get to the heart of the matter. What really causes cancer?
Ames: Bad diets and tobacco are the two big causes of cancer.
There are 40 vitamins and minerals and other substances called micronutrients that you require in your diet. If you don't get enough folic acid, you break your chromosomes. If you don't get enough Vitamin C, you break your chromosomes. If you don't get enough vitamin B6, you break your chromosomes. If you don't get enough vitamin B12, you break your chromosomes. With maybe eight or nine of the micronutrients, there's pretty good evidence that deficiency leads to broken chromosomes. And chromosome breaks lead to cancer. My guess is that about half of the population's intake is too low in at least one of them.
Poor people are eating terrible diets, so they're really in trouble. It's giving them heart disease, cancer, and perhaps harming their brains. We spend practically no money on informing people about the importance of a good diet for health. Yet we spend $140 billion a year in the cost of EPA regulations.
Some Harvard economists have estimated we would save 150 times more lives for the dollar if we put the EPA money into medical interventions instead of toxic interventions. And the lives saved on toxic interventions are fake lives as they are based on a whole series of wrong assumptions.
Banker: Obviously, you’d see it as a step in the right direction to alter where the money is going.
Ames: Yes, but it is hard to change the politics. There is the self-interest of lawyers, activists, scientists, and bureaucrats. Everyone likes to feel they are working for altruism, while “industry” is working for greed. Critical thinking is always much rarer than enthusiasm. We're spending this huge amount of money on "if it's natural, it's good; if it's synthetic, it's evil." Yet, you can kill yourself by eating.
One of the biggest causes of poisoning your kids is when they go out and eat the shrubbery. Plants are filled with nasty chemicals. Even the plants we eat are filled with nasty chemicals that are used to kill insects. And half of those come out as carcinogens if you test them.
Banker: But the way the Food and Drug Administration approves drugs seems logical in its requirement of testing high doses of potentially harmful chemicals on rats.
Ames: The FDA is a different matter. If you have a drug you're giving to people, you're giving them a really high dose. Or if you're giving them a food additive, you want to give them a really high dose.
But these tests on parts per billion of chemicals is where it makes no sense at all, because we are eating parts per thousand and parts per million of all these natural chemicals that come out as carcinogens in cups of coffee and broccoli. I don't think cups of coffee and broccoli are dangerous because they are full of natural carcinogens, because these high-dose tests aren't relevant at the low doses to which people are exposed.
Banker: So you don't have a problem with the FDA?
Ames: No. The FDA is fine. It's EPA, whom we have provided with bureaucratic incentives to cause more and more money to be spent on trivia.
Banker: Have you made inroads with anybody who supports your beliefs?
Ames: The toxicologists are in my camp now. I just wrote the foreword for a leading toxicology book. The toxicologists asked me to give the plenary lecture at their last international congress. I think the toxicologists think all of this terror over traces of synthetic chemicals doesn't have much scientific support. But there are always a few guys keeping all these scares going.
My passion is preventing cancer, and the way to do that is to get people to eat decent diets and stop smoking. Those are the two things that really matter.
Banker: Those two factors cause about 75 percent of cancer, right?
Ames: Smoking is about a third and diet's about a third—the two together are about two-thirds of cancer.
The quarter of the population eating the fewest fruits and vegetables has double the cancer rate for practically every type of cancer compared to the quarter eating the most fruits and vegetables. You're talking about two portions on down for the quarter eating the fewest, and maybe four or five portions on up for the quarter eating the most. So just a few extra portions of fruits and vegetables has a huge effect on our cancer rates.
A lot of that is the vitamins you get from your fruits and vegetables. If we could get multivitamin pills into poor people, they'd be much better off.
In fact, a quarter of the population takes a multivitamin/mineral pill, but it's the quarter eating the best diets. We need to get them into poor people. All this kills people, and it kills poor people.
Banker: You're convincing toxicologists. How can you convince politicians to help alter the allocation of resources for scientific research?
Ames: Eventually they will come around. The conservatives are more sympathetic to this message, partly because they are more sympathetic to business and markets, and more suspicious of bureaucracies. So it's divided along political lines.
The Wall Street Journal and The Economist have articles all the time pointing out that these scares are mostly hype. But you rarely see them in most newspapers or magazines. It's too bad it has become political.
Banker: How bad is tobacco to our nation's health?
Ames: Tobacco is a disaster. It causes a third of cancer and a quarter of heart disease. We have some evidence that male smokers are damaging their sperm. If you don't get enough folic acid from your veggies, we see increased damage to the DNA of sperm. We also find the sperm count goes down markedly in rats when they are depleted of folic acid.
Also, when you don't get your vitamin C and E, it looks as if you damage your sperm DNA. Smokers are depleting their vitamin C and E. It's like irradiating themselves. Smokers need to eat much better diets than non-smokers because they need more vitamin C and more vitamin E. But, in fact, they're eating worse diets.
Banker: Low sperm counts would make it harder for male smokers to have babies. And with the damaged DNA, that could lead to more complications with their babies. Right?
Ames: Men's bad diets will lead to damaged sperm DNA, which will in turn lead to increased childhood cancer in the offspring. Birth defects, too. I think if everybody in the country took a vitamin pill as insurance, we'd be way ahead in terms of health. Smokers particularly need extra vitamins.
However, I don't think one should tell people to take megadoses, because too much of some vitamins is poisonous. You need 15 milligrams of zinc per day: Evidence suggests that less leads to broken chromosomes. You get much over 60 milligrams of zinc and it starts to be poisonous. Same thing with an excess of selenium.
What you want to tell people is to take a multivitamin that has the minimum daily requirements for all the vitamins and minerals. Consider that insurance and try to eat a good diet besides. It costs practically nothing. It's a penny to make one of those pills and they sell them for about a nickel.
Banker: In your review on aging with your postdoctoral fellow, Kenneth Beckman—"The Free Radical Theory of Aging Matures”—you seemed to want to get all the disparate research on aging organized.
Ames: We are starting to understand the mechanisms of aging, and we're making progress in rejuvenating rats. Once you understand the mechanism, there are ways to intervene and optimize the level of each micronutrient in your diet.
Banker: You're looking at a field of 40 micronutrients?
Ames: There are about 40 that you require. Not all of them are going to be that critical. Some of them we’re getting plenty of, but there are a lot of them that we're not. Deficiencies of eight or nine of them lead to chromosome breaks. Chromosome breaks lead to cancer.
Banker: With a total field of 40 micronutrients and only eight or nine that scientists need to concentrate on, it seems it would not take long to optimize them.
Ames: Molecular biology is going like a rocket now. I suspect it will be sorted out in 10 or 15 years. You'll go to the doctor, he'll analyze a little finger prick of blood, and he'll tell you: "You're short of vitamin D. Get some more sunshine or take a vitamin pill or drink some fortified milk." Or "You're short of folic acid. Take a vitamin pill or eat more fruits and vegetables." We'll be able to give people a tune-up.
Banker: Ten to 15 years from now, when people get a tune up and follow the doctor’s orders, what will that mean in terms of life expectancy?
Ames: Members of the 7th Day Adventist religious group live two to three years longer and have half the cancer mortality of the average American. They don't smoke. They don't drink. They're mostly vegetarians. They lead a very moderate lifestyle. They go to church every week.
We are already the longest-lived people in human history. If we behave ourselves, we are going to do much better.
John V. Banker is editor of Arch Publishing. www.archpublishing.com