"Dont smoke and eat your fruits and veggies." If you ask Bruce Ames, that simple, folksy remedy is the best way to avoid cancer.
So why is this 63-year-old professor of biology at the University of California, Berkeley, so controversial?
Ames burst on the national scientific scene in the early 1970s with the development of a method, generally dubbed the Ames Test or the Ames Mutagenicity Test, to determine what chemicals caused a certain bacteria to mutate.
This, in turn, could be used to help determine what chemicals cause cancer.
Ames is the recipient of the General Motors Cancer Research Foundation Prize and of the Tyler Prize for environmental achievement. He has served on the National Cancer Institute board of Bruce Ames directors, and hes a member of the National Academy of Sciences.
At one time, he was the darling of the environmental movement. But now, the members of that movement have turned on him with a vengeance, accusing him of aiding and abetting "Corporate America," although he accepts no money other than his university salary.
Ames problem is that after he discovered that there were a vast number of synthetic chemicals that are carcinogenic – that is, they cause cancer when fed to laboratory animals at extremely high doses – he then discovered that natural chemicals found in everyday food are just as likely to be carcinogenic as those manufactured by Dow, Uniroyal or American Cyanamid.
This, he found, was a very politically incorrect conclusion.
The environmentalist activists, Ames said recently, "have a religion" that says that corporations are behind an exploding epidemic of cancer.
Prodded by a tiny handful of doctors, such as Samuel Epstein of the University of Illinois at Chicago, by a media looking for headlines, and by celebrity spokespeople such as Jane Fonda and Meryl Streep, Americans, Ames says, are engaged in a veritable witch hunt against synthetically produced chemicals and the companies that make them.
"The idea that chemical companies are giving consumers cancer just isnt true," he said.
First, he says, there is no epidemic of cancer, caused by industry or anyone else. True, cancer rates are going up overall, he says, but most of this increase is attributable to an aging population.
In a broad sense of the word, Ames says, aging is the greatest risk factor for cancer. "It doesnt mean that external factors dont influence cancer," he said. "But underlying it all, cancer is a degenerative disease of old age."
Cancer Risk Factors
Other factors in the overall increase of cancer cases, he says, are the increased number of smokers several decades ago who are only now developing lung and other cancers, increased exposure to the sun resulting in melanomas, and increased breast cancers arising from hormonal factors – a result of changes in the role of women in society.
Earlier and more frequent pregnancies, he says, greatly reduce a womans chance of contracting breast cancer, though he grants thats a rather drastic prescription. The best hope for women in preventing breast cancer, he says, lies in drugs that block the adverse effect of hormones.
And not only is there no cancer epidemic, says Ames, but the tests that purport to implicate synthetic chemicals as causes of human cancer in fact do no such thing.
Current procedures to test whether a chemical causes cancer entail exposing animals, usually rats or mice, to massive doses of the chemical, then killing the animals and checking for tumors.
But Ames says there are major problems with this procedure.
One, animals arent necessarily the best stand-ins for humans. In fact, 30% of the time, a chemical that causes cancer in mice wont do so in rats and vice versa, even though these species are much closer to each other than they are to humans.
For another, the dose given the animals is on average almost 400,000 times the dose that the Environmental Protection Agency tries to protect humans against.
The assumption in the testing is that whatever causes cancer in a few rats out of a few dozen at massive doses will, in a population of hundreds of millions of humans, also cause human cancers, even at much smaller doses.
But Ames points out that this theory - generally called "linear" or "no-threshold," or "one molecule" – directly contradicts what is known about chemical poisoning, which says that virtually anything at a high enough dose can kill a person, even if at a low dose it is actually therapeutic or even necessary to life, such as vitamins and salt.
Most importantly, said Ames, while these animal studies are used to indict synthetic chemicals because half the synthetic chemicals are proving carcinogenic, "Half of the natural chemicals come out positive, too."
Ames notes that while Americans are focusing on synthetic chemicals that may cause cancer in humans even to levels of parts per quintillion - that is, per 1,000,000,000,000,000,000 - many of those same Americans are blissfully ignorant of the natural carcinogens.
"There are over 1,000 natural chemicals in a cup of coffee," he said, "and only 22 have been tested. Of these, 17 are carcinogens."
But, said Ames: "I dont want to scare people away from drinking coffee. The problem isnt the coffee – its the high-dose animal tests."
Moreover, he says, a cancer-causing natural agent can be far deadlier than synthetic agents. He compares, for example, aflatoxin, a mold metabolite, which grows on some vegetables and peanuts, with the industrial solvent trichloroethylene, or TCE.
Because TCE is synthetic, the U.S. has spent perhaps billions of dollars in federal Superfund money in an effort to virtually eliminate it from water tables.
"We spend an enormous amount of the GNP chasing trivia," said Ames.
"As long as they were testing only synthetic chemicals and half were proving positive, nobody was worrying much," he said. The revelation that rodent tests were showing natural chemicals to be carcinogenic just as often, he said, "was threatening to a lot of people because theres a whole industry based on this."
The obsession with synthetic pesticides, says Ames, is rather absurd when one considers that natural pesticides produced by plants to ward off insects or animals, which are proving carcinogenic in lab animal tests just as often as their synthetic counterparts, constitute over 99.99% of all the pesticides we eat.
By weight, he said, "There is more carcinogen-causing chemical in a cup of coffee than you are likely to get in synthetic pesticides in a single year. Yet, the average daily intake in coffee is 1,000 times the tolerance level the EPA allows for synthetic pesticides."
"Pesticide residues (that are eaten by consumers) are nothing," he said. "Farmhands are different, and we need strict rules of exposure for them and for chemical workers. But I dont think anyones ever died of residues."
Ames says dont sweat the pesticides, but do eat more fruits and vegetables. Probably a lot more – but dont forget to spit the seeds.
More and more studies, he says, are showing a correlation between food intake and the cause or prevention of cancer.
"People dont know all the answers yet on diet, but it seems clear that fruits and vegetables are good for you. Yet only 9% of Americans are eating the amounts of these they should be," said Ames.
Recently, Ames published a paper suggesting lack of Vitamin C in males as a cause of genetic damage in sperm.
"If you eliminate synthetic pesticides, you make fruits and vegetables more expensive," he said. "People will then eat less of them and more will die of cancer."