Aflatoxins and Furfural

Aflatoxins and Furfural
November 1, 1998



Each year, as we prepare for the holidays and their attendant feasting, we find ourselves awash in warnings about our food supply.

From all sides we hear the voices of the pantry patrol's panicky pundits who urge the parents of infants and small children to feed their kiddies exclusively on organically grown foods to prevent their ingesting deadly, cancer-causing pesticide residues. What most of us don't realize, however, is that pretty much all our food--whether organically grown or not--contains traces of naturally occurring carcinogens.

"Naturally occurring carcinogens?" the pantry patrol asks. "Even in organic foods?"

Yes, indeed.

Each year the American Council on Science and Health publishes a Holiday Dinner Menu--a carte du jour for a sumptuous feast that shows that many, if not all, of the traditional foods on our holiday tables contain traces of 100 percent nonsynthetic, all-natural, all-organic, carcinogenic chemicals--substances with formidable, tongue-twisting names guaranteed to terrify the timid.

Here are some examples:

First, there's caffeic acid, a substance known to cause cancer in rodents. It lurks in that innocently healthful-looking relish tray, in those crisp, bright, carotene-rich carrot sticks. Carrots, whether organic or not, contain traces of caffeic acid.

How about heterocyclic amines? These compounds also cause cancer in rodents. Unless you plan to eat it raw (and risk getting salmonella poisoning in the process), you'll be consuming heterocyclic amines along with your beautifully browned roasted turkey.

Then there are aflatoxins. Toxicologists recognize aflatoxins among the most potent animal carcinogens known. They are produced by a fungus that can contaminate peanut, corn, and other crops. You'll likely find tiny amounts of aflatoxins in your seasonal tray of mixed nuts.

Finally, for dessert, you can have a hint of acetaldehyde and a soupcon of safrole. Both are known rodent carcinogens. You'll find them in that all American favorite, apple pie.

But don't worry: You won't have to ask your family to fast at Thanksgiving. Toxicologists recognize that it requires a leap of faith to conclude that a cancer risk to rodents means a cancer risk to humans. Mouse carcinogens are not always rat carcinogens. Rat carcinogens are not always mouse carcinogens. And neither are necessarily human carcinogens.

For a moment, though, let's assume that furfural--another rodent carcinogen that you'll find in the bread in your holiday stuffing--can cause cancer in humans. You don't have to skip the stuffing, or, for that matter, give up your daily bread. Trace exposures to furfural in human diets are hardly analogous to the high-dose exposures used in rodent experiments. A 155-pound person would have to eat 82,600 slices of bread every day to consume the amount of furfural that increases the risk of cancer in rodents.

And what about the benzo(a)pyrene in your stuffing? Benzo(a)pyrene causes cancer in rodents and is also found in cigarette smoke. The benzo(a)pyrene in cigarette smoke does, indeed, contribute to many smoking-related cancers, but the minute amount you'll find in your turkey stuffing is quite unlikely to pose a significant health threat.

The same is true for the aflatoxins in your nuts: Aflatoxins are very potent animal carcinogens, but they are found in only minuscule amounts in our foods. Nuts on the market may contain traces of aflatoxins, but the FDA requires that the amounts not exceed safe allowable levels. This is both reasonable and achievable. In the cases of food additives and pesticide residues, however, our food regulations in the past have not been reasonable.

The irrationally restrictive Delaney clause--part of a 1958 amendment to the federal Food, Drug and Cosmetic Act--required that no substance shown to cause cancer in any animal be allowed as an additive in human foods. In essence, Delaney meant adhering to a zero-risk standard for any pesticide residue that might be found in foods as well as for any food additive, no matter how small the amount of the pesticide residue or the additive.

In the 40 years since Delaney was enacted, science has progressed so that we now can measure trace amounts of chemicals that are so small that their biological significance is trivial.

And human exposure to these synthetic chemicals is often much less than exposure to the naturally occurring animal carcinogens in our foods.

Fortunately, the grip of Delaney on America's food supply has loosened a little of late. In 1996, after decades of irrational cancer scares, Congress and President Clinton finally moved to extend the same sort of commonsensical regulation we have to deal with aflatoxins to some of the other chemicals--the pesticide residues--that we sometimes find in our foods. That year, President Clinton signed the Food Quality Protection Act of 1996 into law, thereby reducing the scope of Delaney by removing pesticides from the clause's purview.

Now, instead of holding growers and food suppliers to an unrealistic, counterproductive standard of zero risk, the law allows a more realistic standard of reasonable certainty of no harm--a standard already applied to such naturally occurring (and very potent) animal carcinogens as the aflatoxins found in our holiday nuts.

So, this holiday season be grateful to your elected officials--grateful that Congress and the President have taken steps to improve your chances of having an affordable feast today and many more in the years ahead.

But remember, too, that another challenge still lies ahead for our legislators--the challenge to extend the standard of reasonable certainty of no harm to food additives. That would give us something new to be thankful for in 1998!


Elizabeth Whelan Sc.D., M.P.H., is president of the American Council on Science and Health, New York City. She can be reached by email at acshmail@aol.com.