NATURAL TOXINS

IN FOOD

THIS IS A TEACHING AID ARTICLE

face a real problem in the

W United States and Canada due

to the way many people, indeed too many people, regard food ingredients and the way modern food is processed as it moves from the farm to the table. Unless some way can be found for physicians, dietitians, home economists, food technologists, and nutritionists to respond convincingly to the questions being raised by the average person, the nutritional health of the entire public will be adversely affected.

One response, a vivid portrayal of some unreasonable concerns about the safety of the foods we eat, is presented here.

But first let us look at the reason why the purity and virtue of our food supply is suspect by so many people. The reason is wrapped up with many other popular dissatisfactions and disenchantments. First, food supply is business, an enormous business, and we all know that the business community is mistrusted by many people. It always has been, only today, perhaps, it is more so. In

Dr. Hall, Vice President, Science and Technology, of McCormick & Co., Inc., was named the 1976 Chemist of the Year for the Maryland branch of the American Chemical Society. He has recently received an Institute of Food Technology award named for Nicholas Appert, inventor of food canning.

By Richard L. Hall, Ph.D.

a different but parallel vein, we all know indeed we all share - a distaste for the anonymity and complexity of an urbanized, industrialized, increasingly regulated society. Both attitudes affect our views of food, particularly industrially processed food.

Food, moreover, occupies a special place in our lives. It is not only a biological necessity, it is a social activity, an aesthetic experience, and a cultural expression. All of these impose a heavy load of emotional involvement, beginning in infancy. THE MYSTERY OF FOOD

Several generations ago, most of our food was prepared at home, "from scratch," largely from ingredients that were themselves homemade or locally grown. This intimacy bred the confidence that comes from familiarity.

For another thing, in that day the germ theory of disease was new, and very few people other than scientists knew about it or were concerned with its implications. Vitamins were unheard of. People knew what they meant when they spoke of "wholesome food." Analyses for insect contamination, microbiological quality, or pesticide residues were certainly not done on home-grown produce and rarely on foods sold in the "grocery store." The safety of food ingredients was seldom questioned and virtually never tested. We all en

joyed the confidence that comes from innocence.

Today, of course, our food is often grown hundreds or thousands of miles away. In order to assure a continuing supply of wholesome food of uniform quality to 250 million people spread from the Rio Grande to the Arctic Ocean, most foodstuffs travel thousands of miles and are stored for long periods. How this is possible is a mystery to many. Also most food is "processed" by people and equipment we never see. The fact that today's food is cleaner, safer, more varied, and proportionately cheaper than ever before still doesn't inspire the confidence in our food supply that at one time came from personal involvement.

Ironically, the same science and technology that have made our present food supply possible, nutritious, and safe is, at the same time, based on a body of knowledge so large and complex that only a few dedicated people comprehend it. To most, food science and technology are mysteries. In this light, the current worries and misconceptions about the safety and nutritional value of our food supply become more understandable - not more correct just more understandable. The time has come for those of us in food technology and the health professions and enlightened laymen to allay the fears of the public and to assuage their emotional reactions to this circumstance.

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For one thing, we must have production in the most suitable growing areas. The economies of volume and sophistication from industrialized food processing, fertilizers, pesticides, additives, and packaging are necessary merely to feed ourselves properly and economically. Without the wise use of them, we have no hope of feeding the world. FOOD HAZARDS

We should point out that there are risks associated with food, as there are with everything else in our lives. Food does pose problems of disease, poor nutrition, and potentially hazardous components. But we had better appraise these risks clearly and accurately, or we will, in that appropriate phrase from the Gospel of Matthew, "strain off a gnat, yet swallow a camel."

In virtually everything we see or do, we need a sense of perspective. This need is particularly true in coping with food hazards. Without perspective we will concentrate on the trivial and miss the significant.

What are the sources of food hazards? Foremost are the microbiological hazards those which result in food-borne disease which affects perhaps 10 million persons a year. We do not even have a good grip on numbers, because our reporting practices are so poor. Second are the nutritional hazards from overconsumption, poor food choices, and less than optimal intakes of many essential nutrients through ignorance, indifference, or poverty. While vastly more serious in the developing countries, nutritional hazards in some degree affect millions in the United States and Canada. Perhaps one-thousandth as significant as these in terms of known human effects are the hazards in food due to environmental contaminants

room hunters whose enthusiasm exceeds their skill, uncritical imitators of Euell Gibbons, food faddists, and those who eat bizarre diets are by no

means uncommon.

Finally, a hundred or more times less significant than these are hazards from pesticide residues on food and from food additives, the intentionally added minor ingredients in food. There is no known case of human injury or death from a pesticide residue on food. Those rare instances of harm from food additives are not only curiosities widely reported in the scientific literature and general news media, but are invariably associated with extremely distorted food intakes, themselves a source of harm. in part, the pesticide residue and food additive risks are extremely low because a great deal of scientific and regulatory effort has gone into their evaluation, prevention, and control. In part also, they are low because the substances involved are in virtually all cases used by people with some knowledge, or even expertness, in their use. The microbiological and nutritional hazards are large because they are affected by the way the 238 million people in the United States and Canada handle and choose food, and few are experts.

This ranking of hazards is supported by an enormous body of evidence. It is thus paradoxical and frustrating that many people persist in viewing these hazards virtually in inverse and perverse order of importance. It is quite obvious that many people fear what they see as chemical, and are uncritically admiring of what they consider to be natural. Beyond that, many others fear what is new and pay undue respect to the old. We are in the simultaneous grip of two phobias, chemophobia and novophobia, the fear of chemicals and the fear of anything new. They are, like all phobias, irrational. Chemophobia is irrational because chemicals are not a thing apart. Our whole world is chemical. We are each a bundle of chemicals. Nor is the new necessarily hazardous and the old safe. We may be, and in fact often are, simply unaware of the near misses from hazards that we do not recognize.

Toxicologists carefully judge the safety of chemicals in our environment by animal testing, human ex

perience, and informed scientific judgment (see box on page 30). Even if animal tests tend to indicate safety, if a substance is found to have adverse effects on humans, we will be reluctant to use it. In fact, the "Delaney Clause" of the Food and Drug Act stipulates that a substance that is found to cause cancer when ingested by man or animal shall not be permitted as a food additive in any amount. Therefore, by statute, intentional additives that are carcinogens are not allowed in any amount. However, naturally occurring carcinogens are not restricted in

any way.

Sometimes we gain a better perspective by looking at objects from a fresh angle. We shall go through that exercise now, employing on the known, natural components of ordinary foods the same criteria of safety we would apply if those components had not been put there by nature, but had instead been added by man. We will look at what adverse effects of these substances are known from animal testing or human experience. We will apply the 100-fold or other appropriate safety factor and the professional judgments customarily employed. And we will apply the Delaney Clause with its prohibition of added carcinogens as relentlessly as the most ardent advocate could wish! We will do this to the things nature put there, or at least to those we know about. Obviously, we can't do a complete job because our knowledge of the composition and safety of food is now and always will be incomplete. For this exercise, we will take the menu we might be served at a fine restaurant. Imagine yourself there as we serve you a tasty luncheon with delicious foods and wine, coffee, tea, or milk.

APPETIZERS

Now let's the relish tray pass with carrots, radishes, onions, and olives.

Everybody from Bugs Bunny to night fighter pilots knows that carrots are good for you. What is less well known is that carrots contain carotatoxin, a fairly potent nerve poison, with a chemical structure which would excite suspicion in any toxicologist's mind. Chronic feeding studies have not been done, but the acute toxicity and structure are suffi

ciently alarming so that we could not possibly consider carototoxin an acceptable food ingredient. Carrots also contain myristicin. This substance is a hallucinogen and is thus wholly inappropriate for food use. Carrots also contain some unknown substances, probably isoflavones, that show an estrogenic effect; i.e., they mimic one of the female sex hormones. Obviously, by these criteria we should not eat carrots.

Have a radish? Radishes raise a different problem. They contain two substances which are goitrogens; i.e., they promote goiter by interfering with our use of iodine. About 50 grams of radishes, a little less than two ounces, could be expected to have a clinically noticeable effect on iodine metabolism. So, no radishes.

Don't those spring onions look good? Onions contain some fascinating sulfur compounds, including those that make us cry. But the ones we are crying about here are found in a complex, messy, smelly mixture of disulfides and trisulfides, which also exhibit anti-thyroid or goitrogenic activity. Your friends may not tell you, as they say about halitosis, but we will. Scratch the onions.

Like olives? Yes, but consider this: olives, of course, are processed

soaked in dilute lye to remove a bitter flavor, then washed and brined. They contain far too much sodium to be acceptable within the safety factors we must apply here. In addition, they have tannins, which we shall discuss later. But we really need not debate processed or natural, sodium or tannins. Olive oil, obtained from olives, usually contains low levels of benzo(a)pyrene, a potent carcinogen, or cancer-causing agent. Under the Delaney Clause, no level of carcinogen is permitted. Olives, too, must go. They're illegal! Melons wrapped in thin slices of ham are tasty appetizers. You can enjoy them if you ignore the fact that ham is smoked, and most smoked ham contains traces of polynuclear aromatic compounds, including, again, our

• Benzo(a)pyrene, etc.

old friend benzo(a)pyrene. Goodbye ham. For the moment, however, we

are left with the melon crescents.

MAIN COURSE

Well, we have avoided acute food intoxication so far, but we're still hungry. Don't those shrimps look delicious? Sorry. Shrimps are a rich source of several minerals, and among them, pride of place must go to arsenic. Arsenic enjoys a popular reputation largely unjustified in fact. Probably most of the people allegedly done in by arsenic actually succumbed to something else. Nevertheless, shrimps contain some 40 to 170 or more parts per million of arsenic, vastly more than we can tolerate or the food and drug law would allow with our 100-fold safety factor. Not only that. Shrimps are out on any one of several other counts. They can also contain iodine at very high levels and are one of the richest known sources of copper. Two hundred parts per million of copper in the diet is probably the maximum no-effect level in man, and shrimps may contain twice that. We could not possibly eat shrimps with an acceptable margin of safety for at least these three reasons, and that leaves us the Newburg sauce.

Our chef's Newburg sauce consists of lobster butter, brandy, flour, and fish stock. An important constituent of butter is vitamin A. Vitamin A presents us with a significant and curious dilemma. In test animals, both deficiency and excess are teratogenic; that is. it produces deformities in the unborn. Pregnant women beware. Our safety factor for vitamin A does not approach 100; therefore, no butter.

Brandy, of course, contains alcohol, and we do not need to go to animal experiments to study the adverse physiological effects of alcohol. Beyond that, brandy also