I have tried and tried over the last weeks to figure out a way to make it clear why it is that I and so many other nutritionists are not comfortable with calling an edible substance fortified with 8 or 10 or 16 or even 20 vitamins and minerals "nutritious."

As I was pondering the problem one night, I came across a picture of a spade whose short handle was made out of a single piece of ash, split at the top and cross braced to make that familiar spade-handle shape. The article was about the merits-and strength-of various kinds of spade handles. And that somehow provided me with what seemed like the perfect metaphor for fabricated and highly processed foods.

One can take a large tree, cut it down and take a center board out of it at a sawmill and end up with a 2-by-12 board. That board will have certain qualities with which we are familiar because humans have used boards for a long time. But if we want to make use of smaller trees or use up wood scraps, we can chop up the wood, mix it with some Generally-Recognized-as-Safe resins and mold it into particle board.

Particle board is made out of tree just as the board is made out of tree and particle board has certain very good qualities. Its qualities are, however, different from those of the board-in many ways we know about and probably in many ways we don't know about because they are irrelevant to us. Since we don't eat the particle baord it doesn't matter to us whether it is different from a board except in regard to the qualities, strength, size, constancy, price, and so on, which we are concerned about. Obviously there are differences between a particle board and a board which would be significant to a termite but wouldn't be significant to us.

Now oatmeal or even a mildly processed breakfast cereal like shredded wheat are sort of like boards. They are either products with which we have long experience, or modified only slightly from products with which we have long experience. The kinds of products we are talking about here, however, the kinds of products advertised on children's television, are like particle board.

Like particle board, they are claimed by their manufacturers to have certain obvious advantages; they are brightly colored, have intense, if artificial flavors, and they are sweet so children like them. But since children are consuming these products and not merely playing with them, any other ways in which they differ from products with which humans have long experience are also relevant to us. A grain of wheat is not just a bag of starch and vitamins and minerals.

Foods as they occur in nature and as humankind has any extensive experience with them have internal structures. Vitamins, minerals, starches, proteins, fats, sugars occur in them in certain contexts and certain relationships. An orange, for example, is an extraordinarily complex living chemical object. We do not know how to make an orange, and we do not know whether the differences between what an orange is and the kinds of orange imitations we can make are differences important to health. But we believe strongly that they may be.

Which is why heavy fortification does not transform variously colored and flavored "products"-many of them made up of the same few basic ingredients-into the variety of foods which nutrition scientists and educators continue to urge people to eat. We urge this vriety simply because we don't at present know any other way-especially in a free marketplace-to assure humans of good lifetime nutrition.