Q. My 3-year-old daughter likes to eat dog biscuits. I have been hiding them from her, but she occasionally finds them anyway and helps herself. Is there anything wrong with this?
A. The habit of eating nonfood items is called “pica,” and is generally regarded as an indication of some nonspecific nutrient deficiency. Undernourished persons may eat ice, clay, paint, and less-appetizing substances, apparently in search of a missing nutrient. Pregnant women, cancer victims, and anorexics as well as impoverished individuals are more likely to engage in the practice.
From lab experiments, we learn that nutritional deficiency will cause an animal to prefer any novel food to their regular diet, whether the new food has the missing nutrient or not. If it does provide what they were missing, the lab animals will continue to eat the new food even if it tastes worse. If it does not provide the missing nutrient, they will return to their original diet.
This ability to know that something is missing in the diet may also be present in humans, but dietary choices are so much more complex in humans that we can’t be sure. About 70 years ago, in an experiment that would not be performed today, 2- and 3-year-old Chinese orphans were maintained on a diet of nine simple foods. They could choose to eat as much or as little as they liked of each food, but there were no bad choices (for instance, banana was one of the foods, but there were no sugary foods). The children did as well or better than children fed a parent’s choice of foods, gaining weight and developing normally.
An odd observation during the experiment was the occasional “eating binge.” A child that had ignored cod liver oil for weeks would suddenly drink the entire serving for several days at a time, then ignore it again for weeks. The implication of this research is that young children can intuitively select a balanced diet from among wholesome foods. It is apparent from modern observation that older children and adults, with choices driven more by taste and convenience, do a poorer job in such choices.
Actually, the dog biscuits really are good food, so your daughter’s fondness for them may not be pica (defined as eating a nonfood), though it still may indicate nutritional deficiency. The food we feed laboratory animals and our pets generally supplies about five times more of most nutrients than the American diet does. Your daughter, experimenting with an unconventional food, may have found what her body needs, and she wants more, no matter what the taste. The problem is that these animal foods do not taste good, even when warmed up!
There is no way to pinpoint which of the nutrients supplied so liberally in the dog biscuits is the one she is looking for, and indeed there is probably more than one, since deficiency in a single nutrient is rare. While it would not hurt her to continue eating dog biscuits, there is surely a more palatable source of these nutrients. Introduce your daughter to a wide variety of fresh vegetables and fruits, which have more nutrients per calorie than other foods, and see if you can find one or more foods that seem to delight her. It will require six weeks or more to decide whether food alone is sufficient. If this does not solve the problem, there is no harm in spiking her food with a well-balanced multivitamin/mineral powder at about one-third the adult recommended amount. This supplement should be as broad as you can find, including if possible the uncommon nutrients such as biotin, chromium, molybdenum, etc.
It’s a shame that we adults don’t have as much “body wisdom” as some of our children do. We all need to learn to honor the signals our bodies give that would help us stay healthy.
This article appears in July 20 • 2001.