DEAR DR. BLONZ: There has been no clear clinical evidence that food causes behavioral issues in children. I am interested in your thoughts.


DEAR R.D.: The role of food allergies in childhood behavior is controversial, but it is not unreasonable to at least consider it a possibility when other avenues have been unproductive. It is essential, however, to proceed cautiously, calling upon a clinician experienced in this area.

The connection between the behavior and the offending substances might not be readily apparent. Consider what happens if the wrong substance is blamed, or if one simply blames all food additives. Such cases can give rise to changes in parental behavior that can then act as programming for the child: "You shouldn't eat that, it will make you sick." It can turn into ever-growing limits on the child's ability to eat and enjoy life.

The ironic thing is that a parent might observe improvements in a child's behavior even if the wrong substance is identified. Such changes might take place because they are expected -- the placebo effect. You haven't accomplished much if the underlying problem was not allergy-related or if it was caused by an item not originally suspected. If the symptoms resurface, other foods or food categories might get added to the "banned" list, further restricting the child and the parents.

Parents can assist a systematic process by maintaining a diary of foods consumed and reactions observed; this aids the experienced health professional in compiling a list for further testing.


Once suspects are identified, testing in a controlled clinical environment is essential to remove any possible bias from all concerned parties. A gold-standard often relied upon is the double-blind, placebo-controlled food challenge. I would encourage you to discuss this with a physician.

DEAR DR. BLONZ: One of my favorite times of year is when the new crop of potatoes comes to the market. My question has to do with the nutritional value of these fresh potatoes. I checked the USDA database, which says that a medium-size baked potato, or a similar amount of French fries, is supposed to contain about 17 milligrams of vitamin C. You have mentioned that heat destroys vitamin C, among other nutrients. If this is the case, how can these "heated" potatoes still be a good source?


DEAR J.J.: The high heat involved in the preparation process does destroy vitamin C. That level does reflect a reduction from the amount in the raw potato. French fries will have a bit less due to their increased surface area.

A good source for any nutrient is one that provides between 10 percent and 19 percent of the daily value for that nutrient. An excellent source is one that provides at least 20 percent of the daily value. The daily value for vitamin C is 60 milligrams, so one serving of "heated" potatoes would actually be an excellent source.
