The Food and Drug Administration (FDA) regulations relating to the composition of new plant varieties provide that the agency can challenge the generally recognized as safe (GRAS) status of a new variety if its content of nutrients or natural toxicants differs significantly from previously grown varieties. Reference varieties and definition of “significant” are not set forth in the regulation, but the FDA indicates it will consider a 20% reduction of a nutrient and a 10% increase in a toxicant as “significant.”
The health hazard that would result from introduction of a new variety which inadvertently had a high level of some natural toxicant is readily recognized. From past experience, the probability of such introductions appears to be low and few cases have been documented. They are considered most likely to occur in new varieties developed for disease or insect resistance. Examples of toxic compounds and plant families that merit consideration will be given.
The possible impact on nutrition and health from changes, particularly decreases, in nutrient composition is apparent. Recent dietary and nutritional status surveys have shown that a substantial portion of the U. S. population has suboptimal intakes of vitamins A, C, B6, thiamin, folacin, riboflavin, calcium, and magnesium.
Food crops in aggregate provide an important source of these nutrients and a general decline in content could have an adverse effect on nutritional status. The impact of change would vary with the food crop depending on nutrient level and consumption. Thus, oranges (Citrus sp.) provide about 20% of the vitamin C in the U. S. food supply whereas lettuce (Lactuca sativa L.) contributes less than 1%. The impact of a percentage change in content of this nutrient in these crops would be correspondingly relatively large or small. Consumption of a particular food crop may also vary by geographical region, ethnic, age, or income group, and these factors must be considered in assessing which food crops contribute significantly to the intake of one or more nutrients for a significant segment of the population.
The U. S. Department of Agriculture (USDA) has organized a task force for the development of guidelines which will assist plant breeders in identifying nutrients and naturally occurring toxicants which may be important to monitor in the development of new varieties of food crops. Factors outlined above are considered in developing guidelines.