(AI). Like all chemical agents, nutrients can produce adverse effects if intakes are excessive. Therefore, when data are extremely limited, extra caution may be warranted.

For statistical reasons that will be addressed in a future report, the Estimated Average Requirement (EAR) is greatly preferred over the Recommended Dietary Allowance (RDA) for use in assessing the nutrient intake of groups. Table S-1 shows, for example, that fewer than 5 percent of young men have dietary intakes of thiamin, riboflavin, niacin, or vitamin B₁₂ that are less than the EARs for these nutrients. This indicates that dietary intake of these five B vitamins by young men has a high probability of being sufficient to meet their needs. A large proportion of the individuals in the population, especially women, reportedly has a total folate intake less than the EAR. However, because the reported folate content of foods is considered to be substantially underestimated (in part because of methodological problems, content not being reported in dietary folate equivalents, and data being obtained before the fortification of cereal grains was required), it is not known to what extent this discrepancy between the EAR and intake represents a problem.

The determination of ways to increase dietary intake of a nutrient should include examination of the foods that are the major contributors of the nutrient to the U.S. or Canadian diet and the specific foods that are rich in the nutrient. U.S. data on both are provided in this report.

A primary question that must be answered is How can individuals consume the Recommended Dietary Allowance (RDA) or Adequate Intake (AI) if surveys indicate that typical diets contain lower amounts? This becomes a policy issue with regard to choosing methods to increase consumption of that nutrient in order to decrease the number of individuals at risk because of inadequate dietary intakes. Such methods include educating consumers to change their food consumption behavior, fortifying foodstuffs with the nutrient, providing dietary supplements, or a combination of the three methods. It is not the function of this report, given the scope of work outlined, to provide an analysis of the impact of using these three methods.