Ronald Calitri Regional variations in the relationship of diet and income in the United States, 1996c Abstract This paper addresses the uncertainty of U.S. regional nutrient intakes calculated from national food composition tables. The focus is on data from the Continuing Survey of Food Intakes by Individuals. The present CSFII and local regression have been used (with the Consumer Expenditure Survey) to assess responsiveness of nutrient demand to household income and the effects of household and individual factors on nutrient sufficiency. Significant differences in these relationships (and of nutrient adequacy) across income are observed among U.S. regions. Reduction of the considerable remaining uncertainty through further relating the CSFII nutrient intakes with cultural and economic factors, food knowledge, health status and other surveys is approached in view of the possibility of geographic food composition differences. Assuming experimentally that the CSFII has adequately isolated composition differences in processed foods, the literature on geographic variations in primary food composition is reviewed to identify the nutrients most susceptible to under or over-estimation by national averaging and for the geographic scale of reported food composition variation. Regional nutrient contents are modeled using spatial statistics on soil and climate data in conjunction with the economic and individual factors already identified. The outcome is a reduction of uncertainty for insufficiencies in several nutrients.