Nutrient Availability: Documentation

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Using ERS data on the amount of food available for consumption and information on the nutrient composition of foods from USDA's Agricultural Research Service, USDA's Center for Nutrition Policy and Promotion (CNPP) calculates the nutrient content of the U.S. food supply, or nutrient availability. This historical data series estimates the amounts per capita per day of food energy (calories) and 27 nutrients and dietary components (i.e., protein, carbohydrates, fats, vitamins, and minerals) in the U.S. food supply. The series also provides annual estimates for about 400 basic commodities, starting in 1909. The data available here summarize the nutrients and other food components available per capita per day in the U.S. food supply between 1970 and 2004 (newly available), and the nutrients contributed by the major food groups, per capita per day for 1970 and 2004. The entire historical series, including an interactive version of the data, is available on the CNPP website.

Coverage of the Data

Per capita estimates are made for food energy and the energy-yielding nutrients—protein, carbohydrates, and fat (total, saturated, monounsaturated, and polyunsaturated), cholesterol, dietary fiber, 10 vitamins, and 9 minerals. Estimates of percentage contributions of nutrients by major food groups and quantities of food available for consumption are provided for 1970 and 2004 for each of the nutrients and dietary components included in this series.

Constructing the Data

Food composition data used to estimate the nutrients available in the U.S. food supply were obtained from the Primary Nutrient Data Set (PDS), containing about foods and their nutrient profiles and USDA’s Nutrient Database for Standard References developed by the ARS’s Nutrient Data Laboratory (NDL). In addition, food specialists in NDL developed nutrient profiles for unique items for use with food supply calculation.

To calculate nutrient estimates, the annual per capita availability of a commodity is multiplied by the amount of food energy and each of 27 nutrients and dietary components found in the edible portion of the food. Results for each nutrient from all foods are totaled and converted to the amount per capita per day. Nutrients added to certain commodities commercially through fortification and enrichment are also included in the nutrient content of the food supply. Since food availability data represent the disappearance of food into the marketing system, per capita consumption and nutrient estimates typically overstate the amount of food and nutrients people actually ingest.

Nutrient values exclude nutrients from the inedible parts of foods, such as bones, rinds, and seeds, but include nutrients from edible parts of food that are not always eaten, such as separable fat on meat.

Limitations of the Data

Nutrient estimates are based on the ERS food availability data; thus they represent nutrients and foods available for consumption and not actual nutrient intakes by individuals. Nutrient levels of the food supply should exceed recommended allowances because further losses from trimming, cooking, plate waste, and spoilage are not accounted for in these values. Another limitation is that per capita values are averages for the U.S. population, though food is not distributed equally among the population.

Usefulness of the Data

Nutrient estimates reflect market conditions, technological developments, up-to-date food composition values, and nutrients added commercially through enrichment and fortification. Nutrient levels and nutrient contributions from major food groups to the U.S. food supply are used to examine historical trends and evaluate changes in the average American diet over time.

Food availability per capita nutrient estimates have historically played a key role in nutrition monitoring activities. These estimates are needed to monitor the potential of the food supply to meet the nutritional needs of the U.S. population, as well as to examine historical trends and to evaluate changes in the American diet. These estimates provide unique and essential information about the amount of food and nutrients available for human consumption in the United States. Food supply nutrients are closely linked to food and nutrition policy, Federal dietary guidance, nutritional requirement guidelines, nutrition education, fortification policy, and food marketing strategies.

For more information see Nutrient Content of the U.S. Food Supply, 1909-2000, Food Availability documentation, Related Links, and Glossary.

View or download Excel spreadsheets of Nutrient Availability data.