Nutrient Availability Documentation
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 (ARS), 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 (for example,
protein, carbohydrates, fats, vitamins, and minerals) in the U.S.
food supply. 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 2006, 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
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
nutrients available for consumption are provided for 1970 and 2004
for each of the nutrients and dietary components included in this
series.
Nutrient Availability Coverage in ERS Tables
Nutrients and other food components include:
food energy, carbohydrates, protein, fat (total, saturated,
monounsaturated, and polyunsaturated), cholesterol, and dietary
fiber; vitamins (vitamin A, carotene, vitamin E, vitamin C,
thiamin, riboflavin, niacin, vitamin B6 , folate, and
vitamin B12); minerals (calcium, phosphorus, magnesium,
iron, zinc, copper, potassium, selenium, and sodium).
Nutrients contributed from major food groups,
include: meat, poultry, and fish; dairy products; eggs;
fats and oils; sugars and sweeteners; fruit (citrus and noncitrus);
legumes, nuts, and soy; grain products; vegetables (white potatoes,
dark green, deep yellow, and other vegetables; and
miscellaneous.
Constructing the Data
The food composition data used to estimate nutrients available
in the U.S. food supply were obtained from the Primary Nutrient
Data Set (PDS), which contains information about foods and their
nutrient profiles, and from USDA's Nutrient Database for Standard
References developed by ARS's Nutrient Data Laboratory (NDL).
To calculate nutrient estimates, ERS's annual per capita
availability estimate for 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 availability 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 currently based on the ERS Food
Availability Data System and not the Loss-Adjusted Food
Availability Data System; 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 these values do not account for
further losses from trimming, cooking, plate waste, and spoilage.
Another limitation is that per capita values are averages for the
U.S. population, although food is not equally distributed 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.
Estimates of nutrients available per capita in the U.S. food
supply have historically played a key role in nutrition monitoring
activities. These estimates are needed to monitor the food supply's
potential 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 over time. 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 assistance
policy, Federal dietary guidance, nutritional requirement
guidelines, nutrition education, fortification policy, and food
marketing strategies.