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Part One Food Habits: A Lifestyle Choice
to aid consumers in selecting a healthy
diet. These tools continue to be revised
as new information is discovered.
Dietary Reference
Intakes
In the 1990s, the Food and Nutrition
Board of the National Academy of
Sciences and Health Canada began
to work together to develop new
dietary standards for both Americans
and Canadians. In 2005, the fi nal set
of Dietary Reference Intakes (DRIs)
was released. The Dietary Reference
Intakes (DRIs) are reference values for
nutrients and food components that
can be used to plan and assess diets for
healthy people, 4-1. The purpose of the
DRIs is to promote health, and prevent
chronic disease and the effects of exces-
sive or defi cient nutrient intakes.
The DRIs include four types of
nutrient reference standards—Estimated
Average Requirement, Recommended
Dietary Allowance, Adequate Intake,
and Tolerable Upper Intake Level.
The Estimated Average Requirement
(EAR) is a nutrient recommendation
estimated to meet the needs of 50 percent
of the people in a defi ned group. If a
group of people consumes a nutrient at
this level, half would be defi cient. This
standard is based on scientifi c evidence
and is used for calculating the Recom-
mended Dietary Allowance.
The Recommended Dietary
Allowance (RDA) is the average daily
intake of a nutrient required to meet the
needs of most (97 to 98 percent) healthy
individuals. RDAs are based on EARs.
The RDA can be used as an aim for
typical daily intake for an individual.
Adequate Intake (AI) is a reference
value that is used when there is insuf-
fi cient scientifi c evidence to determine
an EAR. Since an EAR cannot be
established for these nutrients, an RDA
cannot be determined either. Instead,
the intake recommendation is based on
estimates and observations of people
who appear to be healthy and well-
nourished. As more research becomes
available, AIs for some nutrients may
be replaced by EARs and RDAs. AIs are
used for all nutrients for infants.
The Tolerable Upper Intake Level
(UL) is the maximum level of ongoing
daily intake for a nutrient that is
unlikely to cause harm to most people
in the defi ned group. Daily intake
above the UL for a nutrient could be
harmful. ULs are not recommended
levels of intake. Not enough information
is available to set ULs for all nutrients.
DRIs are just one type of standard
and should be used primarily by health
professionals for planning and evaluating
the diets of groups of people. To fully
evaluate a diet, overall eating patterns
and health conditions must be taken into
consideration. Such factors as medications
and illness can affect nutrient needs.
A true nutrient lack or excess can be
determined only through medical tests.
4-1 Many people want to know what
foods they should choose to keep their
bodies healthy.