Dietary Reference Intakes (DRIs)

Dietary Reference Intakes (DRIs) are more than numbers in the table, even though that is often how many people view them. The link below takes you to the tables that many people commonly associate with the DRIs. These tables have been updated to include the new RDAs for vitamin D and calcium.

Web LinkDRI Tables

Most of you are probably familiar with Dietary Guidelines. DRIs and Dietary Guidelines provide different information for different audiences.

Dietary Guidelines provide qualitative advice to the public about diet and chronic disease prevention and maintaining health.

DRIs provide quantitative advice to professionals about amounts of nutrients or food components to be of benefit.

DRIs are a collective term to refer to these components:

• Estimated Energy Requirement (EER)
• Estimated Average Requirement (EAR)
• Recommended Dietary Allowance (RDA)
• Adequate Intake (AI)
• Tolerable Upper Intake Level (UL)

*A number of people refer to the UL as simply the “upper limit”, leaving off “tolerable”.

Estimated Energy Requirement (EER) is the estimated number of calories needed to maintain caloric balance. Using weight as a reference, this means you are taking in no more calories, and also no fewer calories, than are needed to maintain that exact weight. To gain weight, you’d

need to consume more than your EER, and to lose weight you’d need to consume less than your EER. Unlike some of the other DRIs, EER is individual-specific and is based on calculations that take into account multiple variables, including an individual’s energy intake, energy expenditure, age, sex, weight, height, and physical activity level3.

The Recommended Dietary Allowance (RDA) is the measure that professionals use to assess the quality of people’s diets. It is the requirement estimated to meet the needs of 97.5% of the population. However, the RDA is calculated using the EAR (Estimated Average Requirement).

Therefore, the EAR needs to be set before an RDA can be set. An Estimated Average Requirement (EAR) is the estimated requirement for 50% of the population (hence the “Average” in its name), as shown in the figure below. On the left vertical axis is the risk of

inadequacy, and on the bottom of the figure is the observed level of intake that increases from left to right. We will talk about the right axis label in a later figure. Notice that for the EAR, the risk for inadequacy is 0.5 (50%) whereas the RDA the risk of inadequacy is 0.025 (2.5%).

Figure 8.41 The EAR meets the needs of 50% of the population, RDA meets the needs of 97.5% of the population.

For nutrients lacking the research evidence needed to set an EAR, an AI is set instead. An Adequate Intake (AI) is a level that appears to be adequate in a defined population or subgroup. As you can see, the EAR is adequate for 50% of the population and is lower than the RDA. The RDA is adequate for 97.5% of the population, and higher than the EAR. The AI level of intake is believed to be between the EAR/RDA and the UL (Tolerable Upper Intake Level), but since it is not research-based, it is not exactly known where this level falls as shown below.

Figure 8.44 The AI compared to the other DRI components, the question mark and dotted line are meant to indicate that it is not known exactly where the AI would fall relative to an RDA if one was set.

The last of the DRIs is the Tolerable Upper Intake Level (UL). This is the highest level of daily nutrient intake that is unlikely to pose risk of adverse health effects to almost all individuals in

the population. To set this, the committee first sets a No Observed Adverse Effect Level (NOAEL) and/or the lowest observed adverse effect level (LOAEL). The UL is then set lower (as shown below) based on a number of uncertainty/safety factors, such as natural constituents, substances intentionally and directly added (i.e. food additives), substances indirectly added (i.e. pesticides), and contaminants such as naturally occurring chemicals, industrial products & by-products, and biological agents.2 The right vertical axis is used to represent the risk of an adverse event. Notice the NOAEL at the point where no adverse effects have been reported. The LOAEL is somewhere above the NOAEL. The UL is set at a level where it is believed that people will not experience the selected adverse effect.

Figure 8.45 Setting of the UL

How are Americans doing in meeting the DRIs? Figure 8.46 shows the percentage of Americans that are not meeting the EAR for some of the earlier micronutrients that had DRIs set. Keep in mind that the EAR is lower than the RDA.

Figure 8.46 Percent of Americans with usual intakes below the EAR1

Figure 8.47 Percent of Americans with usual intakes exceeding the AI1

As you can see, a large percentage of Americans don’t meet the EAR for vitamin E, magnesium, vitamin A, and vitamin C. Also, keep in mind that this also does not include micronutrients that have AI instead of EARs and RDAs.

References & Links

• http://health.gov/dietaryguidelines/2015-scientific-report/06-chapter-1/d1-11.asp
• https://ods.od.nih.gov/pubs/conferences/tolerable_upper_intake.pdf

• Gerrior, S., Juan, W., & Peter, B. 2006. An Easy Approach to Calculating Estimated Energy Requirements. Preventing Chronic Disease, 3(4), A129.

Link

DRI Tables – https://fnic.nal.usda.gov/sites/fnic.nal.usda.gov/files/uploads/recommended_intakes_individu als.pdf