The big question: what's the difference between the RDA and the percent daily value? And what is the DRI?
There are several terms that are used when referring to the percent daily value or nutrient intake amounts. There's one term that's used to describe what you need to get in a day and another term that's used to describe what is present in a serving of a food or a supplement. The two most common terms used for these are the Recommended Daily Allowance (RDA) and the Daily Value (%DV). These terms, along with Dietary Reference Intakes (DRI) are often used interchangeably and they can be confusing.
"DRI is the general term for a set of reference values used to plan and assess nutrient intakes of healthy people. These values, which vary by age and gender, include:
Recommended Dietary Allowance (RDA): average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%-98%) healthy people.
Adequate Intake (AI): established when evidence is insufficient to develop an RDA and is set at a level assumed to ensure nutritional adequacy.
Tolerable Upper Intake Level (UL): maximum daily intake unlikely to cause adverse health effects." [1]
The RDA is the recommended daily intake of a given nutrient for the average healthy person. This tells you how much of a nutrient you absolutely need to consume on average every day. The RDAs are developed by the Food and Nutrition Board at the Institute of Medicine which are part of the National Academies of Science. They vary by age whether you are male or female or pregnant or breastfeeding.
The %DV (daily values) are used in food and supplement labels established by the US Food and Drug Administration, the FDA. The daily value is not a recommended intake but it simply suggests how much of a nutrient is in a single serving of a food or supplement, no matter the age or life stage of the person.
While daily values may sometimes match the RDA, they can exceed the RDA, or they can be lower than the RDA. The real purpose behind the daily value is to help individuals compare one product to another product. For example, if one product label says that this has 20% the daily value for calcium and another one has 100% the value for calcium, you know the one with the higher level will have more calcium.
Now just as a reminder, when we talk about the Dietary Reference Intakes or specifically the RDA, that is the average daily intake that is determined to be sufficient to meet the nutrient needs for nearly all individuals in a specific life stage or gender group. Keep in mind, the RDA is a minimum for average people.
On the other end of consumption, we have the UL or the tolerable upper level, which is not defined as a maximum, but as the highest level of daily nutrient intake that's likely to pose no risk of an adverse health event. Between the RDA and the UL is a lot of room for higher levels of nutrient consumption, still within safe levels, higher than the minimum, below the maximum. If we average all the recommended levels of vitamins for the age groups and the gender stages, we get a value between the RDA and the UL of 2271%, which means that you can consume 22.7 times the RDA on average before you even get to the UL (upper limit). For minerals, it's 870% on average so it means you can consume 8.7 times the RDA before you get to the UL for minerals.
