Dietary Reference Intake is a term for a set of nutrient intake recommendations for healthy people. They include the average daily level that nearly all healthy people should take to meet the nutrient requirements. They also include the maximum level a healthy person could take of a nutrient before it could cause a health problem. These are known as the Recommended Dietary Allowance (RDA) and the Tolerable Upper Intake Level (UL).
A third recommendation sometimes used is called Adequate Intake (AI). This is used only when there isn't enough information about a nutrient to set a Recommended Dietary Allowance. Adequate Intake is a level that is assumed to provide enough of that nutrient.
The RDA, UL, and AI are issued by the Food and Nutrition Board of the Institute of Medicine, an independent nonprofit scientific body. They release reports periodically to update the recommendations based on all of the latest data.
For example, in 2011, new recommendations were released by the Institute of Medicine for vitamin D and calcium.1 They included AI, RDA, and UL levels for different age groups, genders, and for pregnant or lactating women. The experts who wrote the recommendations looked at the national data on what people eat, what levels of the nutrients are in the blood, and all the available data published about calcium and vitamin D. They examined how much vitamin D and calcium people are getting, how much is needed for optimal health, and how much is too much.
Are you getting enough calcium and vitamin D?
You might also be wondering about the Daily Value, or DV, which is found on the Nutrition Facts label of any packaged food or drink. The DV helps you understand the nutrient content of food. For example, the DV for calcium is 1,000 mg. If one serving of a food contains 200 mg of calcium, the label would say that it contains a DV of 20% for calcium. In other words, one serving gives you 20% of the daily value for calcium. If you add up the DVs of calcium you eat throughout the day, you'll have a general idea of how much calcium you got that day. Compare that to your RDA for calcium, based on your age and gender. Then you'll know if your calcium intake was enough or even if it was too much, which might be a concern if you not only eat enough calcium but also take a calcium supplement.