The Reference Daily Intake or Recommended Daily Intake (RDI) is the daily intake level of a nutrient that is considered to be sufficient to meet the requirements of 97–98% of healthy individuals in every demographic in the United States. While developed in USA it has been used in other countries though it is not universally accepted.
Contents
The RDI is used to determine the Daily Value (DV) of foods, which is printed on nutrition facts labels (as %DV) in the United States and Canada, and is regulated by the Food and Drug Administration (FDA) and Health Canada respectively.
The Recommended Dietary Allowances (RDAs) were a set of nutrition recommendations that evolved into both the Dietary Reference Intake (DRI) system of nutrition recommendations (which still defines RDA values) and the RDIs used for food labelling. The first regulations governing U.S. nutrition labels specified a % U.S. RDA declaration based on the current RDA values, which had been published in 1968. Later, the % U.S. RDA was renamed the %DV and the RDA values that the %DVs were based on became the RDIs.
The RDAs (and later the RDA values within the DRI) were regularly revised to reflect the latest scientific information, but although the nutrition labeling regulations were occasionally updated, the existing RDI values were not changed, so that until 2016 many of the DVs used on nutrition facts labels were still based on the outdated RDAs from 1968. In 2016 the Food and Drug Administration published changes to the regulations including updated RDIs and DVs based primarily on the RDAs in the current DRI. Larger manufacturers must start using the new labels by July 26, 2018 and all manufacturers must use the new values from July 26, 2019.
History
The RDI is derived from the RDAs, which were first developed during World War II by Lydia J. Roberts, Hazel Stiebeling and Helen S. Mitchell, all part of a committee established by the U.S. National Academy of Sciences to investigate issues of nutrition that might "affect national defense" (Nestle, 35). The committee was renamed the Food and Nutrition Board in 1941, after which they began to deliberate on a set of recommendations of a standard daily allowance for each type of nutrient. The standards would be used for nutrition recommendations for the armed forces, for civilians, and for overseas population who might need food relief. Roberts, Stiebeling, and Mitchell surveyed all available data, created a tentative set of allowances for "energy and eight nutrients", and submitted them to experts for review (Nestle, 35). The final set of guidelines, called RDAs for Recommended Dietary Allowances, were accepted in 1941. The allowances were meant to provide superior nutrition for civilians and military personnel, so they included a "margin of safety". Because of food rationing during the war, the food guides created by government agencies to direct citizens' nutritional intake also took food availability into account.
The Food and Nutrition Board subsequently revised the RDAs every five to ten years. In 1973, the FDA introduced regulations to specify the format of nutrition labels when present, although the inclusion of such labels was largely voluntary, only being required if nutrition claims were made or if nutritional supplements were added to the food. The nutrition labels were to include percent U.S. RDA based on the 1968 RDAs in effect at the time. The RDAs continued to be updated (in 1974, 1980 and 1989) but the values specified for nutrition labelling remained unchanged.
In 1993 the FDA published new regulations mandating the inclusion of a nutrition facts label on most packaged foods. Originally the FDA had proposed replacing the percent U.S. RDAs with percent daily values based on the 1989 RDAs but the Dietary Supplement Act of 1992 prevented it from doing so. Instead it introduced the RDI to be the basis of the new daily values. The RDI consisted of the existing U.S. RDA values (still based on the 1968 RDAs as the FDA was not allowed to change them at the time) and new values for additional nutrients not included in the 1968 RDAs.
In 1997, at the suggestion of the Institute of Medicine of the National Academy, the RDAs became one part of a broader set of dietary guidelines called the Dietary Reference Intake used by both the United States and Canada. As part of the DRI, the RDAs continued to be updated.
In 2016, the FDA updated the regulations to change the RDI and Daily Values to reflect current scientific information. Until this time, the Daily Values were still largely based on the 1968 RDAs. The new regulations make several other changes to the nutrition facts label to facilitate consumer understanding of the calorie and nutrient contents of their foods, emphasizing nutrients of current concern, such as vitamin D and potassium. The revision to the regulations came into effect on 26 July 2016 and larger manufacturers must comply within two years while smaller manufacturers must comply by 26 July 2019.
Sodium
In 2010, the U.S. Institute of Medicine determined that the government should establish new consumption standards for salt to reduce the amount of sodium in the typical American diet below levels associated with higher risk of several cardiovascular diseases, yet maintain consumer preferences for salt-flavored food. The daily maximum for sodium in the United State had been above estimated minimums for decades. For instance, the National Research Council (United States) found that 500 milligrams of sodium per day (approximately 1,250 milligrams of table salt) is a safe minimum level. In the United Kingdom, the daily allowance for salt is 6 g (approximately 2.5 teaspoons, about the upper limit in the U.S.), an amount considered "too high".
The Institute of Medicine advisory stated (daily intake basis): "Americans consume more than 3,400 milligrams of sodium – the amount in about 1.5 teaspoons of salt – each day. The recommended maximum daily intake of sodium – the amount above which health problems appear – is 2,300 milligrams per day for adults, about 1 teaspoon of salt. The recommended adequate intake of sodium is 1,500 milligrams per day, and people over 50 need even less."