The Recommended Dietary Allowances (RDAs) were first established in 1941 by the Food and Nutrition Board. At that time, nutrition science was still in its infancy: thiamin was the first vitamin to be isolated in 1926; the first Nobel Prize for vitamin discovery were awarded in 1928. The RDAs were developed to aid the American public in following a diet that would provide enough nutrients to prevent vitamin deficiencies. To keep up with the advancements in nutrition science, the RDAs have been updated every 5 years until the 10th and last edition was published in 1989. This final edition delivered recommendations for nutrient intake for protein, 13 vitamins, 12 minerals and 3 electrolytes; these recommendations were provided for 18 life stages and different groups based on gender, age and life stages (pregnancy and lactation) (Lee & Nieman, 2013). The RDAs guidelines have also been used for food labeling, food planning, dietary survey data and other purposes for which they were not originally intended.
The biggest limitation of RDAs consisted in the fact that its dietary guidelines aimed at preventing nutrient-related diseases instead of obtaining and maintaining optimal health. For this reason, in the 1990s the RDAs guidelines were broadened and collected in what is known as the Dietary Reference Intakes (DRIs) discussed below.
Recommended Daily Allowances
The Dietary Guidelines are different than the RDAs in multiple ways: the RDAs give recommendations for 18 life stages and different groups based upon gender, age and life stages (pregnancy and lactation). The Dietary Guidelines has only one set of recommendations for all individuals over the age of 2 and therefore needs to work across a wide range of energy needs. Most Dietary Guidelines are given either as a percentage of total calories or as a recommendation for a nutrient in a certain amount for every 1,000 calories consumed. Another major difference between RDAs and Dietary Guidelines is that there is an RDA for every essential nutrient while the Dietary Guidelines only provide recommendations for those nutrients that are linked to diet-related chronic diseases. For example, the RDA for carbohydrates in adults is 130 grams, while the Dietary Guidelines for carbohydrates is 45-65% of total calories. When nutrition professionals assess a patient’s intake for carbohydrate they look at both references: the use RDAs to look for the amount needed to meet nutrient demands, and they also use the Dietary Guidelines to assess amounts of carbohydrates needed to reduce incidence of diet-related chronic disease.
The Dietary Reference Intakes (DRIs) were first published in 1997 as the result of a collaboration between the Food and Nutrition Board and the Canadian Government. Canadian and American scientists worked together for over two years to bridge the gap between the information provided by the RDAs and the nutrition information the public needed and wanted. The initial report covered only 5 nutrients, but following reports spanning a decade were expanded to include guidelines on all vitamins and minerals, as well as macronutrients, hydration, fiber intake and exercise. The DRIs are updated as new information becomes available.
The DRIs are a collection of nutrient standards. They maintained the RDA’s focus on preventing nutrient deficiencies and added other standards: The Tolerable Upper Limit (UL) and the Acceptable Macronutrient Distribution Range (AMDR). The UL provides a standard for excess intake, while the AMDR provides a guidance on the percentage of calories from the different macronutrients that aligns with consuming adequate nutrient intake.
Dietary Guidelines
The Dietary Guidelines for Americans were first published in 1980 and have been updated every 5 year since. The purpose of the Dietary Guidelines is to provide nutrition recommendations with a focus on preventing chronic disease and to promote healthy eating and exercise habits to “improve the health of our Nation’s current and future generations” (McGuire, 2011).
The Dietary Guidelines are different than the RDAs in multiple ways: the RDAs give recommendations for 18 life stages and different groups based upon gender, age and life stages (pregnancy and lactation). The Dietary Guidelines has only one set of recommendations for all individuals over the age of 2 and therefore needs to work across a wide range of energy needs. Most Dietary Guidelines are given either as a percentage of total calories or as a recommendation for a nutrient in a certain amount for every 1,000 calories consumed. Another major difference between RDAs and Dietary Guidelines is that there is an RDA for every essential nutrient while the Dietary Guidelines only provide recommendations for those nutrients that are linked to diet-related chronic diseases. For example, the RDA for carbohydrates in adults is 130 grams, while the Dietary Guidelines for carbohydrates is 45-65% of total calories. When nutrition professionals assess a patient’s intake for carbohydrate they look at both references: the use RDAs to look for the amount needed to meet nutrient demands, and they also use the Dietary Guidelines to assess amounts of carbohydrates needed to reduce incidence of diet-related chronic disease.
