Dietary Reference Intakes:
Maybe We Got It Right This Time.

World, meet the "Dietary Reference Intakes".  Remember when we had "Recommended Dietary Allowances" or RDAs for vitamins, minerals and other nutrients.  

It seemed pretty simple and straightforward.  The only problem
was that in too many cases it was either wrong or misleading.

The issues with the RDAs were that not everyone requires the same amount of nutrients.  

A persons daily nutritional needs depend on their state of health, age or stage of life, gender and possibly cultural background.

Nutritionists and dietary professionals recognized that a change was needed in the way they approached evaluation of diets in healthy people. 

So in the early 1990s, the Food and Nutrition Board of the National Academy of Sciences took on the task of revising the RDAs and a few years later, in 1997, the RDA became the DRI, the Dietary Reference Intakes.

The Dietary Reference Intakes is plural in that it is actually a family of four nutrient reference values.

The four family members are the:

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

The EAR is a daily nutrient intake value that is estimated to meet the requirement of half of the healthy individuals in a life stage and gender group.  It is used to assess dietary adequacy and as the basis of the RDA.

The UL is the highest level of daily nutrient intake that is likely to pose no risk of adverse health effects for most people in the general population.  As intakes rise above the UL, the potential risk of adverse effects increases.

The AI is a recommended intake value based on observed or experimentally determined approximations or estimates of nutrient intake by a group of healthy people.  They are assumed to be adequate when an RDA cannot be determined.

The RDA is the average daily dietary intake level that is sufficient to meet the nutrient requirement of nearly all healthy individuals in a particular life stage and gender group.

Who were the Dietary Reference Intakes (DRI) created for?

It seems that no one outside of the inner group of professional nutritionists know about the Dietary Reference Intakes.  The DRIs don't appear on supplement labels. 

The label on the vitamin, mineral and phytochemical supplements most people take have two columns; one is "Amount per Serving" and the other is "% Daily Value".

One could infer that the "% Daily Value" is the RDA but there is nothing that says what the daily value is based on.

It is probably safe to say that the Dietary Reference Intakes were in fact created for the benefit of dietary professionals; people who develop menus for hospitals, nursing homes, prisons, military and similar.  They are also used by nutritionists and scientists working in research and academic venues.

Want to do an experiment?  Ask one of your friends what the dietary reference intakes are and see what they say.

There is even confusion among the professionals.  Most of the confusion stems from the fact that the DRIs were rolled out in stages, not all at once. 

For example, the first one released in 1997 addressed the values for calcium and related nutrients such as Phosphorus, Magnesium, Fluoride and Vitamin D.

In 1998 the values for Folate and the other B vitamins were released.  Vitamin C and E, Selenium and Carotenoids
followed in 2000.

Year-by-year values were released for additional nutrient classes until all were completed.

The Dietary Reference Intakes tables are large and complex, covering every possible permutation; age, sex and stage of life.  If female, they address values for pregnancy and lactating.

There are separate tables for vitamins, elements (minerals), Macronutrients (fat, fiber, cholesterol, etc.), electrolytes and water, and special tables for individuals and older adults.

Anyone who has a need to wade through all this data can do so at the Institute of Medicine.

By clicking on the appropriate report shown in the "Reports Index", one can select an option to either buy the report or read it free online.

For comparative purposes, the table below shows the 1989 RDA and the new DRI for 13 vitamins usually seen on multivitamin supplement labels.

RDA and DRI Comparison Table from USDA

Vitamin1989 RDADRIs
Vitamin A
1000 mcg
900 mcg
Vitamin C
60 mg
90 mg
Vitamin D
10 mcg
15 mcg
Vitamin E
10 mg
15 mg
Vitamin K
80 mcg
120 mcg
1.5 mg
1.2 mg
1.8 mg
1.3 mg
20 mg
16 mg
Vitamin B-6
2 mg
1.7 mg
200 mcg
400 mcg
vitamin B-12
2 mcg
2.4 mcg
30-100 mcg
30 mcg
4-7 mg
5 mg

On an mg or mcg basis the differences between the 1989 RDAs and the new DRIs don't appear to be very significant but the percentage differences can be meaningful.

Do the Dietary Reference Intakes
have a future?

Unequivocally, the DRI values have a future if for no other reason than the government will see to it.

Studies are ongoing about the best way to use DRIs on food labels and it is expected that the FDA will weigh in sooner or later.  If change will create or protect jobs and turf, you can be sure change is coming. 

The food suppliers and supplement manufacturers will never change on their own but when the FDA decrees change, the food and supplement companies will comply.

There may be implications for revisions of the USDA Food Pyramid. (MyPyramid), dietary guidelines and various existing food and nutrition policies.

If you linked into the USDA above, you saw that they are already converting their nutritional values to the Dietary Reference Intakes. 

The bottom line is that unless you are a professional dietician or nutritionist or academic, it doesn't make much difference if you follow the RDA values or the DRI values; don't lose any sleep over it. 

It was only presented here as a matter of information so you would know what's going on when your food labels start looking a little different.

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