What Are Dietary Reference Intakes?

The DRI is determined for nutrients and water intake

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Dietary Reference Intakes, or DRIs for short, are a series of values that define the recommended daily requirements, the minimum daily needs, and the maximum tolerable daily amounts for each nutrient. They were developed by the Institute of Medicine of the National Academies in the mid-1990s. (Today, it's known as the Health and Medicine Division of the National Academies of Sciences, Engineering, and Medicine.) Canada and the UK have similar dietary reference values.

There are DRIs for vitamins, minerals, fat, protein, fiber, carbohydrates and even water intake. (They're available here on the Health and Medicine Division's website.)  The DRIs are really helpful for dietitians who plan diets because these values help them design well-balanced meal plans so that consumers and clients will be most likely to get all the nutrients they need every day. 

The DRIs are based on age and sex. Not every nutrient is the same, though. For example, the DRIs for iron need vary considerably by age and sex while the DRI for selenium is about the same for all teens and adults. Also, DRIs have been calculated for women who are pregnant or breastfeeding because they usually require a bit more of most nutrients.

What Are the Values that Make Up the DRIs?

Essentially there are four reference values that make up the DRIs. They're known as the EAR, the RDA, the AI and the UL.

The Estimated Average Requirement (EAR) ​is the average daily nutrient intake estimated to meet the requirement of half the healthy individuals who are all the same sex and of a similar age.

It's mostly used by dieticians when they need to plan diets for large groups and by nutrition researchers. It's not something the average consumer needs to worry about.

The Recommended Dietary Allowance (RDA) is the average daily dietary intake levels that are enough to meet the nutritional needs of about 98 percent of people of the same sex and similar age.

This is when knowing the EAR comes in handy because the RDA is calculated from the EAR of any given nutrient. 

The key thing with an RDA is knowing that as long as you meet your RDA for any given nutrient every day, then it's extremely unlikely that you'll be deficient in that nutrient.

So for example, for women, the RDA for vitamin C is 75 milligrams per day. So as long as you eat enough vitamin-C containing foods to meet that mark, you should have plenty of vitamin C. To do that you'll need to eat some fruits and veggies every day. 

The Adequate Intake (AI) is similar to the RDA but not as exact because nutrition scientists haven't been able to establish an EAR and RDA. But, even though it's not exact, the AI is still based on good science so it's a great estimate that can be used for planning meals plans. 

For example, there's no RDA for potassium intake, but it's certainly a vital mineral. The AI is set at 4.7 grams per day, which is a great mark to shoot for when you're planning your meals.

And just like vitamin C, if you eat plenty of fruits and vegetables, you should be able to meet this AI without too much problem.

The Tolerable Upper Intake Level (UL) is the highest level of daily intake of a given nutrient that won't pose a risk to your health in anyone of a similar age and same sex. The UL is most important for supplement use. It's not common to overdo any one nutrient simply by eating foods. But several nutrients can become dangerous if they're ingested in large enough amounts over time. So if you take dietary supplements for any reason, follow the dosage as directed on the label, unless your health care provider has told you otherwise and is monitoring any health conditions you may have.

An example of an important UL is for vitamin A. Daily consumption of more than 3,000 micrograms per day may result in vitamin A toxicity and liver problems. And women who are pregnant and take too much vitamin A on a daily basis have a greater risk of certain birth defects.

So How Do I Use This Information?

Your dietician knows exactly what to do with DRIs, of course, but they're also helpful for for the average consumer who's just trying to figure out which foods to eat every day. By reviewing the DRIs and keeping track the nutritional value of the foods you consume, you'll know if you're getting enough of all the essential nutrients.

Now, I know that sounds like a ton of work, and before the internet became a daily part of our lives, it was a hassle. But today with sites such as CalorieCount and ChooseMyPlate, all you need to do is set up a profile, type in the foods you eat (or plan to eat) every day and the site will do the work for you. 

How Do DRIs Compare to DVs?

The Daily Value (DV) was designed by the United States Food and Drug Administration to help consumers learn more about the nutrients found in the packaged foods they're buying. The DV is similar to the RDA or AI, but not always the same because it doesn't take age or sex into consideration. Instead, the DVs are based on daily caloric intakes, and when you look at Nutrient Facts labels, you'll see the DV as "%DV" and you'll be able to see what percentage of your daily need for that nutrient is met by one serving of the food product.

Nutrient Facts labels are required for all packaged foods, but not all nutrients will be listed. You will see things like calories, fats, cholesterol, trans fat, sugars, protein, carbohydrates, fiber, calcium, iron, sodium, vitamin A, and vitamin C. Sometimes you'll see more vitamins or minerals listed, but that's up to the food manufacturer.

Sources:

National Institutes of Health, Office of Dietary Supplements. "Daily Values." Accessed June 29, 2016. https://ods.od.nih.gov/HealthInformation/dailyvalues.aspx.

Institute of Medicine (US) Food and Nutrition Board. Dietary Reference Intakes: A Risk Assessment Model for Establishing Upper Intake Levels for Nutrients. Washington (DC): National Academies Press (US); 1998. "What are Dietary Reference Intakes?" Accessed June 29, 2016. http://www.ncbi.nlm.nih.gov/books/NBK45182/.

Institute of Medicine (US) Subcommittee on Interpretation and Uses of Dietary Reference Intakes; Institute of Medicine (US) Standing Committee on the Scientific Evaluation of Dietary Reference Intakes. Dietary Reference Intakes: Applications in Dietary Planning. Washington (DC): National Academies Press (US); 2003. "Using Dietary Reference Intakes in Planning Diets for Individuals." Accessed June 29, 2016. http://www.ncbi.nlm.nih.gov/books/NBK221374/.

The National Academies of Sciences, Engineering, and Medicine, Health and Medicine Division. "Dietary Reference Intakes Tables and Application." Accessed June 29, 2016. http://www.nationalacademies.org/hmd/Activities/Nutrition/SummaryDRIs/DRI-Tables.aspx.

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