Nutritional Guidelines Demystified: Decoding the DRI

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Whether or not they choose to follow them, most Americans are at least aware of the traditional nutritional guidelines set forth by the government. Few, however, know how they are determined. Furthermore, many nutritionally savvy individuals remain confused about the differences between the Dietary Reference Intake, or DRI, and the Recommended Dietary Allowance, or RDA. And many have never even heard of such acronyms as the AI and the EAR. (Say what?)

With the recent publication of the 2010 Dietary Guidelines for Americans, I think it is a good time to define these acronyms, examine their role in the system of nutritional recommendations and determine if the standards are adequate. Let’s first define the tools used to create the nutritional guidelines.

Dietary Reference Intake (DRI)

This is actually somewhat of an umbrella term. The DRI is comprised of both the RDA and the Adequate Intake, or AI, recommendations (explained below). The DRI is a set of nutritional recommendations established by the Institute of Medicine (IOM) of the U.S. National Academy of Sciences, which is used by both the U.S. and Canada

Recommended Dietary Allowance (RDA)

These figures were established in 1941. The RDA was created during World War II in order to lend some guidance to the nutrient standards for food being supplied to the armed forces and civilians. The government wanted a set of dietary guidelines that would keep our troops in fighting condition. However, since food was also being rationed, they needed to take food availability into account, as well. The National Academy of Sciences appointed members to a committee that would establish the RDA, and later become known as the Food and Nutrition Board.

Today, the RDA is widely considered the best, most rock-solid dietary standard. It is, by textbook definition, “the average daily nutrient intake level that meets the needs of nearly all (97-98%) healthy people in a particular life stage or gender group.”

I think what is important to note is that these nutritional guidelines merely “meet the need.” They are a designed to provide information necessary to determine if one is meeting the bare minimum requirement for a vitamin or mineral in order to avoid physical harm or deficiency.

Adequate Intake (AI)

In 1997, these guidelines joined with the RDA to become a part of a larger scale recommendation system known as the DRI. Many people have never heard of the AI, yet we know and reference it frequently. The AI is essentially a very educated guess regarding nutrient intake. For some nutrients, such as vitamin D, chromium and, believe it or not, calcium, there are only daily recommendations based on what scientists believe will meet the needs of an individual in a group. Lack of data or inconclusive data prevent scientists from being able to confidently state a rock-solid goal, such as what is provided by the RDA.

Tolerable Upper Intake Level (UL)

This number tends to scare people. However, if you closely look at the definition, you can see that it shouldn’t. It is defined as “the highest average daily nutrient intake level that is likely to pose no risk to almost all healthy individuals in a particular life stage or gender group.”

Many people believe they cannot consume the UL, but that is not the case. These figures are established under the assumption that one would take that amount every day for an extended period of time. Additionally, they were established as a means of control and protection — not to place a boundary. If one has a specific health concern that requires higher doses of a particular nutrient, they can safely exceed the UL under a health care provider’s supervision.  A good example of that now-a-days is vitamin D. The UL for vitamin D is 2,000 IU. However, as more and more people are being found to have extremely low vitamin D levels, physicians are prescribing up to 50,000 IU to be taken weekly for a period of time. That is perfectly safe. Each UL should be examined and appropriately applied on a case-by-case basis.

Estimated Average Requirement (EAR)

These figures essentially go unnoticed, but they are the important numbers that are the basis for the RDA. They are determined by “the average daily nutrient intake estimated to meet the requirements of nearly half of the healthy individuals in a particular life stage and gender group.”

Daily Value (DV)

This is the number you see on food labels. It expresses the percentage of the DRI for a given nutrient that you will obtain by consuming a serving of the food contained in the package. For strict dieters and nutritionally conscious individuals, the DV does not represent the best measure, since it takes into account all age and gender groups to find its values. It does, however, serve as an excellent way to compare nutrient content in food of the same food group.

The DRI committee also factors in chronic disease prevention. For example, it is believed that calcium intake at certain levels will reduce the likelihood of osteoporosis, so they set lifetime calcium goals based on that evidence.

So how do we put this all together and apply it in real life? That’s where it gets a little trickier. It is important to note these two things:

1)      These figures are based on the “average” amounts needed to prevent chronic conditions and other physical dangers. While the RDA is set to cover 97-98% of the population, it is not based on nutrient intake that may offer health benefits “above and beyond” what is considered “normal.”

2)      DRI intakes are based on recommendations for “healthy people.” These guidelines do not factor in one’s environment (pollution and other factors may slightly increase the need for certain nutrients), lifestyle (habits such as smoking and consuming alcohol increase the need for certain nutrients), or existing health concerns or conditions.

So why do some believe that the DRI values are possibly inadequate? Well, let me preface this by saying that I genuinely believe that the DRI is a helpful tool and that the DRI committee has the best intentions when creating a reference system that is meant to accommodate the greatest number of people possible. However, just by the nature of their creation, it is easy to see where there may be influenced by more than just health. By providing these guidelines and applying them in government-run agencies, they are able to create systems of control that can be applied in terms of, of course, money.

When you consider the intent of the RDA back in 1941, their purpose becomes clearer: to provide the most protection possible while taking into account our limited means. In the U.S., we have programs in place that offer assistance to those who are not in the fortunate financial situation that affords them access to nutritious food. Programs such as unemployment, food stamps and WIC must take nutrient intake needs into account. When these programs are designed and budgeted, they must consider how much money is required to obtain the foods necessary to meet nutritional goals for general health. I’m not suggesting that it is a huge conspiracy, but you can imagine that there might be resistance to suggestions that a nutrient intake recommendation be increased. To do so would immediately require that government funded food programs re-evaluate their budgets.

Another way to understand how the dietary guidelines could potentially be influenced by money is to consider their role in protecting health.  Organizations can say, “consume this much, and we can possibly prevent some of the health disasters that may be lurking around the corner.” Or, more accurately, “consume this much, and we can possibly prevent a hospital stay or life-threatening situation that will cost a great deal of money and possibly increase insurance fees.”

It is true that dietary guidelines are designed to be helpful, but let’s not kid ourselves — they are also regulatory measures. There are many government-run organizations and programs that rely on these stats and figures as the basis of their operation. Oftentimes, the scope of influence that these seemingly simple and innocent numerical values have goes unacknowledged.

When considering all of the evidence, it’s important to note that, while government-sponsored nutritional recommendations take into account the interests of the general population, they are simply guidelines. As you create your personal strategy for achieving optimal health, it’s a good idea to dig deeper, weigh all of the evidence and determine when it is appropriate or beneficial to go above and beyond what is recommended as part of the dietary guidelines. In many cases, it is beneficial to aim higher.

Tags: Daily Reference Intake, Daily Value, DRI, holistic nutrition, nutrient recommendations, nutritional deficiencies, nutritional guidelines, RDA, Recommended Daily Allowance, USDA dietary guidelines