38. What are the dietary reference intakes?
The Dietary Reference Intakes (DRIs) are specific reference values for each nutrient issued by the United States ‘National Academy of Sciences’ Institute of Medicine. The DRIs are the specific amounts of each nutrient that one needs to consume to maintain good health, prevent chronic diseases, and avoid unhealthy excesses.
The Institute of Medicine periodically organizes committees of U.S. and Canadian scientists and health experts to update these recommendations based on the latest scientific research.
DRIs Tell You How Much of Each Nutrient You Need
Since the 1940s, the Food and Nutrition Board, part of the Institute of Medicine, has recommended amounts of essential nutrients needed daily to prevent a deficiency and promote good health. Because nutrient needs change with age, and because needs are different for men and women, different sets of recommendations were developed for each nutrient based on an individual’s age and gender. In other words, a teenager may need more of a specific nutrient than a 55-year-old (and vice versa) and women need more of certain nutrients during pregnancy and lactation, so they all have different DRIs. Since the 1940s the DRIs have been updated ten times.
In the 1990s, nutrition researchers identified expanded roles for many nutrients. Though nutrient deficiencies were still an important issue, research suggested that higher amounts of some nutrients could play a role in disease prevention. Also, as consumers began using more dietary supplements and fortified foods, committee members grew concerned that excessive consumption of some nutrients might be as unhealthy as, or even more dangerous than, not consuming enough. Hence, the Food and Nutrition Board convened a variety of committees between 1997 and 2004 to take on the enormous task of reviewing the research on vitamins, minerals, carbohydrates, fats, protein, water, and other substances such as fiber and developing the current DRI reference values for all the nutrients. As research evolves, changes are made in the DRIs.
DRIs Encompass Several Reference Values
The DRIs comprise five reference values: Estimated Average Requirement (EAR), Recommended Dietary Allowance (RDA), Adequate Intake (AI), the Tolerable Upper Intake Level (UL), and the Acceptable Macronutrient Distribution Range (AMDR). Each of these values is unique, and serves a different need in planning a healthy diet. It may seem like a lot to remember, but you will use only the RDA or AI (not both), the AMDR, and the UL to assess whether your diet is meeting your nutrient needs. The EAR is the starting point in the process of determining the other values.
Let’s look at how the values are determined. The DRI committee members begin by reviewing a variety of research studies to determine the Estimated Average Requirement (EAR) for the nutrient. They may look at studies that investigate the consequences of eating a diet too low in the nutrient and the associated side effects or physical changes that develop, as well as how much of the nutrient should be consumed to correct the deficiency. They may also review studies that measure the amount a healthy individual absorbs, stores, and maintains daily. Additionally, they look at research studies that address the role the nutrient plays in reducing the risk of associated chronic diseases, such as heart disease. After a thorough review process, the EAR for the nutrient is determined.
The EAR is the average amount of a nutrient that is known to meet the needs of 50 percent of the individuals in a similar age and gender group. The EAR is a starting point to determine the amount of nutrient individuals should consume daily for good health.
The EAR for Nutrient X is about 40 units for example. If the recommended reference value for Nutrient X was set at 40 units, then half of the individuals would be able to either meet or exceed their needs. However, the other 50 percent of the individuals would need more than the EAR to be healthy.
This is where the Recommended Dietary Allowance (RDA) comes in. The RDA is based on the EAR, but it is set higher. It represents the average amount of a nutrient that meets the needs of nearly all (97 to 98 percent) of the individuals in a similar group. The RDA for Nutrient X for example is 75 units. So, by setting the reference value at 75 units, nearly all of the individuals in this group will meet their needs for this nutrient.
If there is insufficient scientific information to determine the EAR for a nutrient, the RDA can’t be developed. When this happens, an Adequate Intake (AI) is determined instead. The AI is the next best scientific estimate of the amount of a nutrient that groups of similar individuals should consume to maintain good health.
Because consuming too much of some nutrients can be harmful, the committees developed the Tolerable Upper Intake Level (UL). The UL refers to the highest amount of a nutrient that is unlikely to cause harm if the amount is consumed daily.
The higher the consumption above the UL, the higher the risk of toxicity. You should not try to consume the UL of a nutrient. There isn’t any known benefit from consuming a higher amount, and it may cause health problems.
The DRI committee also developed a range of intakes for the energy-containing nutrients, carbohydrates, proteins, and fats. These ranges are called the Acceptable Macronutrient Distribution Ranges (AMDR) and are as follows:
Carbohydrates should comprise 45 to 65 percent of your daily calories.
Fat should comprise 20 to 35 percent of your daily calories.
Proteins should comprise 10 to 35 percent of your daily calories.
Consuming these nutrient types in these ranges will ensure that you meet your calorie and nutrient needs, and reduce your risk of developing chronic diseases such as heart disease and obesity.
Although dietary recommendations have been established for carbohydrate, fat, protein, vitamins, and minerals that meet the optimal intake of nutrients, no DRI has been established for your energy (calorie) intake. The method used to determine the amount of energy you need, or your Estimated Energy Requirement (EER), uses a different approach than the RDAs or AIs. In addition to taking into account your age and gender, the EER is calculated based on your height, weight, and activity level, and indicates the amount of energy you need daily to maintain energy balance. Individuals who consume more energy than they need will gain weight. Equations have been designed for men and women to provide a general estimate of energy needs. You can find the approximate amount of energy you require daily.
Tip-Top Nutrition Tips
Use traffic light colors to help you vary your lunchtime veggie choices. Add tomato slices (red) to your sandwich and carrots (yellow/orange) to your tossed salad (green).
Pop a snack-pack size of light microwave popcorn for a portion-controlled wholegrain snack.
Say “so long” to the elevator and hoof it up the stairs to work some extra physical activity into your day.
To keep your sweets to a discretionary amount, read the nutrition label and stick to a single serving that is no more than about 100 calories. Note that many big bars and bags contain more than double this amount.
Plan your dinner using at least one food from each of the food groups. Add tomato-pepper salsa (fruits and vegetables) and a can of rinsed black beans (meat and beans) to your macaroni (bread) and cheese (dairy) for a complete Mexican meal.
Dietary Reference Intakes (DRIs) - Reference values for the essential nutrients needed to maintain good health, to prevent chronic diseases, and to avoid unhealthy excesses
Estimated Average Requirement (EAR) - The average amount of a nutrient that is known to meet the needs of 50 percent of the individuals in a similar age and gender group.
Recommended Dietary Allowance (RDA) - The average amount of a nutrient that meets the needs of 97 to 98 percent of individuals in a similar age and gender group. The RDA is higher than the EAR.
Adequate Intake (AI) – The approximate amount of a nutrient that groups of similar individuals are consuming to maintain good health.
Tolerable Upper Intake Level (UL) - The highest amount of a nutrient that can be consumed daily without harm in a similar age and group of individual toxicity The level at which exposure to a substance becomes harmful.
Acceptable Macronutrient Distribution Range (AMDR) - A healthy range of intakes for the energy-containing nutrients - carbohydrates, proteins, and fats - in your diet, designed to meet your nutrient needs and help reduce the risk of chronic diseases.
Estimated Energy Requirement (EER) - The amount of daily energy needed to maintain a healthy body weight and meet energy (calorie) needs based on age, gender, height, weight, and activity level.