What Does RDA Mean for Me?

RDA stands for recommended dietary allowance. The Food and Nutrition Board of the National Academy of Sciences Institute of Medicine establishes RDAs, which recommend levels of micronutrient (vitamin and mineral) and macronutrient (carbs, fat, and protein) intake daily for people in various categories based on sex, age, and certain health conditions like pregnancy and breastfeeding. The RDA is designed to ensure an, "average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%-98%) healthy people," according to the National Institutes of Health.

RDA and Dietary Reference Intakes

The RDA is one of three different types of Dietary Reference Intakes (DRI) established by the Institute of Medicine's Food and Nutrition Board, along with Adequate Intake (AI - an amount of nutrients needed to ensure nutritional adequacy), and the Tolerable Upper Intake Level (UI - the maximum daily intake of a nutrient that won't cause health issues). All of these reference standards have variations based on traits, such as gender, age, and certain health conditions.

History

According to the National Academies Press, RDAs were first developed by the Institute of Medicine's Food and Nutrition Board in 1941, and the first edition of RDAs was published in 1943. Since then, RDAs were edited and revised nine times. All DRIs, including RDAs, are reassessed from time to time as committees and members from the Food and Nutrition Board evaluate new research and information. The most recent update to all DRIs, including RDAs, was in 2003.

RDA and Diet

All the foods you eat contain energy (calories), macronutrients, and micronutrients. Packaged foods have labels that show at least some nutrient information; typically calories, protein, fat (and saturated fat), carbohydrates, cholesterol, sodium, fiber, sugars, vitamin A, vitamin C, and calcium. These labels list the amount of these nutrients per serving, and also offer a percentage of the RDA the food meets. There are also online tools for calculating nutrients for unlabeled foods, since fruit, veggies, and other unpackaged foods typically don't have a nutrition label. In general, nutrition labels assume RDA percentages for an adult male eating a 2,000 calorie per day diet.

Examples

For example, the current RDA for vitamin C for nonsmoking adult men and women is 60mg. This is the established recommendation to prevent scurvy, which is a disease vitamin C deficiency causes. Suppose you eat some fruit snacks, and the label says it contains 20 percent (20%) of the RDA for vitamin C. This means it contains 12mg of vitamin C (60mg x 20%), and you will need to eat foods containing an additional 48mg of vitamin C to meet the minimum requirements to avoid deficiency.

For another example, say you ate an apple, and you were wondering about vitamin A. Since an apple doesn't come with a label, you'd need to look up how much vitamin A it has using a nutrition tool. According to the nutrition calculation, you see the apple contains 1 percent (1%) of the daily intake for vitamin A. The RDA for vitamin A is 900 micrograms daily for men. This means the apple contains 9 micrograms of vitamin A, and you will need an additional 899 micrograms to meet minimum requirements.

Not Meeting the RDA

Depending on how nutrient dense your diet is, you may not meet the RDA for every nutrient every day. On varying days, you may go over for vitamin C and under for vitamin A, but on the next day be over for vitamin A and under for vitamin C. What's important is that you average at least the RDA for each nutrient on a daily basis. So if on Monday you have 75mg of vitamin C, on Tuesday you have 45mg, and on Wednesday you have 100mg, over the course of these three days you have averaged 73mg, which is over the RDA.

Exceeding the RDA

It's important to remember the RDA is a minimum average recommendation to avoid deficiencies. So in most cases, it's perfectly okay to go over the RDA for nutrients provided you stay within one of the other DRIs, the UI (Tolerable Upper Intake Level), which will prevent you from overdose from certain nutrients. However, it's also important to note it's pretty difficult to overdose on any nutrients eating whole foods; however, fortified foods (those that have vitamins and minerals added) and supplements may cause you to exceed UIs. Therefore, it's best to try to meet your RDA of nutrients by eating a variety of nutrient-dense whole foods, such as fruits, vegetables, nuts, seeds, meats, poultry, fish, dairy products, and whole grains. This will help you keep vitamins and minerals balanced. If you eat a nutrient poor diet (one that has a lot of processed, fried, sugary, and fast foods), you may want to talk to your doctor about taking a multivitamin supplement to ensure you are meeting the minimal RDA requirements to avoid deficiencies.

RDA Samples

Using an RDA chart is the best way to determine how much of each nutrient you need to average on a daily basis to avoid deficiency. As an example of how the RDA changes based on gender, age, and health condition, take a look at the following sample RDAs for a few different vitamins.

Why RDA Is Important

RDAs help determine how many nutrients your body needs daily to function properly based on your age, gender, and life stage. This is useful for determining how much of each nutrient manufacturers should add to vitamins and foods and is essential for healthy meal and menu planning.