Common Nutrition and Diet Abbreviations

IU, RDA, DRI, g, mg...All those letters can start to look like alphabet soup. When you read articles about nutrition, diet, and nutritional supplements, you're likely to come across some abbreviations. We're here to decipher them and let you know what's what.

Common Nutrition and Diet Abbreviations

Below are some of the most common nutrition and diet-related abbreviations and their definitions (most are indicated in the 2020-2025 Dietary Guidelines or otherwise noted).

AA—Amino acids: Simple organic components of proteins.

ADEK—Vitamins A, D, E, and K: These fat-soluble vitamins are sometimes grouped together.

AI—Adequate intake: The amount of a nutrient that will meet an individual's daily requirements; it's used when a recommended dietary allowance (RDA) can't be determined.

BMI—Body mass index: A value derived from a person's body mass divided by the square of their height. BMI is a dated, biased measure that doesn’t account for several factors, such as body composition, ethnicity, race, gender, and age. Despite being a flawed measure, BMI is widely used today in the medical community because it is an inexpensive and quick method for analyzing potential health status and outcomes. 

Ca—Calcium: A dietary mineral needed for healthy bones and teeth, normal blood clotting, and nerve and muscle function.

DRI—Dietary reference intake: The general reference values for the levels of nutrients a healthy person needs to consume per day; it includes recommended dietary allowance (RDA), adequate intake (AI), and tolerable upper intake level (UL).

EAR—Estimated average requirement: The intake level of a nutrient that will meet the requirements of one half of healthy individuals in a particular age and sex group.

EER—Estimated energy requirements: The estimated range of calories individuals need, differing by several factors, such age, sex, height, weight, and physical activity.

Fe—Iron: A dietary mineral required to make hemoglobin, which in turn transports oxygen throughout the body.

FTT—Failure to thrive: A significant delay in the growth of an infant or young child.

g—Gram: A metric unit of measure; carbohydrates, fats, and proteins are measured in grams. (Note: One ounce is a little over 28 grams.)

K—Potassium: A dietary mineral that's needed for water balance and healthy muscle function in the body.

kcal—Kilocalorie: A measure of energy that we commonly refer to as a "calorie."

mcg—Microgram: A metric unit of measure; some vitamins and minerals are measured in micrograms. (Note: 1,000 micrograms equal 1 milligram.)

mg—Milligram: Another metric unit of measure; many vitamins and minerals are measured in milligrams. (Note: 1,000 milligrams equal 1 gram.)

Mg—Magnesium: A dietary mineral needed for healthy muscle function and other processes in the body.

mEq—Milliequivalent: A measurement that's equivalent to one-thousandth of a gram, liter, or similar unit.

Na—Sodium: A dietary mineral that's needed for water balance in the body.

RDA—Recommended dietary allowances: ​RDA designates the amount of a nutrient that will meet the requirements of 97%-98% of healthy individuals.

REE—​Resting energy expenditure: The rate at which you burn calories while at rest.

RNI—​​Reference nutrient intake: RNI is used in the UK. It stands for daily nutrient recommendations to meet the needs of the majority of the population.

UL—​Tolerable upper intake level: The highest level of a nutrient that's safe for all individuals.