Understanding nutrient recommendations: Part 2
Micronutrients and interpreting the nutrition facts label.
Do you ever wonder what the terms stand for on a nutrition label or find it difficult to keep track of the language used to describe various nutrients? Most people connect with nutrition terms like macronutrients (nutrients needed in larger amounts like carbohydrates, protein, and fat) and micronutrients (nutrients needed in smaller amounts like vitamins and minerals) by reading food labels. According to the Institute of Medicine (IOM), there have been three eras of nutrition labeling: 1941-1972 focused on Minimum Daily Requirements, 1973-1993 focused on U.S. Recommended Daily Allowance (RDA), and since 1993, Daily Values have been used. As referenced in Part 1 of this series on Dietary Reference Intakes, % Daily Values are usually given as part of a general 2,000 calorie diet on a food label and may be meaningless for those on higher or lower calorie diets.
The new nutrition facts or food label, available in an interactive format here, is designed to inform consumers to make better informed food choices. While the calories are in larger easy-to-read print and added sugars are highlighted, there are still several terms, especially with micronutrients, that could be defined for better nutrition literacy. The micronutrients in the former food label, located beneath the third thick black bar, focused on vitamin A, vitamin C, calcium, and iron. Vitamins A and C are not required to be on the new food label because American diets are no longer considered deficient in these nutrients. Instead, vitamin D and potassium are required to be on the label because they are micronutrients that were found to be lacking in the American diet, according to National Health And Nutrition Examination Survey (NHANES) data from the Centers for Disease Control and Prevention (CDC). The new label also provides actual amounts for micronutrients in a given food instead of just % Daily Value for a 2,000 calorie diet, which is useful for those eating a greater or lesser amount of calories. This means that for the label pictured for this article, 2 mcg is listed along with 10% as the amount of vitamin D for that food item instead of only listing 10% for the % Daily Value.
Micronutrients and measurements
Vitamin D- RDAs for Vitamin D are measured in both mcg and IUs. Mcg is short for microgram, which is 1 millionth of a gram. The biological activity of 40 International Units or IU’s is equal to 1 mcg. Micrograms may also be abbreviated using the “µ” symbol, such as µg with the g standing for gram. Healthy male and female adults need 15-20 µg of Vitamin D each day and the recommendation assumes minimal sunlight exposure.
Potassium- RDAs for Potassium are measured in mg or milligram. One milligram is 1 thousandth of a gram. Healthy male and female adults have an AI or Adequate Intake level of 4,700mg of potassium each day. As defined in Part 1, the given AI is believed sufficient to cover the needs of all healthy individuals in a group though there is a lack of data to set an Estimated Average Requirement or EAR.
Calcium- Calcium is also measured in mg and also recommended using AI. The AI of calcium for healthy male and female adults is 1,800-2,300mg depending on age.
Iron- Iron is also measured in milligrams and has an RDA, which varies for healthy male and female adults. For adult males, 8-11mg per day is recommended. For adult females, 19-50, 18mg per day is recommended and for adult females 51 and older, 8 mg is recommended. The variation for healthy females is due to the lack of menstrual cycle in older adult females.
Micronutrients are given in different measurements because our bodies require different amounts of them to be healthy. While the food label focuses on a few micronutrients considered lacking in the American diet for the general population, primary care providers and dietitians use tools like the Dietary Reference Intakes to make more specific recommendations. The Dietary Reference Intakes or DRI’s outline nutrient recommendations for different life stages and gender groups, which makes it a useful tool for basing recommendations on individual needs. For additional resources on health and nutrition, visit Michigan State University Extension.