4.5: Daily Values (DVs)

Daily Values are used for labeling food and dietary supplements. The Daily Value (DV) is a recommended amount, and a nutrient is listed as a percentage of this amount (% DV). This gives some perspective to the consumer. If told that there’s 1 milligram of zinc in a food, we can’t tell if this is a lot or a trivial amount, unless we have some idea of the recommended amount. It’s much more useful to be told that the amount of zinc in a food is 9% of the recommended amount.

There are many sets of RDAs, so it’s unwieldy to put the percentages of each set on a label. Thus, there’s one adult set of DVs (see Appendix A-4), made by taking the highest RDA for each nutrient for those over age 4 (excluding pregnant or lactating women).* DVs are set at 100%, and the nutrient content is labeled as % DV, e.g., a supplement with 500 mg of vitamin C would be labeled as having 555% DV (the DV is 90 mg; 500 mg is 555% of 90 mg).

DVs are even more generous than RDAs. This means that you don’t necessarily have to get 100% of a DV to get your RDA. For example, the DV for iron is 18 mg—the RDA for women of childbearing age). The RDA for adult men is only 8 mg because they don’t normally have blood losses (women lose iron in menstrual blood). A man getting 9 mg iron would be getting 50% DV for iron (9 mg is 50% of the 18 mg DV), but this is actually 112% of his RDA (9 mg is 112% of his 8 mg RDA).

DVs also include reference values for dietary components such as saturated fat, fiber, sodium. Values for some are based on the recommended amount in a 2,000-calorie diet. For example, it’s advised that less than 10% of our calories come from saturated fat. On a 2,000 calorie diet, this means less than 22 grams of saturated fat (rounded to 20 gm on the label; see Figure 4.3). So if a serving has 5 grams of saturated fat, its fat content is given as 25% DV (5 gm is 25% of 20 gm). This means, of course, that if you eat 2 servings, you’ll have eaten 50% of your “allotment” for the day.

Nutrient deficiency diseases used to be our biggest nutritional problem, but now it’s chronic diseases related to excess calories, solid fats, and sodium, and not enough fiber. So food labels emphasize these. Regulations specify which health claims (e.g., calcium may help prevent osteoporosis) and terms (e.g., low fat) can be used on a label, and also define the descriptions (e.g., a food labeled low-fat can’t have more than 3 grams of fat per serving).

Figure 4.3: Nutrition Facts on Food Labels

Federal regulations require nutrition information on most food labels (Figure 4.3). It’s voluntary for some foods. Grocery stores are expected to voluntarily provide nutrition information for meat and the most common fresh produce and seafood.

Foods are Not Sources of Single Nutrients

Thinking about foods in terms of single nutrients, rather than groups, is a popular way of looking at nutrition in our society, and one which has been carefully fostered by commercial interests. They promote foods that are identified with certain glamorized nutrients.

For example, almost everyone knows that citrus is a good source of vitamin C. So a message used in advertising is that an orange-colored powder which contains vitamin C may be mixed with water and substituted for orange juice. Other nutrients (e.g., folate) also found in orange juice are absent from this product. Informed consumers know that they don’t have to rely on citrus fruits for vitamin C. They might get the recommended amount from a number of lesser sources on any given day—possibly a banana, some lettuce, a few cherries, some string beans.

In looking at food composition tables, we see a pattern: Animal flesh—whether beef, chicken, or fish—is high in protein. Fruits, vegetables, and whole grains are generally rich in fiber, vitamins, and certain minerals. Milk is a good source of calcium, riboflavin, and protein. By grouping foods according to this pattern, and recommending numbers of servings from each group, scientists have come up with an eating guide for getting enough of the essential nutrients.

^{*There are 3 other sets of Daily Values: for infants up to 12 months old, children 1 to 4 years old, and pregnant and lactating women. These are used to label products intended specifically for these groups, e.g., the set for pregnant/lactating women is used for labeling prenatal supplements.}