The FDA requires that the Nutrition Facts label for all processed foods express its nutrient content as a percentage of a suggested daily intake. This dietary reference is known as the Daily Value (DV). For the most part, the DV is designed as a "1 size fits all" based on a 2,000 calorie diet in order to fit on the packaging. However the most accurate reference values are the DRI's (Dietary Reference Intakes) which take into account gender, age, and life stage. Knowing these values can help you further tailor your diet to suit your needs.

Here's a breakdown of the dietary reference timeline -

• 1968: the first comprehensive and widely recognized set of RDA values were established
• 1974: the first update to the RDA was released
• 1980: the second update to the RDA was released
• 1989: the third update to the RDA was released
• 1994: the FDA mandated the inclusion of DV on food labels
• 1997-2004: the DRIs were developed

The DRI calculator below can be used to determine your customized nutritional requirements. This tool is great for meal planning and evaluating supplements such as multi-vitamins. I recommend using it in conjunction with the nutritional analysis tools on the Nutrition Data website.

Gender	Age Group			Printer Friendly
Show A, D, and E in IUs

Nutrient	Unit	RDA / AI (min)	UL (max)	Comments
Vitamins
A				Mixed carotenoids are best, with the most coming from beta-carotene. Separately take minimum 6mg lutein. Lutein and beta-carotene compete for absorption. Take all forms with a meal containing fat.
C (ascorbic acid)	mg
D				Getting 1000 IUs reduces chance of death due to any cause. Less than 10 minutes of sun exposure can meet this dose. D3 is best form. Take with a meal containing fat.
E				Mixed tocopherols are best. Take with a meal containing fat.
K	mcg			Take with a meal containing fat. K2 is best form (mix of MK-4 and MK-7).
B1 (Thiamin)	mg
B2 (Riboflavin)	mg
B3 (niacin)	mg
B5 (pantothenic acid)	mg			Competes with copper and biotin for absorption
B6	mg
B12	mcg			Synergistic effect with B9
B9 (Folic Acid or Folate)	mcg			Folate is the natural form and is preferred. Synergistic effect with B12.
B7 (Biotin)	mcg			Competes with B5 for absorption
Paba		*	*	Doses over 50 mg have been shown to cause health problems
Choline	mg
Minerals
Calcium	mg			New studies recommend taking no more than 805 mg/day. Usually found in 2:1 ratio to magnesium; vitamins D, K, Boron also increase uptake; calcium citrate form has 1 of the highest bioavailability; take no more than 500 mg at a time.
Potassium	g			Synthetic forms may cause stomach upset
Sodium	g			When consuming foods high in sodium, take potassium to counteract its harmful effects
Phosphorus	mg
Magnesium	mg			Usually found in 1:2 ratio to calcium; magnesium citrate form has 1 of the highest bioavailability. The UL for magnesium represents intake from a pharmacological agent only and does not include intake from food and water.
Chloride	g			(combined with sodium in dietary sources)
Fluoride	mg
Trace Elements
Iron	mg			Competes with multiple nutrients for absorption, so take away from multi-vitamin (but with food to prevent stomach upset); vitamin C enhances absorption.
Selenium	mcg
Iodine	mcg
Zinc	mg			Competes for absorption with copper
Copper	mcg			Competes for absorption with zinc. 1.5 - 3.0 mg/day is safe and adequate according to ESADDI. Competes with B5 for absorption.
Manganese	mg
Chromium	mcg
Molybdenum	mcg
Boron	mg
Silicon		*	*
Vanadium		*	*

Legend

ND = Not Determinable
RDA = the 1989 Recommended Dietary Allowances, which may be used as goals for individual intake
AI = Adequate Intakes, which may be used as goals for individual intake
UL = The maximum level of daily nutrient intake that is likely to pose no risk of adverse effects
g = grams
mg = milligrams (1,000 mg = 1 g)
mcg = micrograms (1,000 mcg = 1 mg)
IU = International Unit; used for the measurement of fat-soluble vitamins; conversion to mg varies depending on the nutrient
* = value not established

Definitions

DV (Daily Value): a newer dietary reference term that appears on the food label. It is made up of two sets of references, DRVs and RDIs.

DRV (Daily Reference Value): a set of dietary references that applies to fat, saturated fat, cholesterol, carbohydrate, protein, fiber, sodium, and potassium.

RDI (Reference Daily Intake): the value established by the Food and Drug Administration (FDA) for use in nutrition labeling. It was based initially on the highest 1968 Recommended Dietary Allowance (RDA) for each nutrient, to assure that needs were met for all age groups.

RDA (Recommended Dietary Allowance): established and periodically revised by the Food and Nutrition Board. Value shown is the highest RDA for each nutrient, in the year indicated for each revision.

U.S. RDAs (U.S. Recommended Daily Allowances): values developed by the FDA, but based on the RDAs set by the Food and Nutrition Board (replaced by RDIs to avoid confusion).

DRI (Dietary Reference Intakes): the most recent set of dietary recommendations established by the Food and Nutrition Board of the Institute of Medicine, 1997-2004. They replace previous RDAs, and may be the basis for eventually updating the RDIs. The value shown here is the highest DRI for each nutrient. It includes adequate intake (AI) and upper intake levels (UL).

AI (Adequate Intake): a set of DRI values where no RDA has been established, but the amount established is somewhat less firmly believed to be adequate for everyone in the demographic group.

UL (Tolerable upper intake levels): a set of DRI values which caution against excessive intake of nutrients that can be harmful in large amounts.

Source: Dobnig H, Pilz S, Scharnagl H, et al. "Independent association of low serum 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D levels with all-cause and cardiovascular mortality." Archives of Internal Medicine, 2008;168:1340-1349.
Source: Pilz S, Dobnig H, Winklhofer-Roob B, et al. "Low serum levels of 25-hydroxyvitamin D predict fatal cancer in patients referred to coronary angiography." Cancer Epidemiology, Biomarkers and Prevention, 2008;17:1228-1233.
Source: BMJ 2010;341:c3691
Source: Melamed ML, Michos ED, Post W. "25-hydroxyvitamin D levels and the risk of mortality in the general population." Archives of Internal Medicine, 2008;168:1629-1637.
Source: National Agricultural Library, Agricultural Research Service, U. S. Department of Agriculture
Source: USDA, 2004-2010