Recommended Daily Allowance (RDA):
What Does it Mean?

Supplement labels sometimes give the percentage of the RDA for each nutrient in the product. More often, they list percentages of ‘Daily Values’, which are indirectly based on RDAs.

The RDA is the amount of a nutrient generally thought adequate to prevent deficiency in a normal, healthy adult. These figures do not allow for variations in requirements resulting from illness or body size, and may vary for smokers or people taking medication.

RDAs are meant to provide general guidelines rather than hard-and-fast rules. A therapist may therefore advise you to eat more than the RDA of some nutrients.

Another measure often used by nutritionists is the optimum daily allowance. This is the amount of a nutrient needed to keep the body functioning at its best, which may be considerably more than the RDA.