Home > Recommended
Daily Allowance of Vitamins
Recommended Daily
Allowance (RDA)
Recommended
Daily Allowance (RDA) is the daily dietary intake level
that is considered sufficient to defend against vitamin deficiency
diseases.
Today, the
term "Recommended Daily Allowance" is replaced by new terms "Daily Intake"
and "Percent Daily Value" (% DV). % DV is often shown
on the
label of vitamin supplements. It indicates how much each vitamin is
contained in one
serving compared to the recommended daily intake.
For example, the recommended daily intake of vitamin A for
an adult is 5000IU. If one serving of vitamin supplement contains
15,000IU of vitamin A, its % DV for vitamin A would be 15,000 / 5,000 x
100% = 300%.
Recommended daily intake (recommended daily allowance) of
Vitamins A-K is listed below (for adults only):
|
Vitamin A |
5,000 IU |
|
Vitamin C |
60 mg |
|
Vitamin D |
400 IU |
|
Vitamin E |
30 IU |
|
Vitamin K |
80 mcg |
|
Thiamin (vitamin B1) |
1.5 mg |
|
Riboflavin (vitamin B2) |
1.7 mg |
|
Niacin (vitamin B3) |
20 mg |
|
Pantothenic acid (vitamin B5) |
10 mg |
|
Vitamin B6 |
2 mg |
|
Folic acid (vitamin B9) |
400 mcg |
|
Vitamin B12 |
6 mcg |
|
Biotin (vitamin H / vitamin B7) |
300 mcg |
Notes:
IU - international unit, a measure of vitamin activity
determined by biological or chemical analyses.
mg - milligram (1/1000 g)
mcg - microgram (1/1000 mg):
We can
consider the recommended daily allowance / recommended daily intake as the minimum nutrient requirement
for healthy people to ward off vitamin deficient diseases. However,
these values do not represent
the amounts of vitamins required for optimal health, which vary among
individuals based on their age, diet, health conditions, exposure to toxic
chemicals and lifestyle.
Recommended daily allowance / recommended daily intake is
also not equivalent to the safe dose of vitamins. In general,
vitamins have high safety limits, which can be several times to hundred
times more than the recommended daily intake. Water soluble vitamins
(vitamin C and vitamin B complexes) have a higher safety limit than fat
soluble vitamins (A, D, E, K). Excess water soluble vitamins can be
excreted readily in the urine whereas excess fat soluble vitamins are
accumulated in the liver and can be harmful.
Since
the recommended daily intake represents the minimum nutrient requirement
to avoid vitamin deficient diseases, it is quite common for vitamin
supplements to contain vitamins and minerals above the recommended daily level
(i.e. % DV
higher than 100%). It is safe to consume these vitamin supplements
according to product label. However, consumers should not increase
the recommended dosage themselves without the supervision of health care
professionals.
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