It’s very easy to take too many vitamins, because so many food products like cereal and milk are fortified with them, so when you have a vitamin pill, you could easily go over the Upper Tolerable Limit. Since there’s no evidence vitamin pills and supplements do good, and there is evidence that they do harm or are ineffective, why take them?
Recommended Daily Allowance & Upper Limits for Vitamins and Minerals
The Institute of Medicine has determined upper limits for 24 nutrients. Here is a chart comparing the RDA and UL for all of them. This table only applies to adults age 19 or older. It also does not apply to women who are pregnant or breastfeeding. (Source: September 2012 ConsumerReports p 21 and Institute of Medicine).
Vitamin
or Mineral |
Recommended Dietary Allowance (RDA) or Adequate Intake (AI)
Nutrients with AIs are marked with an (*) |
Upper Tolerable Limit (UL)
The highest amount you can take without risk |
Boron
|
Not determined. |
20 mg/day
|
Calcium
|
|
|
Chloride
|
|
3,600 mg/day
|
Choline
(Vitamin B complex) |
|
3,500 mg/day
|
Copper
|
900 micrograms/day |
10,000 micrograms/day
|
Fluoride
|
|
10 mg/day
|
Folic Acid (Folate)
|
400 micrograms/day |
1,000 micrograms/day
|
Iodine
|
150 micrograms/day |
1,100 micrograms/day
|
Iron
|
|
45 mg/day
|
Magnesium
|
|
350 mg/day |
Manganese
|
|
11 mg/day
|
Molybdenum
|
45 micrograms/day |
2,000 micrograms/day
|
Nickel
|
Not determined |
1.0 mg/day
|
Phosphorus
|
700 mg/day |
Up to age 70: 4,000 mg/day Over age 70: 3,000 mg/day
|
Selenium
|
55 micrograms/day |
400 micrograms/day
|
Sodium
|
|
2,300 mg/day
|
Vanadium
|
Not determined |
1.8 mg/day
|
Vitamin A
|
|
10,000 IU/day
|
Vitamin B3 (Niacin)
|
|
35 mg/day |
Vitamin B6
|
|
100 mg/day
|
Vitamin C
|
|
2,000 mg/day
|
Vitamin D (Calciferol)
|
|
100 micrograms/day (4,000 IU) |
Vitamin E
(alpha-tocopherol) |
22.4 IU/day |
1,500 IU/day
|
Zinc
|
|
40 mg/day
|
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