Appendix A: Comparison of Dietary Reference Intake Values (for adult men and women) and Daily Values for Micronutrients with the Tolerable Upper Intake Levels (UL), Safe Upper Levels (SUL), and Guidance Levels

This table compares the typical levels of recommended daily nutrient intake (RDA and AI), Tolerable Upper Intake Levels (ULs) and the United Kingdom’s Safe Upper Levels (SULs). The Recommended Dietary Allowance (RDA) and Adequate Intake (AI) values are considered to be levels of nutrient intake that meet or exceed the needs of practically all healthy people. The Daily Value amounts, that are currently used as reference values on food and supplement labels, are similar to the RDA/AI values, but differ in some cases. UL values are the amounts that are considered to be the maximum safe level of intake from food and supplements combined. SUL values are the maximum level of intake of a nutrient from dietary supplements that can be considered to be reasonably safe.

How much is too much?

Dietary Reference Intake Values (for adult men and women) for Micronutrientsa

 
Vitamins
Nutrient
RDA/AIb (men / women) ages 31-50
ULc
Selected Potential Effects of Excess Intake
Vitamin A (mcg)
900 / 700
3000
Liver damage, bone & joint pain, dry skin, loss of hair, headache, vomiting
beta-Carotene (mg)
Increased risk of lung cancer in smokers and those heavily exposed to asbestos
Vitamin D (mcg)
15 (600 IU)
100 Calcification of brain, arteries, increased blood calcium, loss of appetite, nausea
Vitamin E (mg)
15
1000e
Deficient blood clotting
Vitamin K (mcg)
120 / 90*
Red blood cell damage/anemia; liver damage
Thiamin (B1) (mg)
1.2 / 1.1
Headache, nausea, irritability, insomnia, rapid pulse, weakness (7000+ mg dose)
Riboflavin (B2) (mg)
1.3 / 1.1
Generally considered harmless; yellow discoloration of urine
Niacin (B3) (mg)
16 / 14
35e
Liver damage, flushing, nausea, gastrointestinal problems
Vitamin B6 (mg)
1.3
100
Neurological problems, numbness and pain in limbs
Vitamin B12 (mcg)
2.4
Vitamin C (mg)
90 / 75
2000
Nausea, diarrhea, kidney stones
Folate (mcg)
400
1000e
Masks B12 deficiency (which can cause neurological problems)
Pantothenic acid (mg)
5*
Diarrhea & gastrointestinal disturbance (10,000+ mg/day)
Biotin (mcg)
30*
No reports of toxicity from oral ingestion
Choline (mcg)
550/425*
3500
Fishy body odor (trimethylaminuria), hepatotoxicity
Minerals
Nutrient
RDA/AIb (men / women) ages 31-50
ULc
Selected Potential Effects of Excess Intake
Boron (mg)
20
Adverse effects on male and female reproductive system
Calcium (mg)
1000
2500
Nausea, constipation, kidney stones
Chloride (mg)
2300*
3600
Increased blood pressure in salt-sensitive individuals (when consumed as sodium chloride)
Chromium (mcg)
35/25*
Potential adverse effects on liver and kidneys; picolinate form possibly mutagenic
Cobalt (mg)
Cardiotoxic effects; not appropriate in a dietary supplement except as vitamin B-12
Copper (mcg)
900
10000
Gastrointestinal distress, liver damage
Fluoride (mg)
4 / 3*
10
Bone, kidney, muscle, and nerve damage; supplement with professional guidance
Germanium
Kidney toxin; should not be in a dietary supplement
Iodine (mcg)
150
1100
Elevated thyroid hormone concentration
Iron (mg)
8 / 18
45
Gastrointestinal distress, increased risk of heart disease, oxidative stress
Magnesium (mg)
420 / 320
350d
Diarrhea
Manganese (mg)
2.3 / 1.8*
11
Neurotoxicity
Molybdenum (mcg)
45
2000
Gout-like symptom; joint pains; increased uric acid
Nickel (mcg)
1000
Increased sensitivity of skin reaction to nickel in jewelry
Phosphorus (mg)
700
4000
Alteration of parathyroid hormone levels; reduced bone mineral density
Potassium (mg)
3400/2600*
Gastrointestinal damage
Selenium (mcg)
55
400
Nausea, diarrhea, fatigue, hair and nail loss
Silicon (mg)
Low toxicity; possibility of kidney stones
Sodium (mg)
1500*
Increased blood pressure in salt-sensitive individuals (when consumed as sodium chloride)
Vanadium (mg)
1.8
Gastrointestinal irritation; fatigue
Zinc (mg)
11 / 8
40
Impaired immune function, low HDL-cholesterol

aDietary reference intakes tables. Government of Canada

b(RDA) = Recommended Dietary Allowance, AI = Adequate Intake, indicated with *

cUL = Tolerable Upper Intake Level The UL is the highest average daily nutrient intake level likely to pose no risk of adverse health effects to almost all individuals in a given life-stage and sex group. Unless otherwise specified, the UL represents total intake from food, water, and supplements.

dThe UL for magnesium represents intake specifically from pharmacological agents and/or dietary supplements in addition to dietary intake.

e The ULs for vitamin E, niacin, and folate apply to synthetic forms obtained from supplements, fortified foods, or a combination of the two

*Represents adequate intake