This table compares the typical levels of recommended daily nutrient intake to the United States 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?

Comparison of Dietary Reference Intake Values (for adult men and women) and Daily Values for Micronutrients with the Tolerable Upper Intake Levels (UL),a,c Safe Upper Levels (SUL),d and Guidance Levelsd

Nutrient
RDA/AIb (men / women) ages 31-50
Daily Value (Food Labels)
ULc
SUL or Guidance Leveld
Selected Potential Effects of Excess Intake
Vitamin A (mcg)
900 / 700
1500 (5000 IU)
3000
1500** (5000 IU)
Liver damage, bone & joint pain, dry skin, loss of hair, headache, vomiting
beta-Carotene (mg)
7 (11,655 IU)
Increased risk of lung cancer in smokers and those heavily exposed to asbestos
Vitamin D (mcg)
15 (600 IU)
10 (400 IU)
100
25 (1000 IU)
Calcification of brain, arteries, increased blood calcium, loss of appetite, nausea
Vitamin E (mg)
15
20 (30 IU)
1000
540 (800 IU)
Deficient blood clotting
Vitamin K (mcg)
120 / 90*
80
1000**
Red blood cell damage/anemia; liver damage
Thiamin (B1) (mg)
1.2 / 1.1
1.5
100**
Headache, nausea, irritability, insomnia, rapid pulse, weakness (7000+ mg dose)
Riboflavin (B2) (mg)
1.3 / 1.1
1.7
40**
Generally considered harmless; yellow discoloration of urine
Niacin (mg)
16 / 14
20
35
500**
Liver damage, flushing, nausea, gastrointestinal problems
Vitamin B6 (mg)
1.3
2
100
10
Neurological problems, numbness and pain in limbs
Vitamin B12 (mcg)
2.4
6
2000**
Folic acid (mcg)
400
400
1000
1000**
Masks B12 deficiency (which can cause neurological problems)
Pantothenic acid (mg)
5*
10
200**
Diarrhea & gastrointestinal disturbance (10,000+ mg/day)
Biotin (mcg)
30*
300
900**
No reports of toxicity from oral ingestion
Choline (mcg)
550/425*
3500
Fishy body odor (trimethylaminuria), hepatotoxicity
Vitamin C (mg)
90 / 75
60
2000
1000**
Nausea, diarrhea, kidney stones
Boron (mg)
20
9.6
Adverse effects on male and female reproductive system
Calcium (mg)
1000
1000
2500
1500**
Nausea, constipation, kidney stones
Chloride (mg)
2300*
3400
3600
Increased blood pressure in salt-sensitive individuals (when consumed as sodium chloride)
Chromium (mcg)
35/25*
120
10,000**
Potential adverse effects on liver and kidneys; picolinate form possibly mutagenic
Cobalt (mg)
1.4**
Cardiotoxic effects; not appropriate in a dietary supplement except as vitamin B-12
Copper (mcg)
900
2000
10000
10000
Gastrointestinal distress, liver damage
Fluoride (mg)
4 / 3*
10
Bone, kidney, muscle, and nerve damage; supplement with professional guidance
Germanium
zero**
Kidney toxin; should not be in a dietary supplement
Iodine (mcg)
150
150
1100
500**
Elevated thyroid hormone concentration
Iron (mg)
8 / 18
18
45
17**
Gastrointestinal distress, increased risk of heart disease, oxidative stress
Magnesium (mg)
420 / 320
400
350e
400**
Diarrhea
Manganese (mg)
2.3 / 1.8*
2
11
4**
Neurotoxicity
Molybdenum (mcg)
45
75
2000
zero**
Gout-like symptom; joint pains; increased uric acid
Nickel (mcg)
1000
260**
Increased sensitivity of skin reaction to nickel in jewelry
Phosphorus (mg)
700
1000
4000
250**
Alteration of parathyroid hormone levels; reduced bone mineral density
Potassium (mg)
4700*
3500
3700**
Gastrointestinal damage
Selenium (mcg)
55
70
400
450
Nausea, diarrhea, fatigue, hair and nail loss
Silicon (mg)
700
Low toxicity; possibility of kidney stones
Sodium (mg)
1500*
2400
2300
Increased blood pressure in salt-sensitive individuals (when consumed as sodium chloride)
Vanadium (mg)
1.8
zero
Gastrointestinal irritation; fatigue
Zinc (mg)
11 / 8
15
40
25
Impaired immune function, low HDL-cholesterol

aFood and Nutrition Board, Institute of Medicine (U.S.). Dietary Reference Intakes Tables.

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

cUL = Tolerable Upper Intake Level (from food & supplements combined)

dSUL = Safe Upper Levels; SULs and Guidance Levels (indicated by **) set by the Expert Group on Vitamins and Minerals of the Food Standards Agency, United Kingdom. These are intended to be levels of daily intake of nutrients in dietary supplements that potentially susceptible individuals could take daily on a life-long basis without medical supervision in reasonable safety. When the evidence base was considered inadequate to set a SUL, Guidance Levels were set based on limited data. SULs and Guidance Levels tend to be conservative and it is possible that, for some vitamins and minerals, greater amounts could be consumed for short periods without risk to health. The values presented are for a 60 kg (132 lb) adult. Consult the full publication for values expressed per kg body weight. This FSA publication, Safe Upper Levels for Vitamins and Minerals, is available at: https://selectra.co.uk/sites/selectra.co.uk/files/pdf/vitmin2003.pdf

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

 

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