RDAs, NRVs and DVs

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You have a unique, individual need for each vitamin and mineral, depending on your gender, age, weight, level of activity and the metabolic pathways and enzyme systems you have inherited. Some people need more of certain micronutrients, while others need fewer.

Nutritional experts have therefore drawn up recommended daily amounts (RDAs) that are designed to meet the needs of just about everyone in the population. These food-based values are calculated statistically to encompass the requirements of 97.5% of the age range they cover.

Why are they knowingly set to be insufficient for 2.5% of the population? A good question! Essentially it’s because too much of some nutrients may cause problems for another 2.5% of the population, at the other end of the statistical scale, whose needs are unusually low. Intakes above 400 mg magnesium, for example, can lead to bowel looseness in some people (not always an undesirable trait, but this does limit magnesium intakes, the upper safe level for which is around 400 mg for supplements, in addition to values obtained from your food).



NRVs and DVs for vitamins

Food supplements feature slightly different values, selected for labelling purposes, known as the NRV (Nutrient Reference Value) in the UK/EU, and the DV (Daily Value) in the US. Different criteria were used to define these, and the DV in particular is based on outdated recommendations made almost 50 years ago. Even so, they allow manufacturers to show, at a glance, what percentage of your daily need is supplied by their product.

VITAMIN UK/EU NRV US DV
Vitamin A (retinol) 800 mcg (2,664 IU) 1,500 mcg (5,000 IU)
Vitamin B1 (thiamin) 1.1 mg 1.5 mg
Vitamin B2 (riboflavin) 1.4 mg 1.7 mg
Vitamin B3 (niacin) 16 mg 20 mg
Vitamin B5 (pantothenate) 6 mg 10 mg
Vitamin B6 (pyridoxine) 1.4 mg 2 mg
Vitamin B12 (cobalamin) 2.5 mcg 6 mcg
Folic acid (folate) 200 mcg 400 mcg
Biotin 50 mcg 300 mcg
Vitamin C (ascorbate) 80 mg 60 mg
Vitamin D (cholecalciferol) 5 mcg (200 IU) 10 mcg (400 IU)
Vitamin E (tocopherol) 12 mg (18 IU) 20 mg (30 IU)
Vitamin K 75 mcg 80 mcg




NRVs and DVs for minerals

 

MINERAL UK/EU NRV US DV
Calcium 800 mg 1,000 mg (1g)
Chloride 800 mg 3,400 mg
Chromium 40 mcg 120 mcg
Copper 1 mg 2 mg
Iodine 150 mcg 150 mcg
Iron 14 mg 18 mg
Magnesium 375 mg 400 mg
Manganese 2 mg 2 mg
Molybdenum Not set 75 mcg
Phosphorus 700 mg 1,000 mg
Potassium 2000 mg 3,500 mg
Selenium 55 mcg 70 mcg
Zinc 10 mg  15 mg

NB In the UK, some multivitamins may still feature an RDA (Recommended Daily Amount), but these will soon change to the newer NRV (Nutrient Reference Value) which are exactly the same for labelling purposes.

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