NRV explained: what the percentage means, and why plants have none

Turn a supplement pack over and look down the right-hand side of the nutrition table. Some of the figures have a percentage beside them. Some have a small dagger instead. Vitamin C might read 80 mg and then 100%. Two lines below, a plant reads 25 mg and then nothing at all, just a mark pointing to a note at the foot of the table: 'NRV not established'.

NRV stands for Nutrient Reference Value. It is one of the very few numbers on a supplement label that the manufacturer did not choose, because it is written into food law and the same figure applies to every pack sold in Great Britain. Knowing where it comes from explains the percentages, the dagger, and why those two things never appear on the same line.

What is a Nutrient Reference Value (NRV)?

The list lives in Annex XIII of retained Regulation (EU) No 1169/2011, the food information regulation that governs what goes on a British food label. Part A of that annex is headed 'Daily reference intakes for vitamins and minerals (adults)', and point 1 of Part A is a plain two-column table titled 'Vitamins and minerals which may be declared and their nutrient reference values (NRVs)'. That table is the entire source. Every percentage printed on a supplement pack in Great Britain is worked out against it.

Department of Health guidance defines the values without decoration: nutrient reference values are 'guidelines about the amount of vitamins and minerals that it is recommended should be consumed on a daily basis in order to maintain a healthy diet'. Guidelines. For a population. On a daily basis. That is the whole ambition of the number, and it is smaller than most people assume.

Which vitamins and minerals have an NRV

The table is short, and it is closed. Thirteen vitamins and fourteen minerals - twenty-seven entries, and nothing else. Vitamin C is 80 mg. Zinc is 10 mg. Calcium is 800 mg, iron 14 mg, magnesium 375 mg, iodine 150 micrograms. If a substance is not one of those twenty-seven, it does not have a low NRV. It does not have one.

The other word worth pausing on is in the heading of Part A: adults. One column, one figure per nutrient, no split by age, sex, body weight or anything else. A man of thirty-two and a woman of sixty-eight read the same 80 mg for vitamin C off the same carton. That is a deliberate simplification, and it is the only reason the number fits on a label at all.

Why do vitamins carry a %NRV and plants do not?

Food supplements sit slightly outside the general rules, which is worth knowing before the detail. The section of Regulation 1169/2011 that requires the familiar nutrition declaration - the panel on a cereal box - expressly does not apply to products covered by the Food Supplements (England) Regulations 2003. A supplement carries its own table, required by its own regulations, which then borrow the reference figures back out of Annex XIII.

Regulation 6 of those 2003 Regulations lists six particulars a supplement pack must carry, ending with (f): 'the amount of any vitamin or mineral or other substance with a nutritional or physiological effect which is present in the product'. Note the phrase 'other substance'. That is the drawer a plant goes in.

The paragraph beneath sets out how that amount has to be given. In numerical form. As the amount per portion recommended for daily consumption - so per tablet, or per two capsules, rather than per 100 g. As an average, based on the manufacturer's own analysis. And then one further condition that applies to only part of the list: where the substance is a vitamin or mineral listed in point 1 of Part A of Annex XIII, the amount must 'be expressed also as a percentage ... of the relevant reference value specified in that point'.

Read that clause twice, because it is the whole answer. The duty to print a percentage attaches to the table, not to the ingredient. Zinc carries a percentage because zinc is one of the twenty-seven. A bark does not, because it is not.

Why the six botanicals carry a dagger instead

Our own six lines read Ginseng 25 mg, Maca 25 mg, Tribulus 20 mg, Guarana 10 mg, Ashwagandha 10 mg and Catuaba 10 mg, adding to 100 mg per tablet. Not one of them appears in Annex XIII, so the nutrition table on the carton prints a dagger against each figure and, underneath it, the line 'NRV not established.'

That footnote is not a hedge, and it is not a gap in our paperwork. A percentage needs two numbers and only one of them exists here. We can tell you there are 25 mg of maca in the tablet. Nobody - not the regulator, not us - has set a daily reference figure for maca to divide it by, because the reference table is a table of nutrients and maca is not a nutrient in that sense. 'NRV not established' is the accurate way to say all of that in three words on a carton.

Which also means the dagger is not the mark to be suspicious of. The rest of the back of a pack is where the real reading is, and the figure that should bother you is the one missing altogether: a plant named with no weight beside it, folded into a proprietary blend total. A dagger tells you a reference value does not exist. A blend tells you the brand has decided not to say.

What is the difference between NRV, RDA and RI?

Anyone who has kept a pack in a bathroom cupboard for a decade will have seen a different abbreviation doing the same job. Older British labels printed %RDA, for Recommended Daily Allowance, and the figures came from the annex to Commission Directive 2008/100/EC - the directive that amended the old nutrition labelling rules, in its own words, 'as regards recommended daily allowances'. The Department of Health's 2011 summary for supplement manufacturers instructed them to print exactly that.

RDA became NRV and the figures stayed the same

The interesting part is that the numbers never moved. Vitamin C was 80 mg under the RDA table and it is 80 mg under the NRV table. Zinc was 10 mg and is 10 mg. Regulation 1169/2011 repealed the old directive, lifted the same list into Annex XIII and renamed the values nutrient reference values. A pack from 2011 saying 100% RDA of zinc and a pack from this year saying 100% NRV are making the identical statement.

'Reference intake', or RI, is the third term, and it is the broadest of them. Annex XIII as a whole is headed 'Reference intakes'. Part A holds the vitamins and minerals; Part B holds a second, shorter list covering energy and the macronutrients - fat, saturates, carbohydrate, sugars, protein and salt. Official guidance for labellers goes a step further and asks that the generic phrase 'reference intakes' be used on packs rather than NRV, which is why one label says one thing and the next says the other while both point at the same table.

None of these should be confused with what a nutrition scientist means by a reference value. The European Food Safety Authority sets dietary reference values, and they are a family rather than a figure: an average requirement, a population reference intake covering the needs of 97.5% of a population group, an adequate intake where the evidence will not carry the other two, a reference range for macronutrients, and a tolerable upper intake level at the far end. They are worked out per age group and per sex, and they run to hundreds of values.

No carton can print that. So labelling law takes one adult figure per nutrient and prints it, which is what an NRV is: the flattened, printable version of a much larger scientific picture. The flattening is the point. It is also the limit.

Does 100% NRV mean the right amount for me?

What '100% NRV' tells you is precise and narrow. The recommended daily portion of this product contains the amount of that nutrient listed in Annex XIII. It is an arithmetic statement about the pack. It is not a statement that you were short of the nutrient, that you needed it, or that the figure is the right one for you in particular. The table has one column and does not know who you are.

Nor does more read as better. Percentages well above 100 are common and perfectly legal, and several minerals also have a tolerable upper intake level - a separate figure, set scientifically, that packs do not print. If you take prescribed medicines, or you are stacking several supplements at once, the person to ask about a very large percentage is a pharmacist or your GP rather than the carton.

The 15% rule: when an amount counts as significant

The percentages are useful at the small end too, and here a careful distinction is needed. Annex XIII sets a threshold for ordinary food: as a rule, 15% of the nutrient reference value is what should be treated as a significant amount, per 100 g or 100 ml, or per portion where a pack holds a single portion. That threshold sits in the part of the regulation that supplements are expressly outside, so it does not bind a supplement label and we are not going to pretend it does. It is still the only published line anyone has drawn between an amount that counts and an amount that is decoration, which makes it a useful thing to hold in your head when a pack lists twenty vitamins at 2% each. That is a list, not a formulation - but the judgement is yours, not the law's.

And a high percentage still measures only one thing. It compares a quantity in the pack against a fixed reference figure. It says nothing about the form the material is in, the quality of it, or whether the brand can produce a certificate of analysis for the batch in your hand. Those are separate questions with separate answers, and none of them is settled by a number in a right-hand column.

Our tablet declares six weights and no percentages, because there are no percentages to declare. Stating composition to the milligram and then stopping is the whole of what our nutrition table does. None of the six plants holds an authorised health claim in Great Britain, so this pack makes no claim about what those six plants do to anybody, and a column of milligrams is what a label has left once it restricts itself to things it can stand behind.

A percentage is only ever as good as the reference behind it. Where a reference exists, the law makes the pack print it and you can check the arithmetic in your head. Where none exists, the honest label says so and gives you the milligrams instead. 'NRV not established' is not a brand dodging the question. It is a brand answering it.

Common questions

† Describes the traditional use of these botanicals (UK 'on-hold' botanical claims under retained Regulation (EC) 1924/2006). Not authorised EFSA health claims. AllMaleUp is a food supplement, not a medicine.